ISC/ISL Boost Foolers, MP changes, turbo upgrades, and ECM Power Modules

[imnprsd]

People always ask:

* What can I do to safely increase horse power?

* Do I need to be concerned about EGT if I do modify my engine?

* Can I easily and cheaply add a “boost fooler” to my turbo to increase HP and/or lower EGT? …Or is adjusting the turbo Actuator a better way to go, to accomplish the results?

To address these questions, IMO, you need to also consider what KNOWN limitations you are working with and then you can make a performance plan to optimize power? …Like what, you ask?

Let’s start by talking about your Allison 3000MH tranny, which has a maximum input torque of 1250 lb-ft. So to understand how that relates to HP, you need to convert your engine HP into torque. …To assist in this effort, I put together a chart based on several dyno runs the folks at Ag-Diesel Solutions provided me when installed their Power Module. We ran the dyno three times, and then we calculated the other torque and HP numbers for comparison.

(See dyno run chart below.)

Note: I chose to increase my HP by 20% using Ag-Diesel #12100 Power Module. And as you can see in the chart my stock ISC-350HP is now delivering 420HP and 1086 lb-ft of engine torque.

What you can’t see in this chart is the improved torque curve. So while we often only talk about HP gains, the real value of adding the Ag-Diesel Power Module is to “optimize” your stock torque curve, because that will give you more acceleration, more safety, and more fun.

I could have asked for a 30% gain, but I felt a 20% HP increase over stock (+70HP) would be a good way to evaluate the Ag-tune “performance gains” while still operating within safe limits. This includes the aforementioned tranny spec-limit and EGT. And as a result I am very happy with that decision.

* The dyno chart also points out a Suggested HP Increase of 450HP to keep your engine torque well under that Allison 3000MH torque limit of 1250 lb-ft. (483HP). However, you may choose to be more daring.

* And since the most ILS owners also have an Allison 3000MH tranny, then they too should not exceed 450HP I my opinion.

WHAT IS RV PERFORMANCE BASE ON?

…They say “Performance” always comes down to HP, Weight and Drag; and that pretty much covers it!

So let’s talk about HP/Weight ratios; and for now, let’s leave drag out of the equation until later when I discuss the effects of using Ag-Diesel Power Module to improve MPG.

* Fundamentally, how do you know if your RV is under powered?

…Well, the RV industry wants you to believe an acceptable performance is in the range of 0.0100. However, if you own an RV with this HP/Weight ratio, then you know it’s a “Dog.” And of course it makes sense the RV industry sold this concept 20-30 years ago, because in the 80’s and 90’s that’s all they were delivering. But today we call that number a dog!

So know let me share my RV stock HP/Weight ratios with you; and then you can evaluate your HP/Weight ratio applicable to your coach so you know you can do better:

Example #1: My stock 2004 Itasca “Horizon” 40AD has a CVGR = 32,000 lbs. So at full gross my ISC-350 gives me a HP/Weight ratio = 350/32,000 = 0.0109, which is acceptable, but not great in my opinion.

What was my complaint? …I often would limp into traffic; and sometimes I felt unsafe when the highway on-ramp was going up-hill rather than down-hill. So this is the most basic reason I wanted more HP in my weight class.

Example #2: Then I increased from ISC-350HP to 420HP by adding an Ag-Diesel #12100 Power Module; and now my HP/Weight = 0.0130, which is so much better and safer! …And now, I have no trouble merging with highway traffic! Plus, I love the new torque curve Ag-Diesel’s Power Module gave me; and now my top-end comfortable speed is higher; and my MPG is 15% better overall.

WHAT ABOUT ISL OWENERS? …If you have an Itasca “Horizon” 40AD with the ISL-400HP option, then your HP/Weight ratio is 400/32,000 = 0.0125. So you owners are probably happy “as-is”. unless you want more HP?

And if you do, I would recommend you first add that boost fooler and then see if you like it? However, IMO, what you really want to verify is that the addition of a boost fooler with lower your EGT when you are under 70% of full power, which would be a good thing. And then, if you still want more HP, and/or a better torque curve, I then would suggest you add the Ag-Diesel Power Module.

Just keep in mind your Allison 3000MH limit is 1250 lb-ft; and it is highly recommended you have a Pyrometer at these HP levels.

(See chart below for Allison Torque Limits.)

ISC OWNERS SHOULD ASK: WHAT’S BETTER THAN AN AG-Diesel POWER MODULE TO INCREASE YOUR HP?

Answer: That would be an Ag-Diesel Power Module… plus a “boost fooler” to get to 450HP total.

That’s 420HP from the Ag-tune, plus 30 more ponies using the boost fooler (approximately). But since your HP/Weight performance is already very good (at 0.0130), the real purpose of adding a boost fooler is to lower your EGT!

WOULD ADDING A BOOST FOOLER OR ADJUSTING YOUR TURBO ACTUATOR TO 30MP MAKE A DIFFERENCE? …I think 30 HP added to a 7,000 lb. truck would, but not a 32,000 lb. RV. However, as already mentioned, lowering EGT is always a good thing.

…Plus adding a boost fooler is only $12; and you can install it very easily yourself! So what have you got to lose?

Just remember, a boost fooler will NOT lower your EGT at full power, but it should lower your EGT anytime you are below 70%-80% power. So why not take advantage of this very effective and inexpensive upgrade and start lowering your EGT!

WHAT ABOUT THE OTHER OPTION OF ADJUSTING THE TURBO ACTUATOR TO BOOST YOUR MP FROM 24 TO 30?

Answer: You can do this, but it’s probably easier to install the boost fooler.

Both methods are reliable, and I don’t think going to 30 would put a heavy strain your CAC and other air tubes -- unless you have a weak spot.

But boost fooler or no boost fooler you might ask yourself this: When was the last time you inspected your air induction system, or cleaned and inspected the CAC and radiator, transmission cooler, and check your turbo for end play, etc.? …And how many miles are on your RV now? ...So maybe it’s time you took a look around!

Note: When you check your turbo for axial “end play” and radial “slop,” I am told you should check it after the turbo rests for a day so all the oil runs out of the turbo. You can do this by hand if you have “have the touch” but there are specialty tools for this. Mostly the turbo should spin freely and not show any wear on the housing or damage to the compressor wheel.

TIP: How many of us know what a “smoke test” is? I didn’t until last week. That’s when I found these YouTube videos and you can do this to your exhaust as well as to check your air delivery system… after you remove your air cleaner for example. Check these ideas out:

https://www.youtube.com/watch?reload=9&v=kmwDGbTqA9Q

…And this one on how to build your own smoke machine.

https://www.youtube.com/watch?v=EhNQiIRsCCk

ANYTIME YOU INCREASE HP YOU REALLY SHOULD INSTALL A PYROMETER TO MEASURE YOUR EGT.

First, you need to know a Pyrometer (probe) should be placed in the exhaust manifold, and just before the turbo intake side. And if you place it anywhere else your EGT will vary by up to 200F. So maybe this explains why some people say they don’t want to exceed 1250F, when other owner say you can go to 1350F. In general, I think it’s safe to say this: “Lower EGTs are always better!” And if that $12 boost fooler can give us that, then why not add it? …Or maybe you can easily shorten the rod on your turbo Actuator to accomplish the same thing?

So please share: What does your EGT run at and what engine do you have?

If your coach does not have an EGT, but you plan to install one, here are a few suggestions:

* First, take a stock EGT measurement;
* Then take another measurement after you plug in your Ag-diesel Power Module;
* And then take another EGT measurement after you add a boost fooler.

This approach will give you the most “peace of mind.”

If you don’t have an EGT to warn you when you are running at full power, then you can do these next best things:

* Baby your throttle response up and down the power curve.
* Give your turbo more time to cool down after you pull over. This also lets oil flow to the turbo which is very important.
* Don’t try to fly over steep grades.
* Try not to floor it unless you need to for safety reasons.
* Use your 450HP advantage sparingly and only when needed.

Now you might think these are just common practices, and you would be right, but I’m guessing a lot of people don’t follow them, or know why they should follow them.

My point is that you need to pay more attention to “good engine practices” if you increase your HP over stock. This will keep you out of trouble and will keep your engine running strong for a long, long time!

In closing, I would like to thank the team at Ag-Diesel for helping me to understand how their Power Module functions in my ISC-350/420 and how I can increase HP safely. For more information, you should call Ag-Diesel at (812)618-9166. They will be glad to help you! Here is their website:

https://www.agdieselsolutions.com/product/12100/

I also want acknowledge and thank Area Diesel Solutions, located in Illinois and Iowa. I spent over 1 hour taking to Van who has been overhauling turbos for Winnebago Industries since the late 90’s.

You may also like to know: Area Diesel is well versed in using the Ag-Diesel’s Power Modules and they have excellent knowledge about turbos, CAPS and HPFR injection systems. So, if you are ever near their DesMoines, IA location, you now know where to get your RV engine serviced. Here is Area Diesel’s website: https://areadieselservice.com/

END.

…Wait a minute. WHAT ABOUT DRAG?

After I installed the Ag-Diesel Power Module and reached 420HP on the dyno... what I forgot to mention is that my MPG also improved by 15%.

Here are the numbers:

Before I added the Ag-Diesel Power Module, I would typically travel at 60-65MPH. This is where I found my “sweet spot” in terms of best MPG numbers; and at these speeds I would average between 7.0-7.2MPG towing a Saturn Aura, in good weather, and on good roads.

After the Ag-Diesel upgrade, the torque in my engine increased from 897 lb-ft to 1086 lb-ft; and now I can do 65-70MPH… and my MPG now averages 7.9 – 8.2 MPG. …But how is this possible?

I think the additional torque I picked-up from the Ag-tune moved that stock “sweet spot” from 55-60MPH up to 65-70MPH. …What else could it be?

I know the “drag” didn’t change, because my RV still looks the same on the outside; and for comparisons all the other parameters that can affect MPG were relatively the same. This includes driving at the same altitudes, same outside air-temp, humidity, and road conditions. Therefore, Ag-Diesel has the “secret sauce!”

And you might also like to know, I fully evaluated Ag-Diesel Power Module over 4,000 miles; and closely monitored my MPG the entire distance. And I did this by keeping detailed records at every fill-up!

That means I leveled my coach before I put diesel in the tank; and I would then fill the tank until I could see diesel fuel “pool” in the fuel filler neck, each time. So these improved MPG numbers are derived from the “old school” way of calculating MPG.

This increase in MPG also means: For every $200 I spend in fuel, I save 15% or ~$30. Which is a nice way of saying, this upgrade will pay for itself if you do a lot of driving. Thank you Ag-Diesel!

The most important upgrade you can do for yourself is to install a FASS-TS-95GPH fuel pump or AirDog-II-4G fuel pump. …Why?

The purpose of installing an 12V FASS or AirDog fuel pump is mostly to protect your injection pump and ECM from premature failure -- that can cost you $5,000 to $9,000 to repair – plus towing charges – and trip distress. There are other benefits to FASS and AirDog fuel pumps as well, but protecting your injection system is the primary one. For more information, you can go to this website on IRV2:

https://www.irv2.com/forums/f123/cum...mp-458337.html

Note: My FASS-TS-95GHP pump cost $670 + 150 in other parts + 2 full days of my labor to install. Of course this was first FASS installation. Consequently, if you can get Diesel Injection Shop to work on your RV, I think they can get the entire job done in 6-8 hours, providing you help them understand what you want. …And to do that, you need to become very familiar with the .pdf write-up I posted on website above.

Don’t be surprised to find out: Most Freightliner and Cummins shops have no experience installing a FASS or AirDog in an RV, but they can figure it out… for a price. However, my recommendation is to find a diesel performance shop who knows all about FASS and AirDog, because they are used to modifying small trucks vs. Freightliner and Cummins who are used to repairing big trucks and the occasional RV engine.

** I realize it’s hard to spend money on an upgrade when nothing is “broke.” But that’s exactly the time you need to do this upgrade! …Please don’t wait until your stock lift pump fails or your CAPS injection pump blows-up!

You can avoid all this stress, and potentially huge repair bills, by installing a FASS or AirDog. So stop driving on “borrowed time”, because that’s what you are doing if your coach has more than 50,000 miles (IMO). In fact, I feel so strongly about this upgrade, I wish I could call you next month to ask if you got it done yet?

I hope you found this write-up informative?

Save driving to us all!

[Vanwill]

Mark, (I think your name is Mark?)

Correct me if I am wrong, but it is my assumption that you still have not installed an EGT gage on your coach, so you do not have any PERSONAL experience with EGT. I assume the statements you have made regarding changes to EGT from either altering boost pressure OR adding fueling as they relate to EGT are just what you have read. If anything I have posted did not come from personal experience I make that disclaimer. There are two things you keep repeating that have proven to be incorrect in my PERSONAL EXPERIENCE.


“Just remember, a boost fooler will NOT lower your EGT at full power, but it should lower your EGT anytime you are below 70%-80% power. So why not take advantage of this very effective and inexpensive upgrade and start lowering your EGT!”

My experiments with measuring EGT at differing boost pressures were for one reason only—to lower EGT at WOT. If increased boost could not lower my EGT at WOT, there was certainly no point in increasing fueling. And EGT at anything other than WOT (or very near WOT) is of little or no consequence…it will always be lower than at WOT. Before increasing boost, my EGT at 70% - 80% was well below 1100*F. But getting almost 1350*F at WOT meant any increase in fueling might cause damage. YES, increasing boost WILL lower EGT at all loads, but especially at WOT.

“That’s 420HP from the Ag-tune, plus 30 more ponies using the boost fooler (approximately).

When I installed the FASS pump, there was no scientific reason (other than any pre-existing fuel starvation) to expect any change whatsoever in power. I expected no change and got none. The same goes for increasing boost. There is no reason to expect any increase in power by simply increasing boost. I expected no power increase, and got none. My objective was only to lower EGT so I could safely increase fueling. I SUSPECT one might get a power increase by increasing boost on an engine that was exhausting black smoke due to over-fueling. But apart from something like that, increasing boost seems only likely to almost imperceptibly REDUCE power of a properly tuned engine, just due to the extra power required to compress the air to a higher pressure.

Your posts are very well detailed. I copied much of what you did when you gave that great write-up about the FASS installation. But those two statements may lead folks astray. I'm certainly not trying to be critical for no reason.

[TR4]

Van, what have you decided on for your stock engine. Are you staying at your increased boost (I think you quoted 30psi) or going back to stock (aprox 24psi). I’ve got plenty of power, I’d only like to reduce EGT at WOT. Is the boost elbow a waste of money or worth a try?

Bill

[Mr_D]

It's too bad Banks had to quit making their kit for the older ISC! New turbo housing, new big head actuator, EGT, wiring harness and Otto mind. The manufacturer of the Otto mind went out of business and they never found another. Made a big difference in my '02 Dutch Star ISC 350/1050 to 435/1250. If the EGT got too high it would automatically dial back the fuel. Installed it in '06 and was still doing it's job in 2015.

[Vanwill]

Originally Posted by TR4

Van, what have you decided on for your stock engine. Are you staying at your increased boost (I think you quoted 30psi) or going back to stock (aprox 24psi). I’ve got plenty of power, I’d only like to reduce EGT at WOT. Is the boost elbow a waste of money or worth a try?

Bill

Bill, I plan to install the Ag Solutions device soon. Several projects ahead of it and I don't have a trip planned anytime soon. When I install that extra fueling I will NO DOUBT have to remain at an undetermined level of additional boost. I would be surprised if anything less than the 30 PSI would adequately control the EGT.

And based on my prior experience with the non-electronic 8.3-250 in the 1993 Dynasty with increased fueling, the boost will be available just from the extra exhaust gas going through the turbo. Although the wastegate, which I had not altered, controls the boost regardless of fueling, it still allows a minor increase in boost if there is additional fueling. On that coach I never increased fueling but a minor amount and EGT rose significantly. I sold the coach just before I had planned to work on raising the boost.

So, understanding that the increased fueling will automatically provide increased boost, I am certain I will have to re-install some sort of boost control. At present, the 30 PSI (previously 24 PSI) is with the wastegate disconnected entirely. Before I install the Ag Solutions device, I will install the Boost Fooler. Had I known where to get one before I started modifying the wastegate, I would have done that to start with.

My EGT, at 30 PSI boost, is now comfortably below what it was previously, but I'm sure when I add even a modest amount of fueling it will rise. I will just have to experiment with the setup to make the compromise between HP, EGT, and boost. Also, I'm sure that if I left the wastegate disconnected and added the fueling, the boost will rise.

I am still hesitant to raise the boost much above 30 PSI primarily because of what I THINK are limitations in the ability of the CAC to handle increased pressure without cracking or rupturing. I know of no reason the engine would have any problem with the increase, but the CAC and all the ducting and couplings I am suspicious of. On the 1993 Dynasty 8.3-250, the CAC had multiple cracks and ruptures. Almost all of them were at the welds where the tanks were fabricated from sheet aluminum. The CAC in this coach has formed end tanks similar to most automotive radiators, so I'm sure it is more robust than the one in the older coach.

Coincidentally, to demonstrate the excess capacity of the turbo and the control of the wastegate, even after having the CAC professionally repaired, the boost remained the same. The turbo was supplying quite a bit more volume with the badly leaking CAC and it had enough excess capacity to do so, limited by the wastegate.

I will keep you posted. Meanwhile, I'm going to start another post asking if anyone has ACCURATE info on the limitations of the CAC.

[Vanwill]

I would like to hear from those of you with ISC / ISL engines about your normal boost levels. I am considering raising my boost slightly above my present 30 PSI. Before altering my wastegate, it was 24 PSI. It is my understanding (not sure) that some ISL engines have stock boost levels in the 35 PSI range. Can anyone confirm that?

My previous 1993 Dynasty with 8.3-250 non-electronic engine had a CAC with welded/fabricated tanks made from sheet aluminum, and it had cracked badly in several places at the welds from a stock 24 PSI boost pressure. The CAC in my present ISC-350 has formed end tanks that are surely more robust than the fabricated ones, but I'm not sure what limit they are designed for.

Has anyone seen a published pressure limit spec from any CAC manufacturer?

[Dutch Star Don]

Just for info, my 2019 Dutch Star with the ISL/L9 DEF motor will occasionally hit 34-35 boost on a hard pull, read via my SilverLeaf VMSpc.

[YC1]

All this is way over my pay grade but what does this extra performance to to a DPF filter

Reason I asked is early on I installed a DigiCrtv module. The performance upgrade was not only obvious under my foot and mileage increase the dyno showed the great improvements.

I posted them many years ago and they probably are not pertinent to this conversation.

However, the early Cummins DPF filters or early learning curves may have been the issue based on the full dumpster I saw at a Cummins dealer at around 20K miles. Another customer that I met had many many issues with his and they blamed it on high idle times. (Dump truck owner),They told me I had high idle times too. I'm not the one that lets my diesel idle to show the world I have one.

In any case, an expensive repair that the extended warranty was said to be emission related and not covered.

I had removed the module of course before the repair and they did many flash upgrades to the ECM. After that repair and not do to the removal of the module the thing never had the same factory power and mileage. I think they may have tinkered with the ECM to possibly cover the early growing pains with DPF filters.

I really miss the extra power.

[Vanwill]

Originally Posted by Dutch Star Don

Just for info, my 2019 Dutch Star with the ISL/L9 DEF motor will occasionally hit 34-35 boost on a hard pull, read via my SilverLeaf VMSpc.

Thanks, Don!

[imnprsd]

Last summer, I started down this engine upgrade path; and up until this time, I pretty much looked at my 2003-ISC-350-CAPS motor as a “big black box.” Why? …Well, for one reason is that I did not know how to work on it; and I did not want to know how it worked.

I also bought into all the hype about how diesels will last 500K – 1M miles! …And it will, with care.

Here’s the thing: Around 70,000 miles you will start doing more than just changing the oil. And by 100,000 miles, which is where I am at, you will find out these big black boxes are not that complicated and you can work on them if you want to. ...Or at least you can keep your diesel mechanic honest if you know how to work on them.

I like to learn about this stuff, because I do not want to end-up stranded anywhere; and occasionally I save money by knowing how to do my own PM. However, these performance upgrades are all about having more fun.

Note: I have overhauled car motors, motorcycles, airplane engines, but never diesel motors. I have a mechanical mind, handyman attitude and ability, electrical engineering degree, and have owned 4 RVs, but in the beginning, all I can say: “This diesel stuff sure is different.”

Moreover, diesel-EGT is especially different when comparing gas 4-stroke motors to diesel 4-stroke motors. So if I may make a suggestion: You can learn a lot by watching some YouTube videos on diesel combustion and power.

In the summer-2019, I upgraded my fuel delivery system by installing a FASS-TS electric fuel pump (aka lift pump). And because that upgrade went so well, I then decided to install the Ag-Diesel Power Module (#12100) in Sept-2019, and that upgrade went extremely well too. Now my ISC-350 is putting out 420HP and I could not be happier with my 420HP/32,000 lbs. ratio of 0.0131. …And because of this I am now focused on lowering my EGT, which is always a good thing, if you can do it safely. ...And, if it is true, this can be accomplished by just adding a $12 boost fooler, on Amazon, then “I’m all in.”

I have not yet installed an EGT, and for a while there, I did not think I needed to install an EGT so long as I baby my motor and did not try to fly up a steep grade. …But now, with the help all those “woodchucks” out there, who have warned me about melting pistons, etc… I am listening... and you people might like to know that I do plan to install an EGT this summer. …But EGT or no EGT, it looks like adding a boost fooler is a good way to go for both stock and chipped engines. (TBD)

…We still need to hear from someone who has used this little device and can back all of us up on what we think are the benefits!

In addition, I tend to think the real purpose of installing an EGT is not to protect your pistons and valves from failure, as everyone says or thinks, but rather it is to protect your turbine wheel in the turbo from failure. …But that is a different subject worth talking about another day. For now, I think measuring EGT is a good idea if you are increasing the performance of your engine beyond the factory numbers.

So, I would like to say: All of the hype I have engaged in, including the possible benefits of installing a boost fooler, is based on Vanwill’s EGT data gleaned after he adjusted his Turbo Actuator – and pushed his MP from 24” to 30PSI -- and after he reported lower EGT at all RPMs and WOT.

However, it is also true that most of us do not want to add a spring-actuator system or come up with a similar change. Therefore, this discussion has turned to the viability of using a boost fooler to accomplish the same results. (TBD)

===

Here is where the confusion starts: Most of us use the term “more HP” to describe engine performance improvements when we/they really mean “more acceleration.”

On top of that, HP is a derived measurement and not a specific measurement with respect to time. And since we need to get our units straight: Acceleration is equal to the “rate of change in velocity, measured over time.”

So why do people say: “I got more HP.” …when the feel it “by the seat of their pants? …Well, I think it is just easier for people (including me) to say: “I got more horsepower…” even though this is not the right description of what you feel. … And other people like to use the word torque; but torque is really a measurement of power; while HP is a measurement of work energy. (Everyone is trying to say the same thing, we just talk different sometimes, so it helps to “read between the lines” sometimes. But every time we get called-out it just make us better!

For example, here’s another one: “ You cannot feel velocity. You can see velocity outside your window, and you can measure it in terms of miles/hour, but you cannot feel it. What you feel is positive-acceleration; and when you brake you feel negative-deceleration.”

===

Moving on… Back to performance improvement: Unless you have a dyno, then you cannot measure the effects of any performance upgrade “at the wheels.” This includes changes you might make to your fuel delivery system (by adding a FASS or AirDog lift pump); or changes you might make to the fuel injection/ combustion and timing (by adding the Ad-Diesel chip); or changes to the air delivery system via the turbo using a boost fooler or other method.

What I am saying is this: Without a dyno to back up your claims, everything you read about engine performance upgrades are based on assumptions and speculations. And sometimes we get the words right and sometime we get it wrong. Oh well. We do our best and learn and move-on.

This summer I plan to visit Ag-Diesel again so I can put my RV on their dyno. I will then take new HP and torque measurements before and after I add a boost fooler. And then I will know how adding a boost fooler affects my acceleration and my HP on the top-end. However, this will not happen until July or August or even September, because I don’t pick up my RV from storage until June in Texas and I have to travel to Indiana. So hopefully, someone else will take the lead on this project. Vanwill seems to be willing.

I also said in my previous posts: “After I installed the Ag-Diesel Power Module, (#12100) I have all the HP need.” Consequently, that means my only reasons for installing the boost fooler, at this point, is to lower EGT -- and from what Vanwill has determined, this should be possible. (TBD)

Vanwill: Does your 1993 Dynasty 8.3-250 use a mechanical type injection system; and is this what they call a 6CTA type engine? If so, this means me we have different inaction systems and turbos, right?

I have a2003-ISC-CAPS system and a Holset 40W turbo, so I’m wondering… Do you think my EGT will drop, even at WOT, if I install a boost fooler in my engine?

Vanwill: I also speculate that if people are experiencing more acceleration after they boost their MP from 24” to 30”… that there may be an incremental HP gain, but I admit this is just a guess. …Still, why do you NOT think a boost fooler will increase HP on the top-end?

My understanding is this: When you are able to force more air into the diesel combustion chamber, you will get a more complete fuel burn & more power. So why won’t this improved fuel burn contribute to more HP on the top end; especially, if we already established you will get better acceleration?

And if diesel engines like to run on the leaner side then this increase in performance & air flow should also lower EGT? …I also don’t think diesel engine are notorious for burning valves like gas engines are when you run with too lean of a mixture. And I think if there is “black smoke” in my diesel exhaust, then there is unburned fuel-energy I may be able to “get-at” by adding the boost fooler. What are your opinions on this?

==> Are there any diesel experts out there who understand diesel stoichiometric and can break it down into meaningful information for us to understand? For example: Can I assume I will get better performance and MPG if I can convert that “back smoke” in to work-HP? …And will a boost fooler accomplish this goal? ...And will EGT drop if I get more HP on one hand… by adding more air (increase MP) on the other hand?)

…Keep in mind, I can change the fuel injection timing using the Ag-Diesel power module, so adding more fuel is not the problem any longer. The problem or challenge is adding more air to the diesel combustion chamber! ...So will that $12 boost fooler accomplish this? ...And if it will, why is this such a well kept secret? ...Or maybe it's just an old secret that has died-off with the rest of the old guys?

THE AFFECTS OF MORE HP

After I installed the Ag-Diesel Power Model in my new-to-me ISC-420HP, my engine had more top-end because I got more HP; I.e., I now comfortably run down the road at 65-70mph vs. the ISC-350HP engine that once liked to run at 58-65MPH (aka “sweet spot”) when my ISC was stock at 350HP.

Consequently, I tend to think of HP value in terms of “top-end-value.” Of course, my torque and acceleration went up too, so this is the primary reason I installed the Ag-Diesel Power Module. …But just so you know, my torque numbers were much lower than what Cummins spec’d from the factory.

One more comment about HP and torque: I found Cummins accurately reports HP because all auto and RV manufactures are required by law to report HP accurately. However, this is not the case when reporting engine torque. So unless you put your RV on the dyno, IMO, all Cummins engine torque specs are likely overstated with respect to your actual torque results you will get when you put your RV on the dyno.

MY SUMMARY ABOUT TURBO UPGRADES & BOOST FOOLERS

* These older Holset 40W turbos (Non-VRT, pre-2006?) use a diaphragm in the turbo actuator to open the waste gate (WG); and if you can control the diaphragm you can control the boost. And you don't need to change the turbine wheel or compressor wheel to increase your engine HP. (Save this for when you need to overhaul you turbo for other reasons.)

* When your engine increases MP, that will force more air into your diesel combustion chamber.

* How far the WG will open is a matter of adjustment: A) If you have and adjusting nut, a shorter rod will result in more MP; B) If you use a boost fooler you can reduce diaphragm pressure by bleading-off MP, and this adjustment is made with an Alan-screw.

* Installing a $12 boost fooler will take 15-20 minutes, once you are under the coach. And it appears this will benefit every diesel RV owner (Cat or Cummins). So IMO, more people should try this little device without fear of exceeding your EGTs!

* Can we all agree increasing MP will lower EGT? Vanwill says yes. But I would like to see results from another owner who has a 2000-2004 ISC/ISL CAPS based injection system motor to verify this.

* Do we know if increasing MP will increase your acceleration? Yes. By all accounts.

* Do we know if increasing MP will hurt your CAC? We think not if you stay under 30”. And while newer RV owners report 35” of boost; these newer RVs may have better fabricated CAC vs pre-2006 model coaches. (TBD) Vanwill says he will pursue this subject in a new thread. (Thank you!)

* Does increasing MP result in more HP? Vanwill says no. I say maybe. (TBD) …And this summer I will attempt to put my RV on the Ag-Diesel dyno to confirm or deny any HP change.

HOW TO PERFECTLY TUNE YOUR ENGINE (Just a guess.)

In order to achieve a perfectly tuned ISC with these modifications, I think you need to achieve “ the right balance” of everything under our control. This includes measuring HP and torque on the dyno; measuring EGT on the pyrometer; and varying the boost pressure using a boost fooler; and varying the amount of fuel using the Ag-Diesel Power Module. …So wish me luck!

in the meantime, the rest of you without an Ag-Diesel Power Module could safely start by adding a boost fooler; and the EGT-pyrometer can come later.

* It also goes without saying: Your first engine upgrade should be to install a FASS-TS or AirDog-II-4G electric fuel pump! ...This has to do with injection pump lubrication and cooling on every stock ISC/ISL (pre-2004 with a CAPS for sure, and maybe every pre-2009, IDK, but if you have a Cummins you should look into this before your injection pump fails!)

In closing, with the help of many of you on IRV2.com, I now do not see a “big black box” when I look at my ISC-350/420. And I thank all of you for your help. However, on this subject of what are the best and safest ways to increase the performance of your ISC, IMO, we are still not there yet, and this is still a work in progress.

[Vanwill]

"Vanwill: Does your 1993 Dynasty 8.3-250 use a mechanical type injection system; and is this what they call a 6CTA type engine? If so, this means me we have different inaction systems and turbos, right?"

Mark, my PRESENT coach is a 2000 Dynasty 36 with ISC-350 with the CAPS system nearly (if not completely) identical to yours. The 1993 Dynasty I owned was indeed a 6CTA mechanical engine with Bosch P1700 (?) injector pump and 12-valve head. To increase fueling on it required me to install a "fueling cam plate" in the injector pump. It worked fine, but resulted in a small amount of black smoke for less than a second when accelerating WOT from a stop. Acceleration was noticeably improved "seat of the pants". I never had it on a dyno. The injection pump also had an adjustment for limiting the amount of fuel under initial acceleration. That adjustment was intended to prevent over-fueling (black smoke) under heavy acceleration. It limited fueling until turbo pressure built to a high enough level to efficiently burn the increased fuel and prevent smoking.

I DID install an EGT gage on both coaches before making any modifications to get a "baseline" for what my EGT's were. Regardless what the EGT gage is protecting you from (turbo failure or damaged pistons/valves) it is providing you data you need if you are exceeding design limitations on your engine.

No, simply increasing MP (manifold pressure) without adding fuel does NOT increase HP or torque. You can almost use the words MP (manifold pressure) and "boost" interchangeably. The only thing that will significantly increase HP or torque is to burn more fuel. In an engine that was already supplying excess fuel (likely emitting some amount of black smoke), increasing boost MIGHT raise HP/torque. I have no PERSONAL experience with that. But in an engine already supplying enough excess air to completely burn the fuel, adding more air does NOT increase HP/torque. In a properly tuned (stock) electronically controlled engine increasing boost does not cause the ECM to add fuel to use all the additional air. If that were true, there MIGHT be no need for the Ag Solutions device...if the ECM sensed extra air, it would increase fueling to use that air.

Assuming it works as I expect it to, the "boost fooler" should be a much simpler solution to raising boost than the wastegate modifications I made. I have one and will install it at some time in the near future.

Yes, based on my personal experience, WHATEVER your EGT is now, it will decrease when you increase boost. And it will definitely be reduced at WOT.

"Vanwill: I also speculate that if people are experiencing more acceleration after they boost their MP from 24” to 30”… that there may be an incremental HP gain, but I admit this is just a guess. …Still, why do you NOT think a boost fooler will increase HP on the top-end?"

I PERSONALLY know only one person who has installed a boost fooler, and he did it years ago. 2000 Dynasty with ISC-350 very nearly identical to mine. He is a good friend and we talked about his installation. He is a tinkerer and just enjoys doing that kind of modification. He does not have an EGT gage. He said he did not think it increased his power or acceleration, but his boost gage showed it did increase boost pressure. That is the only case with which I have PERSONAL experience. His experience was same as mine--increased boost did NOT result in increased HP/torque. One can only increase HP/torque by burning MORE fuel, or burning the existing amount MORE EFFICIENTLY. STOCK, EPA-compliant modern diesel engines run with enough excess air that they emit ALMOST no perceptible smoke. Adding MORE air will NOT increase HP/torque, but will reduce EGT.

"And I think if there is “black smoke” in my diesel exhaust, then there is unburned fuel-energy I may be able to “get-at” by adding the boost fooler. What are your opinions on this?

I THINK you are correct. I don't have any PERSONAL experience to validate my opinion.

I am presently studying the Ag Solutions information. I was already committed to purchasing the device, but tend to study things like that in great detail before purchasing. I think I can SAFELY apply it to my engine since I have an EGT gage. Even if the added fueling increases my EGT to critical levels, I can control it with my right foot. If my curiosity gets the best of me, I'll travel to their location in IN. It is only about three hours off my path to a trip I'm making to CO this summer.

REBUILDING TURBOS--I still have not disassembled the faulty turbo that my heavy truck shop gave me. But I repeat what the tech told me--that 99% of the time they replace/rebuild turbos for only two reasons. 1) They become noisy because one or both impellors are touching the housing due to bearing wear. 2) One of the impellors has flown apart. He told me that as long as the turbo's impellors are not touching the housing, replacing the center bearing does not cause any increase in its performance. It's an "all or none" situation.

Stoichiometric Be somewhat careful in using the term "stoichiometric" because it leads you in the direction of next mentioning "mixtures". "MIXTURES", both lean and rich, have no meaning in the diesel combustion cycle. Near TDC in the diesel engine piston's stroke, the rapidly compressed air is raised to a temperature high enough that it exceeds the SELF-IGNITION temperature of diesel fuel. So, when ANY AMOUNT of diesel fuel is injected, it immediately ignites and burns. Modern diesel engines limit the amount of fuel injected to stay within EPA compliance. To do that, they are almost always supplying excess air (enough boost). The reason gasoline will not burn in a diesel engine is that its SELF-IGNITION temperature is higher than the temperature of compression in the diesel engine...it just won't "catch on fire" due to the temperature. There is absolutely no such thing as diesel engine damage due to "lean mixtures". Damage from over-fueling? YES.

The point frequently confusing people is that mixtures DO have a meaning in SPARK-IGNITION engines burning gasoline, alcohol, or nitromethane. But it is not so much about the concern for combustion temperatures, although that must be within allowable limits. The BASIC problem is SPARK-IGNITION. When gasoline is mixed with air to the stoichiometrically "perfect" mixture (exactly enough air to burn all the fuel) it is extremely difficult to ignite with a spark. To be EASILY ignited by a spark, the mixtures must be significantly rich (more fuel than can be burned by the available air). Modern gasoline engine designers have been working for decades to enable leaner and leaner mixtures to be ignited by a spark. Once ignited, the emissions can be controlled by several other procedures, but for the engine to perform adequately, it MUST initiate combustion by a spark.

Can gasoline and other volatile fuels be ignited by reaching their self-ignition temperature? YES. But in gasoline engines that self-ignition is called DETONATION, and only occurs AFTER the fuel is ignited by a spark.

[Vanwill]

Just ordered my Ag Diesel Solutions device. $673.55

[imnprsd]

Vanwill: Excellent! I think you will very much enjoy your Ag-Power Module… the gift that keeps on giving!

Immediately after you install it you feel the added power in two forms: 1) In your seat you will feel the increase in acceleration; and 2) Your top-end “highway sweet spot” will move up 5MPH. This means everything will happen faster, but you will get use to that.

To build on what you said:

“In an engine that was already supplying excess fuel (likely emitting some amount of black smoke), increasing boost MIGHT raise HP/torque.”

And…

“There is absolutely no such thing as diesel engine damage due to "lean mixtures". Damage from over-fueling? YES.”

I found these videos on YouTube that will assist everyone to better understand the differences between gas (spark) engines and diesel engines:

CLASS IS IN SESSION

Turbo Charger:

https://www.youtube.com/watch?v=DqWKNuTppmU

Air Fuel ratio video:

https://www.youtube.com/watch?v=gPWI8QTRg9g

KEY POINT ABOUT "BLACK SMOKE" AND HOW DIESEL FUEL ONLY BURNS WHEN WITH ATOMIZATION... And note how far away the burn occurs.

https://www.youtube.com/watch?v=qjapJVcdI5s

What's the Difference Between Petrol & Diesel? | Bang Goes The Theory

1)

https://www.youtube.com/watch?v=Zph5usgWkN0

2)

https://www.youtube.com/watch?v=rlK7JIAz9WY

…And for those of you who “learn differently” and/or can appreciate creative humor, I think you will like this video about the history of Cummins. At least I found it very informative and entertaining, and I think it’s a good way to conclude this learning session in a fun way.

https://www.youtube.com/watch?v=Z-JdfXxNflg

[Vanwill]

The subject matter of this discussion has become spread over so many threads that it becomes a bit difficult to follow.

But to recap, I became interested in “chipping” my ISC-350 in a Monaco Dynasty 36 with no slides, weighing in at just over 30,000#. I had added a “fueling plate” in an all-mechanical 8.3-250 in my previous 1993 Dynasty 36 and adjusted the boost settings, but only after adding an EGT gage. That mechanical engine was a great deal more trouble to “hot rod”.

As I considered “chipping” my ISC-350, I soon learned about an unusual number of CAPS fuel system failures. When I began digging into failure reports for the CAPS system, I noticed there were more failures in motor homes than in almost every other category combined. Not all failures could be proven to be the result of fuel-starvation at the CAPS pump, but in the motor home segment enough of them SEEMED to be fuel-starvation at the CAPS pump that I decided I would remedy that problem before I attempted “chipping”.

Thanks in large part to Mark’s (imnprsd) detailed thread on his FASS pump installation, I chose the FASS system as a “precautionary” installation before I did anything to request any more fuel from the CAPS pump. I did look at some other lift-type pumps, including Air Dog, and a couple of designs of my own. In the end, a constant-running pump filtering a large amount of fuel and returning it to the tank anytime the engine was running were the deciding factors for ME. YOU might decide otherwise. I talked to FASS before the installation to verify some things I was unclear about in their design. One of those things was the requirement for a DEDICATED return line from the FASS pump. Think of it this way—no sense arranging to supply copious amounts of excess fuel to the CAPS pump…and then raising the pressure on the CAPS RETURN line by pumping 80+ GPH through its return line. Might it have worked anyway if I had tee’d into that line? Don’t know. FASS thinks it might be a problem. I wanted a bulletproof installation, so I installed the dedicated return line. My fuel tank had a tapping that was available without dropping the tank. ‘Nuff said.

Both the FASS system and the Air Dog pumps use a brush-type DC motor which runs continuously. The FASS system claims a 17,000 hour life, which even in motor home service translates to over 300,000 miles. I suspect the Air Dog has similar life expectancy. The FASS uses a gerotor for the pumping element. I THINK the Air Dog also uses a gerotor. Gerotor design is known for long life and quiet operation.

The Air Dog “bypasses” unused fuel INTERNALLY while keeping the system pressurized, as opposed to the FASS which dumps over 80 GPH of unused fuel back to the tank, AFTER running it through the filters. So, the FASS system is constantly filtering LARGE quantities of fuel in your tank while maintaining positive fuel pressure at the CAPS pump inlet. In an OTR tractor running through hundreds of gallons of fuel each week, that difference might be of no particular consequence, but it is my OPINION that in motor home service it matters. Most of us have had experience with clogged filters due to algae or contaminants. The constant filtration on the FASS unit is just one more bit of insurance against fuel system problems.

So, I installed 1) the FASS system with dedicated return line, 2) a remote-reading fuel pressure gage that measured fuel pressure at the entrance to the CAPS pump, and 3) an EGT gage. All three installations went without issue. What I soon learned was that my totally stock ISC-350 EGT at under 60 seconds of WOT could reach 1340*F. At that point, I decided I would not “chip” the engine if I could not lower the EGT first.

Long story short, one can reduce EGT by raising boost pressure above what is minimally needed for complete combustion. My ISC-350 had a stock 23-24 PSI boost. Once I had an EGT gage installed, I saw the EGT, even in stock configuration, was 1340*F under extreme conditions. That was more than I felt comfortable with. I increased boost to 30 PSI with the stock engine configuration and that brought EGT well under temps I was comfortable with, so I moved forward and ordered the Agricultural Solutions 12100 model “chip”.

Installation was straight-forward and simple with the exception of one detail. The 12100 comes with “breakout” connections for TWO sensors on the injection pump. One is the “Fuel Quantity Sensor”, a four-pin square connector and the other is a “Fuel Pressure Sensor” connection, a three-pin triangular connector. Without going into unnecessary detail, the “Fuel Pressure Sensor” on my CAPS pump had a three-pin OVAL connector and would not mate with the Ag Solutions connectors. Simple solution: Matt at Ag Solutions told me the Fuel Pressure Sensor connector was only for supplying an “ignition key is ON” signal to the Ag Solutions module. All I had to do was cut off the triangular connection and connect the PINK wire to any “key ON” power source. I did so, and everything worked as it should. So…I went for a test drive…

Results:
There is unquestionably more power. It seems to manifest itself more in torque than in more HP. Suits me fine. There is still a slight lag in turbo boost build-up from a standing start. But overall acceleration is noticeably improved. Does it “snap your head back”? NO. And I did not have the toad in tow (5200#). There is NO QUESTION that acceleration is improved and the coach (no toad) can accelerate up a modest incline at 45 MPH and gain speed—something it was incapable of before. But I will not be able to give a thorough evaluation of the 12100 until I’ve put a few thousand miles on it. I am planning a trip soon that will give me that opportunity.

As to EGT with the 12100—It is strange to me that ANY device that increases fueling does not increase EGT by a commensurate amount, but this appears to be true with the Ag Solutions 12100. There is an unmistakable increase in acceleration, but the rise in EGT is almost nil. I was able to reach just over 1300*F by “torturing” the engine—low RPM, low boost, and WOT. My max boost with the Ag Solutions 12100 and NO wastegate actuation is 32 PSI—only a modest increase over the 30 PSI STOCK ISC-350 with the wastegate DISABLED. At present, I have no intentions of installing the “boost fooler” since my max boost is well below 35 PSI.

I have a 600-mile trip planned in a couple of weeks. I’ll report back then. Immediately following that trip, I may head out West for the CO mountains, and that will be the REAL test.