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Old 03-20-2020, 06:25 AM   #1
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Join Date: Jul 2014
Posts: 626
ISC/ISL Boost Foolers, MP changes, turbo upgrades, and ECM Power Modules

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.


…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.)


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!


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:


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


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:


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/


…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:


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!
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2004 Itasca "Horizon" 40AD, ISC-350HP Cummins with 100,000 miles... and the best of 3 Diesels I have owned thus far!
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