Community Forums

greenmachine · 02-18-2016, 09:48 AM

Brett, I contacted Cummins Tech dept. and they said to go by temp on intake and exhaust. Take the hose off the grille and check temp and check temp with hose on. Go to a small grade and see the difference. I asked about the vaccum at the intake and tech said each one is different and not reliable. What you worry about is that temp. Check your cfm on your filter, each filter is different. Well when everything else gets fixed I'm going to try to pull the hose off the grille and with it on the grille on a hot day on a hill.
Thanks Brett
Larry Pate
2003 Alpine Coach 350 Cummins ISC
2007 Jeep Wrangler unlimited
Ky

wolfe10 · 02-18-2016, 10:15 AM

Larry,

Very interesting. Would think intake temperature would be much more closely related to ambient temperature than intake restriction, as you have a pretty robust CAC (Charge Air Cooler= Inter-cooler= After-cooler). So running the test at the same ambient temperature would eliminate that variable.

And, if restriction is enough to change mixture enough that it affects EGT's, would think that would indicate quite a lot of restriction.

Please keep us posted on your results. Thanks.

Brett

Old Scout · 02-18-2016, 10:34 AM

Also need to factor in that the wax valve [03 and earlier models] on your radiator wont activate the engine fan until engine reaches ops temp. On cool mornings, your SL will show a significant increase in-take manifold temps until the engine fan is activated and ambient air is drawn across your CAC.

Ken L. · 02-18-2016, 10:42 AM

If it were a worthwhile effort, the only way to know is to do it? Filter minders are not going to tell us if the Fuel Millage has increased, or the power on a hill is greater than before. I can here my wife saying in the background " if it is not broken then don't mess with it" also. I am wondering if maybe an air deflector mounted to the rear of the intake might not work as a ram air intake
and force the air through the Way Small intake. It would only be effective after the coach was moving. Still thinking on this. Ken

wb7auk · 02-18-2016, 11:19 AM

Hopefully I was able to include a PDF in this reply.

If your filter minder does not show a vacuum after the engine being under full load you have either a bad or leaking minder.
On a good air intake system you do not want more than 2 inches vacuum at the filter input, your factory minder measures after the air filter.
Using temp as a indicator is poor at best just to many factors that effect it.
The things I have found are intake opening to small, hose or pipe to filter wrong type or to many bends or elbows, or to small.

Keep in mind the engine at normal hwy speeds does not use the total air amount the intake can provide only when under load does limited supply have an effect.

Ken L. · 02-18-2016, 01:37 PM

In answer to a question. This intake is the only one in the system, and is about 3" X 10" inside opening. It is mounted about 5 ft. high on the side of the coach. It is connected to air cleaner with a 7" dia. pipe. Ken
PS. I hope these pictures get there???

greenmachine · 02-18-2016, 02:00 PM

Ok, I went out and looked at my Alpine Coach. The Engineering Dept. at Alpine did a fine job. The pipe is right the filter box is right. Right inside the air opening she opens up good. So the grille like Ken said looks a little under sized. That's where we need that pie are square. Ken it opens up wide open right inside there. I think my 2003 is going to stay as is until I have gotten so bored, I'd like to make a bigger intake opening right there. I do have a question and before I make a new post I'll ask and if the answer is no I'll make a post. Does everyone know how to check the transmission fluid level and transmission codes on there coach setting in the drivers seat? If you don't Ill start a post on it.
Larry Pate
2003 Alpine 38FDDS 350 Cummins ISC
2007 Jeep Wrangler unlimited
Ky

Mr_D · 02-18-2016, 02:15 PM

Quote:

Originally Posted by wolfe10

Scientific way to approach it is for those with same engine (Cummins ISL) to read air filter minder gauge BEFORE the coach-side inlet enlarged.

Then reset air filter minder and do a 0-60 MPH at Wide Open Throttle and then read air filter minder gauge.

THAT will tell you whether this is a valuable upgrade.

Brett
2003 Alpine 38FDDS

With our previous rig, a 2002 Dutch Star ISC 350 with Banks kit my filter minder always showed 15 even with a brand new filter. The rig had a fairly small opening on the drivers side mid way up. Was looking for ways to reduce the restriction but never did it.
The present rig with it's ISX shows "0" or very close on the minder after running at 2100 rpm at WOT in 6th (yes, it will do it, no it's not safe!). The inlet opening is huge compared to the Dutch Star as is the filter. Diesels need to breath!

Old Scout · 02-18-2016, 05:25 PM

With the engine running--hold down both the up and down arrow keys at the same time, then release. The selector will count down to zero [zero indicates that tranny is in steady state] then will display fluid level.....

greenmachine · 02-19-2016, 06:36 AM

Thanks Old Scout, You have help me a lot in these Forums. I do thank you and everyone that understands these Alpines. The Temp is going to 63 here today and surfs up!
Again Thanks
Larry Pate
2003 Alpine 38FDDS 350 Cummins ISC

Old Scout · 02-19-2016, 07:22 AM

Still hoping one of our Alpine owners who has made the intake mod you are considering, will chime in with the results they were able to achieve...Don't recall anyone raving about improvement in performance or MPG.

wb7auk · 02-19-2016, 09:34 AM

Quote:

Originally Posted by Ken L.

In answer to a question. This intake is the only one in the system, and is about 3" X 10" inside opening. It is mounted about 5 ft. high on the side of the coach. It is connected to air cleaner with a 7" dia. pipe. Ken
PS. I hope these pictures get there???

The measurements of this grill are equal to a 4.6 inch ID hose or pipe, as I posted above very small when feeding a 7 inch system, it should be twice as
large to avoid restriction. The 7 inch hose should be smooth wall with as short a run as possible and as few bends or elbows as possible.

Ken L. · 02-19-2016, 10:39 AM

OK WB, Thanks for thinking about this. First I am not sure I have a problem, I am guessing about this. But, you seem to have some knowledge on the subject, and maybe we won't have to guess any longer. My Engine is a Cummins ISL 400 = 400HP. It is rated at 672 cfm @ 2100 rpm. The Filter Minder in it's current state is sitting at 8" of H2o or
205 mm of H2o. The filter was just changed last year by Cummins using Fleetguard filter. It has very few miles on it right now. The air intake grill nominal size is 3" x 10", but the effective opening size, taking into account the metal inserted into the frame work, is somewhat less. That is addressed in the opening post on my thread. The Pipe is a 7" thin wall smooth pipe about 18" plus 1 90 deg. smooth rubber elbow from the collector box in the closet to the side intake of the filter housing. It all seems to be in tact and in good condition. From the outlet of the filter to the engine compartment the piping seems to be a bit smaller, maybe 6" smooth wall pipe. I am not exactly sure of the routing or the length. So with this info I hope you can help with this dilemma. And Thank You for your interest. I am going to post this on the thread. Ken PS. My coach is a 38' with 3 slides.

wb7auk · 02-19-2016, 12:15 PM

A ISL 400 has a 543 cu inch displacement.
Where did you get the information that it used 672 CFM at 2100?
I plugged it into the program and it shows that engine with turbo requiring
990 CFM at 2100 rpm.
With this information the air intake grill is way to small and should be almost double
the size something in the order of 5x10 inch or a little larger.
The problem with a restricted air intake is the turbo works harder pulling air in causing a high vacuum across the filter which shortens its service life as well and heating the air that it sends to the CAC then to the intake manifold.
A diesel engine has its best efficiency with engine intake air temp at the engine between 60 to 90 F. For every 10 degrees above 90 degrees you loose 1% of engine horse power i.e. wasted fuel, also with higher intake temps the EGT will be higher which can be a problem if it gets to high.
As to why you do not show a higher filter minder vacuum leads me to think some where it is getting extra air maybe air filter drain holes or bad Duck Bill in the filter as it should be showing about twice as much as it does now if you have pulled any
grades. Either that or someone forgot to put a filter in haha
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