What's the ISL or ISX?

[wernie1]

I have a 2003 500hp cummins , can anybody explain the 3 letters
new to the DP , we have put 12,000 miles on and want to do some service before we head out Dec 5 .

Thanks in advance

[Mr_D]

The "IS" at the beginning stands for "Interact System" which is the moniker for the on highway fuel system Cummins pioneered. The letters denote (to a certain extent) the displacement of the engine.

ISC is 8.3 L
ISL is 8.9 L
ISM is 10.8 L

After that it becomes more complicated.

ISX can be 12.0 L or 14.9 L
Within each size there can be a dozen HP/torque ratings.

[Smitty77]

To add to Mr D's post, your TS should have the ISM, a pretty well sorted out engine in that era. Might check to see if your specific engine would benefit from what I think is called the Ugly Fix... (EGR related, I believe.)

Also in the IS family are:
-The ISC 8.3L engine

-And then to get really blurred lines, is the ISB. Can be from 5.9 for the older engines, up to now 6.7.

And both the ISC and ISM are retired engines. The ISB at 6.7 was putting out power in the range of ISC. The ISX dropping down in size, overlapped with the ISM. And the cost of going thru the required certifications, was enough to send them into the memory lane...

Best,
Smitty

[Mr_D]

Originally Posted by Smitty77

To add to Mr D's post, your TS should have the ISM, a pretty well sorted out engine in that era. Might check to see if your specific engine would benefit from what I think is called the Ugly Fix... (EGR related, I believe.)

Also in the IS family are:
-The ISC 8.3L engine

-And then to get really blurred lines, is the ISB. Can be from 5.9 for the older engines, up to now 6.7.

And both the ISC and ISM are retired engines. The ISB at 6.7 was putting out power in the range of ISC. The ISX dropping down in size, overlapped with the ISM. And the cost of going thru the required certifications, was enough to send them into the memory lane...

Best,
Smitty

I didn't even want to get into the ISB line due to the different displacements, nor the various HP/torque ratings. The ISX can go from around 400 to 650 although the 400 up to 600 are used in Class 8 trucks although the 600 is now used in MH's too. The old 650 was "reserved" for RV's and is no longer in production. Plus truckers buy a higher rated engine and have it derated to get a longer warranty. There are so many combinations I think only Cummins knows them all!

[Augerboy]

Very well worded Mr. D. You have a good grasp on Cummins nomenclature.
I personally own a fleet of trucks powered by Cummins ISX15's rated at 450 HP. They are road speed limited at 65 mph however they are rated at 500 HP with a road speed limiter at 70 mph while in cruise control. This obviously promotes better fuel mileage. Nearly every fleet I know of does this.

[JohnBoyToo]

My eyes STILL glaze over when someone ask what engine I have...
I say it's red and it's a cummins!
that and the datacard say ISL 425, even went to Quickserve and downloaded everything from there and still unsure !

All I know is it works so far and happy it does !=

[Steve Ownby]

Originally Posted by JohnBoyToo

My eyes STILL glaze over when someone ask what engine I have...
I say it's red and it's a cummins!
that and the datacard say ISL 425, even went to Quickserve and downloaded everything from there and still unsure !

All I know is it works so far and happy it does !=

It's an ISL. If your engine requires DEF then it's this engine:

http://cumminsengines.com/showcase-i...s=100#overview

If it doesn't require DEF then it was built before 1/1/2010 and is this one:

http://cumminsengines.com/showcase-i...s=100#overview

They are basically the same engine but meet different EPA requirements.

Up on looking back at your post, I believe your engine doesn't require DEF and is the '07 emissions engine. The 2010 ISLs were 450 hp.

[JohnBoyToo]

Thanks a million Steve,
if you are ever in the DFW area, looks us up !
we owe you (and a few others) a steak dinner youse guys have help so much !

Nope, no def - one of the must haves when we went looking...
the epa stuff bogged down enough of my other engines already - taking that stuff out of the mix was like new engines

Am already looking at an exhaust change just to make it breathe a bit better (as soon as the 5 year warranty is up!)

[38Chevy454]

Mr D explained it pretty well, it defines an engine family for the most part. However as Steve pointed out, there are models within a family that are broken out by the emissions. There are (going from memory here, may be wrong year breaks) 2002-prior, 2003-2006, and 2007-2009, and 2010-newer that generally have increasing emissions equipment as the years get newer. The models are basically the same engine family design and internals, with different external parts. The externals are not necessarily on the engine, they can be part of the exhaust system for example.

The best way to know for sure is just look at your engine. There should be a tag on the valve cover and also one on the head. These stamped tags have all kinds of information about your engine. These numbers will tell you mfr date, family, displacement, rated output, S/N, internal specifics (relates to output), and more. These are what Cummins or other service use to know exactly what you have.

[jwmaustin]

Having worked for (and with) Cummins for many years I'd say the letters (B,C L,M, X, etc) started with the carcass - the block. Engine HP varies but blocks are a foundation that is built on. So a "new" engine sometimes starts with one of those blocks. Bore and stroke can vary and what is hung on it can vary.

I've been with the electronics area but that's what I see.

[Koop]

Originally Posted by Steve Ownby

It's an ISL. If your engine requires DEF then it's this engine:

ISL9 for Motorhome (EPA 2010) - Cummins Engines

If it doesn't require DEF then it was built before 1/1/2010 and is this one:

EPA 07 ISL for Motorhome - Cummins Engines

They are basically the same engine but meet different EPA requirements.

Up on looking back at your post, I believe your engine doesn't require DEF and is the '07 emissions engine. The 2010 ISLs were 450 hp.

I know I'm late to the party but I think you're missing something here Steve. The OP has a 2003 Travel Supreme. It's possible the engine/chassis is 2002. That would be a CAPS era Cummins and 500 HP would be an ISM.

[JohnBoyToo]

Koop,
Steve was being very kind to respond to my thread hijack post about MY ISL425,
not the OP