ISL 400 power specs

[DJLind]

I took my coach to Cummins to have some diagnostic work performed. They pulled a full ECM report as well as performed a dyno test.
All the ECM and dyno specs are in range except horsepower – only 168HP at the wheels. I heard a few possible reasons from them:
- In order to measure blow by, the tech had to disconnect the slobber tube from the aftertreatment system in order to attach the instrument and that threw a fault code, which may have de-rated the engine.
- The “maximum diesel particulate filter differential pressure” reads 3.0, 2.6, 2.8 in/Hg for the last 3 regens. A plugged particulate filter will be ~5.5+ in/Hg. However, all the reported values fall within the “Normal” range. Maybe that is enough to pull down the HP?
- They said that automatic transmissions only allow 50% - 60% of rated horsepower through to the drive wheels. Mine is well below that!
For those of you that have had a dyno report generated, what type of HP result did you get? Any other ideas why this number is so low? Is this a typical HP rating for this engine?

Doug Lindhout
09 Endeavor 41SKQ
14 Ford Edge

[JohnBoyToo]

That does sound low to me too ! While our 425HP seems to do quite well, always willing to see if more is better

I have heard that on many engines, the power is limited on initial startup to not over power the drive train - will be watching this thread !

[MSHappyCampers]

Hi Doug! Welcome to IRV2! We're sure glad you joined the gang!

Sorry I can't help with the questions! Keep her between the ditches!

Good luck, happy trails, and God bless!

[moisheh]

Did they put you on a chassis Dyno? Monaco engineersnever approved of that procedure. Hard on the chassis.

[DJLind]

moisheh,
Cummins has a drive up dyno. I didn't have a chance to actually see it, but I understand they chain the coach in place for the test.

[10Boomer]

Originally Posted by JohnBoyToo

That does sound low to me too ! While our 425HP seems to do quite well, always willing to see if more is better

I have heard that on many engines, the power is limited on initial startup to not over power the drive train - will be watching this thread !

X2, following to see what you find out.

[fcmcelr]

Doug, you mentioned that Cummins downloaded an ECM report. I'm wondering if they gave you a copy of this 50+ page report. In the report there will be a section on long term and short term engine duty cycle performance with graphics on how much torque your engine is producing at certain engine speeds. See if your long term graphic looks like my 425 Cummins in my 08 dynasty with a dpf.

This attached graphic represents the last 634 hours of my engine operating performance.

Then look at your short term map graphics in your report and see if you see a significant drop.

Hope this helps.

Frank McElroy, 08 Dynasty

[DJLind]

Frank,
My report has 3 graphs like this: Short Term Map 1, Short Term Map 2, and Long Term Map. The graph shapes look like yours, with the numbers within the graphs a bit different. Alas, I have no clue how to interpret any of this.

<DJL>

[fcmcelr]

Doug, the percent numbers on the graph are the percent of engine operating time within the limits of the box. So, for example, in my case, 4.1% of the time of over the last 635 hours of engine run time, was spent at between 1400-1800 RPM and was generating between 90-100% of rated torque. The page after the graphic defines peak power of 425 HP at 2100 rpm and peak torque of 1200 ftlb at 1300 rpm.

Now, if you want to see real time engine performance get a Silver Leaf, plug it into your engine diagnostic port and display data on an 8" tablet. Attached is a picture of my display. You will be able to see Load, HP, and torque under real world driving conditions.

Frank

[YC1]

Welcome to the forum. Here is my dyno test. I have an 08 rear radiator 400 ISL.

I had changed out my power stealing fixed blade factory fan for one from Source engineering before this test. I do not have before and after dyno tests for that but did some time to 60 mph tests and the difference was significant as well as felt by the seat of my pants. I lost some down hill engine braking due to much less engine fan drag. My MPG went up quite a bit too.

The picture shows the first run. Then I turned on my engine chip and you can view those results in the second picture.



A User's tinypic most recent media in Fan Kit

[DJLind]

Frank,
Thanks for the explanation. It appears then that the Map graph shows my driving habits, the effect of terrain and how the engine responds. Like your graph, mine shows the bulk of the time spent in the 1400 - 1800 rpm range with the engine torque ranging from 30% - 50%. Probably reflecting the amount of time I'm cruising down the Interstate not asking much of the engine.

<DJL>

[DJLind]

Myron,
I see that your measured HP is pretty close to rated HP. Were these measurements taken at the drive wheels or somewhere else?

Also, I hear you about the fan. I put a 2 speed fan on a previous coach and could really tell the difference. I got !10% fuel mileage improvement. When fuel was $4+/gal it paid for itself pretty quickly. At $2.50, I'd have to put more miles on the coach than I expect I ever will for it to pay off, assuming that same mileage improvement and ignoring of course the performance boost.

<DJL>

[YC1]

Originally Posted by DJLind

Myron,
I see that your measured HP is pretty close to rated HP. Were these measurements taken at the drive wheels or somewhere else?

Also, I hear you about the fan. I put a 2 speed fan on a previous coach and could really tell the difference. I got !10% fuel mileage improvement. When fuel was $4+/gal it paid for itself pretty quickly. At $2.50, I'd have to put more miles on the coach than I expect I ever will for it to pay off, assuming that same mileage improvement and ignoring of course the performance boost.

<DJL>

At the drive wheels. The thing sounded ferocious too.