ISB Questions

[RedRam1]

Hello everyone,

I have been a Cummins Ram owner and TDR member for a few months now. I've learned a lot since joining up, but there's still a lot I don't know. My questions pertain to the 24V 5. 9L "electronic" motor (ISB). Here's a list of questions for the experts.

1. What are the specs for the 275HP "RV" version of the ISB? Is it a 24V head?, VP44 pump?, What other differences are there compared to to the engine on 98. 5 & up Rams?

2. I know some version of the "B" series Cummins is available in larger F-series fords. What are the vital stats for this motor? Is it an electronic, 24 valve version similar to the RV? What is the rated HP/torque?

3. What other versions of the ISB are there? i. e. Marine, Stationary power, etc. ?

Thanks for the help, I'm trying to broaden my Cummins Diesel knowledge base, knowledge is power!

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2001. 5 Flame Red 2500 4x4 Quad SLT SB ETH/DEE 3. 54LS 241HD

 

[hammong]

I'm fairly sure that the RV version of the ISB is identical to the one in our trucks, except for 275 HP injectors and different fueling computer programming. Still has the "electronic" VP44 pump and 24-valves.

The ISB is available in the F-450 trucks, though I'm not sure about the HP/Torque specs for an engine in that role. No doubt the transmission is better... . #ad


Greg



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Y2K Dodge Cummins QC 2500 SLT Laramie 4x4 Long Bed, 4. 10/Auto, Forest Green/Driftwood, 265x75R16 Michelin LTX, 6 speaker CD, Camper/Tow/Plow Packages, Westin Black Nerfs, Mopar bedliner, Ultra bright diamondplate toolbox, K&N Filtercharger, Autometer Ultralite EGT and Boost gauges in 2-gauge pillar w/tweeter, DD Stage II injectors, boost module, and boost elbow. Yee haw!
http://www.rints.com/hammond for photos!

 

[Vaughn MacKenzie]

RedRam1, just go to Cummins' website, a lot of your questions can be answered there: http://www.cummins.com

Vaughn

 

[MikeR]

The ISB that I've seen in the Ford F650-750 is the 195hp version.

 

[Vaughn MacKenzie]

It looks like the most potent B-series is the Marine 12-valve, rated at 370hp. There are some recommendations to not run at full HP & RPM of 3000 for more than 1 hour out of every 8. . . I guess that is reasonable!!
http://www.cummins.com/na/pages/en/products/marine/recreational/370b. cfm

The strongest 24v rating is the 300hp/660tq RV application.

 

[RJRobb]

The difference is pistons, heads, turbo, injectors and programming. Piston has a different design, heads are two piece instead of one (different heat rating), spec is different for the turbo and injectors (this version of the ISB has peak HP at 2200 RPMs and are governed out at 2500 RPMs), different ECM fueling and injectors. Oil capacity on these engines are 16-17 quarts.

 

[Evan A. Beck]

Vaughn, don't forget about the QSB5. 9, which is basically the industrial version of the ISB. It is rated at 320+ HP, not sure on the torque...

The ISB in the pickups is one-of-a-kind compared to the rest of the ISB lineup. The ECM programming is very different, and many of the standard ISB features are eliminated on the Chrysler version.

SOme different physical traits of the RV ISB include a different exhaust manifold, fuel line plumbing, and fuel line size. The RV's I work on from day to day, all have 1/2" fuel lines. Interestingly, I have seen ISB's with 2 fuel filters. One on the suction side of the lift pump, and the other in the standard location. I did a fuel pressure test just for fun, and found the pressure never went below 7 psi. You'd think it would be lower with 2 filters in the system. Plus, this particular RV weighed in at 30,000 lbs, and I did the test on an 8% grade @ WOT. The lift pump is the same as on the pickups, just different fuel line size up to the lift pump. All banjo bolts are the same. One more thing, the lift pump is often 10+ feet from the tank.

Some other differences between the Chrysler ISB and the RV ISB are programming. The timing on the pickups is extremely different from that on the RV's. You can just tell by listening to the motor. The boost is limited to 20 psi on the pickups, whereas there is no limit (other than the wastegate) on the RV's. I have set wastegates on the RV's to 40 psi, and they run great at that level. Also, the EGT's are considerably lower on the RV's, even with more weight, than on the pickups. The reason for that is the injection timing. Another difference in the ECM is the RV's have a dual 50-pin ECM, and the pickups have just a single 50-pin. Features deleted from the pickups include:

--Cruise/PTO control
--Idle control
--Remote accelerator
--Fan clutch output
--A/C pressure switch (for fan clutch)
--4 diagnostic lamps
--Coolant level sensor

**Also, the RV ECM's use two different electronic protocols, a J1587 and a J1939. The pickups just use a J1939.

The ETH High Output in the present 6-speed trucks is very close to the ISB's used in other applications such as school buses and RV's. The timing curve is slightly different, and the compression ratio is a little higher. Also, the cylinder head on the ETH resembles that on the RV's with the valve seats, etc. RPM is limited to 3,400 on the ETH/ETC, but on the RV's you can't push it beyond 2,700. However, the powerband on the RV's is very different, and there is much more toque avialable at lower RPM. I guess Chrysler decided to try and preserve the life of their transmissions by de-tuning the ISB... #ad


Oil pans are also another story on the RV's. I have seen about 4 different styles, ranging from a front-sump 13-quart, to a rear-sump 18-quart. Just depends on model and CPL. Oil fill location is also variable... Some have it in the valve cover (front or back) and some have it in the top of the crankcase breather fitting. Another model/CPL issue there too.

All in all there are dozens of versions of the ISB available, from a mild 185HP/420TQ up to a ground-shaking 300HP/660TQ. The most common, by far, is the ISB 275.

Hope this answers your questions... #ad

 

[Evan A. Beck]

Forgot to add something...

ISB in an F450? I don't think so... I know it is available in the F650 and F750. The only Cummins I know of in a light duty Ford is a B3. 9 mechanical in an F350, and that's in Brazil.

If this ISB in an F450 thing is true, where the heck are they? Seems it would be a popular rig, great for hauling...