correct engiine RPM'S

[DavidD]

Correct Engine RPM'S

Was in the local Cummins store today and picked up the Cummins Power Booster News. Though it was interesting on the back page they talk about the ECM up-date for the ISB. 300HP and 660 ft. lbs. of torque with the ecm modifications. They also mention that many drivers shift the 24VALVE engiines to soon and do not tap the engines potential. The article recommends 2,500rpm's is not excessive and in fact the engine is made to run at that speed.



My son (who is 24) was drive my truck last week and he tended to shift at about 2000rpm's. the truck because of the mods I have wouldmake the transmission shutter at about 1400 to 1600 rpm's because of the torque. i told him to rev it to at least 2300 before shifting. What a dif. I have been shifting at 2300 to 2500 for some time know and the truck seems to really like it. Just thought this might be helpful info for some new TD owners, Dave

 

[Vaughn MacKenzie]

Dave, I think there is no specific or "right" RPM to shift at. It depends on how you are driving and if you have a load.



Like tonight when I was messing with a punk who thought he was real bad in his tricked out Chevy 1/2T. I was shifting at 3000rpm racing him. He didn't seem to appreciate it that he couldn't outrun a diesel up to 60mph. We were dead even from 25-60, and judging by his major burnout at the next light he didn't like it too well Oo.



When I am puttering around town and not racing Chevys, I shift by 2000rpm and cruise around 1500-1800rpm.



Anytime I mash it though I like to be running at least 1800rpm. If I am towing I like to keep it above 1900.



Vaughn

 

[Chipstien]

Humm, ECM update

I wonder if the ECM update would improve your numbers when you already have a Edge Comp. Does anyone know the answer to this?

 

[THancock]

I just loaf mine around town 90% of the time, shifting around 1700 and freeway cruiseing at 65mph @ 1850. I catch myself driving along city streets @ 11-1200rpm. I've only reved mine above 2500 about a half a dozen times or so. Has anyone heard one way or the other if short shifting has any ill effects?

 

[DavidD]

Thanks for your input. I to shift around 1800 often if I am light on the throttle. The article also states that many TD owners wait till they start to lose speed on a hill before down shifting to maintain speed. I have seen this time an again towing with friends in there PS's as I leave them behind on the hills. i used to frive big rigs when moses was around so I now when to shift but there are a lot of new TD owners that drive it like a gas engine. This article points out some important dofs. between the diesel and gas engines. Dave

PS I am going to call Cummins today to see about the ECM update I will let you know what happens. Dave I dont think short shifts hurt anything. I know with my truck if I nail it in fourth or fifth at to low of rpm the transmission makes a nasty growl which I have been told is the gears vibrating that are not being used? dont know for sure. Dave

 

[rashwor]

Keep us posted on the 300hp ECM

Way cool if it is true for our engines... 300 & 660. Keep us posted!



Can you say, "Part number, please?"Oo. Oo.

 

[jtisdale]

whos program?

Originally posted by DaveD

Was in the local Cummins store today and picked up the Cummins Power Booster News. Though it was interesting on the back page they talk about the ECM up-date for the ISB. 300HP and 660 ft. lbs. of torque with the ecm modifications.



I wonder if that is for ECM's running Cummins programs in other trucks. Our Dodge ECM's are programmed by DC. :{ I almost cant believe Dodge would offer anything of the sort. Keep me posted though, it sounds interesting.

 

[Jumbo Jet]

When pulling a load with my 5 spd. , I always shifted at around 2500-2700. It was the RPM loss and resultant power/torque loss that concerned me more than the top RPM.



With my automatic, I will have to figure that out all over.



These trucks can run all day at 2500-2700 without a problem and probably higher. They just get more thirsty.

 

[ghalim]

Bought my first diesel at the end of January this year. A 2001 Quad 4X4 H. O. w/355 diff. Loving every minute of driving it! Around town no load I'm shifting about 1800 to 2000 RPM. Generally I shift to 6th about 45 to 50 when getting on the highway. What do you more experienced H. O. drivers find is your best RPM shift patterns and 6th gear speeds?

 

[Diesel Freak]

Re: Humm, ECM update

Originally posted by Chipstien

I wonder if the ECM update would improve your numbers when you already have a Edge Comp. Does anyone know the answer to this?

the short answer... . NO!





the long answer... the edge comp on 1/5 is basicly an EZ and therefore you are already using the VP44 to its full potential which is what the 300 ISB program does.



once you go above 1/5 you are over riding the ECM parameters with the maps in the Comp (exceeding the pre programed pump limit ie. duty cycle on the solenoid)

 

[dan_gilson]

The questions on short shifting: I tended to do this for the last 60K+ miles. I have seen no ill effects.



I have been edging it up and it tends to improve milage a little. In thinking about it, the HP sweet zone is from 2250 to 2700 so it make sense that you are running more efficiently in that range.

 

[Chipstien]

once you go above 1/5 you are over riding the ECM parameters with the maps in the Comp (exceeding the pre programed pump limit ie. duty cycle on the solenoid)

Well so much for that Idea. Oo.

 

[Piers]

You guys can always put a P7100 pump on your 24 valver, then ya could smile all the way to 4000rpm's:--)

 

[rashwor]

Piers

And ruoghly what is the cost of the P7100 pump? I would still want it toned down to 3200 or so max.

 

[DavidD]

It sounds like we all have our own shift pattrerns. the article mentions shifting at 25-2700rpms when approching a hill dont wait till your rpm's drop to shift. Take advantage of the hp before engine speed drops. Many drivers coming from a gas car or truck new to the towing world dont know this. If you ever owned a VW bus vintage 1957 as I did you learned young to shift early or die! Dave

 

[jtisdale]

Hey Dave D-

Any news on the ECM upgrade? Does it apply to our ECMs? Side note: I did see an upgrade for the 12 valvers on the cummins website.