Engine/Transmission (1994 - 1998) RPM limit

[RHoblitt]

Since new my 98 12 valve has never hit the throttle stop, i have seen 3400 on the tach. I don't go past 3000 if i can help it. Also it has always had 26 psi of boost. When it was dynoed it read 197 RWHP. I ran it to 3000 once in 5th gear and it was still pulling when i let out of it at 100mph. Just wondering if this is unuasual or not, Richard



98 3500 Rcab nv4500 us gear under/drive pac brake borgson shaft, dr performance pump and injectors, AH1141 air filter and box, turbo shield. 288rwhp. KDP fix jan 03 ASE master tech. Oo.

 

[gitchesum]

It's strange how these trucks are.

My first truck was a slug. Wouldn't get up to 3000RPM's no matter how hard I pushed it.

My 97 would pull up to 3100 stock then it was like you hit a brick wall.



Since I've added the PDR Governor Spring Kit. It's pull higher than I ever plan on taking it.

 

[Got Smoke?]

My 97 in stock form would seem like it was running out of steam as soon as 2200RPM. Then I slid the factory torque plate full forward and that gave me 2500RPM no problems. Now I have the PDR 3K Governor Spring Kit and she pulls HARD all the way to 3000RPM Oo. (I don't go over 3K RPM for fear of floating a valve)

 

[Champane Flight]

Limit

Someplace here I read that 6000 RPM was high limit on the Cummins, but 4500 was not out of the question on a steady basis. I may be wrong. Someone chime in here.

 

[Jim Fulmer]

Crank and rods are made to rev to 5400, some push it higher.



Jim

 

[JWaters]

My truck revs 3400 with no load and it will pull 3150 in 5 th gear. It has 3. 54 rear with stock size tires, top speed in 5th is 106 on the govener. I have never done anything to the motor, still like it was when i ordered it in 96!

 

[RHoblitt]

Wow sounds like they are all over the place from the factory. Cummins told me it just like the old 327 chevys, some run better than others. I read on TDR awhile back that some guy blew his up running 4000 rpm's. I know when i drove truck before the big cam engines came out we would run the old 335 /350 cummins to 2600 and red line was 2400 i think. That was over 30 years ago and i forget. The new big cam 14 liter engines don't like high RPM they run from 1200 to 1800 or so. I guess when you have tq from 1400 to 2900 like the 5. 9 does why over rev, just grab a higher gear.