diesel rpm's

[notron46]

I've been reading about the vw tdi, and the 6000 rpm range, how come cummins red lines at 3200 and the vw can go so much higher. ??????????

 

[macdaddy]

Piston Stroke!!!. Cummins is four and a half. The Vee Dub is much shorter.



I believe.



Mac

 

[HBarlow]

Yep, the Cummins inline six cylinder has a huge and heavy crankshaft, rods, and, as Mac wrote above, a very long stroke that makes torque. It doesn't need rpm to make power and high rpm would be very destructive to an engine with such large and heavy components.

 

[ENafziger]

Traditionally, engine rpm has been limited due to maximum allowable piston speeds of ~ 12. 8 m/s according to Heywood's engine combustion textbook. Thus, the larger the stroke, the lower the maximum rpm will be.

Large bore/stroke diesel engines as found on ocean going vessels will have a maximum redline of ~ 150 - 200 rpm.

--Eric

 

[TSPowell]

~ 12. 8 m/s according to Hayworth's engine combustion textbook.



--Eric

Heywood's book Internal Combustion Engine Fundamentals, VERY good reading.

 

[notron46]

rpm's

Thanks for the answer guys.

 

[BIGNASTY]

Piston Stroke!!!. Cummins is four and a half. The Vee Dub is much shorter.



I believe.



Mac

I was wondering about the stroke on our motors, four and a half thats more than I thought it was but I didnt know. I read posts that say the motor runs 3k rpm thats to high for me I dont like high RPM's in my truck just my background in trucks I guess.

 

[CharlieFoxtrot]

IDK about you late-model guys, but IIRC the 12V defuels at ~2200. Mine has mods to support 3K, and when the trans isn't shifting right, it's seen 4K!

 

[HBarlow]

The Cummins engine makes peak torque from 1600 rpm to 2700 rpm, from 1500 in some applications. There is little need to rev it.

 

[BIGNASTY]

The Cummins engine makes peak torque from 1600 rpm to 2700 rpm, from 1500 in some applications. There is little need to rev it.

Sounds good to me

 

[AWeiman]

IDK about you late-model guys, but IIRC the 12V defuels at ~2200. Mine has mods to support 3K, and when the trans isn't shifting right, it's seen 4K!

as my tractor pulling father-in-law would say, if it's got a rev limiter use it. :-laf

course the 12V in his tractor aint quite stock either.

 

[Missouri Mule]

The 12 valves 2nd gen should go to 3000 rpm but usually don't mine will go to 2750 rpm where it starts to defuel.

 

[AH64ID]

Guys are getting more rpms out of their 5. 9s, it takes stronger pushrods and valve springs. 5-6K rpms is possible but really only useful for sled pulling. 4K is pretty common for drag racing.

I was wondering about the stroke on our motors, four and a half thats more than I thought it was but I didnt know. I read posts that say the motor runs 3k rpm thats to high for me I dont like high RPM's in my truck just my background in trucks I guess.

I don't like rpms either, 2500 is about my comfort range for any extended period of time.