Big Cubic inch Cummins

JerrodGlover

JerrodGlover

Pulling God
Joined
Jun 18, 2006
Messages
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There is lots of talk out there about larger then stock cubic inch motors out there. Anyone willing to share there bore and stroke and how you got there?
 
I dont remeber the specifics and even if i did im sure i would be shot for telling them LOL but iirc his motor was like 412 cubic inches. Built with the intentions of making good power at 4000 to 4200 rpms for the 2.6 class.

Tim
 
Last I did the math is seems 440-460 is the physical limit of the block assuming your using a +0.040 6.7 block.

Brandon should have the info.
 
Yea the guy i talked to said it was a 5.9 block idk all the details on it but i think CSI dodge has 417ci motor
 
Why, you can't feed the engine now with a 2.6 charger and the best cylinder head.
That’s why we are shorting the stroke with the biggest bore possible in the limited turbo class.
But if you want bigger then with wet sleves a 4.5 bore is possible, just like in the LSM billet block and with a 5.00 crank would be a 476.88
With a shorter stroke and longer rod , and shorter compression height , the rod to stroke ratio would help greatly in leaving the intake valve open longer , and get more air in the engine
You need to also make power in the upper rpm range, between 4000 and 5000 , grinding metal to 5500 to get tire speed early on. The higher you push the power band , and get away from torque, the more hp possible, and longer the engine combination will live. .
 
Hey COMP461 how would going big on the bore and CI of motor do as far as the drag racing would go
 
I know a well known drag racer that went to a big bore motor...tested..and then went back to stock.....Bigger didn't gain him anything....

Ended up running his best yet with a 5.9 ...

Last I heard anyway....
 
Airflow is everything in making power, and a bigger bore, allows bigger valves, plain and simple. The bigger bore also unshrowds the valve . So if someone did not gain power, then something else was wrong.

if I was ever going to build a Cummins drag racing engine , and I can't see a reason why , I would go 4.250 bore and 4.25 stroke CR
the 4.250 bore allows a 1.450 intake valve and a ton more airflow
 
Correction on my number 438 cubes is what he has in a 5.9 block. I do know that some of the 3.0 guys are making the 5.9 into a 6.7 swinging the 6.7 setup.
 
COMP461 said:
Why, you can't feed the engine now with a 2.6 charger and the best cylinder head.
That’s why we are shorting the stroke with the biggest bore possible in the limited turbo class.
But if you want bigger then with wet sleves a 4.5 bore is possible, just like in the LSM billet block and with a 5.00 crank would be a 476.88
With a shorter stroke and longer rod , and shorter compression height , the rod to stroke ratio would help greatly in leaving the intake valve open longer , and get more air in the engine
You need to also make power in the upper rpm range, between 4000 and 5000 , grinding metal to 5500 to get tire speed early on. The higher you push the power band , and get away from torque, the more hp possible, and longer the engine combination will live. .
Click to expand...

What about classes above 2.6?
 
I'm confused, I thought this was leaning toward the Sled Pulling side of things. But I hear "we are shorting the stroke", look past the grammar and you will see that is a good idea, now just add spark plugs and a throttle body and put it in a 6800lb Light Super. If you still pull in a Diesel Class, you might want to look into what others whom took the "antiquated sled pulling technology" to the tacky pavement and are doing just fine.
 
Smokem said:
I'm confused, I thought this was leaning toward the Sled Pulling side of things. But I hear "we are shorting the stroke", look past the grammar and you will see that is a good idea, now just add spark plugs and a throttle body and put it in a 6800lb Light Super. If you still pull in a Diesel Class, you might want to look into what others whom took the "antiquated sled pulling technology" to the tacky pavement and are doing just fine.
Click to expand...

Top class tractors rival any other major motorsports with technology and data accquisition, if not exceed it...

I've heard most of the billet block guys are running 460 cubes (max allowed)
 
The CSI truck is over 400 cubic inch and flows some serious air thats why its got 2 HX 82s. There are some secrets in that engine most people would be baffled by if they figured it out.
 
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