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Discussion Starter #1
Gear ratio in a tractor puller. My peak horspower is around 7500 rpm, and peak torque is around 6000rpm. The engine is a 526 bbf making 950 hp and 765lb-ft tq. With the gears I am currently running, the engine wants to turn between 85-8800RPM. If i run 82-8500 on the big end, it actually kills the engine rather than pull down and spin out. I am wondering if the load from the sled is hitting so quickly, that it is falling through its peak and killing the engine? Any thoughts?

Thanks Mike
 

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Well Mike your going to have to let us in on your total set up . rear ends used, Rearend gears, tranny used, transfercase used, are you able to change gearing or are you just stuck with one combo...

Then what's your engine parts list look like .... Cam timing and Block, heads and intake used, Internals parts...


We can help.....

I turned my 528 to 8900 Rpm's once and that's the last time I'll do that ..Seems you lose the valve springs faster when you buzz them that high...One puller was only getting 3 runs out of a set of springs buzzing his to 9000 each run.
 

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Discussion Starter #3
combo

My combo is this:
526 CI
premier block
eliminator heads w/ jesel rockers 1.8 ratio (done by Jay Cornell)
diamond gas ported pistons 4.440 bore, 14.5-15:1 comp ratio
grp alum. rods
4.25" stroke from raw forging crank machined by moldex
LSM camshaft: Not real sure, did not receive cam card from engine builder
60mm journals
945 lift at valve in
920 lift ex
286 in dur
302 ex dur
115 lobe centerline, installed at 111
LSM springs
Tit. In valves and Stainless Ex. valves
The class I pull in is an Economy Mod. class:
E-4 Co-op tractor rear-end
titan 2 disk slipper clutch
scs twincounter shaft single speed transmission
30.5 x 32 in puller tires single cut w/ 1/2" lug
Last year with my other engine, I ran 47.29:1 and turned around 76-7700 RPM. This year hear I have went up to 44.54:1 and still turn 85-8800 rpm.
I am just wondering if I am thinking straight, that I need to get the engine back down to where it is making power, not up in the rpm range. Is it possible for the engine to fall too fast and fall right through the power band, not using the torque that the engine is making.
Any thoughts!!
Mike
 

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Well funny you bring this up .. Was drinking some beer with the boy's after a pull a few weeks back and we got on the subject of gearing ..

And it was suggested that the ideal gear was one that would let you go say 500 Rpm's more then your goal.. so when the weight hits you it pulls you back into your Rpm's range and that helps you out the end further.


Now it seems your way out of that now, so to get you back to your Rpm's range I'd say your going to have to get to 40.762 to 1 too a 38.897 to 1 to hold your Rpm's in check..


What kinda wheel speed you guys running and what's the rear gear ratio in that E-4 Co-op Tractor rearend .
 

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Discussion Starter #5
co-op rearend

The gear ratio in the rear end is 33.79 to 1. I have a 1.217 headset and a 1.083 quick change in the tranny. I figure at the 8500 rom it is36.3 at the 8800 it is 37.6 mph. I have asked some of the other guys in the club, and if they are telling the truth, they are turning around 31-33 mph. I was thinking along the same lines as you on gear, I figure some where between 38 and 41 to 1 was where it would need to be to get my Rpms down to maintain the same wheel speed.
 
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