gov. spring questions

[KTA]

My pump must be fubarred. It has the 386 spring at it fuels past 4200rpm, and I have the only 4000+rpm 1st gen dyno sheet to prove it.

[bgilbert]

My pump must be fubarred. It has the 386 spring at it fuels past 4200rpm, and I have the only 4000+rpm 1st gen dyno sheet to prove it.

That's cause you drove it on Dunbar's dyno . Dave woulda let off it at 3200ish when the power fell off .

Guys, a dyno sheet will tell ya what's goin on, when the pump defuels etc. Sure a stock governor setup can rev to 4000 in neutral, (modified linkage, high idle screw backed out etc), but making power above say 3200rpm is tough.

I think the only reason KTA was still making power at 4k (not much from what I seen ) was because he was making SO MUCH HP already at 3000-3300.

Until I see someone prove (dyno sheet) that ANY modified spring will hold the HP curve well beyond 3200rpm or keep it straight etc, I say wipe your blanks with it. 3200rpm spring be done with, look to other means of raising the bar.

[KTA]

Mine goes from 575 at 3400rpm to 350hp at 4200rpm, and its not because the governor is cutting fuel back, its because the pump output is down because it cant fill that fast. At 4000rpm the pump plunger is moving 12000 strokes per minute. That is one injection event every .005 seconds. It is very hard to get 300mm^3 through a .060" hole in .005 seconds. When I race I always shift around 3400 or so because the power just isnt there above that as the pump is oversped.

[Greenleaf]

Yes. Thank-you. Exactly what I was attempting to convey when I mentioned the 3200 spring is adequate and a modified 3200 is an overshoot.

That clears things up.

Sometime when I R&D it don't pay. Sometimes it will. A crap shoot.

[Fnschlaud4620]

Thank for the responses guys,

I think I will get a 3200 spring for mine aswell. Why do pullers run 5000 and 6000 rpms? do their pumps have enough fuel to rev that high, or is it to obtain wheel speed to get further down the track?

[KTA]

A P-pump or other inline pump has 6 pumping units vs one for our pumps. Therefore they have theoretically a 6 times longer fill time than our pumps. Most inline pumps will actually be fueling more at 4500rpm than they would at 3500 for the same rack travel because internal leakage becomes less and the delivery valves become less of a factor. A good inline pump like a Sigma can run 6000+rpms and still make power. The reason sled pullers turn big rpms is because we are displacment limited so the only way to make more power for a given boost is to flow more air, which means bigger cams and heads and more rpm. That is why Nascar motors run 8000-9000rpm ist because thats how they make more power with limited displacment. If they had bigger motors they could make the same power at a more conservative 6500 and live longer but thats not what they have to work with, just like we dont have big cube motors to work with.

[RedneckCumminsLover]

what exactly does the governor spring do? can I run my truck with out it or do I have to have it to function correctly?
thnks

[moose5.9]

3600 rpm is a 082 (460-416-082)

Is this PN a cummins #?