at what RPM does the Eaton start LOSING power
At what RPM does spinning the EATON become counter=productive?

I'm upgrading my pulley from a 3# and I'm not quite sure what to go with.

I like the idea of a bigger pulley and lowering the Engine RPM shift point. I figure with the lower ENGINE RPM it will be less stress on the internals. Plus with the Eaton spinning quicker I'll have a little more power down low.

Also, I'm thinkin' of sending my Eaton to APTEN to have some modifications and make it flow better.

So if I can figure when the EATON runs out of steam, I can go from there with Winter Mods!

Remember I'm running stock 3.55 gears in the rear end.

SO at what Eaton RPM does it become counter productive!


__________________
friends don't let friends, drive stock!
------------------------------------------------

Ford voided my warranty for put aftermarket AIR in my tires.

 

ttt

 

You remind me of me

Your gonna get diff opinions and diff answers on this one.
Yes the eatons can only take so much, lets say MOST of us
will tell you 4lbs is optimal. And I have to tell you every program I ever had shifted at a min of 5500 RPM and now as much as 5700-6000 and I have great power the whole way.

Yet the fact is people like Gator, Vinnie and soo many more were and still are ripping consistant 11's on stock blocks with up to
8lbs of Pulley. V now has a built block)
Is it optimal in summer heat at WOT at normal operating temps,
prob not, but when properly cooled down, prepaired, and launched at the track, that bad boy is gonna run 11's all day.
So first undestand that the more boost you add will make you faster even up to 8lbs. But is it overspinning and under certain situations even overheating the Eaton, maybe,
maybe even probably ?

Personally I have actually found that I run faster with 4lbs of pulley than I do with 6lbs. I have actually had better ET's for two full racing seasons now trying both ways. However last Friday I did finally get into the 11's and in a fairly big way with a 11.81 buy using 6lbs of Pulley and 75HP of Juice. But I did also run Multi 12.0's using only 4lbs and at the time I had 10 less HP of Nitrous jets in the tune, so I do know I would have run 11's with the 4lbs if I had tried it that way. My situation is differant with the juice cause I'm squirting sub Zero into the Motor and keeping the inlet temps way down as a result. But on ALL Gasoline the fact remains I run better with 4lbs.

Your safe with 4, and thats what I would reccommend

 

Oh one more thing

Think of the RPM and shift points this way
And anyone who knows will tell you the same

It's MUCH more important where the RPM's are AFTER the shift

To KEEP IT in the power, the optimal RPM for shift points is gonna
be lets say 5250 RPM to 5500 RPM.
Of course alot of that depends on what Mods you have, how much power you wanna squeeze out of it, and what ET's your shooting for. Obviously you wouldn't want a stock L shifting at 5700 RPM. Without a Chip, modified timing, shift points, rev limiter, torque reduction, tip in, etc, it would be worthless, and unnecessary stress on the motor, especially if you don't have aftermarket pulleys, T/B, Chip, etc....

 

Rob thanks alot.

I'm thinking of having APTEN modify the eaton this winter.
so it will flow a little more air through it.
I figure the 3# lower I have just isn't going to be enough.
I'm thinking just adding a 2# upper (5# total)
But I'm waiting on the dimentions of the upper pulley, so I can put it into my equasion so I know where I'll be.

Other mods:
phenolic spacer,
NGK plugs,
Airaid intake (upgrading to JLP Ram Air),
90mm MAF,
upgraded intercooler (non-leaking model)
I'm adding an E-fan with CObra R water pump in 6 days.
Superchip Flip Chip. Street/race (100 octane)
Factory Tech V/B with deep tranny pan
160 degree thermostat.
Oil sperator with Dime in the tube.
Lakewood traction bars (upgrading to lift bars this winter)
Hoosier slicks 28x10x16.
MAC Cat back Exhaust (might go full exhaust this winter)(maybe?)



I'm thinking with another 2-3# of boost (5-6 total) and the Apten modificaitons to the S/C, I should be where I want to be.
Mid 12's.
the power I put out doesn't matter to me, as long as I can hook up and go!
I'd rather put out 300hp and run 12's than 500hp and run 13's.

Before the Phenolic spacer it put out 389.7rwhp and 497.? rwtrq.
this was on the street side of the chip. (didn't have 100 octane fuel to run "race" side of chip)

The best it has run is a 13.056 and then a 13.058 back to back, without cooling down.

what other modifications do you recommend?

 

also what about my theory that with a 6# I'll shift at a lower RPM than now with the 3# and therefore prolong engine life.
Lets say now I see the stock tach occassion hit 6000rpm's before shifts, with the 6# I'd like to lower that substantially

 

so rob what you are saying is an 8lb lower and 1lb upper is too much for me on a stock eaton?

Please inform me as to how you come up with your hypothesis

 

Thats simple Spanky --> DRUGS, waaaaay too many of them


http://www.timskelton.com/lightning/.../dyno_data.htm

Like I said bro, More Boost equals more power and BETTER ET, Tons of us have proved it. However I've also proved for guys that have NO colling mods, meaning aftermarket Electric fans, Cobra Pump, Intercooler fan switch, Larger Intercooler Heat exchanger, maybe a seperate fan for that, icing the upper between runs, etc, will actually AT SOME POINT go slower with more than say 4-6 lbs of Boost, (especially if hot lapping in the Summer Heat)
All we're doing at that point is throwing more hot air in, and in some cases creating dangeous cylinder temps. The reason is because we're actually over spinning the Eaton past it's optimal performance point.
Where that spot is, everyone seems to differ on.

I love my Eaton and quite frankly think the reliablity is UNTOUCHED. But they were only made to do so much.

Thats why with a KB or Works you can run less timing, less Boost, and have waaaaaay more HP. Because it's displacement is larger, it's more effecient, and it creates more HP Torque and Power without over turning it, or over heating it. It's bigger and better.

When running more Boost, the actual danger comes from Cylinder Pressure not necessarily RPM. In most engine failures, you can pretty much always blame it on some kind of Detonation that was caused be excesive heat in the cylinder.
Thats why with the more boost you have, the more it's extremly important that your not running too lean, or that your Plugs aren't too hot. You need to burn high octane, the correct amount of Fuel, and also dissipate as much heat as possible in the cylinder so all that extra cylinder pressure can equal HP and not extra heat.

Like I said, I once ran like (6) 13.3's in a row, then put the stock size upper on (took away 2lbs of boost) and immediatly ran 12.8
From that point on I raced only with 4lbs (up til Friday that is)
But I still run 6lbs on the street 24/7 and Love it

Of course this is just my take on it, what do I know ???

 

for me it seems like my boost and power just seems to flat line at 4400 rps at 15.5 lbs of boost using a 10 lb lower asp upper. but with my ported heads i did loss about 3 psi of boost before and after.

 

Rob,
whats the diameter of that upper pulley I am thinking of buying?

With that I can figure out exactly where the Eaton RPM's will be at certain Engine RPM's.

then I figure out hte rest of winter mods

 

I have the SFPH Dial-UR-Boost Quick Change Upper System
I have 2.93" & 2.80" pulleys for the hub.
2.93 adds no boost and 2.80 is 1-2lbs

 

The gains are linear up to a 4# pulley. After a 4# pulley the gains start to tail off.

High Roller did all of the work in figuring this out as he dynoed everything one at a time on his second L.

He dynoed a 2#, 4# and 6# pulley. He gained an extra 8 HP and 24 ft. lbs. of torque for every 2#'s he went up in size. After the 4# pulley the gains were cut in half with the 6# pulley only gaining an extra 4 HP and 12 ft. lbs. of torque.

This proves that the Eaton doesn't start running out of steam until somewhere above 4# of extra boost. Apparently after this point the amount of extra heat generated starts really cutting into the extra power that is generated.

I based my decision to stop at a 5# lower on this REAL WORLD data. I figured the extra heat for the smaller amount of return was not worth it on my stock block.

Check this old post out:

Pulleys Dynoed

 

Remember, the numbers you are discussing are for peak rwHP, not "area under the curve."

If the engine redline were 3,000 rpms, I'll bet the gains would be more linear way past a 6 lb. pulley.

 

That is correct.

If a frog had wings then he wouldn't bump his a$$. j/k

 

Mr I-Menace;

I noticed that you're planning on installing a Cobra pump. This probably won't apply to you - but when I went to install my pump, I discoved that when removing my original pump pulley to get at the original pump, the pulley wouldn't clear my 6lb lower blower pulley. I just hadn't thought it happening. So I had to take the blower pulley off to install it. I'd guess the pump pulley will clear a 3lb pulley - but you mite be prepared to take it off just in case.