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Tranny pump efficiencies.

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Old 09-14-2007, 11:57 AM
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Default Tranny pump efficiencies.

I am wanting to know at what point the efficiency drops in the transmission pumps on the following

4T60-E
4T65-E
4T80-E

I'm looking for the highest reving, most efficient pump setup possible.

Thanks in advance.

Additionally, I would like to know why it is said that you should not/cannot run a cam with 1.9 ratio rockers.

Thanks again!
Old 09-14-2007, 12:07 PM
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Combined lift runs into dangerous territory where the piston can smack a valve if the Rocker ratio is too high on a higher-lift cam.

It'* generally kinda bad to have your valves and piston clapping hands together. The good news is they won't do it for very long.

Valvespring coil bind would also be another potential concern.
Old 09-14-2007, 12:25 PM
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I can understand the piston slapping, and it will be accounted for with valve timing. Coil binding won't be an issue if I have my way

Thank you Mr. Wren!!!

What is the most cam lobe lift the 3800 series 2 block can physically accept(fitting through the cam bores basically)? That might be something I have to find out by trial and error, but I'm hoping someone knows so I don't have to do that.


That'* part of the equation. Now for the tranny part. Anyone? Bueller? Bueller?
Old 09-14-2007, 12:37 PM
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I did some digging on the pumps (rpm ratings/rates) etc, with no luck so far.

I can't tell you about the L36, which is what I'm assuming you're asking. Deck height is different than my motors.

I actually have the GM fully-detailed prints of the S1 L67/L27 (second gen 93-95) cylinder heads. That'* what you really need to calculate the lift with rockers and cam specs before the piston hits a valve.

But my info won't do you much good. I'm sure the information is already out there. Try searching on 3800pro.
Old 09-14-2007, 01:14 PM
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Roger dodger! Off to 3800pro with me. I'll keep checking here, and if someone is interested, report back what I find(if anything). Yes, the intended subject is the L36.
Old 09-15-2007, 02:26 AM
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I've read the efficiency drops @ 4800 rpm for the 4t60-e. I can't tell you where I read that though as it has been at least 3 years. I've also seen it discussed how the 60-e was a poor choice for the rev happy LQ1 and would often have problems.
The 4t65 has been reved up to 7k by various GPers, both on n/a and turbo applications.
I reved my 60-e up to 6600k and it didn't last very long. It just dosen't make enough pressure up there. After a while it didn't have enough pressure to shift and would just hang out up there.
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