[lt4camaro]

Any one know approximately how much torque converter slippage in RPMs there is in the A10 SS or LT1 cars ? at WOT over 6000 RPM. I have been doing a little digging to prep myself and my A10 2021 LT1 to get ready for a 1/4 mile pass.
I should be doing enough mods to trap 118 MPH and over. My set up will be with a 27.0 tall tire versus a stock OE tire diameter of 27.7 at 6200 rpm in 5th gear (1.52 ratio) I will be doing 118 mph. The program does not account for auto trans torque converter slippage, conceivably I could be going thru the traps at least 6400 rpm and I would rather not up shift or hit the fuel shut off.

[Vega$69]

I believe it will be pretty much locked up a 6200 rpm

[Drags1998]

Its not possible to measure this, However, at anything over 6K it should be locked up!!!!

[gtfoxy]

Originally Posted by Drags1998

Its not possible to measure this, However, at anything over 6K it should be locked up!!!!

There is not a transmission output RPM sensor of some sort?

At the very least rear wheel speed sensor can be extrapolated to driveshaft RPM, thusly driveshaft RPM can be determined via tire diameter & gear ratio, ergo transmission output RPM.

[lt4camaro]

Originally Posted by Drags1998

Its not possible to measure this, However, at anything over 6K it should be locked up!!!!

So no typical converter slippage at WOT at high rpm your thinking. I just cannot imagine it being like a manual trans and there is absolutely no slippage , but those are my thoughts and I thank you for yours.

[lt4camaro]

Originally Posted by gtfoxy

There is not a transmission output RPM sensor of some sort?

At the very least rear wheel speed sensor can be extrapolated to driveshaft RPM, thusly driveshaft RPM can be determined via tire diameter & gear ratio, ergo transmission output RPM.

Your thoughts are making this way to complicated, I am not trying to measure torque converter slippage at WOT at high rpm, there has to be some and am trying to get some educated guesses on how much. Is it 100 rpm, 200 rpm, etc. The auto trans cannot be like a manual where there is no clutch slippage, so if your gear ratios and tire diameter calculate MPH at a given WOT rpm, I can only assume actual RPM at WOT is higher with a auto trans.

[Norm Peterson]

Originally Posted by lt4camaro

So no typical converter slippage at WOT at high rpm your thinking. I just cannot imagine it being like a manual trans and there is absolutely no slippage , but those are my thoughts and I thank you for yours.

Assuming an OE converter, what about the lockup mechanism? Wouldn't it be fully locked up by the time you got to 5th gear?

If not, you'd have to know more about torque converter characteristics, and probably be thinking more in terms of output/input as a % than fixed rpm numbers.


Norm

[JSH]

Originally Posted by lt4camaro

Any one know approximately how much torque converter slippage in RPMs there is in the A10 SS or LT1 cars ? at WOT over 6000 RPM. I have been doing a little digging to prep myself and my A10 2021 LT1 to get ready for a 1/4 mile pass.
I should be doing enough mods to trap 118 MPH and over. My set up will be with a 27.0 tall tire versus a stock OE tire diameter of 27.7 at 6200 rpm in 5th gear (1.52 ratio) I will be doing 118 mph. The program does not account for auto trans torque converter slippage, conceivably I could be going thru the traps at least 6400 rpm and I would rather not up shift or hit the fuel shut off.

Using:
1/4 mile
6000
118 mph
84.28 tire circu.
2.73 gear

I cal'd huge slippage so something's not right

[lt4camaro]

Originally Posted by Norm Peterson

Assuming an OE converter, what about the lockup mechanism? Wouldn't it be fully locked up by the time you got to 5th gear?

If not, you'd have to know more about torque converter characteristics.


Norm

You are correct Norm, but as far as I know all automatic transmission converters slip , at WOT and at higher RPMs the converter will tighten up but still there is slippage. Also as far as I know any lock up feature is usually not operating when at WOT, not matter what gear you are in. My thoughts are even these very late model torque converters may be very tight at high rpm and at WOT but they cannot be totally locked up where there is no slippage in my opinion.

[Vega$69]

Originally Posted by lt4camaro

You are correct Norm, but as far as I know all automatic transmission converters slip , at WOT and at higher RPMs the converter will tighten up but still there is slippage. Also as far as I know any lock up feature is usually not operating when at WOT, not matter what gear you are in. My thoughts are even these very late model torque converters may be very tight at high rpm and at WOT but they cannot be totally locked up where there is no slippage in my opinion.

You're worried bout nothin.

Redline is 6500 and 7000 won't hurt it. If you trap at 6200 it will be fine.

[lt4camaro]

Originally Posted by Vega$69

You're worried bout nothin.

Redline is 6500 and 7000 won't hurt it. If you trap at 6200 it will be fine.

My concern , not worry , is a upshift by the auto trans, or hitting the rev limiter which I believe is at 6600 RPM . Not a good scenario for a max effort 1/4 mile pass. Trapping at gear ratio, tire diameter calculated 6200 RPM is not going to be actual RPM with a auto trans due to slippage I think.

[KingLT1]

There is no converter slip on the A8/A10 transmissions since the factory converters lock at WOT in all gears. Aftermarket stuff doesn't lock till 4th/5th gear.

[lt4camaro]

Originally Posted by KingLT1

There is no converter slip on the A8/A10 transmissions since the factory converters lock at WOT in all gears. Aftermarket stuff doesn't lock till 4th/5th gear.

That KingLT1 is certainly great to know, I thank you sir. Driving my 2021 LT1 for (just turned 1500 miles today) the past 2 months and have been doing enough WOT pulls , I came to the conclusion there isnt much torque converter slippage at high RPM, you just confirmed that and even better that the converter locks up at WOT in any gear. Today I did my first manual WOT shift very close to redline at the 2-3 shift and the trans does indeed shift quick, virtually no delay . All good to know if I decide to let it shift by itself or If I manually do it in manual mode.

[grampa_ss]

If WOT, let the trans do the shifting.