RPM Drop - What do you think?

[Jerryl]

with the brake on and @ 3000 RPM you are @ 15 psi?

Yes

What RPM are you @ just when the boost gage starts to move off 0? I believe your convertor is way lower than 2800 stall. IMO. Best of luck.

2200


In summary:
0/0 2200 (Trans Brake test)
6 psi - 2800 (Trans Brake test)
15 psi - 3000 (Trans Brake test - Max RPM is what I was looking for here)

I have decided to take the converter out and send it back 4 a restall.
Hopefully it will reduce the RPM drop.

Thanks for all the input and feedback everyone!

 

[Lee Thompson]

Imo

0=2200 rpm-- there is your stall speed, or close to it.

 

[Jerryl]

0=2200 rpm-- there is your stall speed, or close to it.

Update:
Called the manufacturer today and apparently, manufacturers may have different definition and standards for “Stall”.

My TC stalled according to the MFG specs,
2800 @ 5 psi
3000 @12 psi

So the converter is manufactured to “this manufacturers” definition of stall and is “manufactured to their print”.
Therefore there is no discrepancy on my TC, according to the manufacturer and "it works as it should".

Other manufacturers probably define stall at 0/0 and would have had the TC at
2800 @ 0/0

The lesson:
Talk to the manufacturer BEFORE you order to make sure you understand THEIR definition of stall, so you get the converter YOU want/need.

 

[wickedtt]

Update:
Called the manufacturer today and apparently, manufacturers may have different definition and standards for “Stall”.

My TC stalled according to the MFG specs,
2800 @ 5 psi
3000 @12 psi

So the converter is manufactured to “this manufacturers” definition of stall and is “manufactured to their print”.
Therefore there is no discrepancy on my TC, according to the manufacturer and "it works as it should".

Other manufacturers probably define stall at 0/0 and would have had the TC at
2800 @ 0/0

The lesson:
Talk to the manufacturer BEFORE you order to make sure you understand THEIR definition of stall, so you get the converter YOU want/need.

What brand it this ???what size??

 

[Jerryl]

Just some feedback for future searches.
The TC was re-stalled and RPM drop is right around 700.
It's like a different car now.

Thanks again to all who replied!!

 

[Gen1]

Great info. here.

 

[bison]

Just some feedback for future searches.
The TC was re-stalled and RPM drop is right around 700.
It's like a different car now.

Thanks again to all who replied!!

How is the efficiency on the top end. Better, worse, same? Try to post some actual mph/rpm numbers and if they are under the same boost.

 

[Jerryl]

How is the efficiency on the top end. Better, worse, same? Try to post some actual mph/rpm numbers and if they are under the same boost.

Man, I did not realize you asked some questions.
Anyway, here is some data. I STILL think something is up after reviewing logs for about 2 weeks.

Under a full throttle run. Shifts out of second:
5100 @ 61 MPH (26.6" diameter tires)
RPM drops in third to: 4250

To verify slip% in third gear (Unlocked, same run)
4475@75MPH
According to my calculator - 38% slip (hmmm)
No wonder it seems like the car does not pull.
What's next? :smile:


Edit
I am unsure what the previous boost #'s were during testing.
I now have PLC, so MUCH easier to keep track of this.

 

[bison]

Man, I did not realize you asked some questions.
Anyway, here is some data. I STILL think something is up after reviewing logs for about 2 weeks.

Under a full throttle run. Shifts out of second:
5100 @ 61 MPH (26.6" diameter tires)
RPM drops in third to: 4250

To verify slip% in third gear (Unlocked, same run)
4475@75MPH
According to my calculator - 38% slip (hmmm)
No wonder it seems like the car does not pull.
What's next? :smile:


Edit
I am unsure what the previous boost #'s were during testing.
I now have PLC, so MUCH easier to keep track of this.

That slip % is not unrealistic at all. Mine slipped more than that at that mph with the buildup in my sig. The cam you have requires rpm between 4800 and 5700. Id bet if you revved to 5700 the slip would come down to around 10%. Mine still slipped 13% at 6100 rpm at 130 mph. I needed a better converter. You would be better off with less cam and a tighter converter in your application imo. Your better off keeping the rpm down with the hot air set up and the turbo you have.

 

[Jerryl]

That slip % is not unrealistic at all. Mine slipped more than that at that mph with the buildup in my sig. The cam you have requires rpm between 4800 and 5700. Id bet if you revved to 5700 the slip would come down to around 10%. Mine still slipped 13% at 6100 rpm at 130 mph. I needed a better converter. You would be better off with less cam and a tighter converter in your application imo. Your better off keeping the rpm down with the hot air set up and the turbo you have.

Thanks for the advice!
Talked to my trans guy and he said the same thing. Always good to have a GREAT tranny guy!

I am also just now realizing there is a problem with my combo.
Time for the next build. :biggrin: