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1,150+ rwhp club
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Discussion Starter #1
Lately my auto has been hitting the rev limiter 2 or 3 times between shifts 1 to 2 and 2 to 3. It only happens at WOT.

Is she fried? Don't know the signs of a bad auto.

Background info...
stock auto
after market stall
sp67 full kit
fuel
~1.1 bar on pump
 

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That stall could be doing it. Is it a new addition? What's the stall speed? Are you on the stock rev limiter?
 

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1,150+ rwhp club
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Discussion Starter #4
VeilsideTT said:
That stall could be doing it. Is it a new addition? What's the stall speed? Are you on the stock rev limiter?
PI 4k stall. about 4500 miles on it. 2 trips to the track with it.


Yes for stock rev limiter.

I know the auto is a time bomb, but I just don't know the signs of a bad auto. All the searches basically said "upgrade auto bla bla bla" with no real symptoms other then rev limiter.
 

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See if you still hit the rev limiter if you can run lower boost.
Check your tranny fluid. Are you running an extra tranny cooler? The tranny fluid runs really hot with a stall that big.

Long,
 

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Your stall + not enough traction is likely overpowering the shift.
I wouldn't necessarily say you have a tranny problem.
What kind of tires are you using?
 

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1,150+ rwhp club
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Discussion Starter #7 (Edited)
supratt320 said:
See if you still hit the rev limiter if you can run lower boost.
Check your tranny fluid. Are you running an extra tranny cooler? The tranny fluid runs really hot with a stall that big.

Long,

on 1 bar I hit the rev limiter about 1-2x for both 1-2 and 2-3.
on 1.1 bar I hit rev limiter about 3-4x for both 1-2 and 2-3.

2 extra coolers with puller fan.

Checked the tranny fluid. Full and redish/pink color.

Side note - This is the first time I've run anything other than a 19" tire. This last week I put on a set of et streets and went out playing and practicing launching. I used to spin very badly on street tires. With the et streets it was a small bark and go! Could that extra stress have sent her over the edge?
 

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1,150+ rwhp club
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4,438 Posts
Discussion Starter #9
supratt320 said:
Did this happen right after you installed the turbo kit or was it a while afterwards?

Long,

~6 monthes. I have not been to the track yet with the single kit on. Really only 2 hard nights on the street (22psi 110octane). The rest is normal driving.
 

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I don't think there is anything wrong with the tranny, it just comes down to the fact that it can't shift fast enough with the new found power and the torque converter.

Long,
 

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Agreed. That turbo and stall are probably moving through those RPMS so much quicker than the stock setup. I'm sure the problem is worse when your spinning right?
 

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1,150+ rwhp club
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Discussion Starter #12
VeilsideTT said:
Agreed. That turbo and stall are probably moving through those RPMS so much quicker than the stock setup. I'm sure the problem is worse when your spinning right?
Actually the problem seems pretty constant whether I spin or am hooking.
 

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its a slow auto...
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my car started doing the same shortly after i put my 67mm on and was still using the stock tranny and converter.. a couple 19-20psi pulls and it started to do it, then after that anything over 13-14psi would make it hit the limiter between shifts.. if i turned the boost down to say 11-12psi it stopped.lol.. your converter probably isnt helping the situation either..

jay
 

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1,150+ rwhp club
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Discussion Starter #14
jaynite said:
my car started doing the same shortly after i put my 67mm on and was still using the stock tranny and converter.. a couple 19-20psi pulls and it started to do it, then after that anything over 13-14psi would make it hit the limiter between shifts.. if i turned the boost down to say 11-12psi it stopped.lol.. your converter probably isnt helping the situation either..

jay

What did you do to fix it?
 

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JamesN1830 said:
What did you do to fix it?
PUt a th400 in it haha.

I think you could probably fix it with an AEM.

From the way I understand it, the shift tables in your computer are setup to begin shifting at a certain RPM in 1-2-3-4

Basically, it would kinda be like this

1-5500
2-5800
3-6300

This numbers are arbitrary, but basically the ECU is going to tell the transmission to shift at those RPMs depending on what gear you're in (assuming also you're WOT). You have to have it set lower in the lower gears becuase you're pulling much faster through those gears. Setting it lower allows for the mechanical lag that is going to undoubtedly happen between the ECU sending the signal and the transmission actually shifting. With how much more power you're making over stock that "lag" time is signicantly shortened, so you blow through the RPMs and smack the rev limiter before it can shift in time.

With an AEM, you'd be able to go in and lower these points.

There was an issue a couple of years back with the AEM and stock tranny. The stock ECU actualy cuts timing to kill power between shfits and save the spragues in the tranny but the AEM didn't have this option. I think it does now, so that shouldn't be a problem.

That, or replace it with a built transmission that will shift a bit quicker, but I think even with a built BL or SP transmission once you start making enough power you'd probably still run into this issue as the transmission is only one part of the equation.

I don't really know if all of the info I gave is completely accurate. That's they way I understood the way things work together. Maybe if I'm wrong, someone will correct me and we'll both get a lesson. It made sense in my head :dunno:
 
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