Hits the limiter at the top of first but transmission is fine
11-17-2004, 02:52 PM
#1
Hits the limiter at the top of first but transmission is fine I had my dad bring my car into a shop today to check out the transmission and they said everything was fine. They hooked it up to the computer and checked for codes and the pressure and its all fine. It doesn't always hit the limiter though, the shift points seem to vary a bit. It only did it a few times on the street, but both times at the track it bounced off the limiter a few times. It still gets rubber going into 2nd on the street with my dr's too. Also, when I first got my cam in and the tune it was shifting at 5800 each time, then crept up to 6K after a week, not its up to ~6200 and ocassionally hits the limiter. Is there some kind of speed sensor that might be going bad? I really have no idea how to fix it. 
11-17-2004, 04:11 PM
#2
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The amount by which your MPH and RPM diverge,
across the converter slip, will vary a lot with the
torque output. If the engine learned its way into
the mods and is making more power than before
it may well see more RPM at the same MPH that
gates the upshift event.
Hey, at least it'd be nice if that was the reason
I'm clueless whether the LT1 varies the trans line
pressure with temp like the LS1 does, or has any
similar shift time learning (adaptation) going on.
But there's two sides to the shift/rev limiter deal;
when you decide to get started, and how long it
takes to get done.
Are you able to log RPM and MPH, and can you
program this car?
across the converter slip, will vary a lot with the
torque output. If the engine learned its way into
the mods and is making more power than before
it may well see more RPM at the same MPH that
gates the upshift event.
Hey, at least it'd be nice if that was the reason
I'm clueless whether the LT1 varies the trans line
pressure with temp like the LS1 does, or has any
similar shift time learning (adaptation) going on.
But there's two sides to the shift/rev limiter deal;
when you decide to get started, and how long it
takes to get done.
Are you able to log RPM and MPH, and can you
program this car?
11-17-2004, 04:58 PM
#3
I don't have anything to log the RPM vs. the MPH on my car. It does feel alot stronger than when I first got the tune in, and my 111mph trap shows im probably making more than 322RWHP. I mean yesterday i got a chirp going into 2nd at 1/4 throttle on my drag radials, so I think the transmission is fine.
11-17-2004, 06:17 PM
#5
I do have a video of my run at the track if anyone wants to see it to see if they can tell anything from it. Just IM me at speeddmn24 on AIM or email me at spddmn24@bellsouth.net Now that I watch it over and over the 1-2 shift does seem to take forever. I'm thinkin the tranny is toast.
:edit:
Here's the video
http://www.p-r-o-s.net/movies/ROBMOROSO.mpg
Right click save as
:edit:
Here's the video
http://www.p-r-o-s.net/movies/ROBMOROSO.mpg
Right click save as
Last edited by speed_demon24; 11-17-2004 at 07:50 PM.
11-18-2004, 03:36 AM
#6
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Without knowing what you have programmed in the tranny and how it feels at the track, I recommend checking a few things:
line pressure (raise)
TQ reduction (moderate or eliminate)
log a run using HPTuners or EFILive. Monitor the RPM ahd speed to determine when its actually shifting and work from there. Fine tuning the tranny is a time consuming process as not all A4s and cars are equal. Allow 300RPM for the 1-2 shift, meaning if you want to shift at 6500, program the shift at 6250-6300 and set limiter to 6600-6700RPM.
Its still a stock box, and your run looked OK.
line pressure (raise)
TQ reduction (moderate or eliminate)
log a run using HPTuners or EFILive. Monitor the RPM ahd speed to determine when its actually shifting and work from there. Fine tuning the tranny is a time consuming process as not all A4s and cars are equal. Allow 300RPM for the 1-2 shift, meaning if you want to shift at 6500, program the shift at 6250-6300 and set limiter to 6600-6700RPM.
Its still a stock box, and your run looked OK.
11-18-2004, 09:40 AM
#7
So its just the sensor lagging behind? When I first got the tune in it was shifting at 5800 each shift, but now that I fixed the coil and got the a/f sorted out it pulls harder. Its the same exact tune as it was when it was shifting at 5800 RPM's before though, so I don't think its computer related.
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11-18-2004, 10:18 AM
#8
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Well, if it really pulls harder then you -will- have higher
RPM for the same MPH, and if MPH is the thing that sets
start-of-shift your RPM may be higher than you want
when that happens.
On LS1s the shift happens after -both- MPH and RPM
go over their thresholds. If RPM runs too far ahead,
bop-bop-bop-shift.
RPM for the same MPH, and if MPH is the thing that sets
start-of-shift your RPM may be higher than you want
when that happens.
On LS1s the shift happens after -both- MPH and RPM
go over their thresholds. If RPM runs too far ahead,
bop-bop-bop-shift.