Falls on face in between shifts
09-18-13, 01:43 PM
#1
Falls on face in between shifts
So I have this strange problem where my car falls on it's face when I shift.
I have enabled fuel cut on my P1000, yet it remains real rich and my boost plummets to 2 PSI in between shifts.
I can put the pedal to the metal and it jsut sits there...doesn't accelerate.
It is costing me about a second per shift in the 1/4 mile.
Other than that problem, the car runs like a top!
I have checked my coils, thinking one of the trailings might be dead, but that isnt the issue.
Anybody had this problem or know what would cause this?
Thanks!
I have enabled fuel cut on my P1000, yet it remains real rich and my boost plummets to 2 PSI in between shifts.
I can put the pedal to the metal and it jsut sits there...doesn't accelerate.
It is costing me about a second per shift in the 1/4 mile.
Other than that problem, the car runs like a top!
I have checked my coils, thinking one of the trailings might be dead, but that isnt the issue.
Anybody had this problem or know what would cause this?
Thanks!
09-19-13, 03:12 PM
#5
Well, for one, you shift really slow. 
The two shifts in that log are about a full second.
Reason I asked for a dyno chart is to see where the actual power lies in the rev range. I'm guessing the first shift is the 1-2? RPM falls back to around 4500 after the shift. On the next shift it falls to around 5000. On a big turbo, if it doesn't hit full spool until 5k, you're going to have transient issues like this every time you shift.
You made the first shift at 7700 and the 2nd shift at 6500. Aren't you running a half bridge? Even if it's a street port, put your big boy pants on and rev it. A street port should make good power to 8500. Even if it falls off some, you may make big transient response gains by having the revs fall into the boost curve after the shift. A half bridge might make power up to 10k or more, that's where you'll want to shift.
Put it on a dyno and just get an idea of where it makes power. Then you'll know where you need to shift. It might even be a situation where you can go quicker with a smaller turbo that has better transient response.
The two shifts in that log are about a full second.Reason I asked for a dyno chart is to see where the actual power lies in the rev range. I'm guessing the first shift is the 1-2? RPM falls back to around 4500 after the shift. On the next shift it falls to around 5000. On a big turbo, if it doesn't hit full spool until 5k, you're going to have transient issues like this every time you shift.
You made the first shift at 7700 and the 2nd shift at 6500. Aren't you running a half bridge? Even if it's a street port, put your big boy pants on and rev it. A street port should make good power to 8500. Even if it falls off some, you may make big transient response gains by having the revs fall into the boost curve after the shift. A half bridge might make power up to 10k or more, that's where you'll want to shift.
Put it on a dyno and just get an idea of where it makes power. Then you'll know where you need to shift. It might even be a situation where you can go quicker with a smaller turbo that has better transient response.
09-19-13, 04:30 PM
#6
Hey Chris, My engine is not balanced or clearenced.
I have my shift light set at 8200 RPM.
I am trying to get the shifts ironed out...that's the whole point of this post...I don't shift that slow, it just looks like I do.
I have richened up the fuel during the primary stage from 0-3.2 PSI in hopes that will smooth things out.
Where I do the road stuff, I am very cautious and usually don't get past the middle of 3rd because there isn't enough room...guess I better go to the dyno.
I have my shift light set at 8200 RPM.
I am trying to get the shifts ironed out...that's the whole point of this post...I don't shift that slow, it just looks like I do.
I have richened up the fuel during the primary stage from 0-3.2 PSI in hopes that will smooth things out.
Where I do the road stuff, I am very cautious and usually don't get past the middle of 3rd because there isn't enough room...guess I better go to the dyno.
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09-25-13, 10:00 AM
#16
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well, for one, you shift really slow. the two shifts in that log are about a full second.
Reason i asked for a dyno chart is to see where the actual power lies in the rev range. I'm guessing the first shift is the 1-2? Rpm falls back to around 4500 after the shift. On the next shift it falls to around 5000. On a big turbo, if it doesn't hit full spool until 5k, you're going to have transient issues like this every time you shift.
You made the first shift at 7700 and the 2nd shift at 6500. Aren't you running a half bridge? Even if it's a street port, put your big boy pants on and rev it. A street port should make good power to 8500. Even if it falls off some, you may make big transient response gains by having the revs fall into the boost curve after the shift. A half bridge might make power up to 10k or more, that's where you'll want to shift.
Put it on a dyno and just get an idea of where it makes power. Then you'll know where you need to shift. It might even be a situation where you can go quicker with a smaller turbo that has better transient response.
the two shifts in that log are about a full second.Reason i asked for a dyno chart is to see where the actual power lies in the rev range. I'm guessing the first shift is the 1-2? Rpm falls back to around 4500 after the shift. On the next shift it falls to around 5000. On a big turbo, if it doesn't hit full spool until 5k, you're going to have transient issues like this every time you shift.
You made the first shift at 7700 and the 2nd shift at 6500. Aren't you running a half bridge? Even if it's a street port, put your big boy pants on and rev it. A street port should make good power to 8500. Even if it falls off some, you may make big transient response gains by having the revs fall into the boost curve after the shift. A half bridge might make power up to 10k or more, that's where you'll want to shift.
Put it on a dyno and just get an idea of where it makes power. Then you'll know where you need to shift. It might even be a situation where you can go quicker with a smaller turbo that has better transient response.
wow!
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