H/C low dyno's, low MPH..
TECH Senior Member
Joined: Nov 2001
Posts: 10,341
Likes: 1
Re: H/C low dyno's, low MPH.. I bet you ANYTHING it is that damn SLP MAF. Run the stock with the screen removed and use MAFT to tweak your LTRIMS at cruise to -1 to -3. Then dial in your WOT using MAFT or LS1Edit.
Aftermarket MAFs SUCKS ***.
I have seen cars lose 20-45RWHP from them.
Good luck,
Chris
Aftermarket MAFs SUCKS ***.
I have seen cars lose 20-45RWHP from them.
Good luck,
Chris
Re: H/C low dyno's, low MPH.. Okay, time to sit down and make a list of things to monitor and work on the next time you dyno.
1) AF ratio, well you want to be around 13:1 AF if you are NA. IMO you want to be at 13:1 AF from 5000 to the top.
2) Timing, well 28 to 31 degrees the difference is slight so don't worry about it too much.
3) Rich like 11:1 AF will yield lower HP #'s and higher TQ #'s.
4) I would only lock the converter after it's dialed in unlocked.
With GTP heads, 221/224//113 cam a few years ago with a PI3600 I dynoed 350rwhp unlocked and 375rwh locked. With pcm tuning I think 380rwhp or more was possible. I went 11.75@112 unlocked and 114mph locked.
We just finished dynoing my car over two sessions and 13:1 AF and 31 degrees of timing yielded 450rwhp unlocked and 501rwtq... 422ci ARE iron stroker.
You might want to check your your drivetrain, it's weird to break that stuff, is your driveshaft bent?
1) AF ratio, well you want to be around 13:1 AF if you are NA. IMO you want to be at 13:1 AF from 5000 to the top.
2) Timing, well 28 to 31 degrees the difference is slight so don't worry about it too much.
3) Rich like 11:1 AF will yield lower HP #'s and higher TQ #'s.
4) I would only lock the converter after it's dialed in unlocked.
With GTP heads, 221/224//113 cam a few years ago with a PI3600 I dynoed 350rwhp unlocked and 375rwh locked. With pcm tuning I think 380rwhp or more was possible. I went 11.75@112 unlocked and 114mph locked.
We just finished dynoing my car over two sessions and 13:1 AF and 31 degrees of timing yielded 450rwhp unlocked and 501rwtq... 422ci ARE iron stroker.
You might want to check your your drivetrain, it's weird to break that stuff, is your driveshaft bent?
TECH Apprentice
Joined: Dec 2001
Posts: 351
Likes: 0
From: CA
Re: H/C low dyno's, low MPH.. </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Chris ARE 360:
<strong>I bet you ANYTHING it is that damn SLP MAF. Run the stock with the screen removed and use MAFT to tweak your LTRIMS at cruise to -1 to -3. Then dial in your WOT using MAFT or LS1Edit.
Aftermarket MAFs SUCKS ***.
I have seen cars lose 20-45RWHP from them.
Good luck,
Chris</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Sorry, I don't know much about the SLP MAF, is it similar to the Granatelli in that the sensor reading is actually manipulated? I have ported MAF ends and stock sensor, and I don't see how they would cause a problem.
<strong>I bet you ANYTHING it is that damn SLP MAF. Run the stock with the screen removed and use MAFT to tweak your LTRIMS at cruise to -1 to -3. Then dial in your WOT using MAFT or LS1Edit.
Aftermarket MAFs SUCKS ***.
I have seen cars lose 20-45RWHP from them.
Good luck,
Chris</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Sorry, I don't know much about the SLP MAF, is it similar to the Granatelli in that the sensor reading is actually manipulated? I have ported MAF ends and stock sensor, and I don't see how they would cause a problem.
