kwhiteside
June 12th, 2009, 01:41 AM
I've got a 2001 Z06 that I recently put a Fast92 and LS2 TB on. Since then, I've noticed when I engage clutch, my RPM's dive bomb down to 500, then bounce up to the idle around 800. Hasn't actually died yet, but sure seems like it might.
You should know, that I know I don't know what I'm doing :doh2:
That being said, I've used the search tool a lot and have made about 6 flashes to my PCM now.
Started with the throttle cracker table. Noticed in a tune from another Z06 with similar addons that he had zeroed out a few 400,1000,1600 rpm rows and reflected on my logs a bit. When I push in the clutch my wideband shows my AFR shooting to the moon, so I figured, why add more air like the stock throttle cracker seems to be doing. So I flashed like his. Things got worse. Made two more flashes moving back from the zeroes towards the stock numbers. Still no go.
Then I read some posts where it was stated that if you change all the numbers in the throttle cracker to zeroes you will see your rpms fall really hard and possible stall out. Hmmm, if thats true, I'll go the other way. So I tried a couple iterations with bigger numbers. Still no love.
Then I researched "90mm" and found the consenses was B4349 converter is what you change to accommodate the new bigger TB blade. Unfortunately, I found about 50% of the people advising that you need to change the stock .0255 number down to .0196, and the other 50% saying you needed to raise the stock .0255 up to .03. Wonderful, I know I don't know what I'm doing. Now I'm wondering if anybody else knows what they are doing.
So I've taken one baby step with B4349 and changed it from .0255 to .0245, and all the throttle cracker stuff went back to stock. I logged to work this morning and created a very small log file which will show how my car runs after warmed up getting on it a bit, then show two rpm divebombs where I engage the clutch. My wideband (LM-1) seems to be following AFR well at cruise speeds, so I think that is working well.
Also the first thing I noticed when starting the car this morning was that it didn't want to start and blew a bunch of smoke. Never does that, so even though I'm leaning to believe the arguments in favor of a smaller B4349 number, I'm not liking what I'm seeing so far.
Hopefully some of you experience guys can lend your intrepretation to my cars logs. My uneducated guess, is that it goes so lean when I engage clutch and let off gas, everything is messed up. Everyone keeps telling me don't worry about the lean when you hit the clutch. Well, I wouldn't worry about it, if my RPM's would drop to 500!
Thanks in adance from your new friend Ken . . .
You should know, that I know I don't know what I'm doing :doh2:
That being said, I've used the search tool a lot and have made about 6 flashes to my PCM now.
Started with the throttle cracker table. Noticed in a tune from another Z06 with similar addons that he had zeroed out a few 400,1000,1600 rpm rows and reflected on my logs a bit. When I push in the clutch my wideband shows my AFR shooting to the moon, so I figured, why add more air like the stock throttle cracker seems to be doing. So I flashed like his. Things got worse. Made two more flashes moving back from the zeroes towards the stock numbers. Still no go.
Then I read some posts where it was stated that if you change all the numbers in the throttle cracker to zeroes you will see your rpms fall really hard and possible stall out. Hmmm, if thats true, I'll go the other way. So I tried a couple iterations with bigger numbers. Still no love.
Then I researched "90mm" and found the consenses was B4349 converter is what you change to accommodate the new bigger TB blade. Unfortunately, I found about 50% of the people advising that you need to change the stock .0255 number down to .0196, and the other 50% saying you needed to raise the stock .0255 up to .03. Wonderful, I know I don't know what I'm doing. Now I'm wondering if anybody else knows what they are doing.
So I've taken one baby step with B4349 and changed it from .0255 to .0245, and all the throttle cracker stuff went back to stock. I logged to work this morning and created a very small log file which will show how my car runs after warmed up getting on it a bit, then show two rpm divebombs where I engage the clutch. My wideband (LM-1) seems to be following AFR well at cruise speeds, so I think that is working well.
Also the first thing I noticed when starting the car this morning was that it didn't want to start and blew a bunch of smoke. Never does that, so even though I'm leaning to believe the arguments in favor of a smaller B4349 number, I'm not liking what I'm seeing so far.
Hopefully some of you experience guys can lend your intrepretation to my cars logs. My uneducated guess, is that it goes so lean when I engage clutch and let off gas, everything is messed up. Everyone keeps telling me don't worry about the lean when you hit the clutch. Well, I wouldn't worry about it, if my RPM's would drop to 500!
Thanks in adance from your new friend Ken . . .