LT4 stroker tuning
Thread Starter
2nd Gear
Joined: Mar 2004
Posts: 2
Likes: 0
From: El Centro CA
LT4 stroker tuning
Have a stroked LT4, MAP at idle is 73. Using 1995 LT1 PCM. Per suggestion one of the members I changed RPM boundaries to 1200, 1600, & 2400 and changed MAP boundaries to 45, 65, 90. BLM enable temp and closed loop enable temp seem to be okay. VSS provides a signal but it is not accurate.
Using a scanner plus Datamaster the engine starts in open loop & transitions to closed loop. BLM is enabled. Computer only uses cells 16, 17 & 18. I never see the other cells. It uses cells 16 and 17 appropriately for idle and deceleration. Even in cruise stays in cell 18. I have the purge cannister turned off because I do not have one.
I would appreciate any suggestions about what to look at next. If the VE tables are off considerably, would the computer not go into cells 0 thru 15??
Thank you, John
Using a scanner plus Datamaster the engine starts in open loop & transitions to closed loop. BLM is enabled. Computer only uses cells 16, 17 & 18. I never see the other cells. It uses cells 16 and 17 appropriately for idle and deceleration. Even in cruise stays in cell 18. I have the purge cannister turned off because I do not have one.
I would appreciate any suggestions about what to look at next. If the VE tables are off considerably, would the computer not go into cells 0 thru 15??
Thank you, John
Le Mans Master
Joined: Jan 2003
Posts: 8,596
Likes: 19
From: Portland Oregon
Re: LT4 stroker tuning (cxvette)
What cam are you using? For it to idle at a MAP value of 73 it must be a fairly large cam. Are you using a MAF sensor or are you running in Speed Density mode?
Thread Starter
2nd Gear
Joined: Mar 2004
Posts: 2
Likes: 0
From: El Centro CA
Re: LT4 stroker tuning (tjwong)
Thanks for the reply. Using the MAF sensor. Comp Cam hydralic roller cam, 230/236 duration @ .050, .544/.520 lift, 114 lobe sep., rockers l.6/l.5 ratio.
Thanks again, John
Thanks again, John
Burning Brakes
Joined: Nov 2001
Posts: 1,241
Likes: 9
From: Houston TX
Re: LT4 stroker tuning (cxvette)
what does the MAP read when you're in decel, throttle closed?
how about the TPS percentages while all of this is happening?
what kind of fuel trims are happening?
how does the car act under WOT?
-michael
how about the TPS percentages while all of this is happening?
what kind of fuel trims are happening?
how does the car act under WOT?
-michael
