Mods = slower?
#1
Mods = slower?
I've always trapped 111-112 mph at the track in 1/4 mile. Previously had 3.46 gears and JBA shorties. This week I installed 3.91 gears and long tube headers without cats. Last night the best I could trap was 104.
Two weeks ago I was running 12.65@110-111 with 1.85 60s. Density altitude was 4100. Last night DA was 5200 and my best was 12.65@104 with a 1.75 60. I expected it to be a little slower but that seems off to me. I was able to add two more degrees of timing after the headers and still didn't have KR, but it still ran the same numbers three more times.
Any thoughts?
Coupleweeksago:
Last nights:
Two weeks ago I was running 12.65@110-111 with 1.85 60s. Density altitude was 4100. Last night DA was 5200 and my best was 12.65@104 with a 1.75 60. I expected it to be a little slower but that seems off to me. I was able to add two more degrees of timing after the headers and still didn't have KR, but it still ran the same numbers three more times.
Any thoughts?
Coupleweeksago:
Last nights:
Last edited by superGTO; 06-30-2012 at 11:29 AM.
#3
Updated first post with slips. Mods are LS1, stock heads with double springs, stock valve train, cam 218/228 114, and a Maggie 112. Previously had JBA shorties, with catted mids. Like I said the only change was to pacesetter long tubes and 3.91 gears for 3.42s. M6 too. Shift points the same between runs and I dont lift off the gas to shift.
#4
I would get your tune looked at first.. You're doing good in the 1/8.. The back end is killing you. I hope nothing is wrong with your motor, but i would look into the tune.
I figured you would be trapping more than 110 though with a cam and a maggie.
I figured you would be trapping more than 110 though with a cam and a maggie.
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#8
Updated first post with slips. Mods are LS1, stock heads with double springs, stock valve train, cam 218/228 114, and a Maggie 112. Previously had JBA shorties, with catted mids. Like I said the only change was to pacesetter long tubes and 3.91 gears for 3.42s. M6 too. Shift points the same between runs and I dont lift off the gas to shift.
#9
Yeah, 04 GTO. I'm still tuning it. It's a little rich still IMO but running well. I was trapping 111 before the gear change. I was thinking less back pressure from long tubes and no cats plus 3" instead of 2.5 from the JBAshorties. So could still be tune. I didn't change the tune from the times I trapped 111 to now except for the gear change.
Motor is fine. Runs strong and has no issues. I run M/T ET streets at the track. Launch is the same. No spinning issues in the runs I put up with all the 60s pretty consistent IMO. 1/8 mile traps are 86-88. Don't know where you where looking for 96. I'll go in to the tune some more and see if I can put in some more there.
Motor is fine. Runs strong and has no issues. I run M/T ET streets at the track. Launch is the same. No spinning issues in the runs I put up with all the 60s pretty consistent IMO. 1/8 mile traps are 86-88. Don't know where you where looking for 96. I'll go in to the tune some more and see if I can put in some more there.
#11
Yeah, 04 GTO. I'm still tuning it. It's a little rich still IMO but running well. I was trapping 111 before the gear change. I was thinking less back pressure from long tubes and no cats plus 3" instead of 2.5 from the JBAshorties. So could still be tune. I didn't change the tune from the times I trapped 111 to now except for the gear change.
Motor is fine. Runs strong and has no issues. I run M/T ET streets at the track. Launch is the same. No spinning issues in the runs I put up with all the 60s pretty consistent IMO. 1/8 mile traps are 86-88. Don't know where you where looking for 96. I'll go in to the tune some more and see if I can put in some more there.
Motor is fine. Runs strong and has no issues. I run M/T ET streets at the track. Launch is the same. No spinning issues in the runs I put up with all the 60s pretty consistent IMO. 1/8 mile traps are 86-88. Don't know where you where looking for 96. I'll go in to the tune some more and see if I can put in some more there.
#12
Yeah I am WB tuning. Commanding 11.5 right now with 18* timing currently. Like I said I think it can lean out some more and add a little more timing. Doesn't drop anywhere during the run. Spec 3 clutch and it chirps the tires even into 4th.