trans or tune??? my short night at milan

jdustu

jdustu

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i'll preface this by saying i don't know a whole lot about tuning or transmissions, so thanks in advance for the patience

i haven't put 1k miles on the car since stenod put in my "new" motor(25k used ls1 shortblock) and had it tuned.....i blew the old motor last summer, so i hadn't been to the track yet to see how much the 4200 stall i installed last spring improved my previous best of 12.5 at 110......

i've been thwarted by rain, by snow, and by rain again, but tonight i skipped work to head down to milan......i just wanted to get a few runs in, and was hoping for 11s, but if it ran good and hit low 12s i'd be fine.....well, it hit low 12s but didn't freaking want to shift!!! it bounced off the limiter from first to second and from second to third! i only had 2 runs out of six that i didn't completely abort, two from terrible traction and two after it wouldn't f-ing shift to third......

i drive it to work and around town every now and then, and haven't ever thought that the tranny didn't feel good....i don't get on it wot for long jaunts on the street too often, but i have gone 40-80mph or so a few times, and a couple times it seemed like it hesitated with the shift, but usually it was fine.......i attributed it to the car not being fully warmed up, and every time i would try it again it would shift fine.......

by the way, the best time was 12.2 at 111 with a 1.64 60'......it was the only run a hooked up decent, but it still hesitated a bit on the first shift and bounced three times on the second shift.....

is the tranny toast, or is there something lacking with the tune???
any thoughts would be appreciated

josh
 
shift points need to be changed due to the high stall. Its pretty common to tag the limiter before tuning with a high stall
 
yeah, but it was tuned with the high stall in it......actually, i drove it for a few thousand miles last summer(before i spun a bearing), with just hypertech tuning done by me, who doesn't know jack about this stuff, and it shifted fine......a few months ago when the "new" engine went in, it was professionally tuned......but later it was found that there was a bad ground, so i wonder if that could have affected the tune?
 
They probably only ran in 3rd gear. So no shifting was done.
Also the load may be different at the track than a dyno. Dynojets are less than mustangs too. normally they don't do a 1-2-3 wot on a dyno though.
If you still have the hypertech you can lower the shift point.( i think they have +/- mph for shifting) lower it a few mph and see if it works
 
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1BADAIR said:
They probably only ran in 3rd gear. So no shifting was done.
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it doesn't seem like that would be a very good way to tune a car??? i mean, part of the tune is adjusting the shift points, is it not? i guess i'll shoot joe an email, i just didn't want to bug him if it was definetely the transmission....

hopefully it is the tune and not the trans, either way i was pretty pissed to take a night off work, drive an hour plus to get down there and then not get one clean run in......i couldn't hook worth shit anyways, but if it was shifting i would have kept trying:peelout:
 
it wasn't dyno tuned, it was street tuned.......obviously i don't know how much wot tuning can be done on the street....
i sold the hypertech when i blew the motor cuz i figured i'd just get the shop that installed the motor do a fresh tune.....
 
I see. I thought it was on a dyno.
I know of many cases that the shift points have been adjust on a dyno and then had to be redone because it still hit the limiter.
DId you change tire height or anything after it was set. load and other things can affect it too
 
pretty much everything is as it was.......the only thing i can think of, was that it had the ground problem......when the motor was installed, the ground bolt on the back of the head was accidentally left loose.....sometimes it would ground, sometimes it wouldn't, so it seemingly ran fine when they tuned it, but when i got it i was having misfirings and ses lights and whatnot.....i replaced the 02 sensors and found the loose bolt and its ran like a champ ever since......
 
jdustu said:
i'll preface this by saying i don't know a whole lot about tuning or transmissions, so thanks in advance for the patience

i haven't put 1k miles on the car since stenod put in my "new" motor(25k used ls1 shortblock) and had it tuned.....i blew the old motor last summer, so i hadn't been to the track yet to see how much the 4200 stall i installed last spring improved my previous best of 12.5 at 110......

i've been thwarted by rain, by snow, and by rain again, but tonight i skipped work to head down to milan......i just wanted to get a few runs in, and was hoping for 11s, but if it ran good and hit low 12s i'd be fine.....well, it hit low 12s but didn't freaking want to shift!!! it bounced off the limiter from first to second and from second to third! i only had 2 runs out of six that i didn't completely abort, two from terrible traction and two after it wouldn't f-ing shift to third......

i drive it to work and around town every now and then, and haven't ever thought that the tranny didn't feel good....i don't get on it wot for long jaunts on the street too often, but i have gone 40-80mph or so a few times, and a couple times it seemed like it hesitated with the shift, but usually it was fine.......i attributed it to the car not being fully warmed up, and every time i would try it again it would shift fine.......

by the way, the best time was 12.2 at 111 with a 1.64 60'......it was the only run a hooked up decent, but it still hesitated a bit on the first shift and bounced three times on the second shift.....

is the tranny toast, or is there something lacking with the tune???
any thoughts would be appreciated

josh
Click to expand...

Could be some shift exstension from the cooler weather making a bit more power so the Shift point could be a bit to high or the rev limiter needs to be bumped a bit. I am alway chasing shift points becuase even with drag sims we never seem to get them right on the dyno. Odly enough we test drive the crap out of them and still have to change the shift points at the track. Its a common problem. I am heading to lappeer sunday if your out there id gladly take a peak. Then agian the trans if it has some hard miles n it might be starting to let go. Have you checked the fluid level yet ?

Sean
 
Sean said:
Could be some shift exstension from the cooler weather making a bit more power so the Shift point could be a bit to high or the rev limiter needs to be bumped a bit. I am alway chasing shift points becuase even with drag sims we never seem to get them right on the dyno. Odly enough we test drive the crap out of them and still have to change the shift points at the track. Its a common problem. I am heading to lappeer sunday if your out there id gladly take a peak. Then agian the trans if it has some hard miles n it might be starting to let go. Have you checked the fluid level yet ?

Sean
Click to expand...

i didn't check the fluid level tonight, but i changed the tailshaft housing a few hundred miles ago and it was fine then.....the temp thing makes sense, and maybe other factors, like i opened the dual cut-outs as opposed to them being closed during tuning, affected it.........although for my final run i closed them back up and still had the issue......i didn't realize the shift points were so fickle, i guess maybe i'll have to get another handheld or laptop for the future....

i had been thinking about heading to lapeer, but i've got to see my work schedule first.....i doubt i'll make it, but if i do that would be great if you could check it out.....it sucked going down to milan and having no way to tune it, but i guess i really wasn't expecting anything like that....
 
jdustu said:
i didn't check the fluid level tonight, but i changed the tailshaft housing a few hundred miles ago and it was fine then.....the temp thing makes sense, and maybe other factors, like i opened the dual cut-outs as opposed to them being closed during tuning, affected it.........although for my final run i closed them back up and still had the issue......i didn't realize the shift points were so fickle, i guess maybe i'll have to get another handheld or laptop for the future....

i had been thinking about heading to lapeer, but i've got to see my work schedule first.....i doubt i'll make it, but if i do that would be great if you could check it out.....it sucked going down to milan and having no way to tune it, but i guess i really wasn't expecting anything like that....
Click to expand...

Tranny tuning for peak performance is very fickle if you want it truly optimized. I Drove it pretty hard and set it close to the limiter knowing you have the 4200 stall in it etc. Changes in tires/power and even fluid temps will impact the shift times.

I can move it down slightly quick enough for you and give the motor a bit more rpm headroom. PM me and we can meet and take car if it.
 
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