Timeslips, post em up!
- Thread starter oneandgone
- Start date
13.8 @ 100, 2.0 60ft.....On 225 half bald street tires, car broke up at the top of 2nd, and at 80ish mph either tires broke loose or clutch slipped...Judging by my setup it was not a very good time for me...But for it only being my 4th run at the track ever I was happy.
WeDgE said:13.8 @ 105.7mph, T78, 13psi, bald drag radials-P), 3280ft.
Need more boost to get this turbo into its efficiency range!
Although the range is off by a little, you are still missing power IMO...better yet, what are your mods? I know a few running this turbo and trap in the 118-120's with simliar boost but could be that you are not tuned?
Edit: At that altitude, you lose about 3 MPH to sea level too, and the fact that weight and such will also factor in to this.
Duane
Duane, it did feel like I was down on power, not sure why...
I also think my turbo seals went that day...no smoke at all during the entire 1/4 mile, but when I let off, braked and accelerated on the return road, I'd puff a large cloud of blue smoke.
Race weight was ~1710kgs with myself in the car.
Car was "tuned" during our dyno day...although I'm not sure how much I fully trust the tuners...their wideband was off by a fair margin compared to my AEM WBO2 with 500kms on it. They richened it under boost (seems fishy when the OEM ecu is still controlling everything...) Dyno sheet here:http://www.supramania.com/forums/showpost.php?p=319893&postcount=8
Mods: http://www.supramania.com/forums/vbpicgallery.php?do=view&g=110
Hell, if I could trap that high I'd be deep into the 12s!
LMK your diagnosis, Duane.
I also think my turbo seals went that day...no smoke at all during the entire 1/4 mile, but when I let off, braked and accelerated on the return road, I'd puff a large cloud of blue smoke.
Race weight was ~1710kgs with myself in the car.
Car was "tuned" during our dyno day...although I'm not sure how much I fully trust the tuners...their wideband was off by a fair margin compared to my AEM WBO2 with 500kms on it. They richened it under boost (seems fishy when the OEM ecu is still controlling everything...) Dyno sheet here:http://www.supramania.com/forums/showpost.php?p=319893&postcount=8
Mods: http://www.supramania.com/forums/vbpicgallery.php?do=view&g=110
Hell, if I could trap that high I'd be deep into the 12s!
LMK your diagnosis, Duane.
Did some talking with a friend of mine and a change back to the Turbo differential could help immensely. I won't be shifting into 4th right before the end and I'll be putting more load on the turbo, building boost faster/generating more power(I hope!).
WeDgE said:
ummmmmmmmm, you will be shifting to 4th no matter what.....3rd tops out around 85ish....
Everything I have read points to using a lower-geared ratio like the 4.30 as opposed to the 3.73 I have at the moment. I am redlining 3rd at the end of the track at ~100mph, and I wish I could get some use out of fourth gear!
Damien, I'll swap diffs with you if you like and we can see what happens. ;-) I guess for you it depends on the amount of turbo lag between shifts with that T78. My little ct-26 spools fast.
Jim
Damien, I'll swap diffs with you if you like and we can see what happens. ;-) I guess for you it depends on the amount of turbo lag between shifts with that T78. My little ct-26 spools fast.
Jim
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tissimo said:
curse you auto trans!
Heckler said:
the idea is to gear the car such that you perform the lowest number of shifts possible. if you're near or @ redline @ the end of the 1/4, you've done well.
drjonez said:
If I took that literally, I may just try starting off in third! :icon_bigg
I think there are a number of things going on here. We want to maximize the power under the curve, while at the same time minimizing the amount of time between shifts (and the number of shifts), where there is no power to the wheels. But those two goals conflict with a conventional setup.
From what I understand, the reason that auto trannies do so well is that they can minimize the amount of time between shifts, while keeping the car in the right gear. For a manual, shifting time is much slower (including loss of boost, etc) so we lose out. But we still have to keep the motor reasonably within it's power band.
Damien, what is your rpm in fourth gear at the end of the strip? I'd like to do some number crunching and see if I can get an estimate of how close (if at all) I'd be to redline in 4th with the 4.3 diff. Sorry, this weekend is out due to family stuff.
Jim
no, a r154.... just reving to 7600 w/ a 3.73.. lol..drjonez said:curse you auto trans!
the idea is to gear the car such that you perform the lowest number of shifts possible. if you're near or @ redline @ the end of the 1/4, you've done well.
my buddy was maxing out his 4.30 in 4th with a stock ct26 (only like 105 mph at 6300-6500 in 4th).. 4.30 is too short for the 7m.. need more revs to amke a 4.30 work..