Help! My 60' Really Sucks

[nightrain]

I can't seem to get my car to 60' worth a crap. 2.0 - 1.77 best. Using a PTC 9.5 2800 stall converter, rest of mods are in sig. I was using a 9" fake Art Carr that stalled way too low (2000-2200 rpm at 0 vacuum) and switched to the PTC thinking my 60's would improve dramatically. There's actually no change in the 60's, but the top end charge is awesome.

So, I'm using the stock 3.42's with 27"x10" MT Streets and an HR rear sway bar kit. I can leave at 20lbs boost at around 4400 rpm before the PL shows any MPH from zero and I don't feel any shudder from spin. You would think at 20lbs boost I'd either be sliding sideways or feel the tires grab and slip. I'm wondering if the 27" tire is hurting the gear ratio too much (effectively a 3.23). I have a 3.91 gear set on the shelf and can switch to a 30" tire which will bring me back to 3.42, but is that the ticket?

MPH is 120 with a 60' of 1.77; ET 11.44. That's worse than 10 years ago with a smaller turbo, no headers and stock heads. Then again, 10 years ago I used the 3.91's with a 30" slick and got 1.5 60's.

Thanks!

 

[Boost231]

are you sure you arent spining the tires once you launch? has anyone got video of you leaving? i always try to get video so i can watch it in slowmo. i can get 1.60 on my MT street radials and it fells like it hooks good but in the video its still spinning some.

 

[nightrain]

are you sure you arent spining the tires once you launch? has anyone got video of you leaving? i always try to get video so i can watch it in slowmo. i can get 1.60 on my MT street radials and it fells like it hooks good but in the video its still spinning some.

Yeah, my videographer was a bit wobbly, but at least one pass I can hear tire sqeal about 20-30 feet out. I don't hear it on the 1.77 60' pass. I painted a white stripe on the tire, but alas, the video is inconclusive. I have a set of 3.91's on the shelf and figured I'd be going with a 30" slick soon anyway, but thought I should be able to do better than 1.77 on the 27" DOT's. Perhaps I just need to come out with less boost...

 

[V6POWER]

I went to test and tune Thursday night and had three pretty consistent 1/8 mile runs. Boost was 26# with 26/22 timing. Temp. was mid-70s. I was running 93 + meth. I just purchased a PTC 2,800 nlu, 10" tc and it works great. I could launch with 13# @ 3,800 off the footbrake and the MT ET drag radials never even spun. I did lose about 1 mph in the 1/8 with the nlu.

1.603
4.577
7.081
98.71

1.567
4.483
6.979
98.99

1.587
4.511
7.006
98.94

I have 3.42 gears and ran 27" MT ET Street drag radials.

Attached is a Power Logger screen shot of the 6.979 run.

 

[bison]

I got a 1.59 on a 3-4lb launch. The DR's work better on a well prepped track. 10-13 should net 1.40's on that combo.

 

[V6POWER]

"10-13 should net 1.40's on that combo."

bison--Are you referring to my combo? The dr's never spun but I really didn't feel the push back into the seat. I would love to get into the 1.4s.

 

[nightrain]

"10-13 should net 1.40's on that combo."

bison--Are you referring to my combo? The dr's never spun but I really didn't feel the push back into the seat. I would love to get into the 1.4s.

If Bison were replying to me, I have attached the best data file of the night. That was a 1.77 60'.

 

[bison]

"10-13 should net 1.40's on that combo."

bison--Are you referring to my combo? The dr's never spun but I really didn't feel the push back into the seat. I would love to get into the 1.4s.

Yeah. Forgot to qoute

 

[bison]

I can't seem to get my car to 60' worth a crap. 2.0 - 1.77 best. Using a PTC 9.5 2800 stall converter, rest of mods are in sig. I was using a 9" fake Art Carr that stalled way too low (2000-2200 rpm at 0 vacuum) and switched to the PTC thinking my 60's would improve dramatically. There's actually no change in the 60's, but the top end charge is awesome.

So, I'm using the stock 3.42's with 27"x10" MT Streets and an HR rear sway bar kit. I can leave at 20lbs boost at around 4400 rpm before the PL shows any MPH from zero and I don't feel any shudder from spin. You would think at 20lbs boost I'd either be sliding sideways or feel the tires grab and slip. I'm wondering if the 27" tire is hurting the gear ratio too much (effectively a 3.23). I have a 3.91 gear set on the shelf and can switch to a 30" tire which will bring me back to 3.42, but is that the ticket?

MPH is 120 with a 60' of 1.77; ET 11.44. That's worse than 10 years ago with a smaller turbo, no headers and stock heads. Then again, 10 years ago I used the 3.91's with a 30" slick and got 1.5 60's.

Thanks!

Id like to see some data logs. Seems like something is slipping based on those 60's. I doubt the tire height is hurting you. What does a 5lb launch get you? Possible exhaust leak preventing good ramp up after launch?

 

[GNVYUS 1]

Wow, leaving at 20psi and 4400 rpm is going to be laying down some madd torque with your combo. I'd definitely come way down in both psi and boost and then go from there.

Are you using MT ET Streets or the Street Drag Radials?
If you have the first set, those blow and it's not surprising.

 

[TurboK]

A 20 PSI launch at 4400 RPM should be a hell of a launch. It sounds like you have a problem with your torque convertor stator clutch slipping or the support splines are gone

Or, are you running a trans brake ?? If so, it might not be fully releasing at launch.
I wouldnt change gears or tires -- you have some other problem going on.

Good luck!

 

[ttypewhite]

Check for a header leak, tune (maybe too rich), posi (clutches need replacing), and tire pressure. Something sounds way off here. At 20psi you should hailing the tires in the air and throughing you in the back seat all at the same time.

 

[nightrain]

Id like to see some data logs. Seems like something is slipping based on those 60's. I doubt the tire height is hurting you. What does a 5lb launch get you? Possible exhaust leak preventing good ramp up after launch?

Bison,

PL Files: I attached a file of my best 60' of last Friday; 1.76 ("track 4"). "Track 5" is the last run of the night and a 1.95 60'. I shifted a little late on that one.

5lb Launch: A 5lb launch got me a 2.4 60'.

Exhaust Leaks: I have TA headers that are nicely sealed. I spent a fair amount of time getting them straight, as they leaked when I first installed them. That's why I'm sure I don't have any exhaust leaks.

I noticed right before the launch and up to 17mph or so that the timing drops to 19 deg, then jumps back to 26 where I have it set. It does that on every run.

Thanks for looking at the file. Appreciate your opinion.

 

[salvageV6]

Was that at LVD or NED?

I could never 60ft. at LVD.

I use 27" Hoosiers with no problems.

I could only do a 4 lb. launch there on most days with a best of 1.6 or so.

Mostly 1.7's to 1.9.

Spun the rest of the time with more boost.

 

[xcessiv6]

Try flashing the convertor instead of holding it, bring up to 5lb floor it slide you foot off the brake and see if that works.

 

[GNVYUS 1]

Tires, when some say MT Streets it can mean ET Streets or Street Drag Radials, which ones do you have?

I'd be really surprised a 27" tall tire isn't spinning on a T66 turbo at 20psi out of the hole especially on ET Streets.

What rear shocks?