Track day

[Shimy87]

Car ran ok 12.1 was best. Too many cars showed up so only 4 runs. I think my tire height is holding me back but wanted to ask here. All 4 runs were 107.69 to 107.80 MPH and the times were 12.3, 12.1, 12.3 12.2.  short times were best of 1.6 worst of 1.8.

So question is what is the ideal tire height for the 1/4 mile? I'm crossing the line at 3rd at 54XX RPM

My third run I tried leaving it in OD and as you see, same MPH and time but crossed the line at 47XX RPM. Felt like is shifted with about 100 FT left to the line.

Thanks for any help!!

[motorhead]

Is this the cam you are using?

http://www.fullthrottlespeed.com/turbo-buick-v6-performance-parts/buick-turbo-v6-engine-parts/turbo-buick-v6-camshafts/206-206-turbo-cam.html

If so, you are theoretically already trapping 600+rpm past peak.

[good2win22]

What tire diameter are you using now?  28 inch tire will do wonders with a 3.42 gear rear end.  Leave it in 3rd. Locking the converter may help but the tranny better be up to the task.

[Shimy87]

I think that is the cam I have, will check

Have a 26 inch tire now. Only height available in a 17 inch DR

[Forzfed]

What is it shifting at and is the converter locked up?

[Steve Wood]

You have 14-15% converter slippage which is the major problem evident from the data you provided.  You should be in the elevens easily with a 1.6 short time and a locked converter.  I would lock it about 80 mph.  You did not mention your boost, but boost is the best thing you can do beyond locking the converter.

We have told you 28" tires in the past but you have discarded the idea because you need wheels.

[Shimy87]

its shifting at 5400ish

Checked into locking the converter and the place where I got it said it would kill it

Boost is at 23-24, it moves about slightly on the logger

at this point, seems like getting some steel 15inch rims and 28 inch slicks would be the cheapest option? But will this converter issue still fight me?

Converters confuse me. I think I understand I want a 2800-3000ish stall speed. That's what I have now, don't really love it for street driving but can live with it. But the whole lock/unlock thing is hard for me to grasp. And for a 90% driver/10% strip car what is the best compromise if there is such a thing?

Sorry but the more I read up on it the more I struggle.

[Forzfed]

There is probably a good .3-.4 and 4 mph with a locked up converter.  My low milage stock Turbo Buick went just as fast as you and same mph on a hot day with less boost and the converter locked.  You should look into buying a non-lock up converter if you don't plan on using the lockup.

My other car with the 9/11 and 4.1 when I first took it to the track on straight pump gas I was running pig rich on the first pass because I was running pump.  And it went 12.3, without any changes and the converter locked I went 11.9.  I then unlocked it and started to turn the fuel pressure down till it ran in the 11.7-11.8 range without the converter locked.

[Scoobum]

I got Shimy to contact CK about the locking the convertor awhile back...and it was a no go. Basically what he's doing is 'blowing through' the convertor.

[Scoobum]

Shimy...think of a standard transmission car with a slipping wore out clutch. It's not transferring all the power to the rear tires. Same thing happening with your convertor. It's slipping like a whore.

[TexasT]

Whose converter are you using? Lots can be accomplished with a good converter. The stall and the flash stall are generally two different numbers. A good non locking converter can be had and is tight enough to couple well ay the top end of the track giving single digit slip yet still being loose for the launch and having the flash Stall get you a real thump to get it out of the hole and keep that nice 60' you are laying down. These aren't cheap. Expect to be upwards of a grand. I want to try on of the d husek 3021 but I'm good with my custom I got.

As far as  wheels go, any old rally, steel, or cool shiney rim should work as long as it has the bolt spacing and correct back space. I'd go with a 15x8 Chevy rally wheel. Speedway, summit, jegs all have em. And shipped right to your door.

[gusszgs]

I run a LU (Husek 3021) and have run 11.40's 1.58 60' around 117mph in the heat and humidity. Complete stock block with 980's. Key is a decent converter and a 28" tall tire.......... at least in my case anyway. PL shows I'm near 5400 thru the traps

[Steve Wood]

If the backspacing is not right, it will  not fit.  Just any old wheel is not what you want.  Ideally, an 8" wheel with a 4" backspacing will come the closest to fitting in all circumstances

[Scoobum]

Just to add to what Steve said. First off the 28x9 MT slick and the 275/60/15 MT DR have the same dimensions. You can use the stock GN rim with either...as I've done this in the past. Currently I have rims with a 4.5 inch backspace...an d I use a 7/32nd spacer to get the tire off the frame rail. Grumpy ran a 4.5 backspace rim years ago with a spacer with a 275/60/15. 

The bottom line is a rim with a 4 inch backspace works best on these cars.

[good2win22]

If you decide to go the wheel and tire route, give this a thought. The taller tire will take what  mechanical advantage that the tranny has right now and reduce it. If your slip is in the teens already like Steve mentioned, it will be worse with the taller tire. I would suggest you look at the tranny.  If you're going to keep the lock up, I lock mine at 90 mph and was going to lock it it a little later than that but never got another run. Now I'm going with a non lock set up. Fast guys I've talked with say that once you hit the 11.5 mark, the lock up won't get you any faster and will actually make you slower. I have no evidence to back that last statement up