Slow Z28

iTrader: (19)

I know it's something that may not be possible due to the shitty track prep and the car spinning alot, but there's a couple launches in the vid. It always liked about 16-17psi in the QTP's, but man did we have to drop that to get it to hook SOMETHING

Suspension setup:
BMR K-member with upper and lowers
QA1's all the way around(the R's up front)
QA1 springs in front, stock in back with rubber isolator out
Custom LCA's and PHR with rod ends, LCA's are moved in with the spacers, stock location
Spohn tranny mount torque arm, located on BMR TH350 crossmember not the trans
Moser 9", 3.50 gears, 28x11.5 QTP's


http://www.tgdspeed.com/videos/chris.wmv

First pass is on motor(it's a dog, went 1.65 and 11.2x@123mph)

Second pass is 100 shot, 1 on the front QA1's, 5 on the rears, 16psi in the tires hot

Third pass is 100 shot, same thing just 14psi in the tires

(1:00 minute mark) Fourth pass is 100 shot, dropped it down to 12psi hot, followed big tire car and went 1.45, also went up to 2 on the fronts trying not to have the front HOP up and then down too quickly on launch(10.20@133mph)

Fifth pass is 150 shot, dropped down to 11psi, just spun(10.40@135)

6th pass is 150 shot, just tried again right away cause i was pissed with the track prep. accidently bumped the shifter to 2nd right on launch. 1.50 60ft(10.2x@136mph)

I guess my biggest questions are, does the car seem like it's working PROPERLY, save for the spinning? It's not squatting at all, and I always thought that too much was bad. -2 on the torque arm, even preload on the sway bar, car comes out even and is steady down the track. The front end seems to come up an aweful lot, but don't know if i should go to 3 on the fronts.

If there is really nothing valuable in the video because of the spinning, i'm hoping to visit the track soon again. I'm wanting to try off the transbrake, but that might change everything, so I'm just aiming to try for some clean passes. I'm just really looking for those 1.3x short times.

Any help on this? New tires are on the way 3 y/o QTP's aren't doing it. What do you think about rim screw after watching the vid?

Will say it looks like it really wants to get down on that 150 shot though

Sorry for so many questions, and ignore the TX plates, there was a Real Street Drags the next day we didn't want people to know we were going to(not that the other 10 people there really cared, haha)

Chris

PS - "Next" if you read this, did you gain anything taking off the bullets and putting the extensions on? was thinking about trying that this next time wtih the headers I got from you.

rocketman442

iTrader: (8)

You may want to soften the rear so it will squat just a little bit. My friend has a 3rd gen with a BBC, he was running 7.2 in the 1/8 and his car launched just like yous, he softened the rear shocks 2 clicks i belive now he runs 6.8 pretty consistantly now. He is set up almost identical to you but he had 3.73's and a BBC obviously. The old tires may be hurting you also.

GIZMO

iTrader: (8)

What size rim do you run those 11.5" tires on?

sho-me speed

iTrader: (55)

Definitely soften the rear. Your car was jumping up off of the track on the launch on a couple of runs.

MADMAN

iTrader: (4)

You dont need to soften the rears. You need to stiffen the rear. You dont want squat. First thing Is check pinion angle. The check the angle of your lcas. You want them running uphill from the rearend to the body. Then tighten the rear shocks to 7 and run the tires about 12.5 to 13lbs.

Slow Z28

iTrader: (19)

The rims are 15x10 Prostars with the 7.5" BS, typical F-body thing

The T/A is at the -2*

The LCA's run uphill. The rearend has the relocation brackets and they are located at the bottom hole. (Was GeorgeC's old rearend)

MADMAN, thanks for the tips to check.

I'm thinking that on the 'brake then, this thing will hit harder and might end up squatting. Front end seem ok to you though?

vmax1500

Toss the 3 year old QTP's in the trash Unless you need to run a DOT tire, I suggest getting some real slicks and screwing the rims...

Crazy Man

iTrader: (6)

You could try not shooting the nitrous right of the line that would probly help with the spinning lol...

Slow Z28

iTrader: (19)

haha, if the car can't hook a 100 shot, that's pretty pathetic

vmax1500

Spray her out of the bucket Unless you are running a REALLY big shot I think turning the spray on once you are rolling could actually slow you down as it will disrupt your suspension...

You need new tires

gator's 99TA

iTrader: (2)

thank you madman for coming in. i cringe when i hear people say "you dont have enough squat in the rear" uggggggggggg

Pro Stock John

iTrader: (34)

Your slicks are too old. How many passes do you have on them?

Squat is wasted energy, run the rears as stiff as you can. I'd try 5/5 at GLD, but if you can run like 7/7 or 8/8 that would be awesome... Depends on GLD is hooking. Keep in mind that when it gets cold there at nite the track goes away pretty fast.

I start with 1/1 soft in the front, and 5/5 in the back. My Tq arm is set to zero preload. I know Magnus played around with this on his car a while back and when he put too much preload it seemed to hit the tires too hard. I'll link him to this thread.

But you really can't figure stuff out with three year old slicks.

Magnus

iTrader: (4)

When I was cutting 1.2's... my rear QA1's where at 7 stiffness on a scale of 1-12 and my front R's where at 1...

After I bent my first torque arm, I sent to the alston piece and set it to a pinion angle of -.05 degrees. Due to the extreme stifness of my car and how light it was, I didn't need to go with a large pinion angle like many others do.

I also ran the spohn anti-roll bar as well that really stiffened things up.

This was all done without LCA relocating brackets.. Even though I had V6 springs in back with 1 coil cut out, and radiator hose up top..

As soon as I put in the reloc brackets I did a wheel stand for 300' and blew up.

Edit: Reading your post...

I woudln't worry about screwing the tires unless you want to run under 12psi hot... you shouldn't need to do that...

And, if the new tires aren't hooking, go to a bigger tire if you can (if your class doesn't restrict you).. If you have traction issues and your suspension is set, a bigger tire will gain you a lot more in the 60' than may cause you to lose on the big end due to rolling resistance.

I ran a 28x15x10.5W on my car.

Pro Stock John

iTrader: (34)

Chris, maybe check with Larry @ Speed Inc. I swapped over to new 28W's last week, and unless they threw them out, my old W's had <15 passes on them. You are more than welcome to get them if you want.

Slow Z28

iTrader: (19)

my buddy that was lining me up in the vid has some W's that were on his '95 Impala SS that he might be getting rid of. Another guy up by me as some brand new 28x10.5's for sale with tubs for cheap. I won't run the tubes though.

Thanks Keith & PSJ for stepping in. I'm rechecking the pinion angle tonight. And it's just a fun car, so no classes I'm worried about. Forgot to say I do have the Wolfe Solid rear sway bar on there, so the whole rear is pretty level and stiff.

The tires I got in September of '04, haha. So wait, 2 solid years old. Haven't had but 15-20 passes on them. Just like I said in another thread, about 1000+ street miles.

this weather is just being killer and not allowing ANY trips to the track

vmax1500

Street miles & heat cycles kill those tires along with the age... do yourself a favor and get a dedicated set of tires for the track... it will be cheaper in the long run and your car will perform better... the 1st 100ft of the 1/4 are what makes or breaks ET...

FANTAZ28

iTrader: (2)

tires are shot! trust me, i had a buddy that would say teh same thing "they are 2 years old but have 3 pass's on the" that dosent matter having the car sit on the tire alone beats them up.....

new tires and you'll be much happier

Slow Z28

iTrader: (19)

Question -

when reading through a couple other posts on pinion angle and LCA angle...

i found one where it shows a car PLANTING the rear end down. it seperates the tire from the wheelwell(i.e. the gap gets larger)

MINE doesn't look like it's doing that. even though it's just a footbrake, it still should. why isn't it doing that? even on that 4th pass at the minute mark when it actually HOOKS, it doesn't look like the any part of the rear moves. just basically rocks back on the tires.

MADMAN

iTrader: (4)

The rear is going toward the ground. If you look closely the tire smashes against the ground but the fender doesnt get closer to the tire. That is correct we just need some new tires and a little tweaking and she will be able to leave.

The Juggernaut

iTrader: (7)

Buy new tires. I usually run mine 9.75-10.25psi cold.