MWatson17

I'm wondering what you guys with full weight 4th gen F bodies are running in the 60'. I'm currently running 12.02@113 with 1.71-1.76 60 foots. The car is inconsistent off the line. I can feel the tires slipping (not quite what I call spinning) and then grabbing about 20 feet out. I took some slow motion video to try and see what the car is doing, but the videos are inconclusive, at least to me (not an experienced chassis tuner by any stretch).

The car's setup is as follows:
Cam only, 236/242 .615/.615, 111LSA, 3500 converter
275/50-15 ET street radials, tried anywhere from 16-19psi
LCA relocation, stock LCAs
Comp 3-way adjustable rear shocks set on 50/50
All other suspension components stock

I started off with LCAs in the bottom hole of the relocation bracket. Moved them up to the top hole and although it felt like it left harder, the 60' time had zero improvement and that same night I spun really bad on my last pass. As far as the shocks, I'm not a huge fan of the Comp 3-ways, and am looking to get some double adjustables for next year. But there's a few races left before my track closes and I wanted to see if I could figure out why it's not hooking before we put it away. I can post the video if you want to see it.

Any advice is greatly appreciated, I'm new to tuning the chassis so go easy on me.

MWatson17

Here is the video of the car at the line. First video (left lane) was a 1.74 60'. Second video (right lane) was a 1.76, and the car almost got sideways on me it was so bad, but doesn't appear to be spinning. Right lane was poorly prepped that day, my cousin ran right before me and blew his slicks off on that run. Both runs were with the LCA in the bottom hole.

http://www.youtube.com/watch?v=HFoLY...ature=youtu.be

Steinjager

A little bit of preload into the rear sway bar would help to level it out, although it doesn't appear to roll over very much, those tires like to be planted flat and square.

Also, you said you tried top and bottom hole of LCA's with no change in 60 so I would say the top hole may work out better for you. As long as you are still maintaining the proper angle from the rear end to the chassis.

Are you leaving on the convertor or letting the engine have a run at it?

MWatson17

Thanks for the reply! I used to always leave with just a little bit of throttle, about 1400RPM. Lately I've been taking that up to about 2-2500 and it feels like it hits harder, but the 60' times were no different from before, which really confused me.

I will be racing this weekend. I've been meaning to disconnect my front sway bar but haven't got around to it, so I will try that. I may also try adding preload to the rear, until I get a stiffer bar.

MWatson17

Made it out to the track tonight, didn't get a chance to make any changes though. The cold air made a huge difference though, ran a best of 11.83@115 with a 1.68 60'. I got more videos and in these you can see the tire slipping a bit. We also noticed that the tire had moved on the wheel about 3/4 of an inch. I will post another reply with a link to the new videos.

MWatson17

http://www.youtube.com/watch?v=6pofG...ature=youtu.be

z28241

iTrader: (13)

so far with the info you posted, IMO remove that front sway bar 1st and foremost! whats your rear gear and tire height? edit just saw ur tire info

MWatson17

Sway bar is coming off tomorrow!

I have 3.73's on a 26" tire, 275/50-15 ET street radial. 3500 converter, 4L60E transmission, in case anyone was wondering.

z28241

iTrader: (13)

yep that should help, a good TQ arm and aftermarket LCA's should be in order too, stock stuff is flimsy and hurt short times, as far as everything else ur gettin there.

MWatson17

I have a torque arm, but I'm going to put it in over the winter. Tubular LCA's will also be going in over the winter. Also plan on a stiffer sway bar (not a drag style) and maybe double adjustable shocks. Those should help out a lot!

z28241

iTrader: (13)

Absolutley! My LCA's worked better in the bottom hole FWIW, our cams are similar, after some time i ended up going w/ bigger converter (4000) and with some tuning and dropped another tenth of my 60'.

z28241

iTrader: (13)

U may want to add Sub Frame Connectors in aswell. GOOD LUCK!

MWatson17

I do have subframe connectors on it. Disconnected the front sway bar today, I'll see how it does tomorrow!

MWatson17

Well I've been to the track a few more times. Unhooking the front sway bar made somewhat of a difference feel-wise, but still no difference in 60'. After today I believe that the tires in the previous videos I've posted are not spinning at all.

Today there were a couple passes where the left tire wouldn't spin in the burnout (saving for a 9 inch, so that won't happen anymore). As you could imagine, the car spun off the launch after this. In the slow-mo video, you can clearly see when the tire starts spinning, where my other videos where I thought it was slipping, you cannot.

So my thinking now is that the stock LCA and bushings are sloppy and it moves around a little off the start. That's what I'm feeling inside the car, that feels like spinning, but is actually just chassis slop. Sound plausible?

HCI2000SS

iTrader: (2)

I'm just curious, are you running at Milan?

MWatson17

Yes I am.

FU_I_AM_UltraZ

iTrader: (20)

don't feel bad... with my m6 cars i'm only netting 2.0s 60fts lol... I know I need some 15in wheels and DRs...
tubular LCA's wouldn't hurt. I have some founders performance new that I never used... adjustable with 3 pc poly bushing. i think the auto x guys prefer them.