thunderstruck507

iTrader: (18)

The more I read around here the more I wonder if something is up somewhere with my car.

Stock converter, cam/bolt ons it ran 8.4@86-87mph and 2.0 60fts hooking (2000-2800DA).

Went to a built trans, lightly used Yank SS3600 (from a GTO), and new tune and drag radials. Car went 7.8s at 89-90mph with best 60 fts of 1.77 and 1.74 hooking on 325/50r15 M/T ET radials (900-1800DA). 12.24@110mph was the best pass, later made some 12.3@108mph in better air but after valve float had gotten much worse.

Car weighs ~3680# raceweight with a 3.42 rear gear.

Am I in the ballpark or should the car 60ft a little better? These results are leaving off idle. I have tried stalling it up but that results in tire spin.

A friend has a 98 z28: vig 3200, 3.73, 275/50r15 MT, ls6 intake, 220/220 cam, full bolt ons, 3200#s and he has gotten 1.59-1.6 60fts pretty regular.


I recently did new heads/cam and found out my old cam had valve float which was killing the top end for sure (cam had bad lobes), and the new combo is noticeably stronger from idle to redline. Track won't be open until Feb.

c0ncEpT

iTrader: (4)

What kind of power does the car make?

If its only going 1.77 dead hooking something is up.

Although I don't have a Yank my Bolt on car with a 3800 converter goes into the 1.6's even if I leave soft.

My buddys car with an EPS cam and ported 5.3 heads has gone 1.45 with an SS4000 @ 3700lbs.

I know its kinda apples to oranges but its at least something to compare it to.

thunderstruck507

iTrader: (18)

Previous dyno for the car was ~350rwhp unlocked. Before that it dynoed 370rwhp but showed lean. Car had an unknown vacuum leak in the brake booster so it was tuned over that to compensate it seems.

ss454327

iTrader: (10)

If stalling up caused a tire spin I'd say it's hitting the tires harder which could be closer to the sweet spot. Wait til the track opens again and give us an update.

thunderstruck507

iTrader: (18)

I'm not sure if it's hitting harder or just displaying the car's limits on suspension.

It is set up rather stiff so it rides firm and has virtually no body roll. I don't like driving boats that sway along the road haha. Great for cruising, daily driving, autocross, and everything...but hell on weight transfer.



http://www.youtube.com/watch?feature...&v=nqa1rogolBI

01ssreda4

iTrader: (96)

I'd say its close.....your curb weight looks a tad heavier then an f-body so that's gonna show when getting the car off the line. Tune good? I'd take the car back and see how it does with the new combo.

thunderstruck507

iTrader: (18)

Still working out the new tune. Idle stuff is giving me fits. I can get it to run perfect, park it a few days, then it won't run for crap again.

I was hoping to hit the track the last weekend since at that point I had the car running great, but they were rained out.

boostednismo

iTrader: (5)

What psi are you running in the MT's? And have you played around with the air pressure any?

I have the ss4000 but it 60'fts better from a high stall.

thunderstruck507

iTrader: (18)

I started at 18# and have gone as low as 12#. I've had the best luck at 14-15#.

Track prep could be a big issue, I usually end up running on street car fun days. My first pass of the day is always the best unless there is an issue and they VHT the pad.

The track owner said next time out I should try staging out of the groove where no one runs so I will be in the un-molested VHT or I can jump in behind some big tire cars laying fresh rubber.

98TADRIVER

iTrader: (36)

why such a tall tire? That'd definately be one factor when it comes to your 60' times. thats a tire you'd use with 4.30 or maybe even a 4.56 gear. have you tried using a 275 50 15? I have 3.42 gears with a converter and run a 275 40 17 (close to a 275 50 15) and have plenty of mph/rpm left in 3rd gear (with a stock motor)

thunderstruck507

iTrader: (18)

The tires were bought from a friend for $200 with 3 passes on them and fit my extra 15x10 wheels haha. Previous tires were 275/50r15 Nitto 555R which worked really well (1.78 60ft spinning just a hair).

Another set of 555r would have been over $300 shipped and MT 275/50 would have been close to $400 shipped.

I will go back to a shorter tire when these are used up.

blk/slvr02ss

iTrader: (21)

I have cut 1.61 60ft in 275/50/15 Nitto 555r's w/ a bolt-on 02 Camaro SS ! What do u have for suspension ?

speedtigger

iTrader: (16)

Street car fun day is like running in a dirt parking lot after about 15 guys go down the track. I have been to those events and the only clean passes I ever get are when I first get there and when they reprep.

I also think I recall having a conversation with you on here about your suspension set up. I remember telling you that the *** of your car is too high and that causes problems on a-bodies. Our cars work best when they sit level and are fairly low. With all that said, you should hook no problem at your power level. Even if it is less than ideal.

Try going on a race night instead of fun day. I prefer test and tune days for serious tweaking. Street fun days are just for puppy kicking.

PS. I average 1.68 with only a 2800 circle D converter. I torque the converter to about 1800 when staged.

Sofls1

iTrader: (16)

Couple things stand out here to me:

1 Are you logging the passes w hp tuners? you should have some idea if its spinning, post the log if possible. Have a friend video the passes, from about 15' from the car focusing in on the rear quarter panel.

2 suspension is tight? front sway bar? Whats going on here?

3, street tire fun day sucks, stop going on that day if possible

4. Looking at the mods in your sig, I'd say the 3600 is too small. I would send that sucker back for the free restall and have it made into a SS4000.

Besides issue number 4, I'm almost positive your car is spinning. I thought my car was dead hooking, then I talked to a good chassis builder. I straightened out the IC problem I had, and added a dragbar, and went from 1.50 60fts to 1.42 60fts and I'm still spinning with a SS3600 converter, a 3.42 gear and a 10"slick.

green28

iTrader: (8)

Did you have anything done to the suspension, or is it still bascially working with 40 year old parts? Hopefully with whatever motor issues you had those are figured out which could go a long way towards helping your times when the track opens back up. For reference my car is around 3600 lbs. at race weight. With bolt-on's, a little suspension work, a 255/50/16 MT, and an SS4000 I've consistanly ran a 60 ft. of 1.59-1.62 on a decently prepped track. That being said on a marginally prepped track it's more like 1.8-1.9's, I'll never go back on a T&T night again.

Your lower 60's could be a combo of track prep, the motor issue, and suspension.

thunderstruck507

iTrader: (18)

Suspension is gone through but it was not drag specific focused so much as making a sporty ride.

Front:
750# rate springs with height adjusters
remove sway bar for track
Afco 1021 stock appearing race shocks (circle track/course car, not drag)
new rubber bushings

Rear:
Hotchkis 1" drop springs with spacers to retain height
KYB gas-a-just shocks
stock SS sway bar
Lakewood style bolt on traction bars
adjustable upper control arms, stock boxed lowers


So basically just set up to eliminate body roll, firm the ride, and make the car more pleasurable as a driver and plenty capable of attending autox and hitting the back roads. I know this isn't helping so I'm trying to work around it best I can. I'll get some results on a better prep track and with the new combo and start there.

speedtigger

iTrader: (16)

The Lakewoods have to go. They do not work well the stock suspension in place. They create a conflict with the natural movement of your factory 4 link set up and cause the rear suspension to bind and be very stiff.

They are an antique. I would take them to the next swap meet and sell them to a retro or rat rod guy.

You will need some rear control arm braces though. They are very important. These are my favorite design:
http://www.summitracing.com/parts/EDL-5211/?rtype=10

thunderstruck507

iTrader: (18)

I took them off and tried some UMI relocation bars. Not only did I not gain any traction, the tires rubbed constantly. Until I win the lottery and can afford a whole new wheel tire package I need the stiffness to keep the fenders off the tires.

And honestly, when they go I will then have to up the spring rate...the car felt like a 6000lb truck with worn out shocks due to excess body roll and slop. Like I said my suspension will always be some sort of compromise...it's a driver, not a strip only car and I cannot stand sloppy suspension.

speedtigger

iTrader: (16)

The winning formula for a great handling A-Body is urethane bushings, boxed control arms, control arm braces and a 1" diameter rear sway bar on the rear.

Add a 1 1/4 sway bar on the front with good shocks all around and the car will handle. The last ingredient is a fast ratio 12:1 steering box.

I fully understand about the wheels. The right offset will let you get the car down level. Then is will handle and hook better.

thunderstruck507

iTrader: (18)

Yeah, no doubt.


I was just questioning how when as best I can tell and even had some friends look ( I went so far as to put white lines on the sidewall for reference) that the car is hooking the 60ft seems a little high compared to some others.

It might leave harder from foot brake if it hooks, but off idle it seems to be doing the best it's going to and I wasn't sure if that was normal. The added power from the new heads/cam might help.