YellowB4Z

iTrader: (9)

Well where to start..... Ive got a 1999 SS its 3600lbs race weight it has an iron block 6.0 making 515rwhp@6400rpm and 455ftlbs@4600rpm. It makes over 400ftlbs from 4400rpm-6100rpm. It has a SPEC3i clutch, moser 9" rear with 4.10s. All spohn adjustable rear suspension, with 1" drag bar, all stock front suspension with no sway bar and QA1 struts set at 3, QA1 rear shocks set at 6. The LCAs are on the bottom hole on the relocation brackets and the pinion is -3*. I ran 11.14@124mph with a 1.62 60ft last year with a 28" tall tire and a stock LS6 intake. This year Im running a 26" tall tire to get more effective gear ratio and a FAST92/92 and a fresh tune. I ran 11.11@124mph with a 1.60 60ft tonight after the tune and FAST intake. I dont understand why I cant seem to gain any ET. Where Im stumped is when the car pulled 1.57 60fts the 330ft slows down to 4.7 sec. When I spin what feels like a lot it goes 1.60 60ft and 4.6 in the 330ft. I know you dont want to dead hook. I just cant seem to find a happy medium. I am wondering if I shouldnt step up to a 4.56 gear and go back to my 28" tires. If anyone can give some input Id really appriciate it. If any additional info is needed please ask and I will do my best to provide it. Thanks!

Nostang

iTrader: (4)

4.56's and 28's should def help you out (~128mph with 28's @7k rpms). No reason you shouldn' run 10.70's or better at 127mph with that type of power. You need the mechanical torque multiplication of the 4.56's.

Mikey 97Z M6

iTrader: (37)

Do you have a dynograph from your tune? If the hp falls off slowly after peaking, then you can run out the rpm's further in final gear without suffering trap speed too much. If it's falling off fast, then you'll want your shift points, and finish line closer to your peak hp. I found this out the hard way with an old "peaky" cam with XER lobes.

What rpm are you at when going through the traps? What rpm do you currently shift at?

Your MPH is very similiar to mine, but you are making more hp than me. Have you done any weight reduction at all?

Mike

Villain281H

iTrader: (5)

What rpm are you crossing the stripe at?

YellowB4Z

iTrader: (9)

Im thinking the same thing. If I could run 10.7s I would be extatic. I just really want to run 10s NA then spray it into the 9s.

It holds power past peak decent. We only dynoed to 6800 and it was still making 490hp at 6800. Im going through the traps roughly 6500-6600rpm. I shift at 6800-6900rpm depending on how quick I am on the shift light. Ive got a lot of stuff removed. Heat, a/c, carpet, sway bar, seat belts, rear seat, but Ive got an iron block, 6pt roll bar, 9" rear end. So Ive canceled out most of my weight reduction. It weighs 3600lbs on the starting line.



Im going through the traps at 6500-6600rpm.

Villain281H

iTrader: (5)

The rpm band needs to come up a little, or you need to be able to launch it harder. Most low 11 second cars with an efficient driveline will be in the low 1.5 to mid 1.4 on the 60 foot times. That can really add up downtrack.

Derek

YellowB4Z

iTrader: (9)

I agree. The best Ive been able to get the car to 60ft is 1.57 on the 26" tires. The best I ever got on the 28" tires was 1.62. It will be interesting to see what happens with steeper gears and the 28s.

mdacton

iTrader: (3)

damn I am less than 400 to the tire....

but I am low 1.40's been a 36, so the car works.

good luck

WHITE DEVIL

iTrader: (1)

i would go a 4.56 with a 28 if you want to stay on the motor, i would only go a 4.30 and 28 if you want to hit it with the junk

studderin

iTrader: (28)

sounds like my car, Im going to try tsme 26/10.5/16 ETstreets from a friends. Over my 28/10.5 etdrag, with the 4;30s. keep up updatesd

YellowB4Z

iTrader: (9)

Definitely sounds like your car is working well. The auto helps out a LOT. If I had a TH400 or 4L80e I wouldnt be dealing with these issues right now. But thats the price you way if you like banging the gears.

Thats whats been running around my head as well. Ill probibly just get another center section and set it up with 4.10s or 4.30s depending on what the research figures out.

Yeah its all about experimentation. There are so many variables youve gotta try everything and see what works best for your application. I will definitely keep everyone updated.

Nitroused383

iTrader: (10)

Maybe try playing around with your lower control arm position? Have you messed around with tire pressure at all and what DA have you been running in?

slow trap

iTrader: (22)

i am in the same boat pretty much. i ran last year @ 3800 lbs in decent air with a set of 27- 10.5-16 et streets and could only muster a 1.63 60', 11.11 et @ 125 with 517 rw. switched over to a 28 -10.5-s et drag and put skinnies on the front and took off ac and ran the same 60' and mph it was higher da' but still thought i would have picked up. i've only got 3:89 gears so that hurt the launch (it would spin alittle then bog,needed to make air pressure adjustments but didn't get in enough passes) but i plan on making a 1/4 pass on spray one of these days so i'll just stick with those gears .

YellowB4Z

iTrader: (9)

Yeah Ill be moving the LCAs up one hole and see what happens. Ive been all over the place with the tire pressure. Settles around 10-12psi. The DA wed. was 1900-2000ft. We dont get may good DA days here in Indiana.

BADD SS

iTrader: (4)

I think you need to re-gear and run 28's....

If I didnt have trans shifting issue's I should have been in the tens, even with my + 2200 DA.

YellowB4Z

iTrader: (9)

Yeah I will definitely need to regear. My trans isnt too healthy either but its doing the job right now. Are you still making 418rwhp and running 11.0? What does your car weigh?

NHRAFORMULA00

iTrader: (2)

You def need the,4.56 gears,28 inch tall et drags,Also ditch the 1 inch drag bar and get bigger one thats adjustable,Spohn or BMR .My sons SI car was lighting up the right tire with that bar,he changed it out to the bigger Spohn and the problem went away.

YellowB4Z

iTrader: (9)

Ive got the big Spohn bar. I just guessed at the thinkness. It is the big preloadable/adjustable Spohn bar though. Ive got a spool in the car too so I dont have any one wheel spin issues. Thanks for the info. Thats the things Im looking for. Personal experiences and info like that. I have a set of light weight EDM coated 4.44 gears Im gonna try out. I didnt want to spend a lot of cash on a brand new set of gears just in case they didnt work out too well. So I found the closest thing to 4.56s I could find in a used set of nascar gears.

BADD SS

iTrader: (4)

Its A lightweight, 3105

Still its the trap speed, I should be a touch higher then 125, im thinking 126-7 easy, as I had to let off completely between shifts, shift, and come back on with the power.....Not good for racing When I was 200 lbs heavier, and on 26's with 4.11 gears it went 11.13 @ 124, +73 da, so it should pick up alot....

I used to 60' 1.57's on 26's, dropped to 1.50-53 by re gearing and running 28's.

And yes, still 418 rwhp ...

YellowB4Z

iTrader: (9)

Yeah your car is definitely a lightweight. I need to cut some fat off the back of my sweat hog. I really wish I had an LS3/L92 block to stuff all my internals in. That would be an easy 70lbs. Im in the same non-shifting boat. as you can see in my vid here.

http://www.youtube.com/watch?v=VN2RI...e=channel_page