My competition is getting faster

[usetaboost]

a duttneck ic has been in the high 10s. I don't think it's the ic that is holding you back. I think I remember grumpy saying he has been low 10s with a good slic. I doubt a fm would help much in this situation. Stock longblocks have been high 10s also. You never did say what's been done to the rear suspension or what adjustments you've made to the chip.

 

[LETHALV6]

Im not the expert by any means but I have to agree with the other guys here, your tires are way too small for what youre trying to do. I have been fortunate enough to run guys in these same cars in my Supra as well as GN and I can tell you the "dig" is where its at. Neither the Vette nor GT500 have the suspension to get you out of the hole but they will freight train on the back side...however the GT500 weighs a ton. Beleive it or not the 5.0 may be your biggest comp, Ive seen them dyno at 380-ish with no mods and weigh just a shade over 3300#, with a solid axle and tires...its a runner. I would spend your $ on a good set of cheater slicks (full on slicks will only get them crying afterward) and get your car leaving at 8-10# from the line....then its all stab and steer.

 

[Texas gn]

a duttneck ic has been in the high 10s. I don't think it's the ic that is holding you back. I think I remember grumpy saying he has been low 10s with a good slic. I doubt a fm would help much in this situation. Stock longblocks have been high 10s also. You never did say what's been done to the rear suspension or what adjustments you've made to the chip.

From all of the post so far it looks like I need to get it to the track and start my tuning process. I have not messed with chip timing at all and the fuel pressure is still at 43 lbs. Now that I have the PL I need to get to work on that. The rear suspension is stock except for the air bags. I think I will call Gbodyparts and order their rear sway bar. Like it was said before...timing and boost is free.

 

[Texas gn]

Im not the expert by any means but I have to agree with the other guys here, your tires are way too small for what youre trying to do. I have been fortunate enough to run guys in these same cars in my Supra as well as GN and I can tell you the "dig" is where its at. Neither the Vette nor GT500 have the suspension to get you out of the hole but they will freight train on the back side...however the GT500 weighs a ton. Beleive it or not the 5.0 may be your biggest comp, Ive seen them dyno at 380-ish with no mods and weigh just a shade over 3300#, with a solid axle and tires...its a runner. I would spend your $ on a good set of cheater slicks (full on slicks will only get them crying afterward) and get your car leaving at 8-10# from the line....then its all stab and steer.

Good point…it always come back to the tires too. I have the original rims and the Trans am style 16”..those have my MTs on them so I might look for some 28” MTs that will fit the 15” Gn rims and try it out. They are most likely too narrow to handle the MTs and i will have to buy more rims . And yes the 5.0 stock is something to watch out for. I saw a stock one running mid 12s the last time at the track.

 

[threerail]

if u dont have a translater and bigger maf i would def do it, i love my pte slic no heat issues at all, with stock cooling system, just a pain to install. the 28 in tire u need for sure, you are making enough power to pull it to faster times, been there done that. and i agree boost, timing, tune,mean alot. some e85 mix in there can get u more octane if your fuel system is up to it, but dont go too lean and fry your nice ride. regards rob

 

[LETHALV6]

I would def see if you can find some old steel Corvette rally wheels...theyre 8" wide vs your 7" GN stockers and pretty cheap (its what I run on my full slicks) I would double check the brakes and see where that puts you...with a solid launch they wont touch you.

 

[Texas gn]

I would def see if you can find some old steel Corvette rally wheels...theyre 8" wide vs your 7" GN stockers and pretty cheap (its what I run on my full slicks) I would double check the brakes and see where that puts you...with a solid launch they wont touch you.

Are you running the 28x10.50x15 slick on those rims? Fit ok?

 

[PARKBOY]

however the GT500 weighs a ton. Beleive it or not the 5.0 may be your biggest comp, Ive seen them dyno at 380-ish with no mods and weigh just a shade over 3300#, with a solid axle and tires...its a runner.

I thought those cars made 500 hp.

 

[LETHALV6]

I think my M/T ET streets are 28x10 but you'll want to check to be sure, they fit under my car fine but it is tight...I run pro stars on the car with a 275/50 drag radial for reg duty, my memory on the full slicks isnt 100%
The 5.0 is rated 412 I think, and the GT500 is over 500 but I have yet to see one hook up and run strong...my 400hp Supra runs dead even (mph wise) out at the Tx Mile.

 

[PARKBOY]

I think my M/T ET streets are 28x10 but you'll want to check to be sure, they fit under my car fine but it is tight...I run pro stars on the car with a 275/50 drag radial for reg duty, my memory on the full slicks isnt 100%
The 5.0 is rated 412 I think, and the GT500 is over 500 but I have yet to see one hook up and run strong...my 400hp Supra runs dead even (mph wise) out at the Tx Mile.

I misread i thought he meant the gt500 was making 380 hp.

 

[DaySleeper]

I drove a GT500 and I thought it was cool but a pig.

 

[UNGN]

That made perfect since to me until someone awhile back said that going to 28 inch tires will kill my 60 ft times and slow me down. He also said that I need to trap at least 120 mph before going to the 28s. Very confusing….

Your 60ft times suck now:biggrin: . How would 28" tires kill them?

A stock turbo, stock converter car can cut a 1.70 60ft with 28" DR's. Why couldn't a big turbo car with a 3000 stall? The trick is to leave with more boost to compensate... and the 28" tires WILL hold more boost than the 26" tires.

The Crossover point between a 28" tire and a 26" tire is closer to 110 mph with a stock head/cam car and even lower if you don't lock the converter.

My car has run 118+ with 28" tires. It wouldn't go over 114 with 26" tires, no matter how much boost I added... and that was on a perfect day.

 

[Texas gn]

I would def see if you can find some old steel Corvette rally wheels...theyre 8" wide vs your 7" GN stockers and pretty cheap (its what I run on my full slicks) I would double check the brakes and see where that puts you...with a solid launch they wont touch you.

LethalV6….would you mind sharing what back spacing your corvette wheel have? Thanks

 

[Texas gn]

Your 60ft times suck now:biggrin: . How would 28" tires kill them?

A stock turbo, stock converter car can cut a 1.70 60ft with 28" DR's. Why couldn't a big turbo car with a 3000 stall? The trick is to leave with more boost to compensate... and the 28" tires WILL hold more boost than the 26" tires.

The Crossover point between a 28" tire and a 26" tire is closer to 110 mph with a stock head/cam car and even lower if you don't lock the converter.

My car has run 118+ with 28" tires. It wouldn't go over 114 with 26" tires, no matter how much boost I added... and that was on a perfect day.

You guys have made me a believer! I will slip out to the track and get a few passes on my current setup. Then I will make sure the PL is happy and install some 28” MTs tires and do it again. I will post my results! Thanks for everyone help.

 

[LETHALV6]

Cant wait to hear what it does with a good tire under it and a solid 8 lb + launch....I think you will be amazed.
the corvette rally has a 4" bs on it by the way.

 

[TurboTGuy]

I just noticed this from the original post:

"I am looking to spend around a grand for the upgrade."

The M/T's will blow half of that, just so you know.

 

[Mr.Spool]

get the boost to 25psi,go to the 28 tire as it is not about mph but the true gain is in the rollout of the tire.you will have to add boost off the line to compensate for the torque lost in the gear reduction.i used to leave at 14psi off the ebrake on the 28 drag radial on a stock motor and a 3.42 rear.leave off boost they will never run you down.that car should be mid 11's all day.leave the motor alone.

 

[national]

I still dont see 28in tires picking up ET..maybe MPH a lil more but I would think youd lose 60 ft & def have to compensate for it..hoosier made a 27in tire which might work better & less chances of tearing into your 1/4 panel...as far as the stock intercooler thing,,yeah im sure you can go 10's with one but what could you pick up once you switch to a good one?..I went from a stock intercooler to a front mount & picked up several tenths in the 8th mile..didnt do anything different either..how the heck will a bigger sway bar help I would love to know..maybe the driving but not ET..but what do I know I havent tried any of them..

 

[3.8L V-8 eater]

Why not get a decent SLIC it would complement those mods you have well especially in Texas by
helping to keep KR at bay better...I agree with what others say about 28" tires more practice and tuning....

 

[Mr.Spool]

the dutt neck he has provides the flow and the alky cools the charge therefore no need for intercooler upgrade.the taller tire has more sidewall so you can hit it harder off the line.a 3.42 rear geared turbo buick needs to leave on boost to 60ft and get into full boost faster.my personal car as well as others i have worked on all dropped 60ft on taller tires with the proper amount of launch boost.the taller tires are also more forgiving on the tracks that haven't been prepped as well.