what am i doin wrong???

[strictly180]

2012 gt conv 6spd
4200lbs wit me in it
bama tune
434rwhp 389ft lbs of tq
boss manifold
bbk throttle body
pypes super bomb system from header back
3.31s
305/45/18 nitto nt05r
13.3 109mph end of the 3rd gear
2.1
englishtown raceway and island dragway get the same results with both tracks. car feels like it dead hooks, launching 4.5k to 5k rpms.

last season i was stock and rolling on 20in vossen wheels and was running the same 13.3 i am now but 4th gear. what am i doing wrong???

 

[stkjock]

time slip?

 

[strictly180]

i think i threw it away or try to see if i find one

https://www.facebook.com/photo.php?v=551919138202962&l=7288019499669086842

 

[konablue11gt]

what was your 60 foot? that will tell a lot what rpms are you shifting at?

 

[irishpwr46]

that video sounds like you aren't running out the rpms before shifting. sounds like youre shifting way too early

 

[fdjizm]

Run doesn't really sound bad, hmmm in for more info on the run.

 

[strictly180]

This is 2 slips I found not the 109mph and I shift @ 7200RPMs
R/T .845 .170
60' 2.105 2.057
330 5.750 5.625
1/8 8.719 8.625
MPH 82.95 79.84
1000 11.24 11.207
1/4 13.345 13.331
MPH 106.45 105.65

 

[stkjock]

2.1 60' doesn't = dead hook IMO

Right there is a full second in ET for the taking, IMHO

 

[psfracer]

I think 4200lbs isn't helping either.

109 mph isn't bad for 4200lbs. However at 109 mph I would think you should be in at least the 1.8 to 1.7 range minimum 60' wise with 434 rwhp.

the 305/45/18 is a pretty damn tall tire, combined with 4200lbs, its going to be hard to get that to 60 foot. How tall of a tire is that? 29 tall? Sounds huge.

 

[stkjock]

Good pick up Paul on the tire and gear combo. I totally glazed over that.

It is a 29" and 3.31s are a poor combo for a NA car.

 

[NUTCASE]

what is your tire pressure at?
how many seconds do you heat for? is there smoke in your rearview when you heat the tires?

how high to you push the mph when you heat the tires?

also what rpm are you shifting?

I ask most of this because you are getting a spin-bog. basically the tires spin, but then when they hook you bog and pull you out of the power band. with that boss mani it is important to keep the RPMs up. if when you hook you drop down to 3500 the boss mani is actually hurting you believe it or not.

try dropping your tire pressure down. I don't know what to suggest because I don't know if you can do 17psi on 18's

then try heating the tires more. try to get the mph over 40.

try to work the car to a dead hook, if you can flash the converter and stomp it kudos for you but I don't think that will happen with your tires/mods. the go backwards from there. slowly add tire pressure and and watch what your timeslip does. also watch your wear pattern as a 305 tire might be to much for you when the setup and launch is right. once you are to the point that you are getting spin keep adding pressure to make sure that spin isin't actually helping you get in the power band faster.

also, I know this sounds counter intuitive but if you get to the point where you think the balance is perfect try adding 50lbs to the rear, and experiment with more tire pressure from there.

also remember, that boss intake mani needs to be shifted high.

and I imagine 18in rims with 305 tire weigh a few pounds. once again being counter intuitive try putting the stock wheels and tires back on and see what your MPH does.

as far as the wheels and tires being counter intuitive think about this: I have seen guys in 100% stone stock 5.0s run about your number with a FASTER 60'.

2.1 60' doesn't = dead hook IMO

Right there is a full second in ET for the taking, IMHO

if you watch the vid he is clearly spinning and then bogging

 

[psfracer]

Good pick up Paul on the tire and gear combo. I totally glazed over that.

It is a 29" and 3.31s are a poor combo for a NA car.

YEah, especially with that intake on there. It must take forever to get into the power band the first time. The Boss intake likes to go higher then 7200 I believe also.

 

[stkjock]

I didn't watch the vid, doesn't work on the iPad.

 

[psfracer]

He should go with a different DR for track use, 27 tall. Go with a M/T or M&H for 18 inch wheel.

A 305/45/18 spinning? Well it is a Nitto......

 

[kdanner]

How can it possibly weigh anywhere near 4200lbs?

2.1 seconds to cover the last 320' = car isn't making any power.

 

[stkjock]

Vert and driver is a big guy?

 

[psfracer]

How can it possibly weigh anywhere near 4200lbs?

2.1 seconds to cover the last 320' = car isn't making any power.

I still think its the combo. 109 mph out of a 4200 lb car/driver isn't that bad. But that extremely tall tire combined with the Boss intake, 3.31s, and 4200lbs is just all wrong.

 

[kdanner]

Vert and driver is a big guy?

Would have to be really big, a vert is about 125lbs heavier. So you'd figure the car would be 37XX stock.

Now if there is something untold about this story, like a trunk full of stereo shit, then it starts to seem possible if he is a big guy too.

 

[psfracer]

Couple of dead bodies in the trunk?

 

[fdjizm]

I'm going with E-brake on.