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      08-12-2012, 07:42 PM   #1
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HELP: sucky drag racing times



VT2-500 kit, 8psi confirmed on my boost gauge. Bridgestone re-11 tires launching at 1500rpm, anything much higher and I was experiencing wheel hop. 28psi hot in the back.

Temps were high, around 84*F, and very high humidity. On my best run, it probably cooled to 80*F.

For comparisons sake, I ran a hair quicker than a c5 vette, and beat a Viper GTS. The viper's best run was a 12.8@~115

So I see that I took a huge 3 tenths from my average runs because I had a .1 second better launch. I noticed I'm chirping my tires as much as 3 times per shift, which hurts it too. So theoretically I could be running low 12s with a 1.8 or 1.9 second launch, but I doubt my traps would be 7mph higher.

I'm gonna start with a dyno in 2 weeks or so, and get my water/meth kit hooked up to counter the heat.

So here's my question -why isn't a 500hp car hitting anywhere near 120mph trap speeds? The car feels significantly stronger in cold weather, but come on... am I really gonna pick up 7mph in the traps in colder air? Whats wrong with my car?
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      08-12-2012, 07:59 PM   #2
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It's not a drag car (seriously).

It's really only the reasonable explanation. If you don't want wheel hop you probably need drag radials.
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      08-12-2012, 09:10 PM   #3
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Originally Posted by Kgolf31 View Post
It's not a drag car (seriously).

It's really only the reasonable explanation. If you don't want wheel hop you probably need drag radials.
I'm not looking for a competitive drag car, I just want to replicate the numbers my supercharged brothers are running to make sure there's nothing wrong with my car
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      08-12-2012, 09:49 PM   #4
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Quote:
m not looking for a competitive drag car, I just want to replicate the numbers my supercharged brothers are running to make sure there's nothing wrong with my car
That's fair. What size tires, car weight with driver, and torque numbers of your brothers are comparing. We need more information.

Everything adds up. I was recently surprised that my z4mc ran 7 seconds slower than my e30m3 track car. Then I started to add it up:
-600lb less
-sticky hoosiers (but smaller of course)
-suspension 2 times as stiff, that's not taking into account that its 600lbs lighter.
-weight of the car is lower
-btw it is 188 whp.
I don't know much about drag racing but from my understanding, the start is everything just like my corners on the track are EVERYTHING.

Last edited by seank; 08-12-2012 at 09:54 PM.
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      08-12-2012, 10:22 PM   #5
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Are you running a dedicated track tire and doing a hot enough water box burn-out ? If your tires are holding the right amount of heat and are sticky...you should be able to launch at higher initial rpms and really hook up.
Even yet...no slouch !
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      08-12-2012, 11:01 PM   #6
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Originally Posted by seank View Post
That's fair. What size tires, car weight with driver, and torque numbers of your brothers are comparing. We need more information.

Everything adds up. I was recently surprised that my z4mc ran 7 seconds slower than my e30m3 track car. Then I started to add it up:
-600lb less
-sticky hoosiers (but smaller of course)
-suspension 2 times as stiff, that's not taking into account that its 600lbs lighter.
-weight of the car is lower
-btw it is 188 whp.
I don't know much about drag racing but from my understanding, the start is everything just like my corners on the track are EVERYTHING.
well, I don't remember the exact info, but someone here ran high 11s at 112mph with the same supercharger kit, and drag radials. Someone on youtube ran a mid-12@112 or so on a 50hp less Vt1-450 kit

I have 265/35/18 Bridgestone RE-11s, pretty stiff rear suspension because of the coilovers, car weight with driver should be 3365lbs or less. Haven't dynoed the car since I fixed my boost leak

Based on my math, I know I can get into the low 12s with a perfect launch, but its the trap speed I'm pretty sure it means I'm well below 500hp
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      08-12-2012, 11:03 PM   #7
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Quote:
Originally Posted by Dark Schnitzer View Post
Are you running a dedicated track tire and doing a hot enough water box burn-out ? If your tires are holding the right amount of heat and are sticky...you should be able to launch at higher initial rpms and really hook up.
Even yet...no slouch !
well, I'm doing a very ameteur-ish burnout. Worried about eating up my daily driven street tires. I'm basically dropping the clutch in 1st gear, and not touching the brakes, so it only spins for a bit. I was told, at the track, that I should run as low as 18psi on my street tires....
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      08-12-2012, 11:04 PM   #8
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I was hoping that someone with good drag racing knowledge could look at the spreadsheet I posted and tell me whats up
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      08-12-2012, 11:56 PM   #9
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The 60' time tells all the story.
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      08-13-2012, 12:06 AM   #10
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The 60' time tells all the story.
Not really. They aren't bad for street tires.
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      08-14-2012, 02:42 PM   #11
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You're MPH works out to about ~370 whp.... 500 bhp should translate to about 420 whp which should put trap times closer to ~118...

E.T. and 60' times will not change trap speeds much unless there was a completly busted launch, and the easiest way to judge HP (and highway performance) is with trap speeds. I'd imagine with some more time at the track you should be able to get in the 1.8-9s 60' time which would put you in the low 12s no problem.

If you are worried about E.T. it's all about trial and error. Most street tires do not need a big burn out to get to the right temp. but you will need to adjust tire pressure to find out what works for your car on each track conditions.

What I've found that works best on street tires is a high RPM launch with slipping the clutch for traction/control(a little spin is better than bogging).
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      08-14-2012, 04:04 PM   #12
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Yeah i think the #1 issue is the heat, completely KILLING my power output. Im gonna work on a cooling solution. Thanks
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      08-14-2012, 05:29 PM   #13
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tom dont stress to much, hell your not even warming the tyres!!!!! you going straight out and hoping for good times, you can see traction is an issue, at one point you step out in second pretty hard!!

that guy with vt1 on youtube went for it all out but KNEW how to drag..... you could hear him fethering the throttle when he gets wheel hop.
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      08-14-2012, 09:37 PM   #14
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tom dont stress to much, hell your not even warming the tyres!!!!! you going straight out and hoping for good times, you can see traction is an issue, at one point you step out in second pretty hard!!

that guy with vt1 on youtube went for it all out but KNEW how to drag..... you could hear him fethering the throttle when he gets wheel hop.
my trap speeds should be higher, even if I launched it perfectly. Don't worry, I'll either get my meth injection sorted, or install a cooling spray onto the intercooler.

but yeah, sliding towards the wall into 2nd gear looked a lot scarrier in the video than from my seat. heh
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      08-22-2012, 05:03 PM   #15
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What track were you at?
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      08-22-2012, 08:03 PM   #16
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What track were you at?
Palm beach international raceway
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      08-31-2012, 07:24 PM   #17
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You picked up 3.5mph over the course of the night. Temps will have a huge effect on a supercharged car . . . Not sure how the ESS tune works, but on my previous car (2008 corvette) the ECU would start pulling timing once the IAT reached 88 degrees. There was a noticeable drop in power in hot weather, my estimate would be 25-30hp. Run it when it's closer to 60 degrees and you'll see a couple more mph.
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      08-31-2012, 07:56 PM   #18
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Originally Posted by Racer20 View Post
You picked up 3.5mph over the course of the night. Temps will have a huge effect on a supercharged car . . . Not sure how the ESS tune works, but on my previous car (2008 corvette) the ECU would start pulling timing once the IAT reached 88 degrees. There was a noticeable drop in power in hot weather, my estimate would be 25-30hp. Run it when it's closer to 60 degrees and you'll see a couple more mph.

3.5mph, and the temp drop was maybe 5-10 degrees max. hmm. good insight

Im gonna have my AEM water/meth kit working soon, just hunting down the best price on a new controller box. Its out of warranty unfortunately
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      09-06-2012, 02:26 PM   #19
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You do not warm street tires or they get slippery, drag radials get sticky...!

Track prep makes a huge differance as well, what kind of events do they run there? you may want to go out after a NHRA or like event for a properly prepped track.

I can't really hook first or second on 275's being NA so an SC is only making things worse. Hasing the tires where you can't really feel the slip is robbing you of speed. It is sometimes faster to run a slower car...
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      09-06-2012, 04:36 PM   #20
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You do not warm street tires or they get slippery, drag radials get sticky...!

Track prep makes a huge differance as well, what kind of events do they run there? you may want to go out after a NHRA or like event for a properly prepped track.

I can't really hook first or second on 275's being NA so an SC is only making things worse. Hasing the tires where you can't really feel the slip is robbing you of speed. It is sometimes faster to run a slower car...
I was able to go full throttle in 1st and 2nd gear without much wheelspin on most of my runs.

Its a "big" track, so they probably run NHRA events. The track was prepped in the beginning of the night on this specific day
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      09-07-2012, 12:15 AM   #21
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I regularly dragged my z4m in the 1/8th and had 1 run down the 1/4mi.

my setup:
75 shot nitrous(basic setup)
muffler delete
AA tune
rpi scoop
bmc filter

my best 1/8th
60' 1.85, 1/8th 8.00 @ 91 mph in 1500da on worn out mt drag radials

best na 1/8th
60' 2.0, 8.5 @ 85 mph on dunlop direzzas 1200'da

street tired 1/8th
60' 2.2, 8.457 @ 90.08

my only 1/4 mile
missed 2nd gear 60' 2.4, 13.1 @ 117 2000'da


your 1/8th and 1/4 mile traps seem low for 500hp compared to my 75 shot, especially for your high 60' times. I'd assume traps in mid 90's in the 1/8th and 120 in the 1/4. Go on dragtimes.com and get your da for the day to see it more clearly.

your re-11 should be good for 2.0 60's....skip the water box, drop down to 20-23psi to avoid wheel hop, and do a quick burn on dry asphalt before you line it up(no brake application, 1st gear drop) oh yeah,open the hood in the pits, and avoid hot lapping
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      09-07-2012, 11:48 AM   #22
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Quote:
Originally Posted by krnnerdboy View Post
I regularly dragged my z4m in the 1/8th and had 1 run down the 1/4mi.

my setup:
75 shot nitrous(basic setup)
muffler delete
AA tune
rpi scoop
bmc filter

my best 1/8th
60' 1.85, 1/8th 8.00 @ 91 mph in 1500da on worn out mt drag radials

best na 1/8th
60' 2.0, 8.5 @ 85 mph on dunlop direzzas 1200'da

street tired 1/8th
60' 2.2, 8.457 @ 90.08

my only 1/4 mile
missed 2nd gear 60' 2.4, 13.1 @ 117 2000'da


your 1/8th and 1/4 mile traps seem low for 500hp compared to my 75 shot, especially for your high 60' times. I'd assume traps in mid 90's in the 1/8th and 120 in the 1/4. Go on dragtimes.com and get your da for the day to see it more clearly.

your re-11 should be good for 2.0 60's....skip the water box, drop down to 20-23psi to avoid wheel hop, and do a quick burn on dry asphalt before you line it up(no brake application, 1st gear drop) oh yeah,open the hood in the pits, and avoid hot lapping
thanks a lot for the tips. I plan to go again around October 12th
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