|
|
SUPPORT ZPOST BY DOING YOUR TIRERACK SHOPPING FROM THIS BANNER, THANKS! |
Post Reply |
|
Thread Tools | Search this Thread |
08-12-2012, 07:42 PM | #1 |
instagram 997turbotom
279
Rep 7,377
Posts |
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?
__________________
|
08-12-2012, 09:10 PM | #3 |
instagram 997turbotom
279
Rep 7,377
Posts |
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
__________________
|
Appreciate
0
|
08-12-2012, 09:49 PM | #4 | |
enthusiast
48
Rep 1,695
Posts |
Quote:
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.. |
|
Appreciate
0
|
08-12-2012, 10:22 PM | #5 |
CarbonFiber Engineer @ ZeroMassMotorsports
40
Rep 1,481
Posts |
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 ! |
Appreciate
0
|
08-12-2012, 11:01 PM | #6 | |
instagram 997turbotom
279
Rep 7,377
Posts |
Quote:
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
__________________
|
|
Appreciate
0
|
08-12-2012, 11:03 PM | #7 |
instagram 997turbotom
279
Rep 7,377
Posts |
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....
__________________
|
Appreciate
0
|
08-12-2012, 11:04 PM | #8 |
instagram 997turbotom
279
Rep 7,377
Posts |
I was hoping that someone with good drag racing knowledge could look at the spreadsheet I posted and tell me whats up
__________________
|
Appreciate
0
|
08-12-2012, 11:56 PM | #9 |
Midlife Crises Racing Silent but Deadly Class
1821
Rep 5,337
Posts
Drives: 2006 MZ4C, 2021 Tesla Model 3
Join Date: Oct 2007
Location: Welcome to Jamaica have a nice day
|
The 60' time tells all the story.
__________________
Sitting on a beat-up office chair in front of a 5 year old computer in a basement floor, sipping on stale coffee watching a bunch of meaningless numbers scrolling aimlessly on a dimly lit 19” monitor.
|
Appreciate
0
|
08-13-2012, 12:06 AM | #10 |
Captain
160
Rep 892
Posts |
Not really. They aren't bad for street tires.
__________________
CURRENT ll F10 M5 l E85 Z4MR l I01 i3 REX SOLD ll E70 X5M l E85 Z4MR VF570 l E36/7 Z3MR l E36 328i |
Appreciate
0
|
08-14-2012, 02:42 PM | #11 |
New Member
1
Rep 14
Posts |
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). |
Appreciate
0
|
08-14-2012, 04:04 PM | #12 |
instagram 997turbotom
279
Rep 7,377
Posts |
Yeah i think the #1 issue is the heat, completely KILLING my power output. Im gonna work on a cooling solution. Thanks
__________________
|
Appreciate
0
|
08-14-2012, 05:29 PM | #13 |
Major General
423
Rep 5,327
Posts |
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.
__________________
Z4MR VT2 - Clubsport build.
Multi award winning Detailing | Wrap | PPF specialists UK based - www.topwrapz.com |
Appreciate
0
|
08-14-2012, 09:37 PM | #14 | |
instagram 997turbotom
279
Rep 7,377
Posts |
Quote:
but yeah, sliding towards the wall into 2nd gear looked a lot scarrier in the video than from my seat. heh
__________________
|
|
Appreciate
0
|
08-22-2012, 05:03 PM | #15 |
Lieutenant
25
Rep 446
Posts
Drives: 2013 335is
Join Date: Nov 2009
Location: South Georgia
|
What track were you at?
__________________
2013 335is E93 2018 X5 35d BMWCCA / ZSCCA Member |
Appreciate
0
|
08-31-2012, 07:24 PM | #17 |
Major
1030
Rep 1,190
Posts |
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.
|
Appreciate
0
|
08-31-2012, 07:56 PM | #18 | |
instagram 997turbotom
279
Rep 7,377
Posts |
Quote:
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
__________________
|
|
Appreciate
0
|
09-06-2012, 02:26 PM | #19 |
Second Lieutenant
25
Rep 296
Posts |
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... |
Appreciate
0
|
09-06-2012, 04:36 PM | #20 | |
instagram 997turbotom
279
Rep 7,377
Posts |
Quote:
Its a "big" track, so they probably run NHRA events. The track was prepped in the beginning of the night on this specific day
__________________
|
|
Appreciate
0
|
09-07-2012, 12:15 AM | #21 |
Colonel
190
Rep 2,431
Posts |
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
__________________
F80 m3, 997 gt3, 14 ram ctd, f15 x5, drz400sm Gone:z4m, boss 302, c6 z06, m6,z3m |
Appreciate
0
|
09-07-2012, 11:48 AM | #22 | |
instagram 997turbotom
279
Rep 7,377
Posts |
Quote:
__________________
|
|
Appreciate
0
|
Post Reply |
Bookmarks |
|
|