82cetuner

iTrader: (9)

I recently purchased some 17x11 tt2 wheels and nitto 315 drag radials for the back for my 2001 trans am

At the track my 60 foot time really did not improve at all and I am 2 mph slower in the 1/8.

I was running stock 9.5 rims with old khumo extas with barly any tread before.

What might my issues be? I still get wheel spin at the launch but then once the tires hook the car seems to big down.

am I not launching hard enuf or to hard?

the car is mostly stock exept a tune, intake and cutout.

best I could do was a 13.4 quarter I know this car has more in it since last time I ran just the 8th mile on the old tires i was geting 84mph and now only 82

atrain59

iTrader: (31)

What psi are you running the tires at the track?

SuperSlow02

iTrader: (16)

HEAVY *** wheel and tire combo didnt help any.

jc98ss

iTrader: (13)

try 18-20 psi......do a long burnout, heat them up really good.....from my experience, 25psi on the street and the tires will wear evenly, 30psi and the centers will wear out first.....but 18 or so at the track works best

5.3LJimmy

iTrader: (10)

I'm also going to say your MPH loss is due to the heavier wheels, but it could also be weather if conditions were not identical. If you are trying to run a six speed with Nitto drag radials you probably will not be able to hook any better than the street tires.

chevelledave

iTrader: (5)

first things first...whats your 60 ft times?? before and after ?? second start at about 16psi and work up...stick or automatic ...theres a 100 different things that can slow you down ...keep a log book of your passes ...dragtimes .com has a weather station and you can input the closet location ..get D/A humidity , temps etc ...you said it bogged after it hooked ...raise the launch rpm..and get ready to tune the rearend with adjustable shocks ...

custm2500

iTrader: (11)

The big problem is you waisted money on the nittos. That is your main issue. Get some real tires on there and you should see improvements.

82cetuner

iTrader: (9)

yeah i am going to switch to M/T for my next set and my 60 foot times are pretty much a even 2.0 and my 1/8 mile is about a 8.6. those pretty much stayed the same with the street tires and switching to the drag radials. its just the 2 mph loss that concernes. It didnt feel like the rims were much heavier than my stockers when I put them on.

I was also running 20psi on the tires.

I also switched to a MGW shifter the same weekend and maybe I wasnt use to the shifts.

I soubt I will get back to the track before I deploy and while I am gone my mechanic is putting a 402 with a fabbed 9 inch in it for me when I am gone so I will have a new starting point.

I plan full suspension upgrades as well.

sedanman

iTrader: (10)

I would be interested in 60's

Nittos aren't bad tires they just are not as sticky as others. Fwiw my cobra did 1.70 with a 3850# race weight, road race susp and 18 inch nittos.

biggriff

iTrader: (3)

well i have Nittos and a pretty much stock LT1 and i cut 1.6 60's so Nittos will hook, i run 18-20 psi and i roast them before the run... you do have to heat up Nittos pretty good, i also cut 1.5 on NOS...so they will hook ( i am also an auto for the record) good luck...

BlackScreaminMachine

iTrader: (17)

M6 + Drag Radial + Lighten Flywheel = Waste of time.

The rims absolutely hindered performance. I have seen the same results with a similar car with running stock camaro snow flakes vs a heavier aftermarket chrome rim like the TT2.

60 foot times before and after are a must.

82cetuner

iTrader: (9)

my rims are not chrome they are polished aluminum same as the stockers the fronts are the same width as stock, the rears are 1.5 inchers wider than stock. yeah I think maybe I am just not launching at high rpms for the the motor to not bog when hit hooks and not heating them up hard enouph, my best 60s seem to come from the first run right when I am done driving the 25 miles to the strip so the tires are still warm.

BTW this is on my 2001 trans am not the corvette in the tag. it has a stock flywheel and mostly stock everything

BlackScreaminMachine

iTrader: (17)

Weigh those 2 different tire set ups and get back with us. I'll bet money its far more then you think.

223HAWK

iTrader: (11)

Are your radials a different size??? Tire height changes a lot of things..

tim99ws6

iTrader: (31)

Nitto's like lower pressure and a healthy burnout.

Also, launch the car like a man if you have the rearend to handle it (sounds like you dont)

zracer323

iTrader: (12)

Rolling resistance is your enemy as well as the weight of the wheel. Other than the launch a fat tire is a bad for rolling resistance down track

htownws6

iTrader: (1)

Don't forget that weather conditions can EASILY shave off 2 mph. Were you going into a head wind the second time around? Weather and track conditions make et and mph vary so much its hard to tell when you really gained anything (or loss) when you do something different. You almost have to do it on the same day, same track. Even then it could vary. I dropped 4 mph the other day without changing anything, except just running at a different track that faced the south (into the wind). Roughly same DA too...

608kZ28

^^^
this.

ive witnessed weather and track conditions change ET by about a half second and mph by 2-3. and this would be in the same day

1lejohn

iTrader: (9)

Yes Sir burn them down.

99TransAmLS16Spd

iTrader: (8)

are you spinning outta the hole or dead hooking? If you're dead hooking, increase your launch rpm. If you are slipping the clutch, be more aggressive. Once you begin to spin on launch, start tweaking your tire pressure, burn outs, and suspension to try to prevent spin. Your end point, with your set up, should be just a hair of tire spin outta the hole. Radials are tricky when used with a 6-speed.

Your mph, could be from anything mentioned above. My guess is going to be a combination of all of them.