How do you launch a turbo car? 60ft times suck

[ZR8ED]

Hi guys.

 

I just got back from the track, and man is it ever different launching my turboz compared to when i had the n/a motor.

 

I could launch my n/a Z no problems, and my times are pretty good considering I use street tires... well this same car..with the same tires, with my new turbo motor is a whole new ballgame..my 60ft times are almost 1 second slower this year?!!!! I'm having trouble with wheelspin. Also the car is not reaching max boost in 1 2 or 3rd gears?.. under daily driving, I can hit max boost in all 5 gears...but launching hard, I can't hit max boost..till i shift to 4th..at which point it feels like i'm going to launch into orbit.

 

The car seems fine..it appears i have to relearn my launching technique...could someone help me out with some techinques to get off the line?

 

Thanks,

Scott.

[Scottie-GNZ]

Scott,

 

real difficult to diagnose the problems just from a post, but here are a couple of things to ponder for the launching technique. If I have it correct, you went from a 2.8 NA to a 3.0L turbo and what you are feeling is the tremendous difference in torque, especially with that small t3 giving full boost so low. You cannot launch the turbo car like you did the NA. My advice would be to launch it soft and work your way up until you find the sweet spot. If you plan to have fun at the drags with the car, I would say invest in a pair of DRs. One local 300ZX made the NA to turbo swap and had the same problem until he practiced and got his technique down. Now he is in the mid-13s with just a Starion I/C and you are a lot lighter.

 

As for the boost problem, that is strange having it on the street but not at the track. I would first look for a wastegate problem, either the wastegate itself or the signal line. Disconnect the rod and check the movement of the puck lever to make sure it closes all the way freely. There is another possiblity but it depends on how sophisticated the ECM is that you are using. If you are having knock in the lower gears at the track, the computer could be retarding the timing and preventing the engine from achieving full boost. Regardless, at the track I would throw in a couple gallons of race gas to be safe.

 

[ September 23, 2001: Message edited by: Scottie-GNZ ]

[ZR8ED]

Thanks.

 

I do run 94 octane, and i had added a bottle of 104 octane boost before i left for the track.

 

As far as the ECM is concerned, this turbo motor is stock for now..it only has a larger throttle body, custom exhaust (obviously) and a custom intake piping with a large K&N out front.... oh..and a modified popoff valve, and manual boost controler.

 

The suspension is in good shape, and nothing in that area had changed from last year.

 

as a test when we left the track, I eased the car out into the road, and had no problems getting max boost without using full throttle..and when i did floor it, it kept max boost...it must have been because of wheelspin, and not enough load on the engine to get full boost. Ie like reving the car in neutral..boost guage never goes beyond zero because of no load..

 

I never had enough time to get any more runs in, cause my mustache bar bushings started to give out, and it was a 3 hour ride home, so pushing the car was out of the question. I'll go out and get some seat time in the car, and see what i can do...I can't wait for the I/C to go in this winter...

 

Thanks,

Scott.

[Guest Anonymous]

Hmmmm, how to launch a turbo car... A large Trebuche' or perhaps a Titan rocket. Or just drive it at 160+ for a while, it'll launch once the suitable bump has been hit.

[Nigel]

Hey Scott (ZR8ED)!

 

I noticed you and Edmarc (300+ hp 300ZX Turbo) both had a lot of trouble with way too much wheel spin off the line. Like Scottie suggests, I think a softer launch is the key. Lavern did a best run of 13.36 (supercharged 240 dynoed at 200 hp for those who don't know), and he's only got 215 street tires, and he didn't do a burn-out first. And no, you wont get much boost with your tires spinning away madly

 

Cheers!

 

Nigel

[Andrew Bayley]

Scott (not Scotty, or Scottie, just Scott ),

 

Try heating the tires up a bit. I know everyone and their brother says warming up street tires wont do anything to the tire compund, but give it a try anyways! Most people find out that a mild burnout on street tires will warm the tiures for a few seconds. During these few seconds after the burnout, s... l... o... w... l... y... creep your way up to the staging area. What will happen is your tires will pick up all the loosened soft rubber left behind from the full slicks while your tires cool. This will build up a very small layer of soft slick compound on your street tires. Give it a try, it definetly wont hurt anything (unless you've got some high $$$ tires out back).

 

-Andy

[Scottie-GNZ]

Scott,

 

104 Octane Booster, et al, claim to raise your octane by points and to some degree they are correct. What they are not telling you is that what they mean by points is ".x" not "x".

[scottyMIz]

Hey scott i posted a reply on zcar but i will add this in my car the clutch is slipping and it won't hlod full boost when it's slipping.So tire spin is basically the same as my clutch slipping.Andrew is right about the burnout thing it's what i tried and made a huge difference in my car.I did my regular burnout but then crept forward and it picked up the soft stuff and stuck to my hot tires.Worked for me my best 60'time now is 1.73.

[Drax240z]

ScottieMiz, is that 1.73 on street tires? If so, what tires are you running?

[scottyMIz]

My tires are daytona HR/4's they came with the rims when i bought them used.The size is 225 50 R16's they are really bald i mean really bald.The car launches great when i can do it right.But it's in the top end it has problems the clutch can't hold the power the engine is putting out now.