Drag racing results; 12.7 @ 110 mph

[Cody]

>
>Hey Cody, how much easier to launch the car is it with
>the launch control?  I've just about got it working on
>my car.  
>

Well, I actually haven't yet been to the drags with the launch control, and of course <sarcasm> I would *never* use it on the street </sarcasm>, lol. Honestly I have not really put it to a real test because I've never gotten the chance to play with it for any length of time. My issue at the strip (and even off) is that on a hard launch I spin the tires badly, or if I lower the tire pressure it would just fall on it's face until the boost came up. Right now what I'm hoping is that with the launch control I'll have enough boost to spin the tires just a bit even with the pressures lower, which would get me off the line quicker.

For those that don't know what launch control we are talking about, it's pretty simple. Right now my rev limit is set to 6500. What I have is a button that moves my rev limit to a determined spot, in my case I usually keep it to about 4500rpm. This lets me hold the throttle wide open while I'm pushing the button, which lets the boost build up. I can even vary the boost level by finely tuning the fuel mixture at that spot, anywhere between about 1.4bar to 1.8bar. Since Jim can adjust his timing he will be able to pretty much get any ammount of boost he wants, from zero to full. When using launch control just get ready to start your race, push the button and pin the throttle. When the light turns green just let go of the button and the clutch, but make sure your head was firmly against the headrest or else your going to get yourself a headache!

Last time at the drags my 60ft times were in the 1.7 second range with no launch control and all 4 spinning most of the way through first gear (they would get traction once ground speed was about equal to 6000rpm in first gear). I hope that with the launch control I'll be able to lower the pressures and more or less "tune" how much wheelspin I have so that the car will spin the tires until the proper ground speed for about 3000rpm in fist gear, which is well into the area where full boost is availible. I know lost of people are going to be saying "but you don't want the tires to spin at all". The trick is though, that with the tires spinning the engine is able to get into the upper rev range and get the turbo spooled near instantly (eapecially with launch control so it's already making boost even before you start). If you just pull away from the line and wait for the turbo to spool it takes time, and costs time in your race.

>=====
>Jim Green
>'89 90tq
>'89 80q
>http://www.mswanson.com/~jgreen/car_home.html


-Cody Forbes
http://www.500tq.com
'86 5ktq - EFI conversion in progress
'87 5ktq - EFI/k27
'88 80 4cyl
'88 90 4cyl