BPU++ Supra - 11.3 @ 125MPH

[AdamVR4]

I think I zeroed the toe and set the front camber barely negative and the rear barely (degree or less) positive.

[AdamVR4]

RE: AWD launch in the QTP's -- You'll definitely need to clean them off as best as possible first. I think I'd start with 20psi or maybe even 22psi, and adjust the pressure accordingly. If you're blowing them away then drop them 1psi and try again. A 2-step/antilag will truly make life a lot easier; otherwise you're going to have to slip the clutch from a very high RPM to get the car moving. There are 2 ways to go about it 1) dump the clutch and let the tires do the work or 2) slip the hell out of the clutch. If you have a C/C or similar then you can be successful with option 2; however, I prefer to let the tires do the work. You have to leave with the turbos lit with enough power to shock them loose, though; that is where the 2-step comes in. If the car is light enough then you can get away with a free-rev clutch dump like Matt. In the absence of a 2-step it's going to require some experimentation, and the technique will need to be adjusted to suit current track conditions.

Came back to review this nugget because I just bought a WOT box. I guess my plan will be to start the evening at 22 psi, slowly go through the water with all 4 tires, 2-step & dump the clutch @ 5500 rpm's to fling off parking lot debris and water, then roll up and dump the clutch at the same rpm on clean and moist tires...

Last time at the track (November), I was able to semi-effortlessly spin the QTP's after going through the water. It felt completely foreign and terrifying to me because the car wasn't moving, but apparently at least the passenger side tires were spinning. How long should I try to hold it? Until the car yanks itself forward? I've never taken a RWD car to the track. My loyalty to this car has stunted my growth for sure.

[HellBringer]

In hindsight you might want to start with 18-20psi; 22 might be a little high. Worst case with too much pressure is you’ll just blow the tires away. As long as you don’t peg the limiter and sit on it with no forward motion, you’ll want to stay in it, though – you’ll want wheelspin. If you don’t already have one, get a good tire gauge that reads in ¼ or at least ½ psi increments, that doesn’t go any higher than 30-40psi max. Once you really start to dial things in, you’ll be making ½ psi changes. Another thing to consider, which I learned the hard way, is that if one side of the car is facing the sun and the other isn’t, the side facing the sun is going to read higher, and that will affect your adjustments. A mismatch in pressure side to side can cause major stability issues on the big end. If the sun is still shining I would try to keep all 4 tires shaded for this reason. Either way you’ll want all 4 exactly the same Since you can’t really do a good smokey burnout, I would check tire pressure immediately after the run to see how much they’re increasing.

Your plan sounds good, but you might have better success just driving through the water box and then doing your ‘burnout’ without the initial clean-off to minimize the stress on the drivetrain. I might suggest driving through the box and once your rear tires are clear, pre-load the drivetrain with the E-brake, tach up on the 2-step and drop the clutch and let the car continue to spin forward until the tires start to grab hard. As long as the car stay straight I would stay in it as long as you can. If you overshoot the tree without hooking up then either the track is horrible and/or you’ve got too much tire pressure and/or you’re not getting all the water off the tire and the launch pad. In that case, you may want to try your original plan of doing a quick spin to clean them off better first. I wouldn’t try to pedal it too much during the burnout; as soon as you modulate the gas they may end up hooking prematurely when you could’ve benefitted with more heat in the tire.

On the launch I wouldn’t just side-step the pedal. I’d suggest pre-loading with the E-brake as best you can and when you’re ready to ride I’d do a quick slip of partial-engagement to get the car moving and then a full dump from there. This will get you moving forward and the weight starting to transfer before the tires break loose. Another thing to consider is how the 2-step engages/disengages. What I would suggest is a Normally-Closed switch on the top side of the pedal so that the 2-step is engaged all the way until the clutch is fully engaged. If you have it trigger off of the bottom of the pedal travel, then the 2-step will likely disengage prematurely, before the clutch is engaged. Another option (which I’ve used after struggling with working off the pedal) is a momentary switch. If you watch some of my in-car videos where I’m using the 2-step (it failed due to a switch issue on the passes in this thread – so this one won’t help you) I have a momentary button/switch velcro’d to the right hand side of the steering wheel. I launch with both hands on the wheel holding in the switch to engage the 2-step and then when I take my hand off to grab the shifter it disengages. Sort of rigged, but it’s worked well for me, and that lets me control when the 2-step disengages rather than the pedal travel. Now if you have a 2-step that works off vehicle speed like any standalone then that is ideal.

Best of luck and congrats and manning up and running a real tire at the track. It’s a lot to soak in and master, so don’t be discouraged as the learning curve is fairly steep to start. In my opinion there’s no ‘street tire glory’ to be had. I’m more impressed when someone goes out with the right equipment to run a number than someone that struggles with street tires and maybe gets a few lucky passes in. You’ll be way more consistent and your drivetrain will live a happier longer life!

[AdamVR4]

When you preload the trans with the e-brake, do you slip the clutch for just a moment then fully disengage it before launching or do you slip it for a moment, then promptly launch?

I'll keep this post in mind as I'm installing the WOT box. Thank you for all the info.

The tires only made sense. There's a reason they require the sixth point at 9.99 OR 135 mph................