Messing around today with launches....................

[Duke]

and because I have crap tires, decided to get rid of some rubber.

Started with some rolling starts in 1st -
1st gear, hit boost, tires spin, 6000 RPM, slam it into 2nd, tires still spin all the way until 6000 again, slam it into 3rd, some spinning then they catch.

Note - need lots of room due to wandering rear end.

Dead stop - rev engine to 3000 or so, feather clutch, tires spin hard, see above.

At the cars state of tune and low boost, I anticipate spinning the wheels thru 3rd and into 4th when it is tuned and running 18-20 psi.

[Boru]

Hooligan.

[bmw335is turbo]

I can't wait until I get another car.
How is the Tec3 maps comeing any problems and if so are you trying to keep a perfect 14.7 or do you run a little rich to keep it safe?

[Duke]

How is the Tec3 maps coming any problems and if so are you trying to keep a perfect 14.7 or do you run a little rich to keep it safe?

Here is a pic of one of the data log pages.


Was a run up thru a couple of gears with max boost and WOT. You can see this with the yellow spikes as I floored the throttle.

This is at very basic tuning and no dyno work. Much improvement will be made. You can se that A/F ratio is all over the place. I have the wide band O2 input corrections at +/- 20% which is a big indicator of lack of tune. EM does not recommend anything over 10% for a properly tuned engine.

[Duke]

Hooligan.

Thanks!

[shifty]

It makes perfect sense that you'd be spinning all the way through first gear. I mean, hell, I experienced it first-hand! That reminds me, I'm PISSED that I didn't get some better videos of your car. That's a project I'd like to take on when you get back from the sandbox.

Back to the point, I'm more curious about your lack of traction in 3rd gear. It seems like the only reasons you would've had traction problems in third gear, today, are 1) the suspension was unsettled from the gear change and the sudden throttle application helped to unsettle it some more, or 2) the tires are a lot worse than they were on Sunday!

The reason I say this is that it seemed like you had plenty of traction in third gear when I drove it on Sunday. I didn't feel/hear/notice any boost whatsoever until about 3k RPM, but that makes no difference if you're shifting at redline since you'd end up above 3,000 after a gear change.

At any rate, get that beast tuned so you can turn up the boost! That's going to be a CRAZY ride when it gets over 12 pounds. I'm anxious to see how it fares in the TN heat this summer.

Any chance you'd let me take it to 5er Fest for you in May?

[Velocewest]

At the cars state of tune and low boost, I anticipate spinning the wheels thru 3rd and into 4th when it is tuned and running 18-20 psi.

Sounds like time to be looking for a way to get more contact patch. Spinning tires are fun, but gripping tires make speed.

Maybe you should pioneer the first tandem axle e28...

[Duke]

I'm more curious about your lack of traction in 3rd gear. It seems like the only reasons you would've had traction problems in third gear, today, are 1) the suspension was unsettled from the gear change and the sudden throttle application helped to unsettle it some more

BINGO...............they were clutch dumping, gear slammin gear changes. I was trying to keep the tires lit. I even experianced some wheel hop.

Any chance you'd let me take it to 5er Fest for you in May?

Not with the engine noise, I could deal with destroying the engine myself, having it blow up on you would be bad.

Sounds like time to be looking for a way to get more contact patch.

I am running 255/40ZR17 tires now. Can't get much bigger.

[shifty]

Not with the engine noise, I could deal with destroying the engine myself, having it blow up on you would be bad.

Ever heard of a caravan? I'm thinkin' CHASE CARS! Duh!

I am running 255/40ZR17 tires now. Can't get much bigger.

You can adjust the camber to get a better contact patch, though!

[Skeen]

You can adjust the camber to get a better contact patch, though!

You can get a better shape contact patch, but you will not change the area of the contact patch without lowering the air pressure or putting more weight on the tires.

[shifty]

Would altering the rear camber not alter the amount of force placed in the meat of the contact patch? If not, then disregard my previous post.

[Skeen]

Would altering the rear camber not alter the amount of force placed in the meat of the contact patch? If not, then disregard my previous post.

You could change the ride height some to get more weight on the rear. Assuming the car's weight does not change (or the air pressure), the sum of the area of all four contact patches will not change. As weight is shifted in the car, the area of any given contact patch can fluctuate some, but the sum of all four will remain the same.

Edited to add: the force on the tire is normal to the ground (gravity). Force is not parallel to the degree of camber.

[altus22]

Duke,
You probably saw this, but you should beef up your fuel at closed throttle. You're going way lean. I wouldn't want you to mess up those pretty coated pistons and chambers.
Also, I like that method of logging. It's much better than reading through txt docs from MS.