How do i launch my AWD [Merged 6-7]

[jtmcinder]

Originally posted by DaveSM
Some of you guys have been hitting the egg nog too early.

Viscous differntials are 50/50. That is the whole point of them. It wants to spin at the same speed, there is no other mechanisms in there.

Once again, 50/50.

Thanks. That's what I thought. It takes something like helical gears to have something other than a 50/50 split, right?

- Jtoby

 

[jtmcinder]

Originally posted by 1slowgsx
power distribution is 60/40. not 50/.

How? I'm not really interested in any specific number (other than 50/50); I just want one of you that claims that the split isn't 50/50 to say how that is accomplished.

- Jtoby

 

[dsmturboawd]

Originally posted by GSXlaunch
I revved it to 4500 then popped the clutch.

that hurts my feelings. learn to launch your car man.

 

[jtmcinder]

Originally posted by aovsi
Better tires ALWAYS go in the rear.

Nope. On a front-heavy car that has serious understeer issues, the better tires go on the front. Maybe you can break this rule if all you ever do is accelerate straight ahead, but who does that?

- Jtoby

 

[Sotarts]

Originally posted by jtmcinder
Nope. On a front-heavy car that has serious understeer issues, the better tires go on the front. Maybe you can break this rule if all you ever do is accelerate straight ahead, but who does that?

- Jtoby

AWD has serious understeer issues?

 

[CowPimp]

Originally posted by aovsi
AWD has serious understeer issues?

Yes, a stock AWD DSM does have some understeer issues. Granted, they are not nearly as pronounced as on a FWD car, but the problem is there. An upgraded rear swaybar does a lot to alleviate this problem.

 

[kurupt]

why does everyone have such a hard time believing this guys spins all 4 tires? i think if u can't, there's something wrong with your car. man, when my car was bone stock i could lay 4 strips anytime i wanted. i know it's improper launching technique, but damn, if i never hit the really smooth pavement to actually see my 4 strips, i could do it right beside anyone who lined up beside me, hell, i could even get the thing to throw the rear end out to the right like a rwd if i was hard enough on it. but what i really want to point out is this tire issue. you definitely need 4 the same size on an awd car. even small things like a different tire brand can throw that off. here is a simple calculation to calculate your tire diameter:

width in millimetres = 205
aspect ratio = 55
rim size = 16

205 x .55 = 112.75
112.75 x 2 = 225.5 (multiply x 2 because you have 2 sidewalls)
225.5 / 25.4 = 8.878 (divide by 25.4 to get from metric to inches)
8.878 + 16 = 24.878 (add the size of your rim)

diameter = 24.878"

you can use this on any tire comination to see what work together or whatever. definitely best to stick to all the same manufacturer and size on the awd, but it's your car and your wallet. i use 235/70/15 on the front of my jeep, and 275/60/15 on the rear, this works out very close in diameter, and i have no problems, this is just for winter, summer i stay with the same size and manufacturer, 255/55/18 toyo proxes. i would figure a lot of people knew how to calculate this, but last year i met a salesman from pirelli who worked for pirelli for 20+ years and did not know this, turned out nobody at the tire shop knew how either, needless to say, now they do...

merry xmas!!!

 

[Sotarts]

This was based on 205/55/16 stock tires:

 

[CowPimp]

http://www.miata.net/garage/tirecalc.html
That link is for anyone who is too lazy to do the math themselves. Plus, it tells you the diameter differential between two sizes that your input into their applet.

 

[GSXlaunch]

Since no one bothered to respond on the thread...

http://www.dsmtuners.com/forums/showthread.php?s=&threadid=93486

My bro has a 91 Q45 with the 4.7 V-8 that puts out 279hp and closer to 300lbs of tq. He's got head work and exhaust and I think now its closer to 300hp. Anyway...during this launch, I assure everyone all four tires spin. Maybe 1 or 2 revolutions but they are spinning. Eitherway, it was a violent launch (very fun)...but I think the clutch was damaged. What do you guys think it is? The car is driveable and engages every gear. It just feels mushy and harder to go into gear. I also hear a clunk when shifting. Time for an ACT

As for the tires I now have four 225-50-16's all the way around. Same make, model and manufacturer. The two best tires are on the front.

 

[Defiant]

Originally posted by jtmcinder
Thanks. That's what I thought. It takes something like helical gears to have something other than a 50/50 split, right?

- Jtoby

I _think_ the WRX does it with a planetary gear setup:

http://www.canadiandriver.com/articles/jk/031210.htm

 

[jtmcinder]

Originally posted by aovsi
AWD has serious understeer issues?

You don't want to mess with me (again).

Yes, some AWD cars - e.g., 1G and 2G DSMs - have serious understeer problems. If you don't know that, then you obviously can't drive.

- Jtoby

 

[jtmcinder]

Originally posted by Defiant
I _think_ the WRX does it with a planetary gear setup:

http://www.canadiandriver.com/articles/jk/031210.htm

Thanks for the pointer. If I figure out how it works before someone posts an explanation, I'll start a new thread.

- Jtoby

 

[MajouR]

DONT DO IT. Does it sound like a necessary thing to do? It wasn't meant to do it...don't do it, period. My 2 cents...

 

[Samurai Jack]

When I try to launch with my 95 awd auto I do the power brake method and somthing is wrong. I will hold down the brake for 5 secs or so or when I get 10lbs of boost and let off the car wants to launch hard rigtht away but then i loose all boost and get a slow start off the line. The car has to rebuild boost right after the first sec of the launch. Whats causing this???????????

could it be a bad tps?? no cel btw.

 

[nutshot]

What RPM are you launching at?

 

[Samurai Jack]

I have tried all different rpms 3-6 I think. It happens no matter what. It will feel like Im going to take off like a jet then I loose all the power(boost) instantly and I have build it up again after I have taken off.

 

[nutshot]

Which gear is the car trying to launch in? Which boost gauge are you using?

 

[mitsuclipsegsx]

wehat gear should we lauch from drive or OD

 

[nutshot]

I would slap that shifter to the lowest gear you can get, then manually select the next gear when the motor hits redline. Of course, that is how I drive my automatic Firebird... DSM fella's might have a different method.

 

[Awoler]

are you watching the gauge the whole time?what kind if boost controller are you using?if you doubt its operation trash it or try it on somebody elses car to ck it first .then ck for boost leaks to be sure because if these are you symptoms it sounds like your driving around in 3rd or your trans is slipping

 

[Defiant]

"Why are DSMs so unreliable?"

 

[Samurai Jack]

I have tried it with a mbc in and taken out(stock bcs). Overdrive on and off and it still does it. I replaced the tps and that didnt help. No boost leaks either but my car does stutter/backfire in wot once in a while(not an ignition prob either). Why is my car launch like crap

 

[MrPikolo]

mine did that as well. I do not know why. Do you have a vacum leak of any sort? My talon had a very large one, which may have contribute to it. Other than that I do not know.

 

[Rice Over Wheat]

My guess is it's slipping...plus you don't have a high stall torque converter and your stock A/T isn't meant for high revs before going into gear.