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

[GSXlaunch]

Welp, got two fronts...actually these were the same brand as the rears but with better tread life. Both sets are 225-50-16's. Not bad for 65 bucks I guess. Now I just have to practice my launch...

 

[jtmcinder]

Here's hoping that the new fronts don't have so much extra tread-life as to be 1.6% larger than your rears. (This is really funny, if you do the math. Trust me.)

- Jtoby

 

[GSXlaunch]

That would be unacceptable

 

[xcelr8n]

is it better to have better tires in the back or the front??

 

[jtmcinder]

For a variety of reasons, put the better tires in the front.

- Jtoby

 

[TalonRacer18]

keep in mind your front tires are primary in our AWD setup,(80/20 or 90/10 i cant remember.) so a good hard launch will spin the front tires quite a bit.

if you are talking about the power distribution you are WRONG. I believe it is a 50/50 split.

 

[FiReBReTHa]

its not 50/50 i know that its closer to 65/35 more power to the rear.

 

[jtmcinder]

How, exactly, does a viscous-coupling type LSD produce a torque split other than 50/50? I'd really like to know this.

- Jtoby

 

[FiReBReTHa]

im having a long day so dont quote me on this.

but LSD refers to Left to Right Wheel

Whereas we are talking about Front To rear distribution on a AWD car.


like more power to the rear, less to the front.

 

[V8BWARE]

Originally posted by TalonRacer18
if you are talking about the power distribution you are WRONG. I believe it is a 50/50 split.

I would thank you to at least know youre right before you call me wrong.

I know for a fact the AWD DSMs power distribution is biased towards FWD, I DO NOT know the exact percentage offhand.

 

[jtmcinder]

LSD merely means limited slip differential. On a 2G, there are two diffs that have a viscous-coupling (aka "box of goo") type LSD (center and rear) and one open diff (front).

I'd still like to know how a VC type LSD produces a torque split other than 50/50.

- Jtoby

 

[Groomz]

You are ####ing over you center differential with two different tire sizes on it. Whoever told you that if the "50" number on the tire is the same then everything is ok should be shot.

_shakes head_

 

[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.

 

[AWD Eagle]

So what is the stock power distribution??

Oh yea, I have an ACT 2100 on my stock AWD, get some tire spin, but before the clutch absolutely nothing.

 

[bigjangin]

first off, put the same size tires on all 4 corners.

Second, dont drop the clutch, slip it a little. Power distribution is either 50/50 or 40/60(not something rididulous like (90/10).

Even with awd, its still possible to spin all 4 tires. You wont be doing all wheel burnouts, but you can make them spin once or twice before you take off.

 

[TalonRacer18]

Power distribution is 50/50 for fvcking sure...sorry if i sound like a jerk but i just lost in a long ass fvcking game of monopoly.

 

[billdo_83]

When i slip my clutch i get a little bit of wheel hop but I"m not spinning the tires. I have 2 tires that are getting sorta low on tread so that is why I'm doing it.
If you are getting wheel hop check out your motor mounts to see if they are bad at all.

 

[1slowgsx]

power distribution is 60/40. not 50/50 using two different diameter tires will burn up your viscous coupling. which is not good. you can get a viscous coupler eliminator which will cause the power split to be 50/50. i'm not sure how the VC works but i think that it uses something like clutch discs.

 

[Sotarts]

Originally posted by GSXlaunch
Well, I tried my first launch yesterday while driving down a deserted back road yesterday. I revved it to 4500 then popped the clutch. The rpms jumped to 5500-6000rpm before it really dug in and grabbed. I shifted hard into second and got up to maybe 50-55mph before coasting down to a slower speed. I could smell burnt rubber...and a little burnt clutch My question is why did I spin the tires? I know I am not running too much power. My car is pretty much stock...and I am only running about 8-10psi of boost. I do have used Firehawk GTA 215-50's up front and Goodyear Eagle RS-A 225-50's out back. I am running with about 30psi at all four corners. Do I need to go down to 28-or 26psi to make up for the lack of flex? Do these awd cars need the taller tires to flex a bit more on launch? Maybe I need to launch at 4k rpm??? Here is exactly what I did...(I know I need practice but I'd really hate to break something)

Came to a complete stop: Revved to 4400-4600rpm: Popped the clutch: Feathered the throttle a little then nailed it...tires spun for maybe 1-2 seconds before it grabbed (once it grabbed it took off like mad) If I had been racing I would have lost all or most of my awd advantage with that launch.

Thanks for the help.

Tony

You might want to check your transmission/transfer-case for damage since you were runing different sizes in back vs. front.

Better tires ALWAYS go in the rear.

Your fronts will spin first, before LSD catches.

Originally posted by Groomz
You are ####ing over you center differential with two different tire sizes on it. Whoever told you that if the "50" number on the tire is the same then everything is ok should be shot.

_shakes head_

 

[Defiant]

Originally posted by 1slowgsx
power distribution is 60/40. not 50/50 using two different diameter tires will burn up your viscous coupling. which is not good. you can get a viscous coupler eliminator which will cause the power split to be 50/50. i'm not sure how the VC works but i think that it uses something like clutch discs.

Absolutely wrong. Read this:

http://www.dsmtuners.com/forums/sho...86527&perpage=25&highlight=split&pagenumber=1

about how DSM AWD is 50/50 and that viscous couplers do not have anything like clutch disks.

 

[Defiant]

Originally posted by GSXlaunch
Well, I tried my first launch yesterday while driving down a deserted back road yesterday. I revved it to 4500 then popped the clutch. The rpms jumped to 5500-6000rpm before it really dug in and grabbed. I shifted hard into second and got up to maybe 50-55mph before coasting down to a slower speed. I could smell burnt rubber...and a little burnt clutch

O, why are DSMs so unreliable?

I guess the next guy who owns your car will know only too well.

 

[TalonRacer18]

Thanks for clearing up the power dist. madbomber (J/K).

 

[1slowgsx]

this is the first time i've heard about the 50/50 split. i guess i was wrong about the 60/40 thing. i wasn't complely wrong though. the viscous coupler eliminator does force a constant 50/50 split. not just when the front wheels start to spin.

 

[GSXlaunch]

At this point reliability is not an issue. The car is 14 years old. I know things are going to fail...I expect them to fail. Whether its a rear end, tranny or the engine goes. I am just trying to get some technique down on the launch. I'd like to get 13.5's down the quarter with a few more mods/tweaks...but my main goal is mid-high 12's. I am pretty sure this tranny/clutch/3 bolt rear end will be replaced by then. Now if this was my only mode of transportation that would be another story.

Anyhow, I tried launching again last night. This time from 5k rpm. I slipped the clutch a little and when I felt it dig in I let it out. Zero wheel spin, no wheel hop, and no burnt clutch (at least not that I could smell). It took off like a monkey with his ass on fire. It still needs work but it wasnt bad for my second try. Anyhow, thanks for all the help.

 

[CowPimp]

Originally posted by GSXlaunch
At this point reliability is not an issue. The car is 14 years old. I know things are going to fail...I expect them to fail. Whether its a rear end, tranny or the engine goes. I am just trying to get some technique down on the launch. I'd like to get 13.5's down the quarter with a few more mods/tweaks...but my main goal is mid-high 12's. I am pretty sure this tranny/clutch/3 bolt rear end will be replaced by then. Now if this was my only mode of transportation that would be another story.

Anyhow, I tried launching again last night. This time from 5k rpm. I slipped the clutch a little and when I felt it dig in I let it out. Zero wheel spin, no wheel hop, and no burnt clutch (at least not that I could smell). It took off like a monkey with his ass on fire. It still needs work but it wasnt bad for my second try. Anyhow, thanks for all the help.

The method that I have found easiest to use is pretty similar to what you just did. I slip the clutch until I feel it grab, then I dump it.