Back in 2017, I removed my front diff and axles to go RWD. I was running a 1/2 mile event and my car only makes about 500whp, so the RWD with the stock open diff worked fine. It would dead hook in first gear as long as it wasn't below 50 degrees outside. I also had almost new 305 width Pilot Super Sport tires that I put on in 2016.

Fast forward to this year. My car has the same setup power wise, but the PSS tires are now 4 year old and have about 8000 miles on them (surprised with the minimal treadwear). The rubber is clearly a bit harder than it was when they were new. Toward the end of the summer, I started struggling a bit with traction. First was near useless if I didn't roll into it, and depending on the surface, second gear would also spin, especially if I jumped on it hard or shifted hard into second. this was with temps in the 60s-80s. I decided to toss my front diff back in to see if it would make any difference. So I changed the fluid, installed new axle seals (one was seeping when I took it out), and returned the car to AWD. My test drive was on a 45 degree day and first spun a little when the boost hit, but second basically hooked up completely. Should be even better on warmer days.

I was surprised because the general consensus on here seems to be that our AWD is near useless for performance driving. It clearly added a lot more traction for me even on a much colder surface with colder tires.

I'm eventually going to get a trans re-fresh with an LSD when I pull the whole drivetrain for clutch, turbos, and coolant fittings, but for now it seems like the AWD will work great. I'll have to do some dragy runs to see if I lost any 1/4 mile trap speed.

 

I think the common knowledge is a little off too - I snapped a front axle on a dyno pull last month... can't do that with a bad viscous coupling!

 

I like my AWD. You have to tune your suspension to get rid of some of that understeer and it is good. Stock it is so bad, pushes terribly so you can't use any of that grip. For launches you do get a bit out of it.

 

I saw that! Pretty nuts.

My adjustable Eibach sways help immensely with that.

 

I thought of something else to add...

My car had 20" wheels on it for YEARS. They were slightly smaller in the front than the back (im talking OD of tire) , which is supposed to be a huge no no for front diff health. The stock tire setup has the fronts larger than the rears.

This didn't seem to affect my diff negatively over the course of 20,000+ miles!

 

I’m running slightly taller rear tires too. No issues so far (About 3000 miles before I went RWD and have put a few hundred on it since going back) and PSM has been perfectly happy.

 

Word. I switched back to stock but I never had issues with my "forbidden setup" either. lol

Nice thread man.

 

The Porsche limit is plus or minus 3%. I think it might be OK but it just gives you less front drive performance and likely causes drag while you are driving along, possibly heat. My fronts are slightly larger which should actually give the front drive a little more power delivery.

 

I don't think it's plus or minus 3%. The back tires should never be taller than the front tires if you're running awd. Check out this thread.

https://www.6speedonline.com/forums/...lp-needed.html

Later, Steve

 

Your issue was more of a stability/steering concern than tearing up your diff though right? I never experienced that - granted I'm "only" around 500HP

 

I did get the 235/35 315/25 after reading your thread a while back. Most never have issues but maybe you are the wheel man tearing up the streets and everyone else drives like a granny.

 

Yea, this is like an old wives tale or something. AWD tires should always be matched front/rear or as close as possible.

 

Uhh... who is saying AWD is near useless for performance driving? lol. Unless you're defining "performance driving" as strictly being on a track (where AWD is way heavier and a big disadvantage), AWD is a fantastic asset to have for almost all purposes. I assume the "purists" are frowning upon it over RWD for the same reason Manual is frowned upon over PDK. And don't get me wrong, I prefer RWD over AWD as well, I just completely disagree with the original statement about it being useless.

But when it comes to short distances in a straight line (esp with big power), AWD is certainly advantageous. It's no coincidence the Turbo S has been AWD for 25 years and is also consistently one of the fastest stock off the line cars available...

 

I've seen it echoed on this forum for years. Most of it seems to center around the viscous coupling in the front drive unit. I posted this thread to help debunk that and I totally agree with you.

 

I like the system when you slide the rear you can feel the front wheels pulling the car around the corner a little bit.