tire recommendation for 800rwhp+?
 

I know this is a far shot on this forum, but I specifically want to hear from rx8 members. I swear there is something about our rear suspension that doesn't let the tires stick well... I ran mickey thompson street which was recommended by some high whp rx7club forum members, but they really sucked and would spin out as soon as turbo spools up on the freeway. I know there were a few 20b guys here.. just curious what tire you guys run in the back that I can punch from 50mph without worrying about loosing control. I just can't get an R compound because our roads in arizona is sooo sandy that R compounds get coated with sand very quickly. thanks in advance!

OEM spec tire on many super cars, like the 918.

Pilot Sport Cup 2 tires | Michelin US

Less rear camber will help straightline acceleration grip.

There isn't any street tire that's likely to tame your power level. Sandy roads only exacerbate the situation.

I feel like the problem is the pavement at this point. At 800+ hp the car is really suited for the track where the pavement is very grip friendly. More surface area on warm slicks is the best you are going to get on the street.

What width of tire are you running? Wasn't it like a 255 because that's TINY for that much power.

There is no street tire in existence that will be able to lay down 800WHP from a 50 roll.

The only way you're going to manage to put down that kind of power is going to a 15" rear wheel and getting some monster Mickey Thompson ET Street Radials. Not the small sidewall radials, the big ones like a 315/60R15.

Or get an ECU that isn't a piece of junk and can do traction control and boost by gear lol.

thanks 9k, am looking into it.

arca, just because he couldn't tune it doesn't make it a piece of junk ecu lol. I have 285/35/19 rears. I had Mickey Thompson street radials in the past. It was crap! I think the wear rating was around 200. I think there are a few different versions of the MT "street" though... so you may be referring to something other than what I had. I'm getting the microtech remote tuned by my previous tuner when I get a chance, so we'll see soon about the ecu. I actually have been tuning it on the street in the meanwhile, and it's running much much better. I think the tuner could've done a better job honestly. He tuned for power, but the lower end was really shitty. :( I don't think he even touched the lower end... it was super lean off boost--like afr of 15-18. the dwell settings, timing gap, and some timing/fuel map were also questionable at best and some backward in trend when I compared it to maps done by reputable rotary tuners. In retrospect, I think I should've driven it to texas and get it done by steve kan. I feel it's the combination of microtech and rotary thing that he isn't really accustomed. As much as I liked the shop and the crew, I probably wouldn't use their tuning service again for my rotaries. unless there was a huge drop in fuel pressure or something that happened between the tune and my drive... it just wasn't what it should've been.

you're right about microtech on one thing! I hate the fact that it doesn't have traction control. I may end up going with aem infinity 6 or haltech elite just to get traction control afterall.. or stick my racelogic in it... although the thing I don't like about racelogic is that it cuts fuel but doesn't cut spark... so there is chance for super lean detonation possibly... either way, you may see my car back in the shop again. :)

yea camber is close to 0* in the rear. I may end up doing 18x13 rear with like +5 offset to mount 335 tires... i hope that would help. cut out the quarterpanel and glass universal fender guard on it. knowing me, I probably just cut the quarterpanel to fit the wheels, weld the gap, then drive around all ghetto for a couple years.

it will take a 200 wear to hold that much hp. Maybe lower. Any tire with a high wear number will loose grip.

200 wear is good for around 4-500whp. anything higher than 500, you want around 100, or lower.

ahh I read your message wrong I thought you wanted more wear rating.

800whp? Holy s%$. I'm guessing you're not running the stock rx8 rear diff then? Getting a tire to hook at 50mph from a punch at 800whp, chances are you'll break something or things lol.

stock rear differential. It's fine as long as you don't launch it and be smooth when shifting. Also using stock FD transmission. well to be fair, I think the reason why they aren't breaking now is because I can't put the power down unless the car's strapped on a dyno. :p:

I'd think you would want your tires to break free before your axles, or diff, or driveshaft, or transmission, or engine...

...just sayin :)

man when it lets go, it happens in a split second, no warning, nothing... rpm just goes to 9-10k, and the rear starts to step out to the passenger side. I usually wait until rpm drops back down, steer out of it, upshift, and get back on it slowly, but it sucks not being able to put down all the power next to a modified evo, gt2, or gtr. I win but I want to demolish them in about 2 seconds. :p: driveshaft is good to 800ft-lb. broken transmission, axles, and diff would be a price I'm willing to pay to be able to do this :yelrotflm

Well the rear is likely squatting a lot under that kind power output and it builds camber in the process of compressing ...

You might make sure it's not bottoming out on the bumpstops when you're getting on it like that ...


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cool, thanks. you may be onto something. I softened up the rear springs and have the strut set at the softest setting so it can squat on accel. I thought that would be better to put power down. Let me try to firm it up to see if that'd help. Not too sure if it's bottoming out. can't really hear much other than exhaust once I'm WOT.

Old racer trick;

Jack it up and put small tie-wraps tightly on the rear shock shafts down where it enters the top of the shock body. After you've driven on it hard you can jack it up again and see where they are. The shock body will push them up to wherever it moves to. If they're up on the bumpstops then you have your answer.

My opinion of Microtech has been that way long before I even knew your car existed, so please don't assume that is the reason I don't like it lol. The only thing I knew about this whole thing before you made that post above was how much power you made, and saw a thread where you posted the tune on a public forum which is pretty disrespectful. That's it. Hadn't heard anything else on the subject until just now, sorry you feel that way.

Back to the original topic, there are four ways I can think of to deal with traction issues at massive power levels.

Really sticky tires that are also wider than 300mm. R compound like NT01. Or ET Street, the tall sidewall ones not the kind you tried.

Turn the power down, boost by gear.

Traction control.

Right foot technique, pedalling the throttle.

are you running the 3.90 FD3 rear gear ratio or do you still have the RX8 ratio?

edit, just saw your other thread, you need the 3.90 gear which is kind of rare but possible to find used, but it's still available new from Mazda



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