Let's talk traction on these bastardized 86s!

[Clash0901]

I guess we will see. I'm committed to the tire change regardless. There's not many other possible options for me without breaking the bank. I want to keep these wheels and keep the 17's. They look too good and fit perfectly at 17x9 + 35 with the 275/40

[ILLSMOQ]

Originally Posted by Clash0901

I guess we will see. I'm committed to the tire change regardless. There's not many other possible options for me without breaking the bank. I want to keep these wheels and keep the 17's. They look too good and fit perfectly at 17x9 + 35 with the 275/40

I run a 17x9 +40 with the 275/40/17 Hoosier and it rubbed with the Suspension pulled all the way in. Will probably be worse for you with the +35 unless you can pull the suspension in and/or jack up the rear.

[Clash0901]

Originally Posted by ILLSMOQ

I run a 17x9 +40 with the 275/40/17 Hoosier and it rubbed with the Suspension pulled all the way in. Will probably be worse for you with the +35 unless you can pull the suspension in and/or jack up the rear.

I've been running this setup for a year now. Short of some occasional big bumps, it doesn't really rub. And if it does, it just hits the rear bumper corner where the bumper mounts to the body near the tire.

[Icecreamtruk]

Just saying, 275 on 9" you are barely using that tire. Anything past 255 is wasted rubber, you are just bulging the tire out and riding the sidewalls at every turn. I guess turning is not a priority to you, I just figured I'd mention this.

[Clash0901]

Originally Posted by Icecreamtruk

Just saying, 275 on 9" you are barely using that tire. Anything past 255 is wasted rubber, you are just bulging the tire out and riding the sidewalls at every turn. I guess turning is not a priority to you, I just figured I'd mention this.

It's not visually the case though. The tire fits perfectly on the 9" wheel. At 30 psi or 20psi it doesn't have any abnormal shape or overly bulging.

[TRS]

Didnt read the entire thread. Here is what I've done with my LS swap, sure with less power/torque, but maybe closer than OEM, should be some where 450ish:

1: As said before, surprise surprise, use a good tire. But please stay of from generalized pressure suggestions. A good pressure is highly depending on the tire's construction and also the size you are using. In my case I found a impressive while cheap tire with very good traction with a 245/35R18 Federal RS-R.
2: Use a coilover with a stifer spring than OEM, but dont even think about lowering much below OEM ride height. Otherwise the geometry of the rear axle will not work properly without some serious changes.
3: Choose the right ratios. OEM like ratios are nonsense for a high powered swap car. I have a 2.66 1st gear combined with a 3.58 ratio in a OEM rear end casting. Since you are running on even higher torque levels the 3.784 1st combined with 3.78 axle pretty much makes your first two gears useless, even with a hyper pro gold level tire.
4: Dont use hard rear stabilizer settings in case you have a adjustable one.

In my case I cannot spin tires in 2nd and up whithout clutch kick when street is warm and dry and tires are on a working temperature. Under good conditions (good asphalt, tire on perfect temp) even 1st is nailed down once you succesfully closed the clutch without creating slip.

For a comparrison: I used Michelin Pilot Super Sport in the same size before the Federal. I had traction issues with this tire also in 2nd easily. When switching to the RS-R's I started over with the same pressure I found to be perfect with the Michelin. I had realy terible traction issues over all gears with that. Then I reviewed the tire ratings and found a way lower Max pressure rating. So I lowered the Set pressure by 25% and had perfect traction and Improved 0-60mph from 5.1s to 4.1s.

Just my 2cent...

[Clash0901]

@TRS

What rear end is the 3.58? Did you have to swap internals from the pumpkin from something else? Also, what trans are you using? T56 i'm guessing

[TRS]

Yes, transmission is T56 magnum F. Should also be an option for a 2jz, just Google grannas racing. Seems odd on first sight, but a swap to T56 should be less expensive than a custom gear set for the CD009 while providing an overall stronger transmission.

The 3.58 rear end is a Toyota Ring and pinion Set available at Just Differentials. It fits the OEM rear end. Be aware for the different spline count of the pinion if you use this one and buy it together with the matching diff flange. Besides that its a plug&play in the OEM housing and with the OEM LSD unit. Sure, you need to setup play between ring and pinion as with any changed diff gear set, but Besides that plug&play...

[matt88]

Originally Posted by TRS

Didnt read the entire thread. Here is what I've done with my LS swap, sure with less power/torque, but maybe closer than OEM, should be some where 450ish:

1: As said before, surprise surprise, use a good tire. But please stay of from generalized pressure suggestions. A good pressure is highly depending on the tire's construction and also the size you are using. In my case I found a impressive while cheap tire with very good traction with a 245/35R18 Federal RS-R.
2: Use a coilover with a stifer spring than OEM, but dont even think about lowering much below OEM ride height. Otherwise the geometry of the rear axle will not work properly without some serious changes.
3: Choose the right ratios. OEM like ratios are nonsense for a high powered swap car. I have a 2.66 1st gear combined with a 3.58 ratio in a OEM rear end casting. Since you are running on even higher torque levels the 3.784 1st combined with 3.78 axle pretty much makes your first two gears useless, even with a hyper pro gold level tire.
4: Dont use hard rear stabilizer settings in case you have a adjustable one.

In my case I cannot spin tires in 2nd and up whithout clutch kick when street is warm and dry and tires are on a working temperature. Under good conditions (good asphalt, tire on perfect temp) even 1st is nailed down once you succesfully closed the clutch without creating slip.

For a comparrison: I used Michelin Pilot Super Sport in the same size before the Federal. I had traction issues with this tire also in 2nd easily. When switching to the RS-R's I started over with the same pressure I found to be perfect with the Michelin. I had realy terible traction issues over all gears with that. Then I reviewed the tire ratings and found a way lower Max pressure rating. So I lowered the Set pressure by 25% and had perfect traction and Improved 0-60mph from 5.1s to 4.1s.

Just my 2cent...

What pressures have you been happy with on the Federal RS-R's? You said 25% lower than the Michelin but not sure what pressure you started with.

Just had a quick look online. RS-R's not available here in Australia in this size, but the newer RS-RR seems to be available and price looks very reasonable. I would guess whatever pressures you've had luck with on the RS-R's might well be close enough is good enough on the RS-RR's?

[TRS]

You cannot safely say that the same pressure works in the RS-RR. For example the RS-R Pro is also looking like a similar tire in first sight, but indeed it isnt. It has a higher pressure rating while having lower treadwear. The pressures we use on the RS-R are too low for the RS-R Pro to work properly. As well, the RS-R Pro was a try out because of the good expierience with the RS-R, but I have to say that the RS-R Pro isnt a tire I would buy again. It also performs well, but its realy unresonably noisy. Not only a little loader, like it can be found with many UHP tires, its realy noisy. Like having four completely worn out wheel bearings going to throw away the wheel hub in short.

For the RS-R Im running 2.2bar/2.0bar front/rear for daily driving. For track use I slightly lower about 0.2bar on the cold tire.

[ZDan]

Having a "higher max pressure rating" has zilch to do with what appropriate pressure is for these cars. Higher max doesn't mean you should run higher pressures, it just means that you can pump them up to carry more load.

[TRS]

Originally Posted by ZDan

Having a "higher max pressure rating" has zilch to do with what appropriate pressure is for these cars. Higher max doesn't mean you should run higher pressures, it just means that you can pump them up to carry more load.

Didnt say anything like this. But a lower pressure rating needs be taken care of, not only if you load your car.

The pressure rating does not necessarily correlate to the load Index. Even if this is true in some cases, its not true in all. In case of the RS-R the pressure rating is very low. Sure, this doesnt necessarily mean that it needs less pressure then a identically sized tire with a higher pressure rating, but is an indicator that the tires construction is made to work with lower pressure. If this is realy the case of course needs to be tested as perfect pressure settings needs to be tested for any new type of tire used.

Again, I didnt say the pressure rating directly correlates to the pressure to be used for a tire. But to implicate this to my post would also mean to implacte to your post that each tire of a specific size on a specific car, but from different manufacturers and/or different types, will work perfect with one and the same pressure setting, no matter what load Index or pressure rating. And I think you will agree that this also isnt true.

An example: A Michelin PSS in 245 35 18 works great at pressures around 2.4 to 2.6 bar on the 86. Thats at least the pressure for best grip and optimal temperature distribution. For the RS-R this is somewhere between 1.8 and 2.0 Bar. The PSS has a max rating of 3.4bar, the RS-R of 3.0bar. If you set a cold pressure of 2.6 bar, which works good on a PSS, to a RS-R you are risking to exceed the max pressure rating for this tire when warm.

Again, I dont say that this is a always-true rule, but the pressure rating is a indicator for the type of tire constrution and at least needs to be considered.

To keep with the example above, the RS-R has a way stiffer construction then the PSS. It follows complete different attempt of tire design. If you run a RS-R with the pressure you would run a PSS and you call both good, you're at least wrong once. ��

[ZDan]

A given tire's load capability absolutely does correlate with pressure. That's why sidewall markings always list the max load at a specified pressure, e.g. Max load 1609 lb. *at 50psi* on my new 245/40-17 Yok A052s. At 30psi, max load is much less. But of course for my application the max pressure on the sidewall is irrelevant as static load per tire is way less than 1609 lb. Max sidewall pressure again has zero to do with optimizing pressures for performance. I aim for 34-36psi hot (~26-28 cold)

[brzlegend]

A gopro aimed at the rear to see what is happening when it spins might be helpful. Post the video. If you put weight in it, know as the weight gets farther behind the axle the more unstable the car will be, the rear seats would probably be the best. Look up 4 link suspension setup for dragracing to understand more about traction and what is needed.



Seems like air bags would work great for drag suspensionon the more squat the stiffer they get.