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-   -   Keep the 275/ 315 tire setup or trade off for less weight? (https://www.rx7club.com/race-car-tech-103/keep-275-315-tire-setup-trade-off-less-weight-944362/)

855m0n0 03-10-11 08:33 AM

I have used many tires on my track car and hands down the R6 Hoosiers are by far the best. They are very light, the stick well, and last reasonably well. Pretty much everyone I know that is making power uses them. The only people I know that use anything other than an R6 (or A6 for some TT guys) are people in a class with a spec tire....

Hoosier has a good contingency program too.

FWIW I have found that as close to square setup as possible works for my car. I have 395whp (LSx motor) and run 275s R6. I would like more tire but I will probably end up going to 315s all the way around once I have everything else sorted. At this point I dont believe my tire width is effecting my lap times....

I have tried various stagger setups and was always slower with them. I imagine that one could be fast with a stagger but it seems like it takes a LOT of suspension tuning to make that happen... most people I know that had big staggers (285f/335r) are moving to a much closer to square setup if not a square setup... they couldnt ever make the car handle right with the big stagger... If I was going to have a staggered setup I would try something no more than 10-20mm difference... maybe 315F and 335R.

My 18x9.5 with 275s ended up being lighter than my old 17x9 setup with 275s... I dont know the tire weights on the 335s but it may end up being lighter if you go to 18s.

TrentO 03-11-11 06:46 PM

Slicks
 
"So do you think if I go 315's rear and 285 front slicks that it would be too much? I am eager to run slicks, because as you stated they are much lighter and much stickier. "

I'd suggest staying closer to square. The FD was putting down 440 rwhp with the 280/650/18 yokohama slicks on all four corners. Laster year he ran the 260/640/17 up front and the car was understeering quite badly on turn-in.

Here's who we get the slicks from and the catalogue:
http://www.tracksideperformance.com
http://www.tracksideperformance.com/...atalog2010.pdf

We run the S001 (now just called soft) compound and it is fast and still gives reasonable life.
The 20B car we run against had 320/650/18's up front and the 330/710/18's out back. With near 700 hp on tap he didn't appear to have traction issues.

In my FC I found the 280's to hold better through power-on high speed corners than the 260's (you could feel the extra grip). I think anything more is overkill.

-Trent

aoc007 03-14-11 04:57 PM

When I bought my coilovers from re-amemiya I asked the rep what setup he runs and he said 18x9 265/35 front 18x10 265/35 rear on the Fuji GP circuit with 450rwhp. I got the feeling that this was just a street/trackday setup. Interesting to see what those guys over there use since the language barrier makes it so difficult.

btw my post count is great right now :)

blackey 03-15-11 10:59 PM

Just saw this. I would run 285/315 or maybe a 295/315 if you can. 285/285 would be fine too.

I would say the more the better as long as you can keep the front and back about the same. With too much stagger the car will push no matter what you do. - as Guy pointed out. We tried for half a season to get it out and couldn't.

As far as tires go...

R888 Suck - They go off after a few heat cycles like Hoosiers, so why bother...

From what I can tell

Hoosier R6 is worth about .75-1 sec per minute of lap time over an NT01.

From there you can go to Full Slicks or A6's if you need to.

Bill

GtoRx7. 03-16-11 12:33 AM

My Front wheels are 10.5" wide, so I can most likely fit in a 285 and still have room in the fender. I am going to wear out the NT01's first just to get some seat time in the car, then switch to hoosiers. I never shaved the NT's on the car right now, anyone have experiance if shaving will gain a lot more traction? Or just let the tread wear away while tracking it?

aoc007 03-16-11 01:18 AM

shaving is not necessary on nt01s at all, also it may be a bit, thats why people like those tires, they last forever for what they are haha

j9fd3s 03-16-11 11:45 AM


Originally Posted by GtoRx7. (Post 10519714)
My Front wheels are 10.5" wide, so I can most likely fit in a 285 and still have room in the fender. I am going to wear out the NT01's first just to get some seat time in the car, then switch to hoosiers. I never shaved the NT's on the car right now, anyone have experiance if shaving will gain a lot more traction? Or just let the tread wear away while tracking it?

dunno about the NT01's... the Ra1's need to be shaved though unless you're using em as a rain tire

j9fd3s 03-21-11 11:20 AM


Originally Posted by GtoRx7. (Post 10507803)
Yeah, I am extremely interested in the what the result of hankook vs. Hoosier is for you. Hankooks price is really attractive.

we got rain this weekend... the R888's work really well in the rain!

http://www.youtube.com/watch?v=FieUdPeFXoU the edit @8min is 2 caution laps removed

if you look close after about half a lap, there is so much water in the car under braking the relays (for the 25 hour lights) on the passenger floorboard are under water during braking

the green miata is the other car in the class.

GtoRx7. 03-23-11 12:14 AM

Awesome! Sweet video!

PandazRx-7 03-26-11 12:17 PM

Glad to hear about different track set-ups... I just started tracking my FD last year and in the process of fine tuning the suspension and tire set-up. Here's my experience so far...

Initial set-up at Streets of Willow. Running R888's staggered at 265/295, HKS front bar, stock 93 rear bar, it pushes a lot to the point where I have to jerk the wheel on tight corners and use the throttle to move the rear end where I want it. High speeds it feels uncomfortably light up front...

Second set-up made some changes and went to Buttonwillow first time ever. I added my rear stiffer HKS bar along with a 6" custom front slitter and APR GTC-300 wing only at 7 degree AOA. Still pushes on tight corners but not as bad as before...high speed feels more stable but not turning as crisp as I would like and still nervous to push it.

Next step is fatter front tire, thinking 285's, corner balancing and adjusting camber based on my last tire temps. Only thing that sucks about the 285 R888's is they're like $80 more expensive than the 295's. Weird.

Any one know what tire pressures work well with R888's? Can't seem to get the temps above 150F degrees on 70F degree days...

finger lock 03-26-11 02:12 PM

Panda,

A couple of things, you should be able to dial out your push by adjusting the AOA on your wing. I have the same wing and am running it at 0° AOA in the center. (3.5 inch front splitter, 285/30/18 R6 F&R)

Your tires...I'm not a big fan of the R888s. I believe you would do much better with a set of Hoosier R6s, Goodyear Eagle RSs or perhaps the BF Goodrich G-force R1s (I don't know about the BFGs on a FD).

Be patient on the track, the speed will come with seat time.

Best,

Guy

gkmccready 03-26-11 02:33 PM


Originally Posted by PandazRx-7 (Post 10537108)
Any one know what tire pressures work well with R888's? Can't seem to get the temps above 150F degrees on 70F degree days...

High. Aim for 40-45psi hot to get the R888s working.

http://www.aimtire.com/typ_category....&ObjectID=6828

PandazRx-7 03-26-11 04:58 PM


Originally Posted by finger lock (Post 10537227)
Panda,

A couple of things, you should be able to dial out your push by adjusting the AOA on your wing. I have the same wing and am running it at 0° AOA in the center. (3.5 inch front splitter, 285/30/18 R6 F&R)

Your tires...I'm not a big fan of the R888s. I believe you would do much better with a set of Hoosier R6s, Goodyear Eagle RSs or perhaps the BF Goodrich G-force R1s (I don't know about the BFGs on a FD).

Be patient on the track, the speed will come with seat time.

Best,

Guy

Good idea, gonna try 0 degree AOA... Only issue with running the R6's is that I'm not supposed to go lower than 50 UTQG for the Time Attack I signed up in...R888 are at 100 UTQG. Any other recommendations on tires? At this point I think two used 285's might be the cheapest route along with a nice corner balance...

You're definitely right about seat time...I did find that tweaking my driving and learning the track always shaves off the most time. Been to SOW 4 times and with no wing/splitter managed to work from low 1:30's to 1:26.5 w/passenger and 130F tires temps...first time button couple weeks ago managed 2:09 with a new set up and passenger...I know the car easily has 1:50's. Can't wait to learn that track some more.
By the way, what are your spring rates? I'm still on 10K/8K Koni/GC

finger lock 03-27-11 12:14 AM

Panda,

My spring rates are 1100 lb/in F, 1000 lb/in R.

I forget about that "rules stuff" sometimes. For good or bad I run in an unlimited class.

Guy

j9fd3s 03-27-11 08:52 PM


Originally Posted by PandazRx-7 (Post 10537108)
Any one know what tire pressures work well with R888's? Can't seem to get the temps above 150F degrees on 70F degree days...

150F is cold.. we let the tire temps set our pressures, and we run pressures in the 33-36 area. this seems to be backwards from what everyone else does.

AND we're running a 205's and 225's so the wider tires might like something else.

the R888's are good but they like a smooth driver.

gkmccready 03-27-11 09:26 PM


Originally Posted by j9fd3s (Post 10539150)
150F is cold.. we let the tire temps set our pressures, and we run pressures in the 33-36 area. this seems to be backwards from what everyone else does.

What kind of temps do you see?

j9fd3s 03-27-11 09:35 PM


Originally Posted by gkmccready (Post 10539219)
What kind of temps do you see?

we've gone with the AIM tire guide, so we're shooting for 180-200F, and on an "average" day temps will be in the mid 190's, we let it be a little cooler on the outside. on a hot day we'll see a little more.

if they are sliding it around, it'll be higher still, like 210...

we roadrace, and we take temps on the white flag lap, so its like 10-12 minute session

Donovan N. 03-27-11 10:07 PM

does anybody know how wide you can fit in the front without the tires rubbing on the fender well? and in the rear without having to tub the fenders?

thanks

Donovan N. 03-27-11 10:14 PM

^^^^^
sorry for the double post, thought I was still in the 3rd gen section. but this would be on a 93

PandazRx-7 03-28-11 12:23 AM


Originally Posted by j9fd3s (Post 10539150)
150F is cold.. we let the tire temps set our pressures, and we run pressures in the 33-36 area. this seems to be backwards from what everyone else does.

AND we're running a 205's and 225's so the wider tires might like something else.

the R888's are good but they like a smooth driver.

I've tried 32 to 42 hot and still can't get them hot enough... I'm running 550/400lb springs, which I know are considered pretty soft for serious tracking. I'm thinking of going 700lb up front and throwing the 550's in the back. Will stiffer springs help with getting enough heat?

Thanks for all the input guys, a lot of good info here.

j9fd3s 03-28-11 01:12 PM


Originally Posted by PandazRx-7 (Post 10539493)
I've tried 32 to 42 hot and still can't get them hot enough... I'm running 550/400lb springs, which I know are considered pretty soft for serious tracking. I'm thinking of going 700lb up front and throwing the 550's in the back. Will stiffer springs help with getting enough heat?

Thanks for all the input guys, a lot of good info here.

how/when are you measuring temps? for road racing you NEED the probe type temp thing, and you NEED to pull in to the pits HOT and have someone else take temps.

if you go back to the paddock and get out and then do it, it has enough time to cool down, that it won't show you anything useful.

in my experience the tire temp has more to do with lap time than anything else. if the driver is slow, they will be cold, if the driver is sliding the car around too much, it'll be too hot.

PandazRx-7 03-28-11 02:27 PM


Originally Posted by j9fd3s (Post 10540230)
how/when are you measuring temps? for road racing you NEED the probe type temp thing, and you NEED to pull in to the pits HOT and have someone else take temps.

if you go back to the paddock and get out and then do it, it has enough time to cool down, that it won't show you anything useful.

in my experience the tire temp has more to do with lap time than anything else. if the driver is slow, they will be cold, if the driver is sliding the car around too much, it'll be too hot.

I have a Longacre tire pyrometer with probe, displays all 12 temps at once. At SOW, my passenger jumped out and read temps as soon as I exited the track...probably less 20 seconds after my last hard turn. Sooo I guess I'm slow huh? :)

j9fd3s 03-28-11 04:34 PM


Originally Posted by PandazRx-7 (Post 10540450)
I have a Longacre tire pyrometer with probe, displays all 12 temps at once. At SOW, my passenger jumped out and read temps as soon as I exited the track...probably less 20 seconds after my last hard turn. Sooo I guess I'm slow huh? :)

possible. set the car up so you can be comfortable, and keep working at it. we spent 2 YEARS f-ing with our car trying to get it faster, and not getting any real results, it was frustrating!

the solution for us (its FWD) was a rear sway bar that's as big as your leg....

the cool part about fighting the car for so long though is NOW when we wanna make changes, we know what does what

TrentO 03-28-11 05:27 PM

Fast comes with confidence in knowing what your car can handle and pushing it close to the limit. My advice is to go square on the tires, set the corner weights, do a proper alignment and then find a track with a few corners with pavement run-out areas so you can push it. My favorite is a local airport track, lots of run-off space for when it goes bad. Get out there and slowly work up to speed and get a feel for what the car likes for turn in and when/where it settles into a steady cornering state. Learn when you can put the power down and how soon you can roll into the throttle (turbo cars require inputs a little ahead of the actual track to compensate for the turbo coming back on boost after a lift entering a corner.
Once you feel comfortable it is time to start pushing the car. In my experience, the steady cornering traction will surprise you, stay calm and keep the inputs smooth. Push the braking later, but ensure the car enters the corner balanced. I've seen too many guys who blaze into a corner, scrub off a ton of speed and have no momentum out of the corner. Most corners I'll give a little extra speed up in braking just to get on the power sooner. I also like to keep a tiny bit of a safety margin for those unexpected events like brake failure. When it is a full on race, the safety margin gets pretty small and the mid corner prayers go up a lot.

-Trent

finger lock 03-29-11 10:06 AM

Panda,

I saw that you were thinking of making a rear wing adjustment. I would caution you not to make "large" adjustments all at one time. Changing from an AOA (at the center) of 7 degrees to 0 degrees with the APR GTC 300 will result in reduction of rear downforce. See Data I would recommend a few small adjustments to avoid going from a push condition to a very loose condition.

Guy


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