Modified Mag RX-8 project car -- STX here I come!
05-17-2010, 10:40 AM
#26
Hi Dave, welcome to RX8Club & STX. Look forward to following the buildup.
As for the tire test, I'd rather see a 17" vs. 18" test, using the same tire, than another tire brand test. Frankly, swapping brands can lead to changes in balance, and unless you take some time to tweak your setup for each brand it may be difficult to get good data. I think having a good data point on the wheel size debate would be of particular interest to the RX-8 crowd, and would add meaningful data that is currently missing from our community.
So, my vote is to get some 17" RPF1s & 255/40-17 RE-11s and see what happens!
As for the tire test, I'd rather see a 17" vs. 18" test, using the same tire, than another tire brand test. Frankly, swapping brands can lead to changes in balance, and unless you take some time to tweak your setup for each brand it may be difficult to get good data. I think having a good data point on the wheel size debate would be of particular interest to the RX-8 crowd, and would add meaningful data that is currently missing from our community.
So, my vote is to get some 17" RPF1s & 255/40-17 RE-11s and see what happens!
I second this
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05-17-2010, 02:04 PM
#31
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sLaPcHoP edit: Oh, I should also mention I do have some Hawk pads for the car. Got a set of HP+ for the front and HPS for the rear. The HP+ might have a bit too much initial bite for some drivers, but I quite like them for street and autox duty, plus they should be able to handle the heat of some track testing and lapping/TA use. Will go up to a DTC-30 if the HP+ overheat at the track. ...
The stock brakes on the RX-8 are exceptional. I've been unable to fade the HP+ pads in the two years I've been using them on my RX-8. The tracks include VIR Full and Grand East, Summit Point main and Shenandoah. Just finished a weekend on the Shen. I've kept a set of Blues in the parts bin since I first got the car, but haven't needed them yet. Your skill level is certainly higher than mine, but I don't think you'll be disappointed with the HP+.
05-17-2010, 05:25 PM
#32
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Wankelbolt, good to know I shouldn't be concerned about brake fade with the HP+. The test track I use is ridiculously hard on brakes, so if I don't get fade there then I won't get it anywhere (why does this sound like the New York, New York song? Haha).
Guys, I think the idea of a 17'' vs 18'' wheel/tire setup is brilliant. Love it! I'll definitely set this up. I actually have a buddy with a set of 17x9'' Enkei RPF1's, so all I'll need is the tires and I'm pretty sure Bridgestone will take care of me on that since it'll be a doubly good story for them in the mag. I'm going to try to make this happen!
Guys, I think the idea of a 17'' vs 18'' wheel/tire setup is brilliant. Love it! I'll definitely set this up. I actually have a buddy with a set of 17x9'' Enkei RPF1's, so all I'll need is the tires and I'm pretty sure Bridgestone will take care of me on that since it'll be a doubly good story for them in the mag. I'm going to try to make this happen!
05-17-2010, 06:56 PM
#33
^Sweet! It would be great if you could do things like -
- Make sure both sets have roughly the same tread depth when the test is undertaken. The RE-11s have a tread pattern that puts progressively more rubber on the ground as they wear.
- Take a little time to try & determine an optimum pressure for both. Given the shorter sidewall, the 18" might like a bit lower pressures.
- Get some good accelerometer data from the runs so that we can see if the tires excel at different areas of the solo course. Ultimately, it's the final time that matters, of course, but the more detail the better.
Apologies if this is all obvious.
- Make sure both sets have roughly the same tread depth when the test is undertaken. The RE-11s have a tread pattern that puts progressively more rubber on the ground as they wear.
- Take a little time to try & determine an optimum pressure for both. Given the shorter sidewall, the 18" might like a bit lower pressures.
- Get some good accelerometer data from the runs so that we can see if the tires excel at different areas of the solo course. Ultimately, it's the final time that matters, of course, but the more detail the better.
Apologies if this is all obvious.
05-17-2010, 07:06 PM
#34
Wankelbolt, good to know I shouldn't be concerned about brake fade with the HP+. The test track I use is ridiculously hard on brakes, so if I don't get fade there then I won't get it anywhere (why does this sound like the New York, New York song? Haha).
Guys, I think the idea of a 17'' vs 18'' wheel/tire setup is brilliant. Love it! I'll definitely set this up. I actually have a buddy with a set of 17x9'' Enkei RPF1's, so all I'll need is the tires and I'm pretty sure Bridgestone will take care of me on that since it'll be a doubly good story for them in the mag. I'm going to try to make this happen!
Guys, I think the idea of a 17'' vs 18'' wheel/tire setup is brilliant. Love it! I'll definitely set this up. I actually have a buddy with a set of 17x9'' Enkei RPF1's, so all I'll need is the tires and I'm pretty sure Bridgestone will take care of me on that since it'll be a doubly good story for them in the mag. I'm going to try to make this happen!
05-17-2010, 07:43 PM
#36
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^Sweet! It would be great if you could do things like -
- Make sure both sets have roughly the same tread depth when the test is undertaken. The RE-11s have a tread pattern that puts progressively more rubber on the ground as they wear.
- Take a little time to try & determine an optimum pressure for both. Given the shorter sidewall, the 18" might like a bit lower pressures.
- Get some good accelerometer data from the runs so that we can see if the tires excel at different areas of the solo course. Ultimately, it's the final time that matters, of course, but the more detail the better.
Apologies if this is all obvious.
- Make sure both sets have roughly the same tread depth when the test is undertaken. The RE-11s have a tread pattern that puts progressively more rubber on the ground as they wear.
- Take a little time to try & determine an optimum pressure for both. Given the shorter sidewall, the 18" might like a bit lower pressures.
- Get some good accelerometer data from the runs so that we can see if the tires excel at different areas of the solo course. Ultimately, it's the final time that matters, of course, but the more detail the better.
Apologies if this is all obvious.
I use a Driftbox for all my in-car data acquisition (both GPS and accelerometer based data) and I'll definitely take tire temps across the contact patch to see if/how my starting pressures and alignment need to be tweaked for optimum grip. With racing slicks and DOT r-compound tires you want about 20 degrees more temp on the inside third of the contact patch than on the outer third (eg. 180, 190, 200 F from outside to inside), but for autox I'm guessing this will be very difficult to achieve. Plus street tires do provide close to their maximum grip at lower operating temps, but your thoughts on a target temperature range would be appreciated.
I was thinking about shaving my RE-11's to about 5/32nds for max dry grip, but since I was planning to use these as my daily street tires I think I'll leave them at full depth and do the same with a set of 255/50-17's. Then what I might do is get a fresh set shaved for the Nationals if I'm really focused on optimizing the setup for the big show. Problem is, if I optimize my setup to the nth degree and still get my *** handed to me, I won't have a built-in excuse
Here's a couple stories I did on my G35, just to give you some idea of the type of data I'll be collecting while building the 8:
http://blog.stillen.com/wp-content/g...8_APRacing.pdf
http://www.modified.com/tech/modp-10...wer-gains.html
05-17-2010, 10:28 PM
#39
I don't have that info right now. I intended to ask the guys in the Bridgestone truck at the Wendover NT yesterday, but I never got around to it. Hopefully they will be at the Pro this weekend. I'll see what I can learn, and I'll also ask about the ideal temp distribution. I do know getting a realistic temp distribution across the tire can be tough in a typical solo scenario, given the hard braking that is usually necessary at the end of a run.
I will say that the RE-11s can overheat, especially in a two-driver scenario in warmer conditions. Easy to manage with spraying.
Anyway, based on my experience thus far, I'd say their optimum operating temps are much lower than you list above. If the tire feels hot when I place my hand on the tread after a run, I spray. Not very scientific but that's where I'm at right now.
05-18-2010, 09:14 AM
#40
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05-19-2010, 10:25 AM
#42
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I'm taking the 8 for its maiden voyage at Toronto Motorsports Park this evening to baseline it and test the new wheel/tire combo vs the OEM wheels and tires (actually, the tires on the OE rims are Toyo T1R's in the OE size). I'll let you guys know how it goes.
Anyway, in preparation for the track I swapped on the Hawk pads last night and decided to weight the OEM wheel/tire combo to see how heavy it is compared to the new VR.G2's and Bridgestones. I was pretty impressed to see that I've only gained about 1.5 lbs even though rim width and tire width has increased substantially with the new setup.
Not sure how accurate my bathroom scale really is, but presumably the difference between the two is fairly accurate. Anyway, thought you guys might find this interesting.
Anyway, in preparation for the track I swapped on the Hawk pads last night and decided to weight the OEM wheel/tire combo to see how heavy it is compared to the new VR.G2's and Bridgestones. I was pretty impressed to see that I've only gained about 1.5 lbs even though rim width and tire width has increased substantially with the new setup.
Not sure how accurate my bathroom scale really is, but presumably the difference between the two is fairly accurate. Anyway, thought you guys might find this interesting.
05-19-2010, 10:36 AM
#44
Welcome Dave!
Look forward to the progress of the vehicle if you need anything let me know. If you are looking into some light weight brake upgrades I would suggest looking at what Racing Brake has to offer.
http://www.racingbrake.com/v/main/ve...asp?model=RX-8
They have Two Piece Rotors and Lightweight Calipers so they have tons of different options. If you are interested in pursuing that route I am sure I can work something out.
If you have a questions about a specific direction in which to take the car, just ask. There are tons of sources within the community to help.
Enjoy, this should be an excellent read once it is done.
Look forward to the progress of the vehicle if you need anything let me know. If you are looking into some light weight brake upgrades I would suggest looking at what Racing Brake has to offer.
http://www.racingbrake.com/v/main/ve...asp?model=RX-8
They have Two Piece Rotors and Lightweight Calipers so they have tons of different options. If you are interested in pursuing that route I am sure I can work something out.
If you have a questions about a specific direction in which to take the car, just ask. There are tons of sources within the community to help.
Enjoy, this should be an excellent read once it is done.
05-19-2010, 10:52 AM
#45
1% evil, 99% hot gas.
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While that SRF brake fluid doesn't hurt, personally I think it's overkill. I run Castrol LMA in my 8 and Spec RX-7 and have never managed to boil it.
Take some video inside and outside the car! Never enough RX-8 track videos!
Take some video inside and outside the car! Never enough RX-8 track videos!
05-19-2010, 04:04 PM
#48
Are you planning to test the car at any track days at Mosport (Kensai, 6th Gear, Apex, etc)?
Let us know what track days / Solo 1 events you will attend, a few folk from the Toronto area may come out to check out the car and your progress.
What kind of alignment settings are you planning?
Subscribed to the thread.
Let us know what track days / Solo 1 events you will attend, a few folk from the Toronto area may come out to check out the car and your progress.
What kind of alignment settings are you planning?
Subscribed to the thread.
Last edited by Chris_Bangle; 05-19-2010 at 04:12 PM.
05-19-2010, 08:42 PM
#49
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My car has -2 degrees of camber all around with a mild drop. Still eat up the outside edge of the front left tire at a track with predominently right turns and high speed (NT01s 245/40 on stock wheels). Don't have enough miles on my street tires to say for sure, but I think the -2 with 0 toe is fine wear wise.
05-19-2010, 08:47 PM
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Race Roots, thanks very much for the generous offer. I'll be in touch about the lightweight rotors from Racing Brakes.
wankelbolt, I agree on the SRF. It's expensive and overkill on a project like this, but I happen to have a box full of the stuff from a sponsorship deal on my racecar so I figured I might as well put in the good stuff. This way I won't be bleeding brakes often if at all. Normally I like Elf Frelub 650 in my street/track cars since it's worked very well for me and costs 1/4 as much as SRF. I've also had good performance out of Motul RBF600 but it's twice the price of the Elf stuff.
burglar, don't worry dude, I broke the pads in before going to the track and let them fully cool. I used to be a Hawk distributor back in the early 2000's. I learned my pad brake-in lessons many moons ago The brakes performed extremely well at the track tonight, btw. No fade to speak of, which really impressed me since TMP is absolutely brutal on the brakes. Two thumbs up to Mazda for the brakes on this car!!!
Chris_Bangle, I'll probably be at one or two Kensai days at the big track, though to be honest I'm always a bit uneasy about putting a street car on that track. I've seen too many cars go home on a flatbed there to want to push my street car beyond 9/10ths around that track. Anyway, I'll let you know what track days I'm at, just in case you want to come out for some fun. I'll be at TMP pretty often, testing the car every time we upgrade something on it. Will probably do the coilovers next, so I'll let you know when that's going to happen.
For alignment settings, that'll be determined by the tire temperature data and how the car feels to me at the limit, but as a starting point I'll likely go with something like -3 degrees of camber up front along with a bit of toe out (maybe 1/16th on each front wheel, so total toe out of 1/8th) and -2 degrees of camber in the rear along with zero toe or maybe a smidge of toe-in depending the swaybars I go with. That may be a bit less rear camber than some guys like, but I tend to set my cars up for maximum front grip and a little bit of understeer at the limit, so my rear tire temps don't generally indicate I need more rear camber.
Speaking of tire temp data, we collected some good data on the Bridgestones tonight, so I'll post that up once I get a chance. But the quicky version is the rear of the car seems to gain more camber than the front and appears to have more static camber than the front as well, and the tire temp showed this to be the case too. In terms of lap times, the car went 3.5-seconds a lap quicker (best time of 1:25.8) on the Bridgestones than on the OE sized Toyo T1R's (best time of 1:29.3). The Mazda is already as quick as my G35 was with KW coilovers and AP big brakes. I think I'm going to like the 8 -- a lot
Oh, also gotta thank my friend Will Chan from Enmo Racing (who recently won their class at One Lap of America and finished 8th overall in a twincharged EG Civic!) who collected all the tire data for me tonight. It's good to have friends who are SAE engineers
wankelbolt, I agree on the SRF. It's expensive and overkill on a project like this, but I happen to have a box full of the stuff from a sponsorship deal on my racecar so I figured I might as well put in the good stuff. This way I won't be bleeding brakes often if at all. Normally I like Elf Frelub 650 in my street/track cars since it's worked very well for me and costs 1/4 as much as SRF. I've also had good performance out of Motul RBF600 but it's twice the price of the Elf stuff.
burglar, don't worry dude, I broke the pads in before going to the track and let them fully cool. I used to be a Hawk distributor back in the early 2000's. I learned my pad brake-in lessons many moons ago
The brakes performed extremely well at the track tonight, btw. No fade to speak of, which really impressed me since TMP is absolutely brutal on the brakes. Two thumbs up to Mazda for the brakes on this car!!! Chris_Bangle, I'll probably be at one or two Kensai days at the big track, though to be honest I'm always a bit uneasy about putting a street car on that track. I've seen too many cars go home on a flatbed there to want to push my street car beyond 9/10ths around that track. Anyway, I'll let you know what track days I'm at, just in case you want to come out for some fun. I'll be at TMP pretty often, testing the car every time we upgrade something on it. Will probably do the coilovers next, so I'll let you know when that's going to happen.
For alignment settings, that'll be determined by the tire temperature data and how the car feels to me at the limit, but as a starting point I'll likely go with something like -3 degrees of camber up front along with a bit of toe out (maybe 1/16th on each front wheel, so total toe out of 1/8th) and -2 degrees of camber in the rear along with zero toe or maybe a smidge of toe-in depending the swaybars I go with. That may be a bit less rear camber than some guys like, but I tend to set my cars up for maximum front grip and a little bit of understeer at the limit, so my rear tire temps don't generally indicate I need more rear camber.
Speaking of tire temp data, we collected some good data on the Bridgestones tonight, so I'll post that up once I get a chance. But the quicky version is the rear of the car seems to gain more camber than the front and appears to have more static camber than the front as well, and the tire temp showed this to be the case too. In terms of lap times, the car went 3.5-seconds a lap quicker (best time of 1:25.8) on the Bridgestones than on the OE sized Toyo T1R's (best time of 1:29.3). The Mazda is already as quick as my G35 was with KW coilovers and AP big brakes. I think I'm going to like the 8 -- a lot
Oh, also gotta thank my friend Will Chan from Enmo Racing (who recently won their class at One Lap of America and finished 8th overall in a twincharged EG Civic!) who collected all the tire data for me tonight. It's good to have friends who are SAE engineers
Last edited by Modified Dave; 05-19-2010 at 08:52 PM.