Comprehensive Evo STU prep thread?
I've heard information from both sides.
Andy Hollis carried pressures in the RE-01Rs at about the same as the RT-615. Here is what he said: http://grassrootsmotorsports.com/new...-vs-falken.php
John Scheier has a different view:
We've been running 245/40/17 on 8.5" wheels on the BMW at maybe 32F/31R on a really slick surface. Our camber is about the same as John's in the front, but less in the rear. We fight too much rollover in the rear on the M3 by going below 32 or 31psi back there.
The Evo was being run on the same surface, so keep in mind those pressures wouldn't work on a surface with some actual grip.
-Jon
Andy Hollis carried pressures in the RE-01Rs at about the same as the RT-615. Here is what he said: http://grassrootsmotorsports.com/new...-vs-falken.php
John Scheier has a different view:
Originally Posted by John in Houston
As stated earlier in the thread, the RE-01Rs definitely like to run a little softer than other brand STU tires.
17x9s with 245x40s on a 3000 lb E36 with high spring rates. I'm usually running 32/33 front with 30/28 rear. Pyro shows good numbers on sealed asphault. I have noticed that they do react quickly to pressure changes... which makes for an excellent tuning tool.
17x9s with 245x40s on a 3000 lb E36 with high spring rates. I'm usually running 32/33 front with 30/28 rear. Pyro shows good numbers on sealed asphault. I have noticed that they do react quickly to pressure changes... which makes for an excellent tuning tool.
The Evo was being run on the same surface, so keep in mind those pressures wouldn't work on a surface with some actual grip.
-Jon
Swap your springs front to rear or use 8-9k springs on the rear, to decrease understeer.
Last edited by SS RX7 r2; Sep 10, 2007 at 05:39 PM.
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We are fighting the camber issue too. Currently we are at -3.2 up front and the braking sucks so I think we are going to back it down a bit. I'm also coming from an E36 M3 so I'm used to good brakes, and like you, good front grip. Don't spend a lot of time chasing the front grip; it will *never* be like the M3.
I'm not sure of your spring rates; do you mean 700kg/500kg? If so, that seems rather low. We tried a similar front rate and found the grip to be great....until it started bouncing off the bump stops in every turn. If you are hitting the stops it could be the cause of your lacking front grip.
Danny and I hit a test and tune this weekend and managed to get the car a LOT better than it had been previously messing with the rear bar, toe and tire pressures. I was pleasantly surprised to manage a 43.9xx to Corey Ridgick's 43.8xx. We still have some changes to do, but at least we are getting close.
Good luck.
Mike
I'm not sure of your spring rates; do you mean 700kg/500kg? If so, that seems rather low. We tried a similar front rate and found the grip to be great....until it started bouncing off the bump stops in every turn. If you are hitting the stops it could be the cause of your lacking front grip.
Danny and I hit a test and tune this weekend and managed to get the car a LOT better than it had been previously messing with the rear bar, toe and tire pressures. I was pleasantly surprised to manage a 43.9xx to Corey Ridgick's 43.8xx. We still have some changes to do, but at least we are getting close.
Good luck.
Mike
We finally managed to get my Evo out. Power and boost response were down, but we were trying to concentrate on the suspension, tires and alignment.
Cusco Zero 2E set to 4 with 7k/5k springs
Bridgestone 245/45/17 RE-01Rs on BBS MR 17x8 wheels
Front
Camber: -3.5*
Toe: 0
Rear
Camber: -2.0*
Total Toe: 0.25*
The alignment was my first try at an aggressive alignment on the Evo. We've been running ~-3.5* front camber and 245/40/17 RE-01Rs on an M3 for awhile and it has produced an amazing amount of grip. We've run fairly low pressures on the M3 with good success so we started out at 33psi all around with the Evo.
It should have been fast; it wasn't. The tires were unshaved and brand new with only 150 miles on the clock. The car squealed everywhere and felt like no grip was present. Every run out was faster, but, coming from an M3, it was expected that we would adapt to the car. Trying to find more grip, we started dropping tire pressures and finally ended, frustrated, at 28psi front and 30 psi rear.
We checked tire temps in the front and rear of one side, just to confirm our suspicions.
Inner - middle - outer
Front
144 - 130 - 111
Rear
120 - 115 - 110
I'd imagine that the tire pressures will prove to be too low once the tires are gripping and actually rolling over. For now, the car isn't gripping enough TO roll the tires. My only hope is that the tires just need more scrubbing. I know people out there are competitive in the Evo but we were no faster coming from a relatively stock M3.
The other interesting thing we noted was the stark contrast between running my Evo RS and a bone-stock 06 STI. My co-driver matched his times in the Evo when running an unmodified 2006 STI during fun runs. He finished the timed runs in the Evo with a 62s run. For his first run out in the STI during the afternoon fun runs, he matched the 62 and figured he could run a 60s run fairly easily. I did manage to cut 1s off of my time during the fun runs, with a 60.5, so there was more time out there in the afternoon. Anyway, his comments when driving the Evo, time and time again, are always that it is really hard to drive where the STI and the M3 are very natural.
Another friend, and a very good driver, took the Evo out and did no better with a 61s run. I have no doubt he would be faster given another run or two, but he wasn't that far from my pace. Earlier this year, a good driver would have beaten me in my own car but I'm finally to the point where I am faster in my car compared to one of the faster drivers in our region in my car.
-Jon
Cusco Zero 2E set to 4 with 7k/5k springs
Bridgestone 245/45/17 RE-01Rs on BBS MR 17x8 wheels
Front
Camber: -3.5*
Toe: 0
Rear
Camber: -2.0*
Total Toe: 0.25*
The alignment was my first try at an aggressive alignment on the Evo. We've been running ~-3.5* front camber and 245/40/17 RE-01Rs on an M3 for awhile and it has produced an amazing amount of grip. We've run fairly low pressures on the M3 with good success so we started out at 33psi all around with the Evo.
It should have been fast; it wasn't. The tires were unshaved and brand new with only 150 miles on the clock. The car squealed everywhere and felt like no grip was present. Every run out was faster, but, coming from an M3, it was expected that we would adapt to the car. Trying to find more grip, we started dropping tire pressures and finally ended, frustrated, at 28psi front and 30 psi rear.
We checked tire temps in the front and rear of one side, just to confirm our suspicions.
Inner - middle - outer
Front
144 - 130 - 111
Rear
120 - 115 - 110
I'd imagine that the tire pressures will prove to be too low once the tires are gripping and actually rolling over. For now, the car isn't gripping enough TO roll the tires. My only hope is that the tires just need more scrubbing. I know people out there are competitive in the Evo but we were no faster coming from a relatively stock M3.
The other interesting thing we noted was the stark contrast between running my Evo RS and a bone-stock 06 STI. My co-driver matched his times in the Evo when running an unmodified 2006 STI during fun runs. He finished the timed runs in the Evo with a 62s run. For his first run out in the STI during the afternoon fun runs, he matched the 62 and figured he could run a 60s run fairly easily. I did manage to cut 1s off of my time during the fun runs, with a 60.5, so there was more time out there in the afternoon. Anyway, his comments when driving the Evo, time and time again, are always that it is really hard to drive where the STI and the M3 are very natural.
Another friend, and a very good driver, took the Evo out and did no better with a 61s run. I have no doubt he would be faster given another run or two, but he wasn't that far from my pace. Earlier this year, a good driver would have beaten me in my own car but I'm finally to the point where I am faster in my car compared to one of the faster drivers in our region in my car.
-Jon
Judging from your tire temps your pressures are way too low. 36-37 front, 32-34 rear is where you should be. You need to get rid of that rear camber too. -2 is too much.
We are fighting the camber issue too. Currently we are at -3.2 up front and the braking sucks so I think we are going to back it down a bit. I'm also coming from an E36 M3 so I'm used to good brakes, and like you, good front grip. Don't spend a lot of time chasing the front grip; it will *never* be like the M3.
I'm not sure of your spring rates; do you mean 700kg/500kg? If so, that seems rather low. We tried a similar front rate and found the grip to be great....until it started bouncing off the bump stops in every turn. If you are hitting the stops it could be the cause of your lacking front grip.
Danny and I hit a test and tune this weekend and managed to get the car a LOT better than it had been previously messing with the rear bar, toe and tire pressures. I was pleasantly surprised to manage a 43.9xx to Corey Ridgick's 43.8xx. We still have some changes to do, but at least we are getting close.
Good luck.
Mike
I'm not sure of your spring rates; do you mean 700kg/500kg? If so, that seems rather low. We tried a similar front rate and found the grip to be great....until it started bouncing off the bump stops in every turn. If you are hitting the stops it could be the cause of your lacking front grip.
Danny and I hit a test and tune this weekend and managed to get the car a LOT better than it had been previously messing with the rear bar, toe and tire pressures. I was pleasantly surprised to manage a 43.9xx to Corey Ridgick's 43.8xx. We still have some changes to do, but at least we are getting close.
Good luck.
Mike
I am by far the least experienced in terms of car suspension setup but here is what I found out testing with Mike the last few month:
Lower spring rate front and higher spring rate rear will help the car turn better.
Lower the tire pressure in the front will help more grip, but with higher spring rate in front, the car will probably still understeer. Running low front tire pressure will make the noisy RE01R even more louder, and it probably won't last more than 8 events.
At 3.2 negative camber, the tires show considerable wear on the inside and like Mike said, hitting the ABS quickly due to lack of braking surface.
Higher tire pressure will help the tires to last a little longer, less noisy, and you can run higher tire pressure in the front if your spring rate is lower in the front than rear. We tested 36F/32R up to 42F/35R with no significant difference.
We all are trying to find out what the magic spring rate is but the more I speak to the good racers, the more I realized it is a personal preference. But in general lower front, higher rear works.
Dave, we are upping the spring rate and trying to get the shock dynoed after the last AI event. BTW, Corey's Yokohama didn't make any noise at the test and tune and he was the fastest STU car by a hair to Mike's time, Anthony and my RE01s were screaming.... As soon as the tire heat up, the time suffers. Mike's run were running on lukewarm tires and we both lost time when the temp heated up. It would be interesting to see if Yoko setup is better for two drivers.
Nothing else to report other than I still love my bird catcher, Mike has no comment on it, Corey digs it, and Sam hates it. I am thinking cone catcher next to balance it out. (I can picture Mike is now wondering what he got himself into....)
Lower spring rate front and higher spring rate rear will help the car turn better.
Lower the tire pressure in the front will help more grip, but with higher spring rate in front, the car will probably still understeer. Running low front tire pressure will make the noisy RE01R even more louder, and it probably won't last more than 8 events.
At 3.2 negative camber, the tires show considerable wear on the inside and like Mike said, hitting the ABS quickly due to lack of braking surface.
Higher tire pressure will help the tires to last a little longer, less noisy, and you can run higher tire pressure in the front if your spring rate is lower in the front than rear. We tested 36F/32R up to 42F/35R with no significant difference.
We all are trying to find out what the magic spring rate is but the more I speak to the good racers, the more I realized it is a personal preference. But in general lower front, higher rear works.
Dave, we are upping the spring rate and trying to get the shock dynoed after the last AI event. BTW, Corey's Yokohama didn't make any noise at the test and tune and he was the fastest STU car by a hair to Mike's time, Anthony and my RE01s were screaming.... As soon as the tire heat up, the time suffers. Mike's run were running on lukewarm tires and we both lost time when the temp heated up. It would be interesting to see if Yoko setup is better for two drivers.
Nothing else to report other than I still love my bird catcher, Mike has no comment on it, Corey digs it, and Sam hates it. I am thinking cone catcher next to balance it out. (I can picture Mike is now wondering what he got himself into....)
Last edited by dannykao; Sep 10, 2007 at 10:24 PM.
Interesting Danny.
I'm going to test some new dampers if I can get everything worked out in the next couple of weeks. I think I may end up trying some Yoko's for next year too.
I don't understand how the RE01-R's are so loud for you guys. I never really noticed mine were really noisy.
You guys are also running a lot more negative camber than I am too. I'm at -2.7 front. I also don't have ABS to worry about either.
If you get the chance go back and re-read my first page on the thread, I've revised it a few times.
I'm going to test some new dampers if I can get everything worked out in the next couple of weeks. I think I may end up trying some Yoko's for next year too.
I don't understand how the RE01-R's are so loud for you guys. I never really noticed mine were really noisy.
You guys are also running a lot more negative camber than I am too. I'm at -2.7 front. I also don't have ABS to worry about either.
If you get the chance go back and re-read my first page on the thread, I've revised it a few times.
I'd imagine we were fighting a combination of going from RWD to AWD, a really slick sealed asphalt surface, brand new tires, incorrect tire pressures, and a lot of camber. I was quite surprised they were talking as much as they were. Like I said, they aren't normally that noisy on the M's we've been driving.
I got a sponsorship-type deal on my coil-overs and haven't really driven them more than a couple events due to mechanical problems. I see now that the default rates of 7kg/mm and 5kg/mm may not work out for me. I'll probably try to change out the rear springs. Given that the valving is already screwy, going to a stiffer spring may throw it out of whack. There is some disparity on the low-speed vs high-speed valving on the Cuscos where it will work well with one type of bump but not the other.
I do appreciate the feedback you guys have given me. Only problem now is our region is almost done ><. We are considering driving out to Denver in two weeks just to get another event in the car.
-Jon
After another event on the Evo and I have a couple more questions.
To start, the car ran shaved RE-01Rs this time instead of the full tread that was used in the last event. I also decreased camber and am running -2.6 in the front and -1.5 in the rear. It still has a touch of rear toe-in, at 0.10 total toe, and it was left with 0.0 total toe in the front. Finally, my power problems were solved in the middle of last week after eliminating a bad turbo. The car had some preliminary VP100 STU tuning done to accommodate the 1.5kg/cm2 boost spike seen on the healthy turbo and power was, I thought, pretty amazing.
The grip problems I experienced at my last event were all but gone. To best describe the neutrality of the handling, I'd describe it as always gripping with no evidence of oversteer in on-throttle sweepers. My co-driver and I both think it may be nice to increase the grip in the front in hopes of getting it to just stick regardless of throttle so we'll see where we can get with that (M3 style).
I discussed spring rate selections with a couple other drivers at the Colorado Springs event I attended, and the general consensus is that spring rates ought to be stiffer in the rear of the car. I'm in the process of locating a set of replacement springs so I can feel that out. In the meantime, I'm wondering just what that is going to do. First of all, is stiffening up the rear going to shift the roll resistance and add grip to the front or is it going to make the rear less compliant and decrease grip from the rear? Are we fighting an inability to get good grip in the front or a fantastic ability to get grip in the rear?
The second part of this is regarding some tire temp data. I feel I got some useful tire temp data at this event, but I'd like some assistance in deciphering it. The car was being co-driven, we had 5-10 minutes between runs, and tires were sprayed down after every run. The first temps were taken after four total runs and the second temps were taken after seven total runs.
Tire - Inner - Middle - Outer
RF - 131 - 131 - 126
RR - 110 - 110 - 106
RF - 144 - 142 - 141
RR - 123 - 120 - 118
The car is working the fronts more than the rears, that much is obvious, but is it caused by the 60/40 weight bias or grip being biased towards the rear? I believe increasing grip in the front is going to increase temps in the rear, correct? As far as camber goes, aren't those temps saying it is about right?
-Jon
To start, the car ran shaved RE-01Rs this time instead of the full tread that was used in the last event. I also decreased camber and am running -2.6 in the front and -1.5 in the rear. It still has a touch of rear toe-in, at 0.10 total toe, and it was left with 0.0 total toe in the front. Finally, my power problems were solved in the middle of last week after eliminating a bad turbo. The car had some preliminary VP100 STU tuning done to accommodate the 1.5kg/cm2 boost spike seen on the healthy turbo and power was, I thought, pretty amazing.
The grip problems I experienced at my last event were all but gone. To best describe the neutrality of the handling, I'd describe it as always gripping with no evidence of oversteer in on-throttle sweepers. My co-driver and I both think it may be nice to increase the grip in the front in hopes of getting it to just stick regardless of throttle so we'll see where we can get with that (M3 style).
I discussed spring rate selections with a couple other drivers at the Colorado Springs event I attended, and the general consensus is that spring rates ought to be stiffer in the rear of the car. I'm in the process of locating a set of replacement springs so I can feel that out. In the meantime, I'm wondering just what that is going to do. First of all, is stiffening up the rear going to shift the roll resistance and add grip to the front or is it going to make the rear less compliant and decrease grip from the rear? Are we fighting an inability to get good grip in the front or a fantastic ability to get grip in the rear?
The second part of this is regarding some tire temp data. I feel I got some useful tire temp data at this event, but I'd like some assistance in deciphering it. The car was being co-driven, we had 5-10 minutes between runs, and tires were sprayed down after every run. The first temps were taken after four total runs and the second temps were taken after seven total runs.
Tire - Inner - Middle - Outer
RF - 131 - 131 - 126
RR - 110 - 110 - 106
RF - 144 - 142 - 141
RR - 123 - 120 - 118
The car is working the fronts more than the rears, that much is obvious, but is it caused by the 60/40 weight bias or grip being biased towards the rear? I believe increasing grip in the front is going to increase temps in the rear, correct? As far as camber goes, aren't those temps saying it is about right?
-Jon
Last edited by stimpy; Sep 17, 2007 at 09:28 PM.
After another event on the Evo and I have a couple more questions.
To start, the car ran shaved RE-01Rs this time instead of the full tread that was used in the last event. I also decreased camber and am running -2.6 in the front and -1.5 in the rear. It still has a touch of rear toe-in, at 0.10 total toe, and it was left with 0.0 total toe in the front. Finally, my power problems were solved in the middle of last week after eliminating a bad turbo. The car had some preliminary VP100 STU tuning done to accommodate the 1.5kg/cm2 boost spike seen on the healthy turbo and power was, I thought, pretty amazing.
The grip problems I experienced at my last event were all but gone. To best describe the neutrality of the handling, I'd describe it as always gripping with no evidence of oversteer in on-throttle sweepers. My co-driver and I both think it may be nice to increase the grip in the front in hopes of getting it to just stick regardless of throttle so we'll see where we can get with that (M3 style).
I discussed spring rate selections with a couple other drivers at the Colorado Springs event I attended, and the general consensus is that spring rates ought to be stiffer in the rear of the car. I'm in the process of locating a set of replacement springs so I can feel that out. In the meantime, I'm wondering just what that is going to do. First of all, is stiffening up the rear going to shift the roll resistance and add grip to the front or is it going to make the rear less compliant and decrease grip from the rear? Are we fighting an inability to get good grip in the front or a fantastic ability to get grip in the rear?
The second part of this is regarding some tire temp data. I feel I got some useful tire temp data at this event, but I'd like some assistance in deciphering it. The car was being co-driven, we had 5-10 minutes between runs, and tires were sprayed down after every run. The first temps were taken after four total runs and the second temps were taken after seven total runs.
Tire - Inner - Middle - Outer
RF - 131 - 131 - 126
RR - 110 - 110 - 106
RF - 144 - 142 - 141
RR - 123 - 120 - 118
The car is working the fronts more than the rears, that much is obvious, but is it caused by the 60/40 weight bias or grip being biased towards the rear? I believe increasing grip in the front is going to increase temps in the rear, correct? As far as camber goes, aren't those temps saying it is about right?
-Jon
To start, the car ran shaved RE-01Rs this time instead of the full tread that was used in the last event. I also decreased camber and am running -2.6 in the front and -1.5 in the rear. It still has a touch of rear toe-in, at 0.10 total toe, and it was left with 0.0 total toe in the front. Finally, my power problems were solved in the middle of last week after eliminating a bad turbo. The car had some preliminary VP100 STU tuning done to accommodate the 1.5kg/cm2 boost spike seen on the healthy turbo and power was, I thought, pretty amazing.
The grip problems I experienced at my last event were all but gone. To best describe the neutrality of the handling, I'd describe it as always gripping with no evidence of oversteer in on-throttle sweepers. My co-driver and I both think it may be nice to increase the grip in the front in hopes of getting it to just stick regardless of throttle so we'll see where we can get with that (M3 style).
I discussed spring rate selections with a couple other drivers at the Colorado Springs event I attended, and the general consensus is that spring rates ought to be stiffer in the rear of the car. I'm in the process of locating a set of replacement springs so I can feel that out. In the meantime, I'm wondering just what that is going to do. First of all, is stiffening up the rear going to shift the roll resistance and add grip to the front or is it going to make the rear less compliant and decrease grip from the rear? Are we fighting an inability to get good grip in the front or a fantastic ability to get grip in the rear?
The second part of this is regarding some tire temp data. I feel I got some useful tire temp data at this event, but I'd like some assistance in deciphering it. The car was being co-driven, we had 5-10 minutes between runs, and tires were sprayed down after every run. The first temps were taken after four total runs and the second temps were taken after seven total runs.
Tire - Inner - Middle - Outer
RF - 131 - 131 - 126
RR - 110 - 110 - 106
RF - 144 - 142 - 141
RR - 123 - 120 - 118
The car is working the fronts more than the rears, that much is obvious, but is it caused by the 60/40 weight bias or grip being biased towards the rear? I believe increasing grip in the front is going to increase temps in the rear, correct? As far as camber goes, aren't those temps saying it is about right?
-Jon
Was that you guys pitted behind us in the Cobb Evo?
I have two suggestions looking at your pyro data. I think your fronts actually look pretty good. I'm not an expert, but geometrically I don't see how we can keep the optimal contact patch throughout the dynamic range of the front suspension. I think forcing the temps to be uniform across will just net too little static camber at full compression. This is in contrast to how you would look at temps on a double a-arm setup.
As for the rear, you might want to back off a little on the camber. This is something we're actually going to try before next week. We simply don't need as much steady state rear grip as we have. I don't want to run toe-out in the back, because I've had awful corner exit speeds when I've tried it.
I would also like to play some springrate games, but there is simply no time left in the 6 days before I drive to topeka.
donour
Last edited by donour; Sep 17, 2007 at 09:57 PM.
Hey Jon, glad you guys made out to my neck of the woods on Sunday. Those temps look about right for that setup, I typically see the same temperature spread across the tire except not nearly that hot on a single driver car! Not surprising that the rear temps you recorded were pretty high. On all four of my runs on Sunday the car would start out just the way I like it but by the end the car would start tighten up as the rears heated up sliding around on the bottom of the course.
To answer your other questions, it is my opinion that the front works more because of both the 60/40 weight bias and the grip is biased towards the rear of the car. I think you could make an argument for either but at the end of the day both are contributors. As the front of the car works a little better you should see increase rear temps but not much in my experience. Finally, I agree with Donour that you could back off the rear camber. I'm running what you are in terms of rear camber but the more I tweak the more I come back to decreasing it. I do run rear toe out though.
To answer your other questions, it is my opinion that the front works more because of both the 60/40 weight bias and the grip is biased towards the rear of the car. I think you could make an argument for either but at the end of the day both are contributors. As the front of the car works a little better you should see increase rear temps but not much in my experience. Finally, I agree with Donour that you could back off the rear camber. I'm running what you are in terms of rear camber but the more I tweak the more I come back to decreasing it. I do run rear toe out though.
donour, yes, that was me.
Russ, it was great meeting all of you (again for some). Definitely a big thanks for the use of your tire temp gauge and all of your setup information.
I wanted to repost this, because it applies directly to my little tire temp discussion: https://www.evolutionm.net/forums/sh...&postcount=277
https://www.evolutionm.net/forums/sh...&postcount=280
I've read through the whole thread but it is getting difficult to know where all the good info is. I was looking for something else and happened to notice those posts were bookmarked.
-Jon
Russ, it was great meeting all of you (again for some). Definitely a big thanks for the use of your tire temp gauge and all of your setup information.
I wanted to repost this, because it applies directly to my little tire temp discussion: https://www.evolutionm.net/forums/sh...&postcount=277
https://www.evolutionm.net/forums/sh...&postcount=280
I've read through the whole thread but it is getting difficult to know where all the good info is. I was looking for something else and happened to notice those posts were bookmarked.
-Jon
I am still in as well and will be running Nationals next year, hopefully to knock the STis off the podium 
So what is the word on the whole cat debacle? What happened with that at Nationals?
So what is the word on the whole cat debacle? What happened with that at Nationals?