evolutionm.net - View Single Post - Autocross EVO

EVOlutionary · Dec 22, 2006, 10:42 PM

OK, here goes. This is my thought on what it would take to win a National Championship in SM, unless you are a phenominal driver who can make due with less. Starting from the ground up:

WHEELS AND TIRES
The standard is 285/30/18 Hoosiers on an 18x9.5-10 inch rim. Wider is probably better. If you can cut the fenders and/or install a widebody and run 315 or 335 tires, I think that would be best. Of course go with the lightest, strongest wheels possible for your budget. FN01R-C's are popular because they are inexpensive and average weight. If someone can find me an 18x10 that weights 17 pounds or less, me love you long time

SUSPENSION
It's quality, not quantity. You can have a big $$ set of shocks, but if they are not optimized you will get whooped by someone with perfectly tuned JICs. Unfortunately, at the National level, there are not alot of guys who will just give you the setup they are running because they have hundreds of hours and lots of $$ of testing invested into it. All I can recommend is to become friends with someone who knows alot about suspension and work with them/learn from them. Trial and error. Run your shocks full soft. See how the car feels. Run them full hard. See how the car feels. Then work in from the extremes. Most folks run a rear sway bar, some a front sway bar. Some crazy guys

run no sway bar and super stiff spring. The combinations are limitless. You want your car as low as possible to lower the CG, but you need to me mindfull of roll centers. The new Whiteline Roll Center kit is looking promising. . . My suggestion - talk with Navid, Andy, John, Mark, Eric, etc. and learn as much as you can as far as what it takes to make the EVO stick under AX conditions.

POWER
MY FAVORITE! It is my opinion that you will need between 400 and 450WHP to win Nationals in an EVO. Some guys run less, some guys run ALOT more. I, personally am in the middle of that range. Too much low end torque is not always good. If you have really hard hitting power coming out of corners you will spin tires, as the EVO is very prone to lifting wheels and getting light on the inside tires. This may be able to be resolved with suspension work, but so far I have not heard of anyone perfecting it. A 2.3L stroker with a TME turbo is probably not the best way - too much TQ and not enough top end. A 2.0L with a 20G variant, or possibly a 2.0 or 2.3 with a 50 trim I feel will be optimal. I recommend a built motor that can rev to over 8000rpms. Instead of riding the rev limiter in 2nd gear (or *gasp* shifting to 3rd) and losing time and accelleration, get a built motor and take it all the way to 9000 in 2nd gear. With the 285's that should get you to about 75mph. Alternatively, you could get a higher gear (lower numerically) so that you can go faster for the same RPM. Smooth power is key. You don't want compressor surge, BOV stuttering, or anything like that at part throttle. The throttle input should feel as though it is directly liked to boost pressure (just how a stock EVO feels).

WEIGHT SAVINGS
There really isn't a WHOLE lot you can do. Start with an RS so you have the aluminum roof and no ABS crap. Lose the back seats and rear seat belt stuff. Get light weight racing seats. Get harnesses that attach to the rear seat mounting points rather than a harness bar. Harness bars are pretty heavy, and high up in the car. Get rid of AC and stereo stuff. Light weight clutch, carbon driveshaft, brake rotors, wheels, etc. to save rotating weight. Consider the stock FMIC - those big aftermarket ones weigh a ton. Consider a small radiator - you will save weight on the radiator itself, plus water weighs like 9 pounds per gallon or something.

AERODYNAMICS
To be the fastest in a big heavy car like the EVO you need every advantage you can get. Run as big of front splitter as allowed. The rules for splitters and wings are changing for next year, so keep an eye out for what the new limits will be. Some people set up the car to be loose in slow corners to help rotation, then use a big rear wing to stabilize it in high speed corners. But, having too much rear downforce without matching traction in the front is not going to be good. Make sure your car is balanced. Once again, run as big of a front splitter as possible, and one that is properly designed. Just a flat piece of FRP or carbon bolted under your front end may give you some benefit, but is not optimal. Take a look at the Voltex big splitter on the Cyber EVO for one that looks like a well thought out design.
As a side note, I hope that the SCCA "keeps up with the times" and does not continue to shy away from aero modifications, especially in Mod and Prepared classes (including SMod). One look through the pictures from JOnDemand's trip to the Time Attacks in Japan shows just how prevelent this is in other parts of the world. I think America is playing catch-up a little bit in the tuner car aero field. . .

DRIVETRAIN
There is a lot of variation here. You may be able to get away with a VCU center diff and stock F+R LSDs. You may see some folks trying the Cusco 35/65 center diff. Right now my car is tail happy enough, don't think I want to experiment with MORE rear power! Currently I have a Quaife FLSD, stock center and rear. Even with the Quaife I still have trouble with spinning the inside front tire coming out of corners. If I had the money I would be running Cusco diffs in the front and center and a TRE prepped stock rear diff. Never really driven an ACD car, so I can't comment on that. From what I have read it will probably be better than the VCU for autocross, more tunability potential, but heavier and more complicated. Stock tranny is fine. Probably won't break one at the power we will be running. Lightweight clutch, flywheel, and driveshaft will all get you from corner to corner quicker.

Please feel free to add anything I may have overlooked. . .

EVOlutionary

Dec 22, 2006, 10:42 PM	#2
EVOlutionary Evolved Member Personal Sales Rating: (16) 2006 Mitsubishi Lancer Evolution Join Date: Sep 2004 Location: Michigan Posts: 2,641 Drives: '04 EVO VIII, '06 EVO IX RS, '90 1JZ-TT Supra	OK, here goes. This is my thought on what it would take to win a National Championship in SM, unless you are a phenominal driver who can make due with less. Starting from the ground up: WHEELS AND TIRES The standard is 285/30/18 Hoosiers on an 18x9.5-10 inch rim. Wider is probably better. If you can cut the fenders and/or install a widebody and run 315 or 335 tires, I think that would be best. Of course go with the lightest, strongest wheels possible for your budget. FN01R-C's are popular because they are inexpensive and average weight. If someone can find me an 18x10 that weights 17 pounds or less, me love you long time SUSPENSION It's quality, not quantity. You can have a big $$ set of shocks, but if they are not optimized you will get whooped by someone with perfectly tuned JICs. Unfortunately, at the National level, there are not alot of guys who will just give you the setup they are running because they have hundreds of hours and lots of $$ of testing invested into it. All I can recommend is to become friends with someone who knows alot about suspension and work with them/learn from them. Trial and error. Run your shocks full soft. See how the car feels. Run them full hard. See how the car feels. Then work in from the extremes. Most folks run a rear sway bar, some a front sway bar. Some crazy guys run no sway bar and super stiff spring. The combinations are limitless. You want your car as low as possible to lower the CG, but you need to me mindfull of roll centers. The new Whiteline Roll Center kit is looking promising. . . My suggestion - talk with Navid, Andy, John, Mark, Eric, etc. and learn as much as you can as far as what it takes to make the EVO stick under AX conditions. POWER MY FAVORITE! It is my opinion that you will need between 400 and 450WHP to win Nationals in an EVO. Some guys run less, some guys run ALOT more. I, personally am in the middle of that range. Too much low end torque is not always good. If you have really hard hitting power coming out of corners you will spin tires, as the EVO is very prone to lifting wheels and getting light on the inside tires. This may be able to be resolved with suspension work, but so far I have not heard of anyone perfecting it. A 2.3L stroker with a TME turbo is probably not the best way - too much TQ and not enough top end. A 2.0L with a 20G variant, or possibly a 2.0 or 2.3 with a 50 trim I feel will be optimal. I recommend a built motor that can rev to over 8000rpms. Instead of riding the rev limiter in 2nd gear (or gasp* shifting to 3rd)* and losing time and accelleration, get a built motor and take it all the way to 9000 in 2nd gear. With the 285's that should get you to about 75mph. Alternatively, you could get a higher gear (lower numerically) so that you can go faster for the same RPM. Smooth power is key. You don't want compressor surge, BOV stuttering, or anything like that at part throttle. The throttle input should feel as though it is directly liked to boost pressure (just how a stock EVO feels). WEIGHT SAVINGS There really isn't a WHOLE lot you can do. Start with an RS so you have the aluminum roof and no ABS crap. Lose the back seats and rear seat belt stuff. Get light weight racing seats. Get harnesses that attach to the rear seat mounting points rather than a harness bar. Harness bars are pretty heavy, and high up in the car. Get rid of AC and stereo stuff. Light weight clutch, carbon driveshaft, brake rotors, wheels, etc. to save rotating weight. Consider the stock FMIC - those big aftermarket ones weigh a ton. Consider a small radiator - you will save weight on the radiator itself, plus water weighs like 9 pounds per gallon or something. AERODYNAMICS To be the fastest in a big heavy car like the EVO you need every advantage you can get. Run as big of front splitter as allowed. The rules for splitters and wings are changing for next year, so keep an eye out for what the new limits will be. Some people set up the car to be loose in slow corners to help rotation, then use a big rear wing to stabilize it in high speed corners. But, having too much rear downforce without matching traction in the front is not going to be good. Make sure your car is balanced. Once again, run as big of a front splitter as possible, and one that is properly designed. Just a flat piece of FRP or carbon bolted under your front end may give you some benefit, but is not optimal. Take a look at the Voltex big splitter on the Cyber EVO for one that looks like a well thought out design. As a side note, I hope that the SCCA "keeps up with the times" and does not continue to shy away from aero modifications, especially in Mod and Prepared classes (including SMod). One look through the pictures from JOnDemand's trip to the Time Attacks in Japan shows just how prevelent this is in other parts of the world. I think America is playing catch-up a little bit in the tuner car aero field. . . DRIVETRAIN There is a lot of variation here. You may be able to get away with a VCU center diff and stock F+R LSDs. You may see some folks trying the Cusco 35/65 center diff. Right now my car is tail happy enough, don't think I want to experiment with MORE rear power! Currently I have a Quaife FLSD, stock center and rear. Even with the Quaife I still have trouble with spinning the inside front tire coming out of corners. If I had the money I would be running Cusco diffs in the front and center and a TRE prepped stock rear diff. Never really driven an ACD car, so I can't comment on that. From what I have read it will probably be better than the VCU for autocross, more tunability potential, but heavier and more complicated. Stock tranny is fine. Probably won't break one at the power we will be running. Lightweight clutch, flywheel, and driveshaft will all get you from corner to corner quicker. Please feel free to add anything I may have overlooked. . . EVOlutionary Last edited by EVOlutionary; Jan 17, 2007 at 05:18 PM.
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