Hey everyone, I've been lurking here for a while through the ownership of my last 2 E30s. I thought I would finally introduce myself & my car, & figured the Track & AutoX section would be the most fitting place to do that since I intend to build my E30 to contend at the national level in the STX class in SCCA autocrossing. I apologize in advance, this is somewhat of a long read :oops: But hopefully my knowledge of autocross & the trial & errors of this build will be helpful to the members here in the future. So first off, a little about me & what I hope to accomplish...
I have been autocrossing for almost 20 years now in various cars from the stock to street modified level. I have countless local & regional victories, as well as some Divisional, National Tour & Pro Solo championships. Most of my success has been behind the wheel of Miatas, as quite simply they are the fastest & most capable autocross car there is. But I am ready for a change, & for the 2012 season I intend to prep my E30 to compete at the National level in the SCCA's STX class. I believe the E30 has what it takes to win STX, but most in the autocross community rule it out for various reasons. My goal is to document my build process here in this thread while including all of the experts here on set-up ideas, to ultimately provide an easy-to-duplicate in-expensive build that others can follow in the future :mrgreen:.
SCCA STX rules for those that don't know...
The street touring category is the most popular in SCCA Solo, & continues to grow each year. In a nutshell, the cars are stock with the following exceptions
- Emmisions-legal engine bolt-ons limited to intake, exhaust (with cats), chips/re-flash or any ECU programming in the stock case. Otherwise engine must be totally stock & original...no bolting in a "i" motor in an "e" ;)
- The suspension is mostly open allowing most any shock/strut/spring combo as long as the suspension type stayes the same & the original pick-up points & geometry is used. Any sway bar, strut bar, camber plates, etc.
- Transmissions & diffs must be stock, but any limited slip unit can be used.
- Interior must be stock, but race seats can be used, harnesses, any steering wheel, & any shift linkage.
- One of the most desirable aspects of the category though is the tires...no R-compound tires allowed like in other SCCA categories. Only street tires with a minimum of 140 treadwear are allowed, so the tire budgets are more managable than the other categories (it takes a minimum of 2 sets of $1100 Hoosiers to stay competitive in our E-Stock Miata each season, & those are 14" tires!).
Currently, the STX class allows most 2 or 4-door coupes/sedans from 2.5-5.1 liters normally aspirated & 2.0 liters or less forced induction. The current cars-to-have are 3-series 6-cyl BMWs, 02+ 2.0 liter Subaru WRX, Mazda RX8, & the E30 M3. Each of these cars has strong points & can win, but compared to them the 6-cyl E30 is lighter (as much as 300+ lbs lighter), & it's narrowerer, meaning it should get through slaloms & transitions very well. It does have less power, but the power-to-weight should still be very close, & more importantly it has one of the best tire-to-weight ratios.
About my car...It's an 89 325i 2-door. I have now had it since Early March, I bought it from the 2nd owner who had it since the late 90's. He & the original owner had garaged it 95% of the time, so the original Zinnoberot red is beautiful :) It currently has Bilstien Sports with Vogtland springs, H&R sway bars, cat-back exhaust, CAI, MarkD chip, Z3 shifter w/ZHP knob, Momo wheel, "is" front lip & rear spoiler, 15x8 TR Motorsports C1 wheels with 225/45-15 Hankook RS3s, & a few other things.
Here is what I plan to do to the car in the coming months, please chime in everyone with ideas, especially on supension developement.
- Coil overs with front camber plates...looking at AST, TC Kline, & Ground Control, but leaning toward a double-adjustable Koni set-up from TC Kline. I need ideas on spring rates though...
- Sway bars...I'm probably going to ditch the rear bar all-together, I hear that is a popular set-up, plus it takes off some weight ;) Still deciding on front bar...
- Exhaust...Looking for a header that provides good mid-range power & still pulls to 7K, then I will have a custom very light single exhaust built with a high flow cat. Also considering building it with a pre-silencer with a flange on the end so I can just run a turn-down that exits under the car. That would be the lightest set-up, but may not pass sound at some events.
- Race seats, no real preference here, just something light (25lbs min with brackets) that doesn't restrict upper body movement too much.
- ECU/chips...I like my MarkD, but I may go to something more tunable like the War chip, or maybe just have Mark build me a custom tuned chip based on my A/F ratios...
- LSD diff...the original open 3.73 diff is still in the car, but I have a S3.73 waiting to bolt in. The question is, rebuild it with 2, 3, 4 clutches, or spend the $$ on an OS Giken or KAAZ unit? I'll probably just start with rebuilding it with 2 clutches & see what the traction is like...
That's about it for the first stage of this build, once I get all that put together it's time for testing :D I will continue to update this thread as I go along, but please chime in if anyone has any ideas, comments or suggestions! Sorry for the long read, hopefully this will be a great starting point for future E30 owners that want to get into autocrossing.
I have been autocrossing for almost 20 years now in various cars from the stock to street modified level. I have countless local & regional victories, as well as some Divisional, National Tour & Pro Solo championships. Most of my success has been behind the wheel of Miatas, as quite simply they are the fastest & most capable autocross car there is. But I am ready for a change, & for the 2012 season I intend to prep my E30 to compete at the National level in the SCCA's STX class. I believe the E30 has what it takes to win STX, but most in the autocross community rule it out for various reasons. My goal is to document my build process here in this thread while including all of the experts here on set-up ideas, to ultimately provide an easy-to-duplicate in-expensive build that others can follow in the future :mrgreen:.
SCCA STX rules for those that don't know...
The street touring category is the most popular in SCCA Solo, & continues to grow each year. In a nutshell, the cars are stock with the following exceptions
- Emmisions-legal engine bolt-ons limited to intake, exhaust (with cats), chips/re-flash or any ECU programming in the stock case. Otherwise engine must be totally stock & original...no bolting in a "i" motor in an "e" ;)
- The suspension is mostly open allowing most any shock/strut/spring combo as long as the suspension type stayes the same & the original pick-up points & geometry is used. Any sway bar, strut bar, camber plates, etc.
- Transmissions & diffs must be stock, but any limited slip unit can be used.
- Interior must be stock, but race seats can be used, harnesses, any steering wheel, & any shift linkage.
- One of the most desirable aspects of the category though is the tires...no R-compound tires allowed like in other SCCA categories. Only street tires with a minimum of 140 treadwear are allowed, so the tire budgets are more managable than the other categories (it takes a minimum of 2 sets of $1100 Hoosiers to stay competitive in our E-Stock Miata each season, & those are 14" tires!).
Currently, the STX class allows most 2 or 4-door coupes/sedans from 2.5-5.1 liters normally aspirated & 2.0 liters or less forced induction. The current cars-to-have are 3-series 6-cyl BMWs, 02+ 2.0 liter Subaru WRX, Mazda RX8, & the E30 M3. Each of these cars has strong points & can win, but compared to them the 6-cyl E30 is lighter (as much as 300+ lbs lighter), & it's narrowerer, meaning it should get through slaloms & transitions very well. It does have less power, but the power-to-weight should still be very close, & more importantly it has one of the best tire-to-weight ratios.
About my car...It's an 89 325i 2-door. I have now had it since Early March, I bought it from the 2nd owner who had it since the late 90's. He & the original owner had garaged it 95% of the time, so the original Zinnoberot red is beautiful :) It currently has Bilstien Sports with Vogtland springs, H&R sway bars, cat-back exhaust, CAI, MarkD chip, Z3 shifter w/ZHP knob, Momo wheel, "is" front lip & rear spoiler, 15x8 TR Motorsports C1 wheels with 225/45-15 Hankook RS3s, & a few other things.
Here is what I plan to do to the car in the coming months, please chime in everyone with ideas, especially on supension developement.
- Coil overs with front camber plates...looking at AST, TC Kline, & Ground Control, but leaning toward a double-adjustable Koni set-up from TC Kline. I need ideas on spring rates though...
- Sway bars...I'm probably going to ditch the rear bar all-together, I hear that is a popular set-up, plus it takes off some weight ;) Still deciding on front bar...
- Exhaust...Looking for a header that provides good mid-range power & still pulls to 7K, then I will have a custom very light single exhaust built with a high flow cat. Also considering building it with a pre-silencer with a flange on the end so I can just run a turn-down that exits under the car. That would be the lightest set-up, but may not pass sound at some events.
- Race seats, no real preference here, just something light (25lbs min with brackets) that doesn't restrict upper body movement too much.
- ECU/chips...I like my MarkD, but I may go to something more tunable like the War chip, or maybe just have Mark build me a custom tuned chip based on my A/F ratios...
- LSD diff...the original open 3.73 diff is still in the car, but I have a S3.73 waiting to bolt in. The question is, rebuild it with 2, 3, 4 clutches, or spend the $$ on an OS Giken or KAAZ unit? I'll probably just start with rebuilding it with 2 clutches & see what the traction is like...
That's about it for the first stage of this build, once I get all that put together it's time for testing :D I will continue to update this thread as I go along, but please chime in if anyone has any ideas, comments or suggestions! Sorry for the long read, hopefully this will be a great starting point for future E30 owners that want to get into autocrossing.
If I wanted to keep winning whenever I wanted, I would just keep running the Miata, but I like the challenge this car presents!
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