SCCA STX E30 Build/Introduction

[InuFaye]

The XXR 530 should fit an e30 easily.

[110stx]

Here, Jon, let me get you a tissue for that *cough* :-)

How much do these freakin' wheels weigh anyhoo?

Enkei RPF1s 17X8 (the light ones) are about $230 apiece at about 15 lbs.

Yeah, I'm doin' some window shopping. A guy can dream BIG right?

[team9]

You should have a decent sampling of Street touring competitors in your area. See if you can't get some worn down scrubs or something from someone. 235/40-17 or 245/40-17.

XXR has some new wheels that should be a good fit. They are cheap, so it's minimal outlay to give it a try and should be easy wheels to resell later.

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XXR 530

17x8.25", 4x100, +25mm
$115 each = $460 set
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XXR 527

17x8.25", 4x100, +25mm
$115 each = $460 set
------------------------------------

They look like great options to try. Otherwise Rota has a 17x8.5 D2, but it's a lot more $$ for an experiment.

I think it can be made to work and will really help the E30 on a national level.

I'd love to help someone in a region near mine give it a try and get the setup dialed in *cough* Doug H.*cough*

Thanks - Jon

The 527's can fit a 255 on the rear with a little bit of fender rolling. Those wheels weigh in at 19.8 lbs which is pretty darn good for a 17" considering. The best part is the offset. +25

[110stx]

19 lbs is heavy when your car is already underpowered relative to its competition.

Make that "my" car ... :-)

[Chris916]

I was also looking at the xxr's however not sure about the weight. 19lbs isnt terrible, but its not great either. Would love to be able to run 245/40-17 conti scrubs :D

[GotCone?]

The 527's can fit a 255 on the rear with a little bit of fender rolling. Those wheels weigh in at 19.8 lbs which is pretty darn good for a 17" considering. The best part is the offset. +25

can you elaborate on what tire brand/model you're running 255/40's in please?

19 lbs is heavy when your car is already underpowered relative to its competition.

Make that "my" car ... :-)

Perhaps... but, is it worth double the money for 20 lbs of un sprung weight to you? Especially in an attempt to try something new and on a wheel that is .25" skinnier? Another question is, what offset are these enkeis? I'm betting they are higher offset and will require spacers, thus you're adding more weight to fit them.

My $0.02 Try it with cheap wheels first, if it shows merit, then you can consider cheaper more expensive options down the road.


Doug, I'd love to help you setup your car to fit something like what is being discussed here. I'd travel to KC for a weekend just for that purpose.

[team9]

can you elaborate on what tire brand/model you're running 255/40's in please?.

I was running on Kumho Ecsta XS's. Switching to Hankooks this year, but will still run the same size. The Hankooks are better and cheaper. win-win.

[110stx]

Perhaps... but, is it worth double the money for 20 lbs of un sprung weight to you? Especially in an attempt to try something new and on a wheel that is .25" skinnier? Another question is, what offset are these enkeis? I'm betting they are higher offset and will require spacers, thus you're adding more weight to fit them.

My $0.02 Try it with cheap wheels first, if it shows merit, then you can consider cheaper more expensive options down the road.


Doug, I'd love to help you setup your car to fit something like what is being discussed here. I'd travel to KC for a weekend just for that purpose.

Well, the ultimate answer to your question has got to be, Yes, 20 lbs of unsprung weight would be worth the extra bucks. Of course, money is the only thing standing between me and going this route. :-)

At this point, I don't see changing from the 15s this season ... I am anticipating a slight increase in rear spring rate, say to 685 lb-in.

I would love to work on the car with you. You know that. In a freakin' HEARTBEAT, bro'.

However, I would rather bring the car to you and see how it works at LAP, as that's better than tuning it for MCC.

dh

[race2win]

I was running on Kumho Ecsta XS's. Switching to Hankooks this year, but will still run the same size. The Hankooks are better and cheaper. win-win.

The 255/40-17 XS is 25" tall & has a 10.2" section width, that is well over an inch wider & taller than what I run now, I HAVE to see how you stuffed that much tire under an STX legal non-M E30 fender....

I was also looking at the xxr's however not sure about the weight. 19lbs isnt terrible, but its not great either.

19.8 lbs is VERY heavy, even for a 17. After you factor in the extra weight of the tires, my car would gain around 30 lbs over all compared to my current 15x8 set-up...& I don't have the lightest 15x8s out there. I believe 5-10 lbs difference is just noise...30 lbs however will show up on the watch.

I see benefits to a 17" package as I have mentioned before, I hope to do some testing this summer to see if they are indeed faster. However, going with heavy wheels such as the XXRs may provide false information, if I am going to do it I would rather spend extra on the Arc8s so that I am within that "noise" to get an accurate comparison.

Depending on the results of that testing & budget permitting, if/when I go to Lincoln this year I would like to bring 3 sets of tires/wheels...

1. My current 15x8 225/45-15 RS3 set-up - great gearing out of corners, light, best warm/hot weather tire, should be the best in tight stuff & transitions.
2. Light 17x8s with 235/40-17 Dunlop Star Specs - great all around tire, will work well in colder temps and/or damp, slight width gain over 15s, & will provide a gearing bump for those longer courses.
3. Either Continental ExtremeContact DWs or Michelin's new Pilot Super Sport for standing water/wet sitiations, as both will provide better wet grip than the Dunlops, & especially the Hankooks. These would also double as street tires for the car to drive to & from events, & general weekend use. I just wish they made something smaller than a 17 in the new Michelin...

For now though, locally, I'm sticking with my 15" package...unless it rains, then I may enter my GTI ;-)

[GotCone?]

I would love to work on the car with you. You know that. In a freakin' HEARTBEAT, bro'.

However, I would rather bring the car to you and see how it works at LAP, as that's better than tuning it for MCC.

dh

Well then. Rand and I may have just made testing easier for you. We've been needing a rain set for the E30 project and have settled on that this weekend. 17x8.25 XXR 530s wrapped in 245/40-17 Hankook RS-3. Wheels are pre-order, so not sure when we'll have them and the tires all mounted up, but I'm sure we can give them a try on your car Doug.

I'll post up pics once I have them mounted and if they show up in time before I start to modify the fenders, I'll get pics of them on the E30 as it sits today.

Thanks - Jon

[GotCone?]

I was running on Kumho Ecsta XS's. Switching to Hankooks this year, but will still run the same size. The Hankooks are better and cheaper. win-win.

255s will be pinched on an 8.25" wheel. I'd be curious to see your actually measured section width. 255s on a 9" wide just barely fit up front in an E30 M3, trust me I know from experience ;) The skinnier wheel may help fitment some, but stuffing a wider tire will hurt responsiveness, especially with those XS.

[GotCone?]

19.8 lbs is VERY heavy, even for a 17. After you factor in the extra weight of the tires, my car would gain around 30 lbs over all compared to my current 15x8 set-up...& I don't have the lightest 15x8s out there. I believe 5-10 lbs difference is just noise...30 lbs however will show up on the watch.

A valid point. Ever see the GRM article where they tested heavy verses light wheels? Didn't really affect the times, but it wasn't quite a full 30lb increase.

You can't just factor weight. If you're adding better gearing (saving 2-3-2 shifts) and a wider contact patch, it may overcome the weight deficit. May...

I see benefits to a 17" package as I have mentioned before, I hope to do some testing this summer to see if they are indeed faster. However, going with heavy wheels such as the XXRs may provide false information, if I am going to do it I would rather spend extra on the Arc8s so that I am within that "noise" to get an accurate comparison.

Going to a 7.5" wheel is an even more unfair comparison. You'll need some data to really see if you're picking up gs and or time in sections with the taller/wider combo. That's my point. test cheap, if it shows merit, then you can get lighter wheels or perhaps even find some with just a little more width to them too.

Depending on the results of that testing & budget permitting, if/when I go to Lincoln this year I would like to bring 3 sets of tires/wheels...

1. My current 15x8 225/45-15 RS3 set-up - great gearing out of corners, light, best warm/hot weather tire, should be the best in tight stuff & transitions.
2. Light 17x8s with 235/40-17 Dunlop Star Specs - great all around tire, will work well in colder temps and/or damp, slight width gain over 15s, & will provide a gearing bump for those longer courses.
3. Either Continental ExtremeContact DWs or Michelin's new Pilot Super Sport for standing water/wet sitiations, as both will provide better wet grip than the Dunlops, & especially the Hankooks. These would also double as street tires for the car to drive to & from events, & general weekend use. I just wish they made something smaller than a 17 in the new Michelin...

Good plan. I have been loving the Toyo R1-R in the rain fwiw. I beat Matt McCabe (2 time CSP champion) raw in Lincoln last year in an STS CRX in the wet.

[race2win]

A valid point. Ever see the GRM article where they tested heavy verses light wheels? Didn't really affect the times, but it wasn't quite a full 30lb increase.

You can't just factor weight. If you're adding better gearing (saving 2-3-2 shifts) and a wider contact patch, it may overcome the weight deficit. May...

Agreed...potential benefits of the 17s are slightly wider contact patch & better gearing for longer courses. Downside is more un-sprung weight & taller gearing on shorter courses.

Going to a 7.5" wheel is an even more unfair comparison. You'll need some data to really see if you're picking up gs and or time in sections with the taller/wider combo. That's my point. test cheap, if it shows merit, then you can get lighter wheels or perhaps even find some with just a little more width to them too.

The ARC8's are actually 17x8s, which is the ideal 17" size for an E30 IMHO. I feel that size/weight wheel with 235 Star Specs is about as close as possible to a fair comparison to my 15x8/225 set-up to determine if those benefits mentioned above are reality. The problem with the heavy 20lb wheels is that I will always wonder how much time I would be giving up due to the extra weight. But I agree, testing as cheap as possible is ideal.

Good plan. I have been loving the Toyo R1-R in the rain fwiw. I beat Matt McCabe (2 time CSP champion) raw in Lincoln last year in an STS CRX in the wet.

Nice! That's no small feat, Matt can wheel with the best of them. I know some of the CSP guys well...Scott Fraser & Ruben Padron (in the ex-Palmquist car) are good friends, we all have great times battling for top PAX here locally :).

The R1R's are definitely a great choice in the wet, especially on the smaller/lighter cars. However, there is a LOT of chatter in the Street Touring world right now about the new Michelin & how good it may be in standing water. Last year, IIRC, most people with the larger/heavier cars ran either the Continentals or Star Specs in the wet.

[BlackbirdM3]

Wow, great thread. I've just started autoXing my E30 M3 with NorCal UFO. My current setup really sucks. Bilstein sports up front with Koni sports in the rear. The springs are Racing Dynamics, but I don't have a clue as to what the spring rate is. That said, the car does not rotate at all. The back end is very well planted and eventually overwhelms the front end about mid corner. It turns in fine, but if I get on the power early it becomes less inclined to turn. I've been autoXing since '06 with a VERY tail happy Datsun roadster (190+ hp, less than 2000 lbs, and locking diff with a live axle and leaf springs and very little weight in the back.) and going to the M3 is proving to be challenging. I'm guessing the spring rate is a little soft, but it feels like I need more front camber (its eating the outsides of the front tires, Hankook RS3s, and leaving the insides untouched) and perhaps more caster. What do these things like in terms of camber, caster, and toe? I have a set of custom valved Koni sports, treehouse racing control arm bushings and ground control camber plates on order. I'm not sure where I should set it up however. I'm thinking -2 degrees camber, 0 toe, and as much caster as I can run (I can't feel the car at all. I'm thinking of dumping the power steering, its WAY overboosted for my liking.). I'll likely end up installing a set of H&R race springs to both raise the front end up some (improving roll center), and adding some spring rate to help make it rotate. I was thinking of adding a big rear sway bar, to get it to rotate, but that has its drawbacks as well. I'm totally fine stepping the back end out, and catching it, I've gotten really good at that with the Datsun.

I'd love to hear any thoughts. In the cars first outting, it was the fastest BMW there, and it was totally undeveloped. The class I run in is perhaps the most highly competitive class that runs out there. I'd like to do better than a somewhat distant 4th place against cars that are 20 years older than it.

Thanks,
Will

[GreyLens]

race2win,

Thanks for this thread. I'm a dedicated MINI JCW pilot starting my third year of autox. I stumbled across your thread looking for ideas. I had a "STX Prep" thread on Motoring Alliance last year for MINI drivers that several folks found useful. I started one a couple of weeks ago for 2012 referencing your thread. Here's mine:

http://www.motoringalliance.com/forums/autox/11732-scca-stx-2012-r56-class-prep-introduction.html#post113110

Though I'm not really planning on going to Nationals this year I like to think I will one day. Not a single MINI was entered in STX at the Nationals and the R56 is certainly not an ideal platform for STX. So I really like your effort to take the "underdog" E30 as far as you can go. Way cool! Much of your discussion and ideas are applicable to our little beasts so I thought I'd just let you know some of us are paying attention.

Good work.