Road race / AutoX classes to suit build?

[Eric]

Autocross is about as fun as second gear gets. Stick to road circuit racing and start off with a stock car, no mods whatsoever! Also, you NEED to at least be capable of getting all the licensing in GT4 or another racing simulator. The experience and little tricks that you learn with a simulator are irreplaceable on the race track. Just don't get into bad habits, or they will scare the shit out of you on a real race track.

I didn't like autocross when I was young dumb and full of cum either. I spent too much money on parts I thought were cool that put me in a class I was completely uncompetitive in on all season because I couldn't afford good tires (spent it all on "race" parts remember?).

A bit older and a bit wiser with a car built to the maximum of the class for the series I run in and Autocross is a blast.

You probably have long stopped reading Mr. pants, instead thinking of some smart-ass retort right now, but Autocross is great at teaching you skills that would be dangerous on a race track.
- understanding the adhesion limits of a car in aggressive maneuvering situations
- fast reaction inputs
- high eyes and moving quickly from one segment to another
- low speed throttle steering adjustments
- breaking threshold, lock-up limits.
- aggressive weight transfer control
- identifying the "line" quickly and maximizing the corner


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[Nsquared97]

Our BMW CCA club runs this scheme for class alignment. http://autocross.rmcbmwcca.org/Class.php

I'm actually really glad you posted this. My local BMWCCA chapter has a similar style points sytem (which I really like), but ours isn't as in depth/polished as this. Thanks for sharing!

I'll break this up and give you my input, but this is strictly autoX related, mainly from my experience in Stock/STX.

I'm curious about how much of a difference shocks will make in the lower and higher classes. I don't think I'd spend the money to be more competitive in any case but my knowledge must be wrong because I figured revalved Bilsteins or full hard Konis were already pushing the limits of how much stiffness can help a car. I went down a few of my local bone crusher roads, and in the hardest compressions I've hit in my IE stage 3 + Koni SA car it feels like it stomps the road, throws my passengers around and stays steady and planted. It doesn't roll around all too much, has a more direct controlled feel and I thought outside of lowering the car a bit more an uber hard setup wouldn't do much more for its grip.

As already mentioned, shocks definitely make a difference. There is just so much more to them than hard/soft. Keep in mind the name of the game suspension wise is keeping the car as planted as possible (thus making the best use of available tire grip), and shocks play a big part in that.

As far as the IE stage 3 springs, trust me that isn't stiff enough. Remember, the more grip you add to the car, the more weight transfer you get. Running all seasons on the street isn't going to get you much body roll, but good, wide street tires on a smooth clean surface definitely can. One thing to note, where your racing obviously plays a role in desired stiffness. AutoXing on a glass smooth airbase lets you run much stiffer rates than a broken up parking lot, where the car would just be bouncing and skipping all over the place.

With all of the things new cars do better I could understand handling being better with bigger tires and chassis refinements to suit them over many years. Same tire grip to work with I don't get how any refinement over an already decent if old chassis in the E30 can do more than make up that big of a weight and polar moment of inertia gap. At least not to the point where something like an E92 would be weaving through all of them in the twistys.

Again, this is from an autoX perspective. Biggest issue I see is the rear suspension not being able to put down power coming out of corners, like say an E36 can. That's huge when dodging cones. Another annoying handicap to deal with is the incredibly slow stock steering rack. You can swap it out in SM and prepared (?) but for Street, STX and DSP you have to keep the stock rack. You can change driving style to try an accomidate for it, but man does it suck. Also for classes where you aren't allowed to cut/flare fenders, tire fitment is an issue. E30's can't fit as much tire as a lot of cars they compete against.

I agree that a good simulator can teach track layouts and is good for practicing technique, but GT4 is NOT a simulator.

This. Forza taught me the line and got me familiar with Road America, but being on track there is entirely different.

Well I've played the snot out of GT4-6 on my wheel setup, so there's that. It taught me the whole Nurburgring which I love it for...

Not trying to be a prick, but have you actually been to the Nurburgring? If not, all you know is the GT's interprutation of the track, not necessarily the track itself.

[whitebulat22]

Well I've played the snot out of GT4-6 on my wheel setup, so there's that. It taught me the whole Nurburgring which I love it for and helped me in numerous ways handling wise. My first chance to clutch kick my car for real nothing really surprised me because of those and other games. A touch of general feel can come from them alone.

It couldn't do too much to help me tune and refine a car as I'd hoped because of things like non adjustable tire pressure, unknown tire size, negative camber actually reduces your handling, every shock is the same with the same range of stiffnesses etc. but I'll agree that there's a nice amount to take away from a good game. It's creator uses it to practice for real races for a reason, I don't know how he can take the vacuum cleaner noise experience seriously enough but it works for him.

[agent]

you NEED to at least be capable of getting all the licensing in GT4 or another racing simulator. The experience and little tricks that you learn with a simulator are irreplaceable on the race track. Just don't get into bad habits, or they will scare the shit out of you on a real race track.

I agree that a good simulator can teach track layouts and is good for practicing technique, but GT4 is NOT a simulator.

[pantelones]

Right now I'm playing with my stock eta engine on narrow tires to get to know the car, but long term I want it to be really fast. Like 300-350 WHP ish fast.

To race a 300+ whp e30 you are talking 3-7k in motor alone, and an additional 10k in suspension, brakes, and safety equipment. Don't forget tires, fresh motor oil, (proper weight...) track entrance fee's, food, entertainment, and a place to sleep for the weekend...

Which race class(es) fit the BMW powered 11-12 sec quarter mile E30 range the best? Suspension is centered around IE Stage 3 springs + Koni SAs and I will try to run a square 245/45/16 tire setup or 225s up front if I don't have the heart to hack the fenders. Those unless someone suddenly decides there should be more 255-265/35/17s or 245-255/40/16s, or some sort of wide 15 that isn't more than an inch off in diameter. I would prefer to stay in something with street tires for financial reasons but might be down to run the 275/35/17 Hoosiers on it one day.

Thanks r3v

Science be praised, buy a damn Caterham and cut out the e30... Autocross is about as fun as second gear gets. Stick to road circuit racing and start off with a stock car, no mods whatsoever! Also, you NEED to at least be capable of getting all the licensing in GT4 or another racing simulator. The experience and little tricks that you learn with a simulator are irreplaceable on the race track. Just don't get into bad habits, or they will scare the shit out of you on a real race track.

[BLACKCHARM88]

You are going about this the wrong way if you are looking to be competitive in autocross or any kind of timed track racing. You need to get the rule books of any organization and find a class that will suit what you have in mind and then build the car around those rules. If you just build a car and then look to go racing(and be competitive) you are going to end up spending a lot more money going back a fixing/removing/changing things that are not legal.

Thanks for the infos...

[Shangsta]

You are going about this the wrong way if you are looking to be competitive in autocross or any kind of timed track racing. You need to get the rule books of any organization and find a class that will suit what you have in mind and then build the car around those rules. If you just build a car and then look to go racing(and be competitive) you are going to end up spending a lot more money going back a fixing/removing/changing things that are not legal.

[whitebulat22]

With those later models shopping for body kits it feels like the selection is as big as a Need for Speed game! That's amazing that there are E30 M3 dream cars out there with those engines. Aero wise everytime I look at a picture of one I cringe because it just looks so much more effective than mine, especially embarassing with that eta trunk spoiler mine has. I do like this kit from dtm fiber but I wish they would talk more about it's downforce and the M3 wing wouldn't be limited by the stock rear window rake + trunk height. I guess you can't have everything without paying recent M3 money.

Technically CFD isn't out of the cards because I'm studying mechanical engineering, but that never meant me knowing what I'm doing with any of these programs. If this is what the soul crushing pain is giving me in the future at least that's comforting.

[MX339]

I'm curious about how much of a difference shocks will make in the lower and higher classes. I don't think I'd spend the money to be more competitive in any case but my knowledge must be wrong because I figured revalved Bilsteins or full hard Konis were already pushing the limits of how much stiffness can help a car. I went down a few of my local bone crusher roads, and in the hardest compressions I've hit in my IE stage 3 + Koni SA car it feels like it stomps the road, throws my passengers around and stays steady and planted. It doesn't roll around all too much, has a more direct controlled feel and I thought outside of lowering the car a bit more an uber hard setup wouldn't do much more for its grip.

The aero part too. For everything I love about my car it annoys me looking at it everytime and seeing how far behind it is aero wise to any other modern car and especially the M3. However, big slick tires w/ camber and suspension vs big slick tires w/ camber and suspension I feel like these older cars with 700 lb or more weight advantages would be able to mostly if not completely seal the handling and acceleration gap. With all of the things new cars do better I could understand handling being better with bigger tires and chassis refinements to suit them over many years. Same tire grip to work with I don't get how any refinement over an already decent if old chassis in the E30 can do more than make up that big of a weight and polar moment of inertia gap. At least not to the point where something like an E92 would be weaving through all of them in the twistys.

To list everything I'm considering for say E30 and E46/E92 on track,
E30 pros- low weight, short length, small frontal area, balance. Cons- Trailing arms give similar camber but not independent of toe change, very poor downforce.
E46 pros- Lower drag coefficient, even more balance, much more downforce, refined rear suspension. Cons- Weight

All just for knowledge sake while I'm here because I haven't seen up close old and new stuff of all eras duking it out on Hoosiers.

Remember that all of these classes are balanced through horsepower to weight ratio, putting the E30 at a disadvantage everywhere. It's not just that the E30 is at a drag coefficient disadvantage either. The E36's/E46's/E92's don't make much downforce from the factory, but they've all got off the shelf aero kits from Bimmerworld, Turner, Etc. You'd have to develop your own setup through wind tunnel testing or CFD, which I assume is going to be out of the cards. I may have mentioned it before in this thread, but there are actually some fairly competitive E30 M3's running B-Mod (Big Power E46/E92 M3 class) in BMW CCA Club Racing. Granted there's not much E30 M3 left. I know one has an S65 (sounds oh-so glorious) and I'm pretty sure the other is still running an S54. Both obviously have plenty of aero devices and seriously high dollar suspension, but it does prove that it's possible to be competitive through a huge amount of work and money. Ah, found that S65 build thread: http://forums.bimmerforums.com/forum...58-E30-M3-v4-1
I'm referring to NASA's GTS classes and BMW CCA's CR by the way, I can't speak for the Auto-X side of things.

Oh, and on the suspension side of things. It's not about the stiffness, most any dampener can be re-valved to perform with a certain spring rate. The difference in the high dollar suspension is the efficiency of the dampening and the extremely high level of adjustablility, with the ability to adjust high/low speed dampening and high/low speed rebound. I'd give you examples of the usages of each adjustment, but I should really brush up on the topic first.

[BLACKCHARM88]

Sure you can do well in SM depending on who's running, but if you are running against cars that are prepped specifically for SM it takes a lot to make an e30 competitive. Like 350-400hp, Motons and 275 Hoosiers. I plan to run my e30 s54 in SM next year, it will probably be competitive at Regional events, but not national

Let me know how you do, I will be doing a S54 swap this winter myself and trying to play in the 450hp ballpark.

[whitebulat22]

Funny, I really wanted to pull my m42 and swap something more kool and faster in, but I've done two autoX's and now I just want to learn what its capable of now! Last autoX it rained and I lost 11 secs off the dry run 15 mins before. I'd like to make that time lost shorter! More HP won't help my skillz! I'd love to learn to drift better too:nice:

Also like you said, I'll probably pick up an e46M by the time I'm done with college and stuff, so the e30 will have to be swapped to more speed to keep up!

:D This is what my E30 wants to do. White out everything, max itself on track, drift in rain, bring chaos to old rear tires using old unopened engine:



If it can do that stock I want to know how to tame it before making it any faster.

Sure you can do well in SM depending on who's running, but if you are running against cars that are prepped specifically for SM it takes a lot to make an e30 competitive. Like 350-400hp, Motons and 275 Hoosiers. I plan to run my e30 s54 in SM next year, it will probably be competitive at Regional events, but not national

I'm curious about how much of a difference shocks will make in the lower and higher classes. I don't think I'd spend the money to be more competitive in any case but my knowledge must be wrong because I figured revalved Bilsteins or full hard Konis were already pushing the limits of how much stiffness can help a car. I went down a few of my local bone crusher roads, and in the hardest compressions I've hit in my IE stage 3 + Koni SA car it feels like it stomps the road, throws my passengers around and stays steady and planted. It doesn't roll around all too much, has a more direct controlled feel and I thought outside of lowering the car a bit more an uber hard setup wouldn't do much more for its grip.

The aero part too. For everything I love about my car it annoys me looking at it everytime and seeing how far behind it is aero wise to any other modern car and especially the M3. However, big slick tires w/ camber and suspension vs big slick tires w/ camber and suspension I feel like these older cars with 700 lb or more weight advantages would be able to mostly if not completely seal the handling and acceleration gap. With all of the things new cars do better I could understand handling being better with bigger tires and chassis refinements to suit them over many years. Same tire grip to work with I don't get how any refinement over an already decent if old chassis in the E30 can do more than make up that big of a weight and polar moment of inertia gap. At least not to the point where something like an E92 would be weaving through all of them in the twistys.

To list everything I'm considering for say E30 and E46/E92 on track,
E30 pros- low weight, short length, small frontal area, balance. Cons- Trailing arms give similar camber but not independent of toe change, very poor downforce.
E46 pros- Lower drag coefficient, even more balance, much more downforce, refined rear suspension. Cons- Weight

All just for knowledge sake while I'm here because I haven't seen up close old and new stuff of all eras duking it out on Hoosiers.

[RoccoB517]

Nope, you were misinformed. Swaps are legal in SM as long as they are from the same manufacturer. However, also for SM rules you must have your complete interior except for the back seats. So, if you have no carpet, door panels, etc. then you're in XP.

Thanks for the clarification. Still XP for me based on the lack of interior, but that wasn't always the case. Oh well!

[tinkerputzer]

Has somebody made an easy to class website for the SCCA rulebook? I'd like to see where my M3 is classed, but I don't feel like sifting through the cumbersome rulebook.

I think you'd be in SM since you are swapped. E30 m3 can also compete in STX which i think it would be competetive with the right set up and driver.

[matthugie]

When I first looked for information on classing my car I was directed to this rule by some folks from Scca:
D. Drivetrain and related components (induction, ignition, fuel systems, etc.) are unrestricted except for the following limitations:
1. Engine block must be a production unit manufactured and badged the same as the original standard or optional engine for that model.

I was told that my M50 swap puts me in XP because it wasn't a factory option an E30 chassis. It doesn't affect me too much, since I rarely AutoX anymore, but it would be interesting to learn that I was misinformed, and didn't have to go to war against so many nasty Prepared cars.

Nope, you were misinformed. Swaps are legal in SM as long as they are from the same manufacturer. However, also for SM rules you must have your complete interior except for the back seats. So, if you have no carpet, door panels, etc. then you're in XP.

[Eric]

Just wanted to throw my $0.02 in on this and clear up some possible mis-information:

Our BMW CCA club runs this scheme for class alignment. http://autocross.rmcbmwcca.org/Class.php

Has somebody made an easy to class website for the SCCA rulebook? I'd like to see where my M3 is classed, but I don't feel like sifting through the cumbersome rulebook.