Consulting Solo II Racers- What can I get away with in ES with an S5 GTU?
 

I have an '89 GTU that I will be racing in the ES class Solo II and fo the most part it is really basic. I have a lot of left over parts from previous NA FC's and Iwas wonder just what all I could use.

The main things I have that I want to use are the four-piston calipers and the manual steering rack (If it is at all advised to use. Car is now equipped with the engine speed dependant p/s rack.)

The next issue I run into is tires, I was unsure while reading the 2012 rules if tire size is at all allowed to be changed. As in going from a 60 profile to a 50 profile. I know it will look weird but I can handle that to gain some performance from a nicer tire.

Then it is on to suspension bushings. Are only OEM rubber bushings allowed or can you use polyurathane bushings instead?

Thanks for any help, this is my first season so I'm still trying to learn.

for the most part you can only swap in stock parts that were availible as on option on your trim. so according to the FAQ:
https://www.rx7club.com/showpost.php...27&postcount=6

neither manual steering or 4 piston brakes were optional.

you can run whatever size tire you want as long as it stays on a stock sized wheel.

you can't replace the bushings at all, but you can replace the fornt sway bar and endlinks which I would suggest. That's probably going to be your biggest performance enhancer (behind race tires of course)

i'm looking at the rules here http://www.moutons.org/sccasolo/Rules/stock.html

it says "Except for modifications authorized below, Stock Category cars must be run as specified by the factory with only standard equipment as defined by these Rules. This requirement refers not just to individual parts, but to combinations thereof which which would have been ordered together on a specific car. Any other modifications or equipment will place the car in Street Prepared, Prepared or Modified Categories as appropriate."

so since manual steering isn't an option for an S5, running it is probably illegal, although if you're not winning nobody will care.

i think you could run the 4 piston calipers, its an option, although if you're nitpicking the 4 piston calipers came on the GTUs or GXL, so there is other equipment that should go with the brakes.

i'm confused about the tire rule, i dont know why they don't specifically say you must run the same size tire as stock, but they don't actually mention size. you should ask people. it does need to be a DOT tire, so the hoosier is out.

it looks like the bushings need to be standard, which is fine, new bushings are actually really cheap. you will want to align the car to get the most negative camber in the front as you can, and then try a couple of toe settings front and rear, and see what you like best, it makes a huge difference.

actually starting in stock class is nice, the car prep part is pretty short and simple, and it'll let you work on the driver prep part, which is way more important in the long run

actually Hoosier A6s are DOT. (that's why they have the 2 tread lines on them). everyone in stock class runs them.

They did just introduce a street tire stock class though. it uses a PAX modifier so all the stock classes compete against each other in awd, rwd, and fwd categories. It's kind of complicated and odd at the moment.

as for brakes, yes, you could completely swap over to GTUs or GXL trim to run them, but the weight alone would probably make it not worth it, bigger brakes don't give you much on an auto-x course besides more unsprung weight.

the thing that might make it worth it are an LSD and the stiffer sport springs that come cars came with. but it doesn't really seem like he's deep enough into to make that kind of commitment and it would probably be easier just to buy a different FC in that case.

Thanks guys. And yea that's why I am starting in stock class (other than the fact I want to try to keep the car as OE as possible). I know that I will not be winning for the first season maybe two since, well, it is my first two seasons and I don't have the experience of others. The biggest performance increasers will likely be tires and breaks. Since I can't really increase power or decrease weight, I can always increase stopping power (via pads) and increase overall grip (via tires.)

As far as sway bar end links, I assume the RacingBeat units would be the best reccomended replacement?

And you are right, I'm not that committed yet, however, I am just trying to see just what I can and can't do within my class limits.

actually the mazdatrix links are going to be the best. they use bearings instead of polyurethane bushings.
http://mazdatrix.com/h6_86-92.htm

you'd also want to go with the suspension techniques 86-88 front sway bar (yes, they fit S5s) it's the stiffest (cost effective) front sway bar available for FCs.

what size wheels are on your car?

Stock class is gay. Since when is running a semi-slick competition tire anywhere near stock?

Run a street-tire class and then you really won't have to worry about the modifications... and you can get a set of Federal 595 RS-Rs (140 tread wear) for half the price of a set of DOT autocross tires.

Driving a sports car without a bucket seat isn't fun anyway....it's just tiring. And it's not REALLY fun until you've got a harness.

FWIW, you can get away with almost anything if you aren't winning on the regional level and the people you beat aren't anal whiners... the worst thing that can happen is they take your plastic trophy away.

I can't believe people would complain about upgrading the brakes... since the difference between the trims doesn't even change what class you're in unless you're a turbo. Not to mention four-pot brakes and a manual rack won't really make the car that much faster in autocross anyway (the weight reduction of the P/S pump would be offset by the calipers almost).

In the coming years I'll move to a more 'fun' class, but for now just getting involved with racing will be fun enough. I start college in the middle of summer (July 26th) so I won't exactly have tons of cash to spare. After I get out of school in a couple years and have a stable job (most likely working for BMW or Mercedes as a tech) I will be more financially inclined to build something for a higher class.

And as far as the brakes, I guess as long as nobody is really going to notice, it can't hurt to have that little extra stopping power. After having two FC's with the 4-piston calipers, the braking performance of the single piston is noticeably worse by a decent margin. I assume the master cylinder would need to be changed, or no?

No... it's all the same stuff if memory serves. I think the part numbers might even be the same.

I did the research before and bought some used cylinders but didn't have the money for new brake lines and pads. lol.

But seriously, running in stock just because your car is stock is no good for your self esteem if you're the only guy running with street tires. Because you will never, ever win. Just run in the street tire class (STX IIRC) if you don't have money. You don't have to nitpick over mods since it allows many common tuning mods (tower bars, filters, etc). If anything a stock car with street tires versus a modded car with street tires will probably fare better than a stock car with street tires against a stock car with DOT R-compounds...

they've implemented a street tire stock class... I'm sure at least a few people will run it in your region.

ORYL?

I didn't know that. It's been a few years since I've autocrossed in the US.

I remember posting on a forum saying that it was weird how there is no street tire version of stock class, and I think I got laughed out of the place...

Like I said before though, I am not looking to win these first 1-2 seasons, I am merely trying to build up some skill before I start modifying the car to be more competitive. I would understand trying to find the best class for the car if I were road racing, but since it is just simple autocross, I am not too concerned about how I do.

For me, just improving my own skills as a driver will be most important.

If you don't care about winning than there's no reason to run in E Stock to begin with. It really doesn't matter what class you run if you're not going to use r-compounds and don't care about winning.

So don't worry about what mods you can get away with. Just do the mods you want do do and worry about classes later. The mods that makes any car the fastest and the most fun to drive are an aftermarket steering wheel, racing seat and a harness belt. Both of which are illegal in E Stock, of course.

The wheel is legal, but not the seat and harness. I won't be looking for a new wheel for a while though, as I had my Nardi-Personal with the NRG quick release 2.5 attached to it stolen out of my car a few months back.

I'm still content with running E stock though. Nothing is really going to change my mind on that anytime soon.

Right, I added the wheel as an afterthought. They are legal as long as it's not smaller than a certain size. It's not the wheel itself that's important, although having a smaller size and being able to choose a shape you like is nice, it's the ability to adjust the distance to you with spacers that's really important. This alone makes the difference between a slow car and a fast car when it comes to autocross. Also, having a perfectly round wheel helps with countersteering and having a D-shape wheel helps with legroom, especially on FDs.

Sucks somebody stole your wheel and half your spacer. That's one of the reasons I just use regular bolt-on spacers. Cheaper anyway.

The difference between a stock seat and a bucket seat is night and day. Add a harness and it makes driving the car at max speed almost effortless.

Yea next time ill just get a momo hub and Monte carlo wheel. And I had a buddy who used to have two Bride Vios III seats with 4-point Sparco harnesses and man was that a fun car to scoot around in. Didn't feel a cm of movement in the seat.

Good thread, let's keep this rolling. (on a side note, I just picked up said Federal RSRs before seeing this thread at the recommendation of a friend that shared that a recent SK1 winner with S2K was running these tires - hoping to try them out this Sunday)

that's good actually, go and have fun! there is a lot to be had with just aligning the car, playing with tire pressure and improving the driver.

I would support building and modifying your car to fit the rules as they are written. First this gives you a place to race your car and second this can save you money because it provides direction and sets limits. Also, the SCCA solo rule set is designed to be progressive. So the modifications you make to be competitive in Stock class can be used in Street Prepared, Street Touring, etc.

Some modifications that are cost effective and will transfer to faster classes are a bigger front sway bar, quality adjustable shocks and struts, cat-back exhaust upgrades, and a quality suspension alignment from a professional that is familar with Solo.

As far as tires are concerned, running on a quality DOT comp tire in stock class is not gay. These kinds of tires are necessary of you want to be competitive in non-street tire Stock classes. So if that is what you want to do then go for it.

All things being equal, tires are the most important thing in any form of motorsports including Solo. There are many great options out there besides Hoosier A6's. Hankook, Kumho and BFG also make great DOT comp tires. If you want to save money and run in a street tire class check out the Hankook RS-3 and the Kumho XS

Good luck with your efforts

my friend dropped 2 seconds off his time @thunderhill just by switching from hankooks to hoosiers, last weekend. tires matter!

That is exactly my thoughts! I missed the first round today in favor of spending time with my family and going to Chicago for a tour of Wrigley Field, and it was good that I did because I'm still waiting on important parts for my car to come in before hitting the cone-track.

Its because the rule for requiring DOT tires is from the 1960s. Tire technology has evolved tremendously since then, and the rule was never changed. It gets revisited every once and a while as someone like you writes a letter to the SEB, and every time the rule is held because the spirit of the rule hasn't changed. If a tire is legal for you to drive on the highway, then its legal to run in Stock.

Technically since Hoosier A6s are DOT legal, you could drive on them on the street, although I wouldn't recommend it as they really don't like standing water.

Stock doesn't mean "from the showroom", and the quicker you figure that out the happier you'll be :)

And the new Road Tire classes (RTR, RTF, and RTA) are provisional starting this year. They were created because a lot of regions already had similar classes and people requested them at national tours. Right now they are indexed based off of Stock classes and will likely remain for the next two years as the nationals office gathers data, and then decides how to modify the classes.

You may want to change your standard differential for a LSD out of a GXL. I switched mine after I got tired of spinning the inside rear wheel coming out of a tight corner and loosing time.

Not legal in ES unless he converts completely over to a GXL. Swapping parts between different trims is an all or nothing in stock