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Old 02-11-18, 03:48 PM
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A-Street-Prepared (solo) tire/suspension setup

I've been enjoying autocross and rallycross for the past few years and I bought an FD to turn into a big boy car. I'd like to try my hand at track days, drift events, tarmac hillclimbs, maybe road racing and see what sticks.

Before the roll cage goes in and **** gets real, I'm going to mostly do autocross. I'd like to be somewhat competitive in A-Street Prepared. No limits on wheel size, or coilovers.

What suspension should I choose and what size wheels/tires?

I'm eyeing the Ohlins road and track, and I'm thinking that 17x9 square would be a good wheel size, but I'm still combing through forum posts and looking for feedback here.
What are the hot tires for Autocross these days? Is it still the RE-71R's? Should I do 16 inch? 17 inch? 18 inch? There are so many choices!

I'll only be driving this car on the street to get to/from events for the most part, maybe the occasional weekend drive.

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Old 02-11-18, 04:44 PM
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I run my FD in ASP for local events.

In Street Prepared you are somewhat limited in front wheel/tire fitment because you cannot trim/clearance anything inboard of the wheel mounting surface besides removing the fender liner. This means that you are limited to a 25.3" tall tire so it doesn't rub the sheetmetal up by the front headlight buckets or you could run a higher ride height and limit front suspension travel (not ideal).

So, you are effectively limited to 295/30-18 up front instead of the 315/30-18 that would be run in SSM- though I am sure you could make 315/30-18 work with some compromises.

The set-up I came up with after much measuring was 295/30-18 on 18x11 +45 front and rear with rolled and slightly pulled front fenders (max available camber of course) and just the rear fender lips rolled under with minimum available camber.


I am on the Ohlins, but if your budget allowed you could go with Penske, Moton/AST, JRZ, etc which already have solutions engineered for the FD chassis for the SSM guys.

Tires-
If you are on Hoosier A7s (the hot tire) you are going to want more spring rate than the Ohlins come with out of the box. I run whatever tire is cheap/on sale (R888, Ventus TD, used R1-S, etc) and still could use more spring rate than the 11/11 of the Ohlins out of the box. I think you could do 13/13 without a re-valve or go through SakeBomb and have a custom set-up done that is still half the cost of the big boy suspension.

I actually would like to run RE-71R because I am too lazy to change wheels/tires for street driving, but they are crazy expensive. They are $307 for the biggest 285/30-18. Federal FZ-201 are $165 for 285/30-18 and faster, last Ventus TD I bought were $150 and faster, R888R are $240 for the 295/30-18 and maybe a bit faster, etc etc.

Previously, I ran $140 265/35-18 Federal 595RS-R with the Ohlins and that scant grip was about right for the 11/11 spring rates.

You will want an OS Giken Super Lock diff especially if you go with sticky tires- it can lay the power down even when you are leaned over in the narrow stock body FD where the stock Torsen starts to act like an open diff.
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Old 02-11-18, 04:45 PM
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My local club holds the Re-71r as the gold standard currently. I have seen many recommend running a 9.5 with 255/40-17 (widest 17 “ 71r) or even a 10” wide wheel.

I have ridden in a couple FD’s with Ohlins, and they are nice. I have the FP Spec, with 10k/8k. Wanted to be able to tune with sway bars and maintain comfort for the street. Caveat: I Am NOT Competitive.

As for being super competitive: Talk to the guys that are winning nationals or consistently winning locally and regionally, in an FD chassis. (Blue TII has quite a bit of applicable experience on this topic)They will have the best recommendations to be competitive. I have seen some crazy amounts of money spent piecing together suspension builds and havin them custom valved.

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Old 02-11-18, 04:59 PM
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Would SSM be a better class to run in? I'm not gonna minimax the rulebook no matter what class I'm in - not trying to go for nationals, just want to be close enough to the top guys to have something to chase. Are there more competitors in that class?
I just chose street prepared because I will be running a power FC and I don't think you can use that in street touring.

[EDIT] actually, it looks like they are going to allow cars older than 1995 to use a standalone ECU in street touring in 2018
https://www.scca.com/articles/200828...l-for-feedback

[double edit] so I can run A street or A street prepared, but I guess the FD has no street touring class, which kinda sucks

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Old 02-11-18, 05:09 PM
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As for the Penske's - I've been looking at them too. That's stretching my budget a little bit to make the start of the season, but it's doable if they are really worth it. How much better are they really?

They are easier to rebuild, right? How often would I need to rebuild the Ohlins? Can I justify the cost by rebuild savings or something?

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Old 02-11-18, 05:16 PM
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I was initially thinking of just running a street tire, but if hoosiers are allowed in the class, I might as well run them. I don't have a trailer right now, and would rather spend that money elsewhere for the time being - will 4 meaty wheels fit in the trunk of the FD with a floor jack? Probably not in this tiny car, right? Do you need an accusump when running hoosiers with the 13b?

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Old 02-12-18, 02:49 AM
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Yeah, to our requests SCCA says FD performance is beyond the intended scope of Street Touring classes (but Evos and C5 "Vettes are fine?).

SSM is the Super Spendy Moneypit class. I like ASP because it does put some limits on what I can spend money on.

Nope, big wheels and tires do not fit in the FD at all, you have to do a trailer hitch on the FD (U-Haul) and a tire trailer, truck and trailer or just drive on your DOT-Rs as I do.

Do you need an accusump when running hoosiers with the 13b?
FDs seem to do ok with the stock baffled 13B-REW pans, FCs need an aftermarket baffle as the pan is open. You will have to get a gel or solid state battery because you will slosh all the acid out of a liquid cell battery.
I would do an aftermarket oil pan with higher capacity, straight sides, baffles and trap doors (like Built to Apex unit or Len Bacon) before I would do an accusump as the latter is another point of failure and load on the oil pump to refill.

You will need fixed race bucket seats and harnesses to get the most out of sticky tires.
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Old 02-12-18, 12:06 PM
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Alright, well now I'm considering downgrading a few parts back to OEM so I can just stay in A street. I really don't wanna skimp on parts (I'd rather just take longer to build it) and I think that getting Hoosiers, Penske coilovers, adjustable control arms, oil pan, ecu, wheels, etc for prepared won't happen until mid season. If I just downgrade to stock it will cost about $400 in parts, but then I can roll RE-71R's and not worry about getting Hoosiers to the track. Then I can do chassis prep over the winter and move up to ASP next year.

That slows down my modification path, but it would be a lot easier to be competitive this year.

aftermarket parts on the car I bought -
Aluminum intercooler, upgraded radiator, downpipe, catback, cold air intake, no tune from what I can tell.

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Old 02-12-18, 09:56 PM
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your probably better off hanging out in stock class for at least a season or 2 to get the hang of the car... and then slowly move up classes.

I have a trailer hitch on my street modified FC and tow my tires to the event with a small harbor frieght trailer. it works out pretty well:



The problem the car has in stock class is the cars wheels are too small. you can't really compete with C6 Corvette Z06s...which have 18x9.5s up front and 19x12s in the back... but it's a good place to learn the car and won't cost much.

Moving up to ASP I'd cram the biggest hooosiers you can fit on it (probably 285/30/18 is the way to go since they're a short tire) and some penskes and call it a day add power to taste.

street modified gets out of hand fast:
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Old 02-12-18, 09:59 PM
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The only tires to run in ASP or SSM are hoosier A7s.

Stock class your choices are either Bridgestone RE71Rs or BFG Rival-S

but again, if you're not being competitive, any decent "extreme performance" summer tire is fine.
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Old 02-14-18, 08:14 AM
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Alright, well I ordered some datalogging gear and most of the stock parts I need. Street class it is this year.

Thanks for the help!
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Old 02-14-18, 08:46 AM
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You guys getting the Nankang AR-1 over there? these just came onto my radar recently. Very affordable, if it's anywhere near 888 comparable it is a winner at about 2/3 the price.
https://nankangtyres.com.au/wp-conte.../04/AR-1-L.jpg
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Old 02-14-18, 10:59 AM
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Originally Posted by sudoprime View Post
Alright, well I ordered some datalogging gear and most of the stock parts I need. Street class it is this year.

Thanks for the help!
In case you haven't seen this, it's great for autocross:
https://www.petreldata.com/

That's what I use for logging and video generation in combination with a race capture box.


Originally Posted by WANKfactor View Post
You guys getting the Nankang AR-1 over there? these just came onto my radar recently. Very affordable, if it's anywhere near 888 comparable it is a winner at about 2/3 the price.
https://nankangtyres.com.au/wp-conte.../04/AR-1-L.jpg
that wouldn't be legal for street class (nether are the R888s). Street class has to be 200TW or more. also, R888s are no where near as good as hoosier A7s for higher up classes (I have NT01s on my car for street tires and hate autocrossing on them, they take too long to warm up)
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Old 02-14-18, 01:24 PM
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You guys getting the Nankang AR-1 over there?

I haven't even seen a grey market importer bringing containers of them in yet in the USA.

We can get the Federal FZ-201 grey market or through sponsorship of Federal in the USA though and it is similar price point/performance from what I have read.

This is the kind of crap tires I run on locally, but like eage8 says- not going to cut it at nationals level competition or against drivers in your local club on that level. Lets just say I feel good when I beat our local nationals levels competitors raw time in their Miatas. Doesn't look so good for me on the old PAX index though...

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