DaWorstPlaya

iTrader: (31)

Hey, since the SM and BSP guys are doing it why not us. As far as suspension, wheels/tires, power, etc are concerned, I used a lot of it from the SM and BSP thread. Thank you EVOlutionary, GTLocke13 and Dave Mac * (for most of the suspension contribution)!

Power: Since we have to keep our cars EPA legal with the recent rules update, we are limited in what we can use for high flow cats. I have a Randomtech HFC cat and it throws a CEL, so I'll be switching back to the stock cat some time this year. If anyone else has had better experience with a different brand please feel free to chime in. Please understand some HFC won't throw a CEL for the 1st XX,XXX miles but may start thrown the cat inefficiency CEL down the road. So far stock cat seems to be the best bet.
Standard upgrades allowed:
Intake (upto turbo)
Header
O2 housing
Downpipe
Catback
ECU tunes (no boost modification allowed)

Suspension: There seem to be plenty of good quality coilovers to choose from, eg: Ohlins, KW V3, Bilsteins, Motons, Koni Race (ZZYZX). The ZZYZX EM sport setup seems to be a very affordable alternative. Various combination of spring rates and sways can be used. Soft rates with bigger bars or stiff rates with stock bars, choice is yours. Feel free to share why you are chosing one over the other and your experiences with them concerning grip, handling, balance and comfort. I can understand if some of you wish to keep the details secret. Since we can't do the roll center fix like the SM cars can, so we're limited to fixing the roll center with camber plates and then fixing the camber with offset bolts. Also it seems like lowering the car too much is not a good idea since this will affect your roll center.

*A good starting point for springs seem to be 450-600 front/600-800 rear. The amount of spring that you'll be able to run is dependant upon; 1. Pain tolerance 2. Quality of your dampers 3. Valving of your dampers 4. Your driving technique (stiffer springs require a smoother driving style). There are LOTS of opinions regarding soft vs stiff springs just as there are fast drivers on fast and soft springs.

Ride height is hotly debated, the truith in STU is you CAN lower your car too much. A .75"-1" drop up front and a .75"-1.50" drop in the rear is a good starting point. Super low is NOT good BTW, you'll screw up your suspension geometry. Up front the drop is not as detrimental to handling *IF* your spring rates are high enough. Here is a GREAT thread on ride heights and some explanation as to why you don't want to go too low. https://www.evolutionm.net/forums/sh...d.php?t=295713

Camber: Can be got with eccentric camber bolts or camber plates. Some coilover systems may give you enough range to get to the following suggested settings. Camber plates are better in that if you need to adjust camber/caster you may with some repeatability since you may mark you settings. Brands of some camber plates are Ground Control, Cusco, Ohlins and several others that I'll add later. Suggested settings look to be -2.5 to-3.50 front and -1.0 to -1.5 rear camber. The camber setting that you end up with is determined by your spring rates and the grip that your tire generates. Here is an example if extremes to clarify; Less spring+more tire grip=more negative camber, more spring+less tire grip=less negative camber. Your ultimate setting will vary due to your experience and driving style.

Toe in/out are up to your individual driving style, 0 and 0 is a good place to start. Again, your own driving style will factor into the effectiveness of toe, camber and ride height. Some competitors add rear toe out to get the car to rotate on turn-in to help point the car in sweepers but beware, it's a handful in slaloms.

Sway bars, in a word...maybe. Use spring rate first to get the roll mitigated THEN use swaybars to fine tune steady state cornering. You will also notice a change in turn-in response if you upgrade the rear sway bar. Another consideration is swaybars are an option if you don't have the $$ for coilovers. Since you can't change the springs as readily as you may with coilovers swaybars (adjustable) would be an option. Hotchkis or Perrin seem to be the most popular rear sway bars amongst the STU crowd.

Bushings: Trailing arm bushings, swaybar busings, engine mount bushings, rear diff bushings and many rear suspension bushings can be replaced with a superior nylon/delrin bushing with NO increase in metal content from stock. Kits from Energy and Works seem to be the most widely available. There are a TON available from Japan but I don't have room to list them all. Keep in mind you ride will become more harsh if you replace many of the stock bushings. NOT all bushing replacements are legal. You MAY NOT add anything that changes the mounting points from the original suspension mounting points. So, NO bump steer correction kits (front of car, the rear looks to be legal) or steering fix kits that change the mounting points. If you are not sure post here and ask. We've got LOTS of National level competitors here that can answer your questions or debate legality. *

Wheels: 17" or 18", the choice is yours. It's probably a good idea to save on the weight of the rims if you can afford it. Since we are limited to 245 wide tires, 8"-9" wide rims should work fine.

Tires: We are limited to 245 wide tires on AWD platforms according to STU rules. Treadwear rating of 140 or higher. Choices for the most competetive tires are:

Yokohama Advan Neova AD07
Dunlop Direzza
Bridgestone RE01-R
Falken RT-615
Hankook RS2 Z212
Toyo R1R (coming in the future)
Kumho XS (comeing in the future)

Apparently Kumho is coming out with a new tire that is supposed to compete in this segment. From what I have read and heard the Advan Neovas have a slight edge over the competition. Discuss away and please feel free to share your experience with these different brands of tires.

Weight savings: Take out spare tires, tools etc from the trunk. Seats can be replaced for a little weight savings. Some of the stock exhaust components can be replaced with lighter and freer flowing counterparts. Light weight battery.

Drivetrain: Not much here. Just remember we're pretty much limited to the stock clutch at this point.

Aerodynamics: Some may argue the use of larger wings with crazy angle of attacks at SOLO speeds and I'm not going to plead either case. But we are allowed to replace the wing on our car and install a front lip. The benefits of those aren't fully known but if you have any input feel free to share. Regardless it is important to maintain a good balance.

donour

iTrader: (6)

Haha. I wondered when this one was going to get started.

d

EDIT: I use a vishnu high-flow cat. I have no idea who the original manufacturer is, but I don't throw the P0420 code. Cirodesign also sells a 300 cell unit which should work without problem.

TrEvoRS

iTrader: (5)

Looking forward to the info on high-flow cats... You may want to add Toyo R1R to tire choices (I belive the Kumho is called XS), battery to weight savings, and a word or two about bushings (especially which provide the most benefit).

I am struggling with wheel choice (width/weight/cost compromise). I will be specific and list what I have narrowed it down to in order to help others who are just starting a similar research (all fit without spacers). I would really appreciate if someone can provide some feedback on the difference in performance between 8.5", 9" and 9.5" wheels.

17x8.5 - rpf1 (16 lbs)
17x9 - FN01R-C (19 lbs), SA-70 (17lbs), CE28N (16.5 lbs), TC105N (15.7 lbs)
17x9.5 - NTO3+M (19.5 lbs), TC105N (16.3 lbs)

Finally would TRE rear diff upgrade be legal in STU?

Dave Mac

iTrader: (2)

Wider=better, it optimises your tires contact patch. Most of the nationally competitive Evos are on 17x9 wheels. There are one or two on 17x10's but not many. I don't know of anyone running an 8.5 rim.

GTLocke13

iTrader: (1)

Just to chime in here...

The current 'hot' tires are the Advan and the RE-01R. From what I gather on my region's message board the RE-01R doesn't do as well on heavy cars. The civic guys love them, but once you start putting a lot of weight on them they get very ponderous in transitions.

The wing issue is open to interpretation, I think. If it's like any other class (and since I'm addicted to R-compounds I haven't studied the ST rules much) there's a clause that says "the spoiler may not function as a wing." This would limit any aftermarket aero to the ridiculous plexiglass stuff seen in some of the SP classes.

[disclaimer]
^^ This may be completely off base. Do not take anything I say as gospel here because it is based in complete bull**** and is probably absolutely wrong.
[/disclaimer]

GTLocke13

iTrader: (1)

Nevermind... dumb post

CoreyR

iTrader: (5)

I haven't had any CEL problems with the COBB HF cat. It's probably the smallest metalic substrate cat I've seen too.

Corey #89 STU

Dave Mac

iTrader: (2)

I've had no CEL issues with my Perrin HFC. It also has a very small substrate.

Caffeine Slug

iTrader: (3)

I ran in STU locally for most of 2007 with just camber plates, 17x9 FN01R-C's, and a set of Neovas. This year I'll finally be able to add coilovers (as soon as the next batch of ZZYZX EM series is ready), exhaust, and tuning. My 100-cell cat from Rick has been sitting on a shelf in my garage for months now.

One question I had, what's the best route to go on the O2 housing? Keep the stock one, or port the stock one, or get an ebay (or similar) housing? I've had some concerns over an ebay housing cracking, but maybe that's not a well-founded idea.

Also, would anyone happen to know if the RS shares a trunk lid with other models? I've heard somewhere that the RS lid is lighter (lack of wing aside), but I was considering picking up a spare GSR/MR trunk lid to use with one of the STU-spec non-functional wings. If it's a different part though, I don't think I could use it. I'd really rather not drill holes in my RS trunk lid as well.

donour

iTrader: (6)

I'm actually going back to 8.5 from a 17x9. My 8.5s are like 3 lbs lighter per wheel and I'd _really_ have to pony up to have to get 17x9s that are 15lbs or lighter. On the 245, I measured the contact patch and it's really only like 1/4" wider on 9s than 8.5s. With all the deflection you get, I'm not sure it makes that much difference.


Plus the 245 ad07 is wider than the 245 RE01R. As much as most of us love the bridgestone, the yoko is faster.

I'm probably switching. In the meantime I have have several sets of 245/45/17 bridgestones (and falkens). Anybody want them really, really cheap?

I think some of the big APR wings actually aren't legal, but I think this is more like a nobody-gives-a-damn case. I'm more than happy to let me competition spend cash on big wings that do next to nothing rather than invest in driving schools.

d

donour

iTrader: (6)

Shouldn't be long. The the very first set (me ) should be ready in about two weeks. After that, I expect there'll be a month or so of us guinea pigs running around trying to break things, then he'll start building like crazy. The second order should be pretty lucky because you get to avoid all the tooling and logistic delays.

I wouldn't worry about that too, but is it really worth it. First off, it's a lot of work for only ~10 hp. Secondly, are all of your runs within about 0.2s? If not, then 10 hp probably won't make much of a difference. It doesn't for me. Hell, I even tried boost control on some fun runs and only got a little bit faster and that was like 35 hp.

The trunk is the same (and steel), but the trunk "spring" is different. There MR/GSR has a bigger one to force it open with the wing weight.

d

Caffeine Slug

iTrader: (3)

Not that I've actually done the work, but would seem like a reasonable "while I'm in there" modification. My exhaust is entirely stock right now, but if I'm doing it all (turboback w/cat, exhaust manifold) at once, I'd think it's pretty trivial to replace the O2 housing while I'm at it. 10hp is 10hp, and it adds up. I figure I'm giving up more ground to the Subarus in power than anywhere else, so I should do what I can within reason to fix that.

FWIW, my runs usually are fairly consistent, I'm not new to the sport. Maybe not as fast as I'd like, but at least consistent.

Czubaka

iTrader: (11)

The O2 housing really isn't a "while I'm in there" mod when doing an exhaust. It's more "while I'm in there" when changing turbos. The downpipe is super easy to change, but getting access to the O2 housing bolts on the turbo side require removing the rad and/or the turbo...as I understand it...

Caffeine Slug

iTrader: (3)

If I'm changing the manifold as well, isn't pretty much everything coming out?

Czubaka

iTrader: (11)

Doh! I missed the exhaust manifold part. Yeah, that would cover it!