tweekscratch

I want to spend the winter building up my EVO and max out its potential in the STU category. Toward that end I've made a shopping list by just looking at what a few shops are offering (see below). My question is: are these mods legal and are they really the best choices for the application?

TIA

Shopping list:

Tein FLEX Coil overs
Tein EDFC controller
Tein S. Tech springs
Cusco Type OS AL rear strut tower bar
Cusco 23mm rear adjustable sway bar
Cuscu V2 lower arm bar
Cusco front adjustable camber plates
Vishnu Stage 1 signature (catback, high flow cat in stock location, down pipe, XEDE w/o boost controller, Adjustable cam gears)
Safety harness
17X8 wheels w/ Yokohoma A046 tires

Did I missing anything?

Kwman

iTrader: (4)

I'm pretty sure they're legal but when it comes to performance mods id go with buschur racing or buy parts independently and go with the AEM EMS instead of XEDE. I'm sure the XEDE is great but IMHO id rather buy the parts separately (makes trouble shooting easier). Oh and for suspension my items of desire are Zeal super function R coilovers but i dont yet have $5k. I hear good things about Tein as well though and for the money you can get the flex with EDFC for pretty cheap.

jbrennen

iTrader: (1)

You've got quite a few things there which aren't STU legal...

EDFC controller - in general, not legal, unless it is impossible for the shocks to be adjusted while the car is in motion. Basically, to be legal for STU, you'd have to remove the EDFC or mount it in the trunk or some such thing.

Cusco V2 lower arm bar - not legal in STU.

Vishnu XEDE - possibly legal in STU, but you probably need to get clarification from Vishnu. STU permits piggyback controllers which modify sensor signals into the ECU, but does not permit piggyback controllers which drive engine control functions directly. Basically, an STU legal piggyback only modifies signals going into the ECU -- it may not modify or replace signals coming out of the ECU. I don't know if the XEDE meets this description -- if the XEDE drives the injectors directly (for instance), that would make it illegal in STU. The XFlash, on the other hand, would be legal as long as the boost control parameters are not touched.

Adjustable cam gears - not legal in STU.



And as for the AEM EMS, not legal in STU.



As for what are the best choices for the application... The Tein FLEX are not bad, but you'll probably have better performance if you go with slightly stiffer springs than the ones that ship on "stock" FLEX units.

And definitely upgrade to wider 17x9 wheels -- the wider contact patch will make a difference. Look to keep wheel weight under 20 pounds a wheel.

Consider upgrading the brake rotors and pads. Two-piece (aluminum hat) brake rotors can save a lot of unsprung rotational weight. I run Porterfield R4S brake pads, which are much more fade resistant than the stock pads -- in fact, they seem to stop better the hotter they get.

chrisw

iTrader: (2)

Tein EDFC controller - definately not legal
Cuscu V2 lower arm bar - not legal, the type 1 should be ok.
Vishnu Stage 1 signature - everything should be ok, minus the cam gears. The Xede without boost control is legal. As an alternative, the XFlash should be legal too as long as you don't touch boost control systems on the ECU.

Like JBrennen said, you should check with Vishnu to confirm the XEDE operation.

FT@SELGP

two-piece rotors are not legal in STU. Replacement rotors have to at least the same weight of original.

My general comment however is: the overall setup is not going to max out the potential. Car setup is not a list of parts; it is balancing components' integration and tuning them for the specific driver. IMHO, Tein and Cusco stuff are the wrong components to begin with, but that's just my opinion.

jbrennen

iTrader: (1)

Are you sure, FT?? You could be right if the rules have changed since the 2004 rulebook came out, but quoting from that book (STX rules, 14.11, item 8 -- STU inherits all STX allowances):

FT@SELGP

I am/was pretty sure about the rotors; but worth double checking. If the rule stands, should we really go STU ?

RonA

If you go with the FLEX Coilovers you won't need S. Tech Springs. The coilovers come with springs and the S. Tech's are meant for use with aftermarket or stock struts (althought I wouldn't recommend upgraded springs with stock struts).

Good Luck,

Ron

nix

Not sure what the specific rules are in the STU category, but IMHO the SINGLE most important standard parts necessary would be the Evo RS FRONT and rear differential units.

If the rules allow, try the following:
Swap-out the front transfer case with its "open" diff, for an RS ("TorSen" helical LSD) transfer case (or whole RS gear-box.)
[The FRONT RS LSD is the most important mod you can do to reduce understeer... PERIOD. Only correct alignment is MORE important!]

Swap-out the fragile AYC & its "flakey" handling for RS rear diff (LSD) set-up.
[Outside Group "N", how many rally & track cars do you know using the AYC unit?]

Good luck with your set-up

tweekscratch

I'm sort of clueless about the whole coil over thing. Sort of a situation where everybody says you gotta have them so like the wooly sheep I am I just follow along w/o asking too many questions. Luckily I have plenty of time to do my homework.


My goal at the end of the modding spree is to have a car that will mop the track w/ the DFW scubbies and still be able to drive to the grocery store.

jbrennen

iTrader: (1)

For competing in STU, coilovers are going to give you the biggest performance increase compared to any other single modification. That is, assuming that you properly tune the coilovers and learn how and why to adjust the suspension.

The last autoX where I ran my Evo, I gained over half a second on my last run by just turning the rear shock adjustment knobs by one click each. The car had been tail happy on the previous runs, but that simple 20-second adjustment made the car much more balanced.

It really is that simple sometimes. Turn a knob and go faster. Obviously it takes a bit of a learning curve before you know when to turn the knobs (and how far to turn them in which direction) but it doesn't require higher math or anything -- it just requires testing and trusting your seat-of-the-pants feeling.

nix

Sorry! I forgot that you all don't have the stupid AYC unit on US Evo 8s.
Forget that suggestion. Use US Evo 8 RS set-up, with/without UK Quaife front LSD; see: - https://www.evolutionm.net/forums/sh...0&page=1&pp=40 for Group buy.
This is only really necessary for SERIOUS abuse &/OR HIGH power output (needed by MOST Evo drivers then? )

Check diameter of GSR vs. RS rear anti-roll bar. Use bigger of the two. Try to get Bilstein struts/rear shocks (2005 model) if available.

That should be a good starting point.

JT-KGY

iTrader: (3)

Any front LSD will be illegal in STU for EVO.

You might want to move up to 245 tires too with lightweight 17x8.5 or 17x9s.

tweekscratch

front LSD - If I'm (or anybody else for that matter) wants to go that far, may as well trade in our 03's for an 04 RS or MR and be done with it.

Silencer

iTrader: (4)

Unfortunately, the 04' rulebook does not mention replacement of the down pipe or 02 housing. However, it does allow for an aftermarket cat, header, upper strut bars (no V), aftermarket suspension bushings, and lightweight battery (relocating is legal). There is also allowable suspension changes that relate to sway bar relocation.

JB, CW, Where does it say that STU is allowed wider wheels? STS is 7.5" and STX is 8". Was it mentioned in Fastrack? I agree in using a lightweight 17x9 to stretch the limited 245mm tire.

Thanks

Dave