STX WRX Setup / Discussion thread

[MNbiker]

Originally Posted by ButtDyno

So are you saying it's actually worse than running the OEM manifold, or that it makes more power than the OEM manifold but levels off sooner? What does it look like midrange?

The results I've seen indicate that the powerband moves up at least 300-500RPM, depending on the header/manifolds. The problem with this is that the small turbo on the '06-'08 cars runs out of boost well before redline, so by moving the powerband up, you end up with a narrower "sweet spot".

So, IMHO putting a header or ported manifolds on these engines comes down to a trade-off between a bit more power from 3K-6K RPM or better low-end punch. I opted for the better low-end, which also happens to cost me less.

-Steve

p.s. The biggest advantage of a header may actually be the resulting reduction in weight on the front wheels.

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[Splash]

Don't forget to factor the I.D. of the runners on these. The smaller runner headers (like the original Perrin) won't do this, or at least not much. The 2.5L engines are not as interior volume sensitive.

Plus, it is documented that uncoated/unwrapped headers lose response time due to the energy loss inherent in the cooling of the exhaust pre-turbo.

I would be surprised if a wrapped/coated small runner header lost any low-end on a 2.0L and I'm all but sure it wouldn't on a 2.5L. The 2.5 can take the larger (but not HUGE) runners. I would not run any header non-coated and/or wrapped.

The problems with many header tests, especially "shootout" style ones, are that none of them get wrapped, and often the tune does not change. The lack of tune tends to affect the total power results, while the lack of wrapping affects the onset of the powerband.

[MNbiker]

Originally Posted by Splash

...I would be surprised if a wrapped/coated small runner header lost any low-end on a 2.0L and I'm all but sure it wouldn't on a 2.5L...

Still haven't seen a single documented test where a header didn't make less power than the stock manifolds under 3,000 RPM on a 2006-2008 WRX. For reference, Perrin claims their small-tube header makes more power from 3,300 RPM.

FWIW - If someone wants to send me a header, I'd be happy to have Ron tune & test it on my car, to see how the results compare with my current 93 and/or 100 octane maps. Heck, I'll even supply the header wrap!

-Steve

[Splash]

You likely won't either. I don't know of any that were specific to 06-08 WRX. Most of the header tests you see were either done on 2.0L WRXs or STIs.

That said, there are quite a few 2.5L header tests that show the opposite of what you're saying.

I figure if I can show an STi with a header that makes more power than it does with the stock manifold under 3000rpm, then a 2.5L WRX with a smaller turbo should be able to at least match it.

Besides, how much of your time on course is spent under 3000rpm?

[MNbiker]

Originally Posted by Splash

...Besides, how much of your time on course is spent under 3000rpm?

It's not so much the amount of time spent below 3,000 RPM as the importance of those occasions. Assuming I could get another 6-8WHP and 10-15 WTQ with the right header, I'm not sure I'd notice much of an improvement on a typical autocross course. It wouldn't help the car dig out of slow corners better, and wouldn't provide more kick at the top of the RPM range, which is the real weakness of the '06-'08 engines.

Frankly, a little more power doesn't really make much difference in steady-state sweepers or many transitional elements, where handling and grip will be the primary variables. Of course the largest and most important variable is the driver, but none of use likes to admit that!

[Splash]

Right, but if the vast majority of these situations are 3300 or higher, then the extra torque can matter greatly. That's why I asked how often you were really that low.

Frankly, if you are faced with courses heavy in steady-state sweepers and transitions, how early the header works won't matter. The other STX cars will eat you alive.

[MNbiker]

Originally Posted by Splash

...Frankly, if you are faced with courses heavy in steady-state sweepers and transitions, how early the header works won't matter. The other STX cars will eat you alive.

You pretty much described our experience on the West course at 2013 Solo Nats.

That's also the reason we're focusing almost exclusively on ProSolo's this year. Pretty much the only place a WRX has a chance to win in STX, and the situation will only get worse as the Twins become fully developed.

[UWMechEngr]

Originally Posted by MNbiker

You pretty much described our experience on the West course at 2013 Solo Nats.

That's also the reason we're focusing almost exclusively on ProSolo's this year. Pretty much the only place a WRX has a chance to win in STX, and the situation will only get worse as the Twins become fully developed.

So, how were the 'kooks at Lincoln?

[gixxer7fiddy]

Everyone that I was with in Lincoln loved them.

[UWMechEngr]

Cash contingency is a big draw too... I mean, not for me, I'm not going to trophy in this pile...

[MNbiker]

Originally Posted by UWMechEngr

So, how were the 'kooks at Lincoln?

The Hankooks worked well at Lincoln. I like the feel of the ZII's better, and they may be a bit faster on the WRX until they overheat, but the Version 2 Kooks still seem to handle heat well - so a lot less difficult to keep in their happy zone.

Not great in the rain, but perfectly acceptable in damp/wet, as long as there wasn't too much standing water.

The car was a handful at Lincoln. I had an alignment problem I unfortunately didn't discover until the drive home that made the Tour runs pretty much a disaster. The car was loose some places, and pushed others (incorrect toe & camber on one rear wheel will do that... )

[UWMechEngr]

Ouch, tough break.

Doing Evo School this weekend, hopefully I can learn to drive on the z2s, since I don't think I've figured them out yet.

[MNbiker]

Originally Posted by UWMechEngr

Doing Evo School this weekend, hopefully I can learn to drive on the z2s, since I don't think I've figured them out yet.

Could be interesting using ZII's for an Evo School. The tires really don't like heat, so they're going to be greasy for your last few runs.

The ZII's reward precision, and don't like a ton of slip angle.

[Splash]

I never thought of myself as a precision-type driver until I spent a season trying to find the "happy place" on Rivals, which doesn't really seem to exist. They don't peak so much as plateau. Coming from Z1s, this was frustrating and I never felt like I got all I could out of them. I went back to Z2s because I don't live where it stays hot enough to keep RS3s happy.

[UWMechEngr]

Phase one was alright, because it was a big class so lots of time between groups. Phase two was a bit more wham bam. Still very helpful.

But now I have a new problem. After taking some cone hits, my entire driver's side fender lining came right off on the way into my apartment. What do? I could get protested for this if I don't replace it, right?

[screechf50]

Yes, you can.

Rockauto had some for my 06 WRX for around 15 bucks each plus shipping. I think the dealer is right around $30, but I don't recall 100%.

[EAghost3]

Hey guys I am thinking about getting RPF1s with RE-11A for my 2011 wrx. Having trouble deciding between 17x9 and 17x8......It looks to me like the 17x9 will look a bit better and have a bit more grip. Is there any reason NOT to go with the 17x9 (would be planning on 255/40/17 tires.

[BeBop86]

Well, if you want to race in STX, you have to use 17x8.

Also, I'd personally go with the Dunlop Z2 over the RE-11A, but both are rated well.

[UWMechEngr]

Originally Posted by EAghost3

Hey guys I am thinking about getting RPF1s with RE-11A for my 2011 wrx. Having trouble deciding between 17x9 and 17x8......It looks to me like the 17x9 will look a bit better and have a bit more grip. Is there any reason NOT to go with the 17x9 (would be planning on 255/40/17 tires.

So...why ask in here?

The 09+ WRXes are in STU, where wheels are unlimited but tires are limited to 245 width. The RE-11s aren't really the best tire you can get for autocrossing right now. The Dunlop Z2 is a great all arounder, if you keep them cool. The new Hankook RS3 V2 might be a wonderchild.

If you're asking from a non-competition standpoint, there's other forums for that. But 255 on 9" work fine.

[UWMechEngr]

So... what course elements are we supposed to be good at? Crow's Landing is almost all transitions and I sucked today. Though I'm willing to chalk that up to never having been on concrete before, and not having the balls to push it the way I should.

[Splash]

Any element that lets you accelerate. For about everything else, you might as well have a Jetta.

[UWMechEngr]

Well, I was the fastest awd car at the Packwood Tour... But I'm fully giving up on this. Car will be for sale soonish, if anyone is looking for an STX/ESP(ASP) project.

[Annihilator817]

What is everyone's thoughts on sending the 2009-2014 WRX to STX?

Personally, Im not even sure it would be the car to have. Its got more power than the 06-07, but no rear LSD and a 4.5" longer wheelbase.

Due to the open front/rear diff, you cant necessarily take advantage of swaybars like the GD's can. What good would that extra power be without being able to apply it?

These cars have no where to go besides stock, errr, street class, and in my experience, the 09+ basically tears itself apart stock in stock trim.

Just curious to hear what people have to say about it before I start writing letters to the STAC.

[14stu]

I think the 09+ WRX would fit in stx, they would be competitive and could give the FRS/brz some healthy competition.

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[BIGSKYWRX]

^ agreed