2015 WRX auto-x impressions

[Dixie Audacity]

We run a 25mm Perrin rear sway. Would try something bigger if it was available. Still spins the inside front wheel on corner exit.

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[hackney1]

Originally Posted by Kostamojen

What's the general preferred rear swaybar?

Trying a front bar now but I'm not a fan so far, also having fit issues with it (Superpro) and the endlinks cause Superpro put 10mm holes instead of 12mm holes in the bar.

I have Eibach 25mm front, KartBoy links, & happy handling.

[Kostamojen]

Originally Posted by hackney1

I have Eibach 25mm front, KartBoy links, & happy handling.

Tried a front bar, it was terrible. (STI not WRX)

[vlad11591]

Looking to run some swift Spec R springs, with a 255/35/18 on Pilot as4's, and some option labs wheels (18x9.5 +35mm offset)

How much negative camber in the front should I be trying to dial in, as opposed to rear? If I'm trying to reduce understeer, I should be trying to max out negative camber in the front, and add some positive in the rear correct?

without modifications, can I adjust camber slightly? Also, this set up will put me in street modified correct because of the wheel width?

[Kostamojen]

Originally Posted by vlad11591

Looking to run some swift Spec R springs, with a 255/35/18 on Pilot as4's, and some option labs wheels (18x9.5 +35mm offset)

How much negative camber in the front should I be trying to dial in, as opposed to rear? If I'm trying to reduce understeer, I should be trying to max out negative camber in the front, and add some positive in the rear correct?

without modifications, can I adjust camber slightly? Also, this set up will put me in street modified correct because of the wheel width?

Not sure what you are trying to do or what your goals are, but none of those items are good for Autocross.

Yes you would wind up in SM.

[Suba_Roo]

Originally Posted by vlad11591

Looking to run some swift Spec R springs, with a 255/35/18 on Pilot as4's, and some option labs wheels (18x9.5 +35mm offset)

How much negative camber in the front should I be trying to dial in, as opposed to rear? If I'm trying to reduce understeer, I should be trying to max out negative camber in the front, and add some positive in the rear correct?

without modifications, can I adjust camber slightly? Also, this set up will put me in street modified correct because of the wheel width?

Please dont add positive camber in the rear. Not exactly sure on the newer cars but you want about half a degree of negative camber more in the front than in the rear. So if you can get -1.5 in the back, then you want -2 in front. If you can only get -1 in back than -1.5 to maybe -2 in front. Zero toe all around.

It's not about max one or the other it is about having somewhat more camber and therefore more grip in the front. If you max the front and go positive in the back you will be wildly tail happy

[vlad11591]

Originally Posted by Kostamojen

Not sure what you are trying to do or what your goals are, but none of those items are good for Autocross.

Yes you would wind up in SM.

Doing more research it seems like I wouldn't be able to "have the best of both worlds" meaning the desired look for wheel/offset/tire set up and functionality. You'll be sacrificing one or the other.

In order for me to stay in STX, max would be 245/40/18 and 8.5 wheel width. I could go STU and run 255, with the 9.5 wheel width. My offset would still have to be within 7/mm of stock wheels? In that case, i could get by by running spacers, if i wanted that +35/38 offset..... Then i have to spend more money ... blehhhh

Originally Posted by Suba_Roo

Please dont add positive camber in the rear. Not exactly sure on the newer cars but you want about half a degree of negative camber more in the front than in the rear. So if you can get -1.5 in the back, then you want -2 in front. If you can only get -1 in back than -1.5 to maybe -2 in front. Zero toe all around.

It's not about max one or the other it is about having somewhat more camber and therefore more grip in the front. If you max the front and go positive in the back you will be wildly tail happy

thanks... This is more for what I was looking for.

To give a bit more insight... This will also be my dd. I'm assuming I'll probably be around the first specs with the drop. Probably a bit less. It'll be my first event, and i have absolutely no experience. The only reason i might get a new set of tires/wheels is because my OEM tires have low tread. (Dunlop sport maxx) I might just run stock for the first season, or until they're cooked.

[Kostamojen]

Originally Posted by vlad11591

Doing more research it seems like I wouldn't be able to "have the best of both worlds" meaning the desired look for wheel/offset/tire set up and functionality. You'll be sacrificing one or the other.

In order for me to stay in STX, max would be 245/40/18 and 8.5 wheel width. I could go STU and run 255, with the 9.5 wheel width. My offset would still have to be within 7/mm of stock wheels? In that case, i could get by by running spacers, if i wanted that +35/38 offset..... Then i have to spend more money ... blehhhh

You don't have to sacrifice looks if you don't want to, but if you care about "stance" and that kind of thing then yes, you might not be able to care about a "flush" setup because running that kind of setup is less important in Autox than fitting the widest tires you can under your fenders. That means higher offsets, lighter wheels, and fatter tires of course. But I think my "proper" autox setups have looked quite good:

BS prepped Type-RA

STX suspension/brakes/wheels/tires BRZ

FS prepped Chevy SS



As for springs, I've been there and done that with running "just" springs. Either run your stock suspension and stay in stock class, or get coilovers. Don't waste money going on the "in-between" setup and then wind up buying coilovers later anyway. Wheels are the same, buy the wheel size/setup people are running for competitive setups in your class right off the bat instead of buying 2 or 3 sets of wheels trying to figure things out.

If your car is your daily, run TWO sets of wheels/tires. Running the VERY expensive pilot super sports you mention for tires are a total waste for Autox as not only will you wear out good expensive daily driver tires, but you also won't be competitive. Run whatever setup you want for looks (BTW I recommend Firehawk Indy 500's over PSS if you really are concerned about money as they are 95% as good as the PSS but almost half the price) and run a second set for Autox. Swap out the day before the weekend, only takes 30 minutes or less to swap wheels.

[cmiovino]

Can backup the claims above.

Stock suspension for street class or coilovers in touring, period. I'm running STI pink springs on KYBs and it's incredibly hard to be competitive, even with RE-17Rs. I'll be buying a BRZ in the future and plan on going to a solid coilover setup when I modify. No monkeying around.

Also ran RE-71R's as daily tires. Slight toe out in front, so the insides are all worn and will probably fail first. Not to mention the tires themselves are probably heat cycled out at this point, mainly from the daily aspect.

Get a $125 impact gun, extra set of wheels, swap um. I've gotten it down to about 7-10 minutes to do the entire swap each event. Worth it IMO if you daily it at all or if the event if more than 30 minutes away. If you're goofing around with anything other than RE-71Rs or the BFG Rivals, you're putting yourself at a huge disadvantage. There is no compromising on tires. You're either running competitive ones or you aren't competitive.

[Norm Peterson]

Originally Posted by Kostamojen

You don't have to sacrifice looks if you don't want to, but if you care about "stance" and that kind of thing then yes, you might not be able to care about a "flush" setup because running that kind of setup is less important in Autox than fitting the widest tires you can under your fenders. That means higher offsets, lighter wheels, and fatter tires of course. But I think my "proper" autox setups have looked quite good:

For sure.

It's very much a case of "beauty is in the eye of the beholder", where they look just right to you and enthusiasts with similar car activity interests because you know exactly why they look the way they do (and that impressing those who don't know anything about autocross or track day driving isn't part of it). In a way, it's like being privy to "insider knowledge".



I haven't pushed the new WRX past 6 or maybe 7/10ths yet, but I do notice the EPAS. More accurately, what I notice is what it isn't letting me feel.


Norm

[vlad11591]

Thanks for all the helpful insight fellas....

If I want to stay in Street, i'll have to keep my tire size at 245. I have an AP and some shifter upgrades so that will take me out of DS.

I have enkei Kojins, for the winter set up, so I could use those (not super light weight, but better than stock) for now, or just pick up some Enkei RPF's, (18lbs a wheel). As for the tire.... I might go to a couple events on stock and get a feel for everything (non competitive) before I go balls out on some new tires. Indy hawks are dirt cheap, and it doesn't seem like I would compromise too much with going with those tires.

I'm running swift Spec rs with possible LCA's, to adjust camber, so that will also put me out of DS.

[vlad11591]

Update: Went with Enkei TS10's (lightweight 18lbp wheel) 18x9.5 +38 mm offset, wrapped in indyhawk 500's , on Swift spec r springs.

Alignment- Got some SPC front camber plates to get a little more negative camber but basically was able to get -1.5 front and the rear was obviously not able to be adjusted without lower control arms. Sat at about -2.4/-2.2 . AS close to zero toe all around.

with the wheels/suspension I should still be at STH. I know I won't be awfully competitive, but I want to do a couple of runs on this set up to see where I can improve in (the driver).

Then i'll get some coilovers/lca's/end links to adjust suspension/camber a bit

[Wes7143]

Originally Posted by cmiovino

Can backup the claims above.

Also ran RE-71R's as daily tires. Slight toe out in front, so the insides are all worn and will probably fail first. Not to mention the tires themselves are probably heat cycled out at this point, mainly from the daily aspect.

Does your car have camber plates? Last autox I went to, a cool guy showed me a trick he does on his '06 STI. He has his alignment set so that when his camber plates are set to max, he has like -3.5 degrees of camber and a little toe out. But when he needs to drive the car to and from the autox, he slides the camber plates to a marked position near the middle where he has 0 camber and 0 toe. Saves his tires from wearing on the street. I'm not sure if the newer Imprezas have the steering on the same side of the knuckle as the GD tho. It would have to for this trick to work.

[LehmanZ06]

I'm thinking of running 275 bfg 1.5 on either the front or all around.

Anybody try 275/35 18 on front with the 245/40/18 in back ?

I've got two of each so I was thinking of trying this.

Any idea if the .1 diameter difference will beat the crap out of the diffs ?

This is on a 2018 WRX performance package.

Thanks !

[yellowblur]

If you can get the 275's on 8.5 rims, I'd say go for it. The 275 front / 245 rear might be a better choice for the rotation necessary for AX. It has been my experience than whenever adding overall general grip to a WRX (i.e. better tires or wider tires), the rear tends to get more of it making the car unwilling to turn. I think that's why fast DS WRX's run massive rear sway bars. I don't think a rear bar is available to balance a WRX with (4) 275's, but there is only one way to find out. The Street rules don't allow the lateral cross bracing of the rear sway mounts which I think might be necessary with a 24mm+ bar on full stiff.

[z06fun]

Originally Posted by LehmanZ06

I'm thinking of running 275 bfg 1.5 on either the front or all around.

Anybody try 275/35 18 on front with the 245/40/18 in back ?

I've got two of each so I was thinking of trying this.

Any idea if the .1 diameter difference will beat the crap out of the diffs ?

This is on a 2018 WRX performance package.

Thanks !

I ran this exact setup back when I had my 2015. Back then it was only on 8" wheels, but still worked really well. The diff is viscous so it won't care about that small diameter difference. I would image this would work even better with the 8.5" wheel now. Besides helping reduce the overall understeer, the side benefit of the stagger is that the tires heat up more evenly so the balance is more consistent through out a run.

Anyone know if Dennis had issues in the Pro finale? Maybe he will give us an update at some point.

[JasonS82]

Going to be picking up some Fortune Auto 510's for the WRX and looking for advise on spring rates. Current set-up is 255/40/17, -2.4 up front and zero toe all around and a stage 1 tune from MAPerformance, and hawk pads. I race in a local club with pretty open rules for the "modified" class. Plan is to get the 510's with swift spring 8k fr and 9k rear. Any opinions?

[gtsilver944]

Spring rates are very much personal preference. Many seem to prefer a rear bias (RCE for example runs 9/10k on their Tarmacs). Despite coming from a RWD background, I'm not terribly keen on oversteer in the WRX as the rear is so light. Increasing front grip is better than directly inducing oversteer, IMO. I'm happy with the 9k/7k my Ohlins came with - I get handling neutral via adjustable sways, relatively less rear camber than front, and tire pressure.

Besides the basic high temp brake fluid and bleed - consider adding brake ducts to the front. Search for the Porsche GT3 ducts that are popular with the BRZ/FRS crowd. Cheap, effective, and easy install. The back of the WRX dust shields are already slotted for airflow to the center. I've had mine on year round for several years in New England without issue.

[Norm Peterson]

Originally Posted by gtsilver944

Spring rates are very much personal preference. Many seem to prefer a rear bias (RCE for example runs 9/10k on their Tarmacs). Despite coming from a RWD background, I'm not terribly keen on oversteer in the WRX as the rear is so light. Increasing front grip is better than directly inducing oversteer ...

This.

In general, fix front grip first before trying to fool the car into thinking it's neutral or oversteerish by throwing away rear grip.


Norm

[Thorium06]

Originally Posted by Norm Peterson

This.

In general, fix front grip first before trying to fool the car into thinking it's neutral or oversteerish by throwing away rear grip.


Norm

In general yes, but you need to do some math. Even starting with just the motion ratios front to rear, you need a stiffer spring in the rear than the front to even be neutral.

[Norm Peterson]

Originally Posted by Thorium06

In general yes, but you need to do some math. Even starting with just the motion ratios front to rear, you need a stiffer spring in the rear than the front to even be neutral.

Let's just say I'm aware that many other things are involved (I've run through the math in developing a TLLTD spreadsheet app that even considers chassis torsional stiffness and tire spring rates).

You still want to fix the 'weak' end as much as possible first.


Norm

[gtsilver944]

Yeah, I did the math before installing the coilovers and thought I would need stiffer springs in the rear (something like 9k/10k or 8k/9k) with the constant for the motion ratios being about 0.96 front and 0.67 rear, IIRC. But - the grip level is excellent and I can't even get close to 10/10th's on the street.

It's art as much as science (coming from someone with a hard science background). To the OP, 8k/9k will work. Depends on exactly what you are after. If you don't hit it off the bat, there's are multiple ways to dial it in to your liking.

[subaru_gc8]

Originally Posted by yellowblur

If you can get the 275's on 8.5 rims, I'd say go for it. The 275 front / 245 rear might be a better choice for the rotation necessary for AX. It has been my experience than whenever adding overall general grip to a WRX (i.e. better tires or wider tires), the rear tends to get more of it making the car unwilling to turn. I think that's why fast DS WRX's run massive rear sway bars. I don't think a rear bar is available to balance a WRX with (4) 275's, but there is only one way to find out. The Street rules don't allow the lateral cross bracing of the rear sway mounts which I think might be necessary with a 24mm+ bar on full stiff.

I think those are kinda big for a 8.5, youre probably going to get alot of slop

[Norm Peterson]

Originally Posted by subaru_gc8

I think those are kinda big for a 8.5, youre probably going to get alot of slop

Autocross is a rather unique case, particularly in the Street Category classes where wheel width is limited (to OE) but tire size is not.

Apparently if you can stay on top of the compromised response and precision you can gain more from increased peak grip than the compromises cost you. Fortunately, the Tire & Rim Association rim width guidelines are not inside-you-pass/outside-you-fail in nature.

Lots of autocross tire to wheel fitments are outside T&RA guidelines, but reasonably do-able because autocross runs are of such short duration and because tire life under autocross conditions is pretty short. That makes outside-T&RA-guideline fitments OK only for autocross; they're still a poor idea for any other driving.


Norm

[F1SC]

Has anyone driven a 15+ WRX and a 15+ STI on track/autocross - i'm keen to understand just how much the DCDD/Diffs on the STi make to the amateur track day entrant.