If you want to switch off, Id go to -3.5* up front. but, yes your toe will greatly change. you will have lots of toe-in, and the driving feel and handling will suffer. Switching is best, but you would have to set toe every event.

 

I just set mine to -3* all the time

 

I would say have -3deg. of camber and zero toe and leave it, and just get another set of cheap race wheels with your tire of choice. I'm not sure about other people, but when I manage to get an alignment just right, the last thing I want to do is keep messing, even if it's to keep it more "tire friendly". As long as you have some high-treadwear all-season to run daily, you'll be fine.

A buddy of mine runs -3 to -3.5 camber in the front of his Subaru daily (350+ miles a week daily) on some Sumitomo all-seasons. They have about 20k+ miles on them and they are still have another 20k or so left in them. It's all about the zero toe.

 

True about tire wear.


Unfortunately for tire wear, having 1/32 to 1/16th of an inch front toe out is worlds better for handling feel.

 

There's several ways to skin this cat...

To make a near stock "plow buggy" car understeer less I tend to "up" the front tire pressure a LOT (stiffen the tire carcass, reducing tire rollover) and lower the rear pressures (lowering rear grip to a degree) to help the car rotate while still maximizing front grip - the one thing that's most needed on "pushy" cars. I've run wacky tire pressure set-ups on badly handling Stock cars (esp. those w/o a big front bar, good shocks, best alignment, etc) with as much as 50 psi front, 25 psi rear. This extreme "front pressure bias" trick tends to really only work on very soft, screwed up, hopelessly plowing cars.

I almost never share our tire pressure numbers because I don't feel there's a magic, perfect tire pressure for any brand or set-up or even course - we often tweak tire pressures at each event to suit the handling feel (transient response + turn in), visible scrub, pyrometer readings, and data logging of that course, that day. I would agree that certain tires (RE01R) need a lot more pressure than others (AD07) due to significant differences in tire carcass construction/stiffness.

Sorry, that was a sort of generic alignment guide we use for lots of cars. AWD and FWD with a lot of front weight bias, cars that all tend to plow in stock form, probably need more tricks to REMOVE REAR GRIP to allow the cars to rotate. I'm not a huge fan of personally racing in cars with extremely compromised setups (that most Stock classes tend to be limited to), so I admit to not knowing the precise best alignments for AStock EVOs.

There's also the trap of "making the car slower to make it feel better". I've tested with cars that handled perfectly neutral, but were still slow in class and posted low grip numbers. Big bars on a car can make for a crisp turn in, but too much of a good thing can mean a loss of overall grip. Just because a car "feels" right doesn't mean its as fast as it could be. Sometimes, due to class rules or chassis limitations, a setup that has some understeer is still the fastest setup. Any time you are limiting grip on purpose you have to make sure that the car is faster for the effort... and doesn't just "feel faster".

After autocrossing the EVO X with the stock suspension I was amazed at how badly this car plowed, pitched, rolled, dove and responded sluggishly in stock form. We get spoiled racing in prepped ST or SP or Prepared cars most of the time that its always shocking when I get into a totally unprepped Stock car. (shudder) The before/after handling differences in the other two "Stock" prepped cars we added new AST shocks to just this week (EStock Miata and FStock Mustang) were very dramatic. That's two more Stock class racers turning to the Dark Side of Street Touring - and the cars feel so much better for the effort.

 

hey man, i was going through some of the same problems you were having this last autoX season. i am by no means a suspension or brake expert, but i will tell you what helped me the most. seat time. and more importantly than that, get someone to ride passenger with you. that way the more experienced drivers can help you with throttle input and braking techniques along with stearing and getting the car to rotate. that was the single biggest improvement that i saw. aside from that i too will be looking into getting a RSB for the spring season...

also consider a harness, having one keeps you planted in your seat and lets you really focus on driving rather than sliding around in the car. gl my man enjoy the car

 

Dang lot of info. Thanks to all you guys who contributed.
Yea, I think a lot of it was that I needed to get adjusted and used to the power (near stock evo to a 370whp 360wtq monster). Once I got over that things went a lot smoother.
+1 about the harness.. I bruised my left knee holding my body against the door lol

 

While that is completely backwards to conventional wisdom, I can see having to do it if you're rolling the front tires badly. I raced mine on the stock Advans for about half a season and never really had too many problems with terminal understeer. Once I went to the R-compounds, I was neck and neck with a guy in a GXP for first in my region at most events. Having to go do it again, I would have run more pressure in the rears and kept adding rear toe out until I got the rotation I wanted on turn-in.

Of course, I ended up co-driving the GXP, which is a car that has no compromises in stock form. Going from the Evo to that was like night and day - I was at least a second faster in my very first event. If you can't get your hands on a GXP, try to co-drive a Miata to drive a car that behaves the way a car should.

 

i know a lot of ppl have strong and mixed opinions about harnesses to say the least. but without getting into a competition or an argument about them, from personal experience i have noticed that i am able to focus way more on driving, proper braking and accelerating, driving line etc and ended up decreasing lap times significantly. went with a schroth harness after loads of research on this forum. i cant speak highly enough about matt and the guys at HMS motorsports, you should look them up and give them a call if your going to be racing more in the spring. gl hope all this info helps...

 

Hmm.... not trying to be a jerk, but what I wrote is not completely backwards from conventional wisdom. Increasing front tire pressure is the textbook cure for understeer via tire pressure changes - this is from textbooks, twenty years of racing and testing, talking to tire engineers, etc. Did I mis-read what you meant? This is not a debatable thing or an opinion - one of us here is just... misinformed.

Really? I... don't know how to respond to that, either. These cars do understeer, dramatically, in bone stock form - we've proven this with many miles on a road course as well as the autocross track, with multiple drivers. I know what the magazine hacks say about these cars, but most of them couldn't drive their way out of a paper bag, and are paid for favorable opinions. We maxed out the front camber to negative and ran some front toe out, and it was still a big plow buggy - as are most cars in stock form this side of a Lotus Exige.


Cars with this much bodyroll rarely have textbook perfect handling

I don't know you or how hard you push the car, and I truly mean no disrespect, but usually when I see someone that defends the neutral handling of a bone stock sports sedan at an actual autocross or track event, they are under-pushing the car. Honestly, about 80% of the people at any given autocross event or track day are under-driving their cars, and in doing so, they keep the car from getting into ugly handling areas (and don't approach the handling limits or potential of their cars). These folks are rolling around at 8/10ths and just having a good time - nothing wrong with that. Again I don't know you or your level of experience, National competitiveness, etc., its hard to tell this from an internet forum post, but I assure you - the EVO in stock form understeers like a pig when pushed to 10/10ths.


(click to see video of data logging of 2 drivers in the same EVO X)

We have the data logging to prove how hard we have pushed our (currently) stock EVO X in base form (other than the performance alignment and our 245mm Dunlop Star Specs). It pulled 1.02g lateral on an asphalt autocross course, even with that hideous amount of dive/roll/squat. And on the road course, where you can push it for longer in smoother corners, it made 1.10g lateral, tires squealing the whole way. Two weekends of laptimes at Eagles Canyon Raceway, with many laps at 2:11. That's not rolling around at 8/10ths. We wanted to get an accurate baseline for comparison with future suspension set-ups.

There are lots of tricks you can perform in SCCA Stock class to combat this (big front bar, shocks, alignment, etc) but its there to begin with, and probably still there when prepped to the limit of the rules (in its fastest form). When you have ~60% of the weight over the front wheels, and the car has braking, turning and acceleration going on through those wheels, a slightly pushy setup is usually still fastest. If you have a car like that oversteering, its probably sacrificing grip and speed to do so. See that happen all the time.

Adding rear tire pressure will increase rear grip, up to a point, then when you have the carcass so stiff that the tread surface starts to balloon the grip will fall off dramatically. I've seen a handful of people use this trick to reduce grip, but it usually comes with other, negative side effects.

 

Everyone I know uses this method. I thought it was textbook. The theory behind it is that the sidewalls of the tire are a component of the total spring rate of the suspension. More pressure stiffens the tire and adds to the total effective spring rate. I know on the GXP I drive we run 36F 34R to make sure the rear is a little more stable than the front. We forgot to reset it once after rotating the tires and the car was an oversteering ***** until we figured it out.

Now, you can be on the other end of the pressure curve, where less pressure = less grip due to not having enough air in the tire and rolling over onto the sidewall. A lot of FWD understeer monsters have this issue in stock form. You end up having to run 50 lbs of air to not roll the tire over.


I understand the body roll issue:



And I know how to push a car to 10/10ths. I've only been driving for three seasons, but this year I was 1st in AS at the Atlanta Pro, 2nd at the DC Pro, Devens Tour, and Atlanta Tour, and managed to snag the last trophy spot at Nationals. (All not driving an Evo - more on that later).

When I was racing my Evo it was actually pretty quick, and as long as you treated the car right, it wasn't all that pushy. If you did the wrong thing behind the wheel it would understeer into the weeds, but if you entered the turn the right way you could get by with only a little mid-corner push. That being said, it wasn't Nationals fast. The GXP I'm co-driving now absolutely blows the Evo out of the water in stock form. Check out the last few posts in the Stock setup sticky for a more detailed explanation.

I'll agree the Evo understeers in stock form, I just didn't find that it was as bad as what you described.

 

What's wrong with running the same psi all around?
Pretty soon here I'm gonna be set up with gtworx springs, bilstein hd's, whiteline front and rear sway bars, whiteline rc kit, bumpsteer kit, front control arms and rear trailing arm bushings
Anything else I need to get my handling spot on?? (besides an alignment)

 

I used to run the same pressure in all four tires and it drove pretty well. I think that's a good starting point. From there you can dial in the car with tire pressure.

I used to start at 40/40 on the stock tires. If the car is loose, take some pressure out of the rear. If it's tight, take some pressure out of the front.

 

Nothing is "wrong" with running the pressures wherever they need to be to minimize tire scrub/carcass deformation. There is no magic bullet setting for every car/driver/suspension combo/tire model.

First, you should get your car aligned now if you plan on racing it before you get your lowering springs and such. Get the maximum front negative camber you can achieve. Get camber plates for the front if you can afford it - it helps achieve more static negative camber which increases front grip more than any other single mod (well, except for R compound tires!).

Run the front toe at around 1/8" total toe out to promote turn-in. The rear... meh, its not doing much on a car with 60% of the weight on the front tires so its not as critical. You're going to always want to run a "front tire pressure bias" (more pressure in the front) on a front heavy car, misapplied theories be damned, as this prevents the overworked front tires from destroying themselves doing a lion's share of the turning, braking and accelerating on these AWD cars. I'd start at around 40 psi in front and check for edge scrub after each run, possibly adding more pressure until you've got a real suspension under the thing. On some stock plowbuggies with crappy tires I've run as much as 50 psi in the front to get them to understeer less. Once you have a no compromise autocross tuned suspension on the car you might get the car to maximize front grip with less - maybe 30-35 psi, depending on the tire.


AST equipped EVO 9 at a Vorshlag Test-N-Tune practice event

The rear tire pressures really don't matter as much, but I'd start with 30-35 psi. Again, the rears aren't doing nearly as much work as the fronts on front-biased AWD cars - heck, sometimes they aren't even on the ground. I will stick by my statement from 2 decades of autocrossing and designing suspension systems for a living: run less rear tire pressure to help a front heavy, understeering car to rotate. This is of course a Band Aid for a better roll/suspension control with stiffer spring rates, swaybars, etc. Once you have sufficient rates and adjustable camber, shocks, bars, etc., you can quit using tire pressures as the only crutch for tuning the handling balance. But don't take my word for it - go out and test, test, test. Do 25-30 events and 3-4 day long practice events every year and you'll make your own well informed decisions.

Cheers,

 

Hmm I think with my set up Ill be runnin around -1.8 deg in the front and -1.5 in the rear with zero toe as to not compromise tire wear.. it is my dd after all =]