I am considering adding a larger front sway bar to increase traction on the front tires. I have heard though that adding a larger front bar can promote more understeer, which we all now is a problem in Evolutions to begin with.

I am currently running a Perrin 28mm rear adj. bar with end links as well as FLT-A2s. I am currently aligned to 2.5 negative degrees camber up front, 1.25 negative in the rear and 1/16th total toe out in the front and zeroed in the rear. I am also running Robispeced Enkei NTO3+Ms with 10mm spacers up front and 4s in the rear on Falken RT-615s.

With that all being said, the car handles quite well but, I am always looking to improve upon it. I compete heavily in autocrosses as well as Time Trials and Attacks.

Thanks

 

Swaybars effectively reduce traction on the end they are installed on, so putting one on the front won't necessarily "increase traction" up there. (that'll get the forum junkies fired up, but it's basically the truth) You put one on the back to quicken the weight transfer and reduce traction back there, allowing the car to rotate or oversteer more.

For more front traction, make sure your rear-bar is set as tight as it will go. (inside mount points) You can also soften the front suspension and tighten the rear, along with a myriad of other more complex solutions. (like wider tires/wheels in front, etc)

 

BTW, I've heard that installing a front swaybar is a huge PITA. Consider drilling a second set of holes on the stock front sway bar closer to the inside if you still want to try a stiffer front.

 

Thanks. I was thinking along the same line about a larger front bar actually promoting understeer but, I was told otherwise by a few guys at the last track day that swore I was wrong and they were right.

I have thought about drilling additional holes in the front bar but, the car handles just nice as is, so I figured I'd leave well enough alone

 

We have pretty similar setups, and I see in your reg. that you are running aftermarket wheels, but I gotta recommend some wide wheels if at all possible. I just put some 9.5" wide wheels on mine and now it just snaps into the turns with much less tire flex. (running 265s and they are somewhat stretched) It does make the car "hunt" more if you're driving across grooves or ruts in the pavement, and pulsing/warped rotors are much more prominent since the wider stance gives the tires more leverage on the steering wheel, but the handling response is awesome. (and I've got a Racing Brake big brake kit on the way )

 

I'd dig around a bit more before you decide to or not to try a larger front bar. The STi responds VERY well to a larger front bar. Counter-intuitive I know, but it does keep the car from losing dynamic camber in turns therefore preserving the optimal contact patch of the front tires and increasing grip. I have found after building a couple of competitive cars, there are no absolutes in suspension tuning.

Dave Mac

 

sway bars can reduce grip and the can add grip.

They will only add grip if they help minimize roll and therefore keep the tires contact patch in its sweet spot. So on a car with stock soft suspension they will increase grip.

They, in race car terms, decrease grip (on that end) because as soon as the springs are stiff enough and minimize roll themselves (and keep the contact patches happy) then all the bar does as you stiffen it is reduce grip on that axle because it lifts up on the inside tire (it is more complex than that but that is the general result).

so everyone is right

 

So I guess my initial thoughts were right about the front bar in that with my setup (FTL-A2s and other things) they will just help to reduce grip on the frontend (ie. understeer).

FYI - I am now running Robispec'd NTO3+Ms with a 10mm spacer up front and a 4mm in the rear and man has it made a HUGE improvement in initial turn it. The car just snaps right into the turn and generally stays there. Where before the tires would lose grip and understeer. Unfortunetly I am stuck running no wider that 245s in STU (autocross).

Thats funny about the STi. A few of my competitors have said the exact same thing about adding more front end grip on their STis. Counter inituative

 

Evo8Dad and I were discussing this the other week. I am running in an '03 Evo in SCCA Solo A Stock class, so front bar changes are our only choice for tuning. I want the fattest front bar I can find for two reasons.
1. To keep the front suspension out of the bad parts of the camber curve
2. To get the rear tires closer to, or on, the ground.

We are lifting the rear tire in corners over 6 inches with stock suspension and sticky Kumhos. When the tire comes off the ground, handling becomes non-linear and somewhat unpredictable. Also it kills our ability to put power down off the apex, until the tire touches back down. The car would be killer in A Stock if we can get enough front bar to use all the power.

 

Jon?? Welcome to evom The consenus is that the larger bar would hurt an Evo but help a STi due to the drivetrain being balanced more towards the front on an Evo and more towards the rear on a STi.

My biggest fear in adding the larger bar is promoting more understeer and we all know that the Evo already suffers from that with the stock front bar.

The other alternative is to simply drill a hole closer to the inside of the bar to get a little more stiffness out of the stock bar. That may be an option because then you guys can see if it improves it or just makes things worse.

If you do a search through the DIY section you'll find the write up on how to do it. Its real easy and only takes a 1/2 hour.

Adam

 

Yes, it is Jon. I've always been something of an iconoclast. Busting through conventional wisdom to see what is on the other side makes me giggle.

Playing the '03 cards we've been dealt, we need to control the rear behavior better. We already get crazy, nearly uncontrollable understeer when we accelerate to hard from the apex with the rear tire flying. This makes us slow. So we hope the bigger front bar will allow us to put down power sooner, making us faster overall, even if there is some more steady-state understeer. Your car will respond a bit different since your rear tires isn't sailing over the cones. (Hmmm, maybe we should use that to our advantage, remove the front bar and just get really close to the cones with our front tire and lift the rear tire over the cones like a dog going pee.)

 

After playing at a local track and doing many many laps the rear is the area that needs attention. Not once did the car rotate the way I thought it would, before I went tracking I did a more agressive alignment which right away even on the street the car turned in so much better, maybe thats what you should try first. If I hadnt done the alignment my track day would have been a waste of time.

best of luck on what you decide to do

 

dog peeing

I am assumming you guys have eaked out as much negative camber as the OEM equipment will allow? Are you guys allowed camber plates in A stock? As you are well aware since co-driving with Nate, these cars love as much negative camber as you can give them within reason because there is always the battle of finding something manageable for everyday driving and then something that will perform during race conditions.

FYI - I am runnig -2.5 degrees camber up front and -1.25 negative in the rear with 1/16th total toe out up front and 0 toe in the rear. Brad over at Phoenix did the alignment. The other thing that was a huge help was upgrading to the 9.5 wide wheels. The car turns in like nothing I have every driven. There is virtually no understeer, unless its driver induced

Oh by the way, I am upgrading from the FLTA-2s to Robispec'd KWs (double adjustable with stiffer spring rates) at the end of the year.

See ya Sunday?