What diameter is the stock rear swaybar on the Evo?
The Cusco setups are offered in both 18mm and 23mm, the 18 being 3 way adjustable. I don't want to go too much larger, as my previous car tore the swaybar mounts after increasing the diameter too much.
Also if anyone knows the stiffness % increase on both it would be appreciated.

 

The stock rear bar is 22mm (from my quick measurement after removal).

The rear swaybar mounts are completely different from any other car I have had, and seem much much stronger overall. They have 3 bolts holding them into the sides (2 on th rear side 1 on the front, horizontally) of a frame rail, not just 2 bolted vertically into the frame like most cars. It would be very difficult to tear them out.

I have the Cusco 23mm bar with Perrin endlinks, set to the stiffest setting. Makes for a nicely balanced feel, with much better oversteer characteristics than the stock bar.

 

Do the Perrin endlinks come with the bar?
Where did you get them from?
Thanks for the quick answer!

 

Vivid has the Perrin Endlinks. Or I think you can get them from Perrin directly! Perrin always makes good stuff, plus theyre from Oregon!

 

2Cool,

Did you replace the end links and the sway bar at the same time? Just wondering if there was a noticable improvement from just the end links?
Have you been to a road course with this setup? Like many others I find the handling is brilliant, but if you go into a corner to fast you get nothing but understeer. I would like to get the car to initially oversteer, with the AWD and front weight bias I just cannot get the rear end to hang out there under power. This is my first front/awd car so...

I have ordered a rear sway bar and was considering the end links, I guess I was looking for a better description of "better oversteer characteristics ".

Thanks fo the info,

Eric

 

I too would like to know about how the endlinks and bar behave both separatly as well as together.
Last night at the autocross though, I adjusted the air pressure to 34 psi front and 39 psi rear, and it handled much better. Very neutral with just a tiny bit of oversteer.
getting the sway bar would be a much more desirable solution though.

 

Just to add my 2 cents here:

Specs: The rear bar, as mentioned already, is 22mm; and front is 24mm. The car has 60% of its weight on the front.

Every auto-x I participated I saw the Evos lifting their inside rear wheel. Clear indication that the rear bar is too stiff in 0.9g+ cornering. Thus, increasing the rear bar might transfer some more weight to the rear during turn-in, but unfortunately, because of the 60% weight (~3450 lbs running weight, not curb), it is bound to understeer mid-turn. Lifting the rear inside wheel certainly hurts handling and grip.

I do not think you can reduce front A/R bar either as the side lean is already over 3 degrees. Increasing the front bar would certainly make the understeer worse.

So, the only way to somewhat offset the understeer or come closer to neutral balance is to go to stiffer springs on the rear and stiffen bumb on the fronts during auto-x.

 

That's interesting, I have not had the opportunity to watch an EVO closely from the inside of a corner. Isn't this partly due to a relatively high center of gravity? I use my car as a daily driver/track car, while I would love to do a fully adjustable coil over system, IMO on street tires this car has a fantastic balance of handling/ride comfort.
I was hoping a minor rear sway bar upgrade would give me less understeer. I do tend to agree that springs would be better, so what are the stock spring rates? And then how much should we increase? Can the stock shock handle the increased spring rate? Does any one sell an upgraded rear spring for the EVO, (I think the front stock setup is fine).

I am not ready to spend $1500 or more on a whole new coil over set up, when the stock system is so freakin good, I just want to tweek it a bit.

Thanks for the info.

Best regards,

Eric

 

Eric,

Amazingly, the Evo is the first car that I have seen with such stiff A/R bars for the good or bad of it Lifting of the inside rears on any car is THE indication that the A/R bar is too stiff for near-limit cornering. The Evo has great handling, frankly much better than my expectations. General rule of thumb amongst chassis tuners is that if the weight transfer is beyond 59%/41% towards any end of the car, it is very difficult to manage the dynamic and static weight transfers. Again, Evo just amazes me in this regard. I have not driven an STi, so I cannot comment on that one. However, BMWs are famous for the their 50/50 balance, but some racers still complain that they do not get enough weight on to the back for earlier application of throttle on corner exits.

Any how, to keep it relatively short: I cannot answer your questions as of yet. I am still working on the calculations to figure out the best (for my taste and purposes) spring rates. I am working backwards off suspension frequencies, which is the ultimate determinant of the harshness and road compliance of the ride. I am hoping to have something soon, but not in the immediate future.

Can the stock shocks handle higher spring rates? Normally, a well built shock should handle roughly +/- 40-50 lbs without revalving. I would not worry about it if the springs you choose are in that range. JIC, Eibach, and I think HKS should have rear-only springs for you. Unfortunately, some of this is trial and error as the manufacturers do not publish some critical information for precise tuning of the suspension. On top of my head, I think, going over about 50 lbs on the rears without height changes should be fine. However, you really have to be in tune with the car to notice the difference. Both JIC and TEIN have suspension that are only adjustable in ride height under $1000. You might want to check those out as well. If you can go about 100 to 150 lbs higher on the rears with about 1.5" lower rider height (which also requires adjustments on the fronts then), I suspect that setup should give great results. But... I am yet to test and prove it