[ESmooth]

So Im still on T2s, 27F, 24R bars, ALK, etc etc (see sig) but I recently upped my rear spring rates from 400lb/in to 500lb/in. I wouldnt recommend this setup to everyone since my car is unique in that its fairly light at 3050 pounds with fuel and no driver with a gutted trunk and back seat and no bumper beams. At my next to last track event (Cal Speedway Roval), it became fairly evident that I had either too much rear grip or not enough front (or a combination of both) since I couldnt get the rear end to come around no matter what I did, attacking the curbs, scandinavian flick, etc. Myles and I went over a few options like a bigger rear bar, going up or down on the front bar and what I finally ended up doing which was going with stiffer rear springs for a final 500F/500R setup.

This past weekend I did a track day at Buttonwillow 13CW which is used for a lot of time attack events here in SoCal. Since I plan to do some time attack events later this year, I wanted to get a good benchmark of how the car was working not only with the new setup, but also to compare it against times that have been set at past time attack events. I ran on both street tires and race tires and the results were fantastic. The car felt the best it ever has on track and there's still some fine tuning to be done. On street tires (245-40/17 REO1Rs) I ran a 2:06 flat with a passenger which would have gotten me around 5th or 6th place in AWD Street in the most recent Redline Time Attack. With the front bar on soft and the rear bar on stiff, the car was almost perfectly neutral which can be seen in the slide/drift I did through the long sweeper. I entered the corner a little hot and the back end started to come around but slowly and predictably. With some countersteer and throttle modulation I was able to hold the slide and carry it all the way through the corner which I have never been able to do in my car before. I have footage of it in the video which I will link to below. After looking at my line and videos, Im sure I could shave another .5 to a full second on street tires for an even better finish, this with less than 300WHP which is a lot less than the other cars that ran.

On my race tires (Hoosier GrandAm Cup Endurance Slicks, similar grip to most R-comps) I ran a 2:02.6 which would have been around 6th or 7th in AWD Mod in the same event. I did feel like I still had some understeer with the race tires which may have been from the suspension rolling too much. I didnt run any more that day, but I think going up to full stiff on the front bar and adjusting tire pressure would have solved it for the most part. Either way, the car was great and really capable with the new settings. Now I just have to work on adding about 50 or so more WHP and Ill be ready to run with the big boys and be a giant killer! I plan to keep the stock turbo but do a race fuel map, 750 injectors and a fuel pump and maybe even an EWG setup for better boost control which should get me just over 300WHP on the Harman Motive Mustang Dyno (which reads about 13% lower than most dynojets). Right now the car is doing about 260 wheel on the mustang, 290 on the old dynojet. If that doesnt do it, Ill probably have to add on an APS SR40, DARN!

Heres how the car is looking with my Time Attack theme:




And here's a link to the video from the event. Be sure to check out the slide around 2:40

YouTube - 06 STi Buttonwillow 13CW 5-31-08

[Chinky_Sti]

wow you car is great.. nice sliding in the vid.. is your car also a dd?

[ESmooth]

no, I picked up 98 Civic EX 5 speed for daily driving. No matter how hard I drive it I never get worse than 27MPG

[token-negro]

So whats now 500? Front or Rear?

[ESmooth]

500 front and rear up from 500F, 400R

[antonch]

Car look nice. Any links to pics and stuff?

What alignment settings are you running?

Originally Posted by ESmooth

no, I picked up 98 Civic EX 5 speed for daily driving. No matter how hard I drive it I never get worse than 27MPG

Probably has something to do with the fact that no matter how hard you stomp on it, doesn't put out much more than 100hp

[ESmooth]

We did -3.2 front, -1.5 rear zero toe all around with a good 50-50 corner balance. 3/4 turn from stiff front rebound, 1 turn out compression, .5 turn out rear rebound, 1 turn out compression.

Here are some more pics:






Thats pretty much the interesting stuff, everything else is pretty basic or seen before elsewhere.

[SD 05 STi]

Wow man, great driving in that vid. I too was out there that day, but running in the green group. I remember your car quite well.

I still have a lot to learn on that track, so your video will be a good learning tool Best time I pulled out that day was a 2:09.072 with RE01Rs.

What tire pressures are you running on the RE01R?

[stretch]

The car looks very fast, but what made you go with firmer rear springs instead of a firmer rear sway bar? I think that is the proper way to do things. A 500lb/in rear springs sets the spring frequencies pretty stinkin' high, which in theory isn't the right thing to do. I think I understand why folks find this is necessary in practice, though, and it's an easy fix.

I think the rear sway bars aren't have the proper effect for many users because they are connected to the rear wheels through very soft bushings in the lateral links. This means the rear sway bar doesn't provide resistance immediately whereas the rear spring does, necessitating that folks run firm rear springs to compensate for a sway bar that just isn't working.

Try replacing your rear lateral link bushings with Group-N or poly parts, if you're interested, and report back. And, while it might not matter now since you already have the springs, you could try going back to 400lb/in springs but going up to a Racecomp 25mm rear sway bar.

The advantage to the softer spring approach will be mostly limited to imperfect surfaces or quick elevation changes, so any advantage would be slight on a reasonably smooth track. Still, an improvement is an improvement. Your car already looks really fast (very) on that track. Great driving, too! (Your times are too, any members here able to beat them?)

[MGizzle]

I don't understand why you would do either stiffer rear bar or stiffer springs. You are loosing grip with booth options. Why not go softer springs in front or softer bar in front. Quick check would be to take off the ARB links completely and zip tie your ARB. Run a few circles on a lot or something and see if the car plows worst or not. Now, with the STi completely taking off the front ARB might be bad but with a softer bar setting it would be better.

I hate giving up grip for balance. It is the easy way out.

[ESmooth]

Good points guys and I did think about them all. The simple answer is that with my position in the aftermarket industry and who I work with regularly, the springs ended up being free so I decided to give them a shot. I do my own alignments and corner balancing as well so it made the most sense. I eventually plan to go with new lateral links and change out the rear bushings but that would have meant ordering and installing parts which I didnt really have time to look into before the event.

As far as losing rear grip, thats what I needed to do since no matter what I did it wouldnt break loose. Lift off mid corner, pounding over curbs, DCCD set to rear with judicious throttle, nothing would make it come around. I even had another fast driver try it out and he felt the same way. The car has lots of front grip so getting more will probably be tough so the easiest way to free up the back end was to stiffen it up. You also have to remember that the rear of my car is much much lighter than stock so it wont react the same way. Just by removing the rear bumper beam I took about 35 pounds off the extreme end of the car which made a huge difference in ride quality and the way the suspension felt. More front camber would probably help as would more rear bar, maybe even narrowing the rear track or widening the front. Either way, the springs did exactly what I wanted them to do and with the way the car is currently set up, Im really happy with it. As I address the bushings, lateral links and trailing arms, the springs and bars may need to change but thats all part of the fun.

[ESmooth]

Oh and stretch, MXPOP is much faster than me at BW with an AWD street class record in the 1:56s. Granted he has 500+ WHP and seemingly no fear which makes a bit of a difference in lap times on a fast track. Weve been working together on setup and lines and are hoping we both get better becuase of it, not only in our STis, but in his spec Miata also which is a really good learning tool. I swear I have hadmore fun in that car than Ive ever had in the STi up until this past event.

[stretch]

I didn't think MXPOP was human, so his time doesn't count. I've seen his vids- crazy.

No fear > all.

In regards to what MGizzle said, he's suggesting that you could increase the overall grip of the car by softening it overall. Going stiffer in the rear will change the roll resistance bias similarly to how going softer in the front will, and he's suggesting that you should have done the latter to get the handling bias you want AND make higher overall grip. Especially with the lost weight in the rear, you shouldn't need as much spring in the rear.

What makes you think front-end grip is great? I mean, the problem here is that everything is relative to an unknown potential. The feeling of immediate turn-in associated with a stiff front suspension does not necessarily mean great peak grip. After all, your installing firmer rear springs should have improved front grip over what you used to think was already great. This goes back to what MGizzle was suggesting in that the stiffer rear springs might get front grip where you want it relative to your rear grip, but it might not get your front and rear grip closer, overall, to their peak potential. Know what I (he) means?

The downside to being softer overall is that you'll get some vertical roll center migration in turns, which can lead to the car not settling in turns. You can alleviate this a small amount with the Whiteline roll center adjuster or by not lowering the car too much. On the other hand, stiff suspensions are usually less predictable, so which is worse? That's for you to decide. Even if you went a little softer, I don't believe loss of camber would be a major issue. The point is that softer won't necessarily be better, nor will stiffer, but it's important to know what behaviors are caused by each so they can be addressed instead of covered up. There's definately a stiffer = better mentality on this forum, but I think stiffness should be more of a last resort.

Either way, if I had access to free springs, I'd of probably done the same things, just as an experiment. But now that you know you like the change in handling bias, you might consider- time and budget permitting- finding an alternate way to get the same handling bias.

[ESmooth]

Good points, and I do have the roll center kit on the car now with only a mild drop. As things progress, I will be looking more into some of the finer details, but for now its more or of a brute force approach to get me in the ballpark. Concerning the stiffness, with the hoosiers, I feel that I need the relatively high spring rates due to the grip they offer along with the good sized bars. Ive run on track with 400/350 springs and 500/400 with some different sway bar setups including the WL 27/24 and it just seemed to roll too much without the higher rates.The car is suprisingly comfortable driving around town, even with the track shock settings (a lot can be attributed to the sparcos though) and on bumpier tracks like buttonwillow, I never get the feeling that Im losing grip or bouncing over rough patches. I feel like Ive been driving around a less than perfect setup for a while and have still been quick so its been really rewarding to get the car to feel the way I think it should

[ESmooth]

Originally Posted by SD 05 STi

Wow man, great driving in that vid. I too was out there that day, but running in the green group. I remember your car quite well.

I still have a lot to learn on that track, so your video will be a good learning tool Best time I pulled out that day was a 2:09.072 with RE01Rs.

What tire pressures are you running on the RE01R?

Not a bad time at all! Feel free to say Hi next time youre out there. Im usually instructing and am more than happy to ride along or give rides and work on the line. I was running the tires around 40 hot all the way around, that goes for the RE01Rs and the Hoosiers.