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Old 06-21-2009, 10:40 AM   #1
gr8r rex
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Default Car Setup Help

Ok, I believe this will be the right area since I have some questions and it all pertains to setting my car up for autocross. I was originally trying to work at getting it for track days, but realized price is just way too expensive and I can have a TON of fun every other weekend racing this way!

Now I am in SM because of my upgraded turbo. I like the power and I want to stay in SM and not go back to the stock although I know I`m not close to really competitive in my class. This past event I was running about 1.2 seconds slower then the fastest car in SM so I`m not too far off for local and I know a lot of that is driver because my one buddy was co-driving my car and he had one run that was only .2 seconds slower than the fastest SM car but he hit a cone so I beat him still. Well I`ll give a quick rundown of my cars mods.

Power:
-VF39
-Straight Pipe (one resonator)
-Catless uppipe
-STI intercooler
-550CC injectors
-Open Sourced

Suspension:
-Koni Shocks
-Ground Control Coilover Conversion with 450F, 400R lb springs
-Whiteline adjustable swaybars 27F,24R both on full stiff
-Koni shock extenders for the front (I forgot their real name)
-Kartboy Endlinks F/R
-Group-N Rear Tophats (thanks Buttdyno!)
-PDE Front Camber Plates
-Rear Camber Bolts
-Fender Braces
-Whiteline ALK
-Steering rack bushings
-Rideheight is about 13 3/4" all around

Alignment:
-2.6 degrees FD/2.6 degress FP
-1.6 degrees RD/1.7 degrees RP
-0.00 toe all around

Wheels/Tires:
-17x8.5 SSR Comps
- 255/40/17 Kuhmo XS (I know I am still learning which is why no R-Comps yet)
- Pressures: 36F/44R


So I have three problems, rotation, response and a clunk. First off, I am not rotating right still. I am running much higher pressures in the rear to help me with some rotation and it actually is starting to a little but I think I need to bump up my rear spring rates to 500lb anyways which should help a lot with rotation. If I bump with spring rates, what should I do with swaybars, should I use less or what?

Second big problem I have is response with my turbo. It just doesn`t spool too well which was making me loose pretty big times with my car. I`m thinking headers/EWG and some more bolt ons with a new tune should help a lot? What else?

I am also thinking that motor/tranny/rear-end bushings could help with response a little and get rid of some of that slop as I like a really right car.

My last problem is a clunk. At first I thought it was my struts bottoming out or something but at closer look I am pretty confident that is not true. I think it might be the swaybar hitting or something like that? It is a loud metal on metal and it happens in straight line and corners with bumps. It happens under a loud or just driving.

Thanks ahead of time. I am mainly out for just having fun which I have been having A TON OF IT bashing some cones. BUT I have a competitive side and I want more power! Any other things you guys suggest?

Oh, and a picture for the fun of it:
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Old 06-21-2009, 10:55 PM   #2
JhnBrackett
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Don't have any recommendations, just subscribing for the answer. You've got a lot of similar mods & I'm hoping to start some AutoX this fall.
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Old 06-21-2009, 11:51 PM   #3
Splash
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Things I would change:

Stiffer springs - both ends, rear stiffer than front.
bigger rear bar
smaller front bar
more negative camber in the front
change out the ALK for stock brackets with KCA375 offset bushings (you DO want to be legal for SM, right?)

Things I would add:

rear lateral links or bushings/bearings in what you have.
trailing link bushings
outrigger and diff mount bushings
engine/tranny mounts
plated 1.5-way rear diff
either a helical or a 1.0-way plated front diff

When you get wheels/tires, choose between:
15x10 and 275/35-15 Hoosiers
18x10 and 285/30-18 Hoosiers

The top RPM you see in 2nd will help decide this for you. Both are shorter than what you have now, which should also help the spool issue.

Related to that, you will eventually need a tranny, I recommend a PPG gearset in a '04-'05 5-spd tranny. That should last a lot longer than a stock '02 box. Their gearing choices will dictate your tire size choice as well.

Lastly, you can always build up a 8500 rpm 2.0 longblock to better fit the boost profile of the bigger turbos, or use the WRX heads on a 8000 rpm 2.5L shortblock and go for a ARMS 7760.
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Old 06-22-2009, 12:54 AM   #4
gr8r rex
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Quote:
Originally Posted by Splash View Post
Things I would change:

Stiffer springs - both ends, rear stiffer than front.
bigger rear bar
smaller front bar
more negative camber in the front
change out the ALK for stock brackets with KCA375 offset bushings (you DO want to be legal for SM, right?)

Things I would add:

rear lateral links or bushings/bearings in what you have.
trailing link bushings
outrigger and diff mount bushings
engine/tranny mounts
plated 1.5-way rear diff
either a helical or a 1.0-way plated front diff

When you get wheels/tires, choose between:
15x10 and 275/35-15 Hoosiers
18x10 and 285/30-18 Hoosiers

The top RPM you see in 2nd will help decide this for you. Both are shorter than what you have now, which should also help the spool issue.

Related to that, you will eventually need a tranny, I recommend a PPG gearset in a '04-'05 5-spd tranny. That should last a lot longer than a stock '02 box. Their gearing choices will dictate your tire size choice as well.

Lastly, you can always build up a 8500 rpm 2.0 longblock to better fit the boost profile of the bigger turbos, or use the WRX heads on a 8000 rpm 2.5L shortblock and go for a ARMS 7760.
Ya, first off, thanks for the great reply! Second, with tranny, I already have a 05 wrx box in my car. And I am planning on eventually doing a full drivetrain (diffs/tranny) down the road! I am mainly looking for how to help this power until I do a built motor/turbo after the tranny/drivetrain stuff is all done!

I am going to be getting 500lb rear springs, I put the rear swaybar on full stiff and front swaybar on as soft as it will go and I will see the difference there. You think more negative camber upfront? How much? All the bushings are on my soon to do list (diff, outrigger, trailing links, lateral links, engine, tranny) but I want to get the other main stuff done first as those are a smaller effect and something i can do little by little!

Thankyou for pointing out the ALK, I didn`t even realize or think about that until you mentioned that and I reread the autoX thread!
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Old 06-22-2009, 02:27 AM   #5
Splash
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I run my STi in STU and I run 600/500 springs and COBB bars.

The BSP car my GC/Konis came from ran 1050/800 springs and no bars, just as a point of reference. If I ran BSP, I'd likely still use a front bar, but only to reduce the front spring rate a bit. Any front wheel lift, and I'd likely put it back.

Both cars have (had) stocks diffs, which helps explain the front spring bias. Most STX WRX's run stiffer out back on springs and bars.

FWIW, Both, Daddio's SM winning EVO, and Hoops's SM winning EVO had (have) a FP EVOGreen turbo and they use 2.0L engines too. I realize their exhaust path is shorter, but I can't tell you why spool would be that bad with a VF39 on a 2.0L Subaru engine. That turbo is WAY too tiny for a 2.5L, but I'm stuck with mine.

I run -3.7 front camber and -1.9 rear camber right now, and my tire temps are pretty even across the face, as long as I get some one to measure it right when I come off course. If I measure it in my grid spot, the insides are a bit warmer. You'd be surprised how fast temps equalize. I used to run -3.0, and that works, but I still warmed the outsides a bit too much for me. -2.6 would likely roast the outsides and grip significantly less. I also try to get as much as I can via the camber bolt, then get the rest with the plates. It cuts down on the included angle mucking with your camber as you turn the wheel. Also, the wider the tire, the more precise the camber needs to be.

R-tires are a game-changer and any setup work you do now will likely need re-done once you're on them. Just go into it knowing that.
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Old 06-22-2009, 08:13 AM   #6
gr8r rex
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^Thanks! Well looks like I`m going to be throwing on some more camber in the front!

Ya, I know once I go to R-comps, my whole setup is going to need to be changed again and stiffen up a lot for the grip that will be added with those tires.
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Old 06-22-2009, 05:36 PM   #7
waktasz
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More front camber, less rear camber.

I had a problem with my GC/Koni setup where the rear nuts on top of the strut were cranked all the way down, and there was still room for the strut to travel up and down in the top hat. I didn't notice until I took them off to sell them and the threads were all jacked up, but I really needed about 1/4" of washer in there to fix the issue.
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Old 06-23-2009, 08:53 PM   #8
gr8r rex
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^Thanks! And I`ll check that this week when I take them apart!

Looks like next season should have some more stuff and a different setup on my car!
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Old 06-23-2009, 11:27 PM   #9
bcblues
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Try running more pressure in the rear tires than in the front. The front pressure should be based on your maximum traction (in the front). Then begin with that same pressure in the rears, and steadily increase the pressure until you get the rotation you want. I have used this method with several different tire brands and types, and it works pretty well (at least for my 04 STi - but it also worked for my old 02 bugeye).
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Old 06-24-2009, 12:31 AM   #10
Splash
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Quote:
Originally Posted by gr8r rex
Wheels/Tires:
-17x8.5 SSR Comps
- 255/40/17 Kuhmo XS (I know I am still learning which is why no R-Comps yet)
- Pressures: 36F/44R
You mean like he does already, or did you mean more?
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Old 06-24-2009, 08:13 AM   #11
gr8r rex
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Haha, ya I already am doing some high pressures to *try* to help rotation
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Old 06-24-2009, 01:52 PM   #12
bcblues
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You may want to try setting your rear swaybar to a softer setting. It may also help rotation to run a little less negative camber in the rear as well.
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Old 06-24-2009, 02:11 PM   #13
Ebonysti
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First yes more camber in front less in the rear, less bar in front more in the rear and just so you have something to work with see attached below.

Adjustments Decrease Understeer Decrease Oversteer
Front Tire Pressure Higher Lower
Rear Tire Pressure Lower Higher
Front Tire Section Larger Smaller
Rear Tire Section Smaller Larger
Front Wheel Camber More Negative More Positive
Rear Wheel Camber More Positive More Negative
Front Wheel Toe Toward Toe-Out Toward Toe-In
Rear Wheel Toe Toward Toe-In Toward ToeOut
Front Wheel Caster More Positive More Negative
Front Springs Soften Stiffen
Rear Springs Stiffen Soften
Front Anti-sway Bar Soften (Thinner) Stiffen (Thicken)
Rear Anti-sway Bar Stiffen (Thicker) Soften (Thinner)
Weight Distribution More Rearward More Forward[/font]

this is a few easy things you can do to change things at the track [/font]

Last edited by Ebonysti; 06-24-2009 at 02:14 PM. Reason: did not fit right
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Old 06-24-2009, 10:25 PM   #14
solo-x
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Mac strut means you need to put a monster front bar on the car.

Less rear camber, less rear toe in or more rear toe out, more air in the rear tires, more air in the front tires, more spring and bar up front. If you can find a tire combo that lets you run a wider front tire then rear tire, that'd help as well.
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Old 06-24-2009, 10:26 PM   #15
gr8r rex
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^Cool Thankyou!!

EDIT: For next season, I`m going to try to get the stiffer springs and a better more autocross oriented alignment (~3.5 degrees in the front, ~1.2 in the rear) (those are musts for next year)

Last edited by gr8r rex; 06-24-2009 at 10:32 PM.
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Old 06-25-2009, 06:08 PM   #16
Boxologist
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i beleive ur still on the ej205. that's a major killer right now. with ur inexperience, you'd benefit from the torque, as ur trying to catch up to the lag on the oversized turbo. add another half degree rear camber to start.

oh, and you're missclassed. Ur in XP w/ Fender Braces/ALK/turbo swap.
do you have any locals who participate in Tours or Divisionals, how do u pax vs them? any hot shoes who help correct bad habits. Thats what u need to work on first.


then figure what class u want to be in, STX or XP. underprepped in XP will be more fun if this is your only car, but i would look at changing short blocks and definitely injectors(min 650)

as your car nears its first decade, it will be time to get new bushings.

and most importantly, well second most important is seat time, you're already having fun.
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Old 06-25-2009, 06:15 PM   #17
gr8r rex
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ALK is already taken care of. I got the new bushings from whiteline sitting here and will be in before the next event. I was under the impression that the turbo swap and fender braces are both SM legal mods?
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Old 06-25-2009, 06:37 PM   #18
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sorry, ur car came w/ fender braces stock, so it is SM legal (2pt), and the turbo is OK, just included because it bumps FP->XP.

ur pulling out the ALK and pressing the offset bushing into the old mount, correct?
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Old 06-26-2009, 02:03 AM   #19
gr8r rex
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^Yes sir! Staring at them on my desk as we speak and will be in for the next event!

Also, thanks for clearing those up for me!
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Old 07-14-2009, 12:07 PM   #20
Dirty25RS
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Default Just saying Hi

Hi, I worked turn 1 or 2 with you last weekend. watching the FSAE cars bounce around. I am subscribing to this because you and I have the same rotation issue. Tomorrow night I am corner weighting/realigning/maybe hawk HP plus brake padding my go cart for this weekend. If you want you can stop by, PM me if interested. Maybe we can get some stuff done on you car too.

PS. Another, more professional than I tuner will be there helping me. I have ECU Flash and the Tactrix cable and all that jazz if you want some engine tuning adjustment.
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Old 07-18-2009, 03:44 PM   #21
gr8r rex
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^PMed you back!
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Old 07-19-2009, 01:35 PM   #22
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Quote:
Originally Posted by gr8r rex View Post
So I have three problems, rotation, response and a clunk. First off, I am not rotating right still. I am running much higher pressures in the rear to help me with some rotation and it actually is starting to a little but I think I need to bump up my rear spring rates to 500lb anyways which should help a lot with rotation. If I bump with spring rates, what should I do with swaybars, should I use less or what?
The easiest thing to do with the mods you have today is just get some camber taken out of the rear and added to the front.

Quote:
Originally Posted by gr8r rex View Post
Second big problem I have is response with my turbo. It just doesn`t spool too well which was making me loose pretty big times with my car. I`m thinking headers/EWG and some more bolt ons with a new tune should help a lot? What else?
2.5L block That should help response quite a bit. I've seen a number of stage 2 STis put down 300 whp/350 wtq which would be plenty nice for local events. In terms of bang for buck that may be your best bet.

Quote:
Originally Posted by gr8r rex View Post
My last problem is a clunk. At first I thought it was my struts bottoming out or something but at closer look I am pretty confident that is not true. I think it might be the swaybar hitting or something like that? It is a loud metal on metal and it happens in straight line and corners with bumps. It happens under a loud or just driving.
Try disconnecting your front endlinks, seeing if it happens, and then disconnecting your rear endlinks, and seeing if it happens. That helped isolate a swaybar clunk for me.

Are you daily driving this car?

Really though - if you are going to switch to R-comps next year I would hold off on doing any serious changes. Maybe change the alignment for this year to get the car to rotate better and then don't worry about springs or whatever til next year.

(btw, I have a set of 8" 500 lb/in 2.5" ID Hypercos lying around )

john
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Old 07-19-2009, 03:43 PM   #23
gr8r rex
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Quote:
Originally Posted by ButtDyno View Post
The easiest thing to do with the mods you have today is just get some camber taken out of the rear and added to the front.
I was planning on that and the 500 pound rear springs since I`ll be on that setup atleast all next year. This will be the max that Mark said I could run with my Konis. So if I need to upgrade from there, it will be a completely upgraded setup for the R-Comps.

Quote:
Originally Posted by ButtDyno View Post
2.5L block That should help response quite a bit. I've seen a number of stage 2 STis put down 300 whp/350 wtq which would be plenty nice for local events. In terms of bang for buck that may be your best bet.
Thats on the list of things, but I want to try to avoid that in the meantime. I want to do my tranny setup before I do that and being a college student I am trying to figure out ways to do stuff a little cheaper! I know if I get a STI block, I`ll want to do a built one for the future of wanting like a 30R setup with built heads. So it wouldn`t be cheap.

Quote:
Originally Posted by ButtDyno View Post
Try disconnecting your front endlinks, seeing if it happens, and then disconnecting your rear endlinks, and seeing if it happens. That helped isolate a swaybar clunk for me.
I was thinking about taking them off, throwing anti-sieze all over the bolts/washers and seeing if that got rid of it since I don`t really hear the clunk on the street really.

Quote:
Originally Posted by ButtDyno View Post
Are you daily driving this car?

Really though - if you are going to switch to R-comps next year I would hold off on doing any serious changes. Maybe change the alignment for this year to get the car to rotate better and then don't worry about springs or whatever til next year.

(btw, I have a set of 8" 500 lb/in 2.5" ID Hypercos lying around )

john
Yes I am daily driving this car currently. But I plan on that changing hopefully next summer.

I won`t be changing till R-Comps till atleast after next season so I figure the springs would be worth it in the meantime!

We may be talking about those springs! I am just scared about the height being too tall at 8inches with the GroupN rear tophats. I want it at 13.75 inches in the rear and 14 front approximately.

And thanks for the help John!
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