When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Be cool to develop a bit of a database of what everybody is using for suspension components/ rollbars etc! see if maybe we can develop some rough guidelines on what seems to work and what doesnt also..
Ill go first,
Maybe reply with something along the lines of the following:
Shock/ coilover brand and model: Tein Mono Flex
Spring rates front and rear: 12kg front 14kg rear
Anti Roll bars front and rear: whiteline 26mm non adjustable front bar. adjustable knuckles 3 settings. Whiteline 24mm rear bar. 3 point adjustable on bar.
Level of competition: mid to high end circuit competition.
Level of happiness with current setup: medium
Ohlin's R/T's 10k/12.5k springs
DallasJ top plates
Whiteline RCK
Offset Perrin PSRS
Custom rear trailing arms
255/40r17 NT01's
Stock swaybars
ER ACD tune
TRE Max lock rear diff
Alignment: Camber -3f, -2r, zero toe front, smidge of toe in rear, front cast usually fell between 6.5-7*.
On this setup the car was very composed even on bumpy sections of track, had lots of grip, put power down well, and changed direction similar to a gokart. The only I didn't like about it was there was a large disparity in balance between 0 throttle, and maintenance throttle. It rotates very well with zero throttle or heavy throttle-WOT. But it was pushy if you're only on maintenance throttle.
So, I am making some changes while the motor is out-
Bumping front springs to 11k
whiteline RSB, going to start on "soft", so 10% stiffer than stock
Ciro front swaybar brackets/links - will play with settings
275/35r18 NT01's
And my tcase that has the wavetrac front diff is going back in the car - hoping this doesn't cause to much understeer being a mostly track car
Alignment to be determined based on testing- tire temps, balance, etc..
So we'll how that does.
Last edited by letsgetthisdone; Jul 30, 2018 at 02:13 PM.
Ohlins Flags 10F/12R (still need to spend more time dialing the damping in the rear)
SSB tophats (20mm caster correction)
Custom SSB offset LCA bushing
Whiteline RCK
Whiteline 24mm rear bar
Whiteline 26mm front bar
Hardrace front spherical LCA bushings
Shep 12 plate rear diff
Wavetrac front diff
About 1" of rake
Alignment: Camber - 3F/2R, Toe - 0F/0R, Caster - 5.5
Car handles amazing in the dry, steering is telepathic and the car just goes where I point it. Usually find myself able to get back on throttle earlier than I thought possible. Car communicates very well when it's being over pushed and it's very catchable even when it's going through snappy transitions. Only issues I have are:
1 - some nasty wheel hop coming out of low speed corners which I think I can fix with some diff bushings and dialing the damping on the rear shocks right.
2 - The car pushes extremely bad in the wet. I think it's mostly due to my very worn out street tires that have a ton of shoulder wear which I've been using for wet days. A proper set of dedicated rain tires should fix this.
1" of rake measured how and which direction? Rake only effects the RC distribution which can be used to balance cars like a corvette or miata with similar F/R suspension. An evo has 2 massively different RC movements with high change. Its 3:1 change up front and 1:1 change in the rear.
Will post up my setup later, heading to a meeting now
Positive rake (front lower). Measured by distance from pinch weld to ground.
This was the ride height the car was at when I got it (actually have raised the front a smidge) and I decided to leave it because I don't think lowering the rear will benefit me. The car rotates very well and it's crossed my mind that having a higher CG in the rear may be helping this (not sure if it actually does or not) and it also may be giving some aero benefits to run a bit of rake.
I never measured my rake, but the front fender gap is def a lot large than the rear. I want to say my front LCA's are level, or just below level, and the rear camber arm is also slightly below level. The rear tire is damn near tucked at ride height.
If you've lowered from stock then the front LCA is def not level. It's pretty much level stock and even the most basic lowering drops an inch putting it fairly inverted.
You should definitely look again at it. Also note, the casting seam does not intersect both pivot points. The ball joint pivot is somewhere below that, I have pictures and a model I used to find as close as possible the pivot but don't recall the exact number.
Shock/ coilover brand and model: AST 4100.
Spring rates front and rear: 9k front, 10k rear
Anti Roll bars front and rear: Robispec RSB, OEM front sway bar with front and rear adjustable end links (home made).
Level of competition: Minimal time attack events, until next year, in the mean time: mostly HPDE, and autoX to get my driving fix.
Level of happiness with current setup: Extreme. I'd like a bit less body roll, but I'm okay with the compromise. May raise spring rates for TA, if it shows my times improve. The car is very neutral and predictable.
Alignment: 13mm rake, 2.8* front camber, 1.6* rear camber, 0 toe front/rear, 7-7.5* caster. Perrin PSRS
Electronics: ACD tune.
Add'l: Full poly bushings everywhere that's not spherical. Removed front strut tower brace in favor of "fender braces". Vorshlag camber/caster plates. Weir 12-plate rear differential, OEM front/center diffs.
Tires: Anything from stock-sized R-S4s to 255 RE71s or NT01s. The car likes all of them.
FWIW: I could swear my control arms are the same as Sean's. I lowered the car until the front and rear arms were level. I then raised one end or the other until I had the rake I needed. I know the front clears curbs and parking blocks. I guess I could be wrong, as I haven't looked in a while, though I remember posting pictures last time this topic came up.
The reason I say you should probably double check is comparing to what I have. This is ~25 5/8" with a 25.3" wheel. The angle down is right at 1deg which on these arms with the spherical center position gives just about 0.25" lower on the outside than inside. This is with 2" roll correction on my uprights and 25 5/8 isnt really slammed. Im going about 3/4" lower as soon as I switch back from these 295s back to 285s in a month.
Shock/ coilover: Ohlin Flags w/ SSB goodies (Canister locating tab, 20mm caster offset top hats, Rear coaxial spring perch)
Spring rates: 900 front, 1200 rear. As I shift weight around I may go up in rear or down in front to maintain 0.2-0.3hz split.
Anti Roll bars: No front, WL 26mm rear (full soft right now, may change)
Level of competition: National AutoX
Level of happiness with current setup: Car is a scalpel. But being so sharp, it seems a little bit off really effects balance. Have to maintain balance with tire pressures depending on surface and tire life cycle.
Alignment: -3.1 deg front, -2deg rear. 0 toe all around. 7.5deg caster. Once I get some other goodies setup will be playing with understanding relationship between camber and caster (mx+b if you will)
Electronics: ACD tune.
Wheel/Tire: Enkei PF01 18x10.5+38, Hoosier 295 A7. (switching back to 285 A7s)
Add'l: SSB Front control arms (extra caster, solid bushings, optional ball joint lengths), RTErnie trailing arms (soon to swap out for SSB arms just to continually test).
Shock/ coilover: Ohlin Flags w/ SSB goodies (Canister locating tab, 20mm caster offset top hats, Rear coaxial spring perch)
Spring rates: 900 front, 1200 rear. As I shift weight around I may go up in rear or down in front to maintain 0.2-0.3hz split.
Anti Roll bars: No front, WL 26mm rear (full soft right now, may change)
Level of competition: National AutoX
Level of happiness with current setup: Car is a scalpel. But being so sharp, it seems a little bit off really effects balance. Have to maintain balance with tire pressures depending on surface and tire life cycle.
Alignment: -3.1 deg front, -2deg rear. 0 toe all around. 7.5deg caster. Once I get some other goodies setup will be playing with understanding relationship between camber and caster (mx+b if you will)
Electronics: ACD tune.
Wheel/Tire: Enkei PF01 18x10.5+38, Hoosier 295 A7. (switching back to 285 A7s)
Add'l: SSB Front control arms (extra caster, solid bushings, optional ball joint lengths), RTErnie trailing arms (soon to swap out for SSB arms just to continually test).
900 front 1200 rear is 16kg 21kg? or am i converting that wrong.
Very interested to see all of you running 0 toe. id have to check my setup book but im pretty sure im running like 2mm toe front and 3mm rear or something like that. Mainly using the toe to heat the tyres up quickly ( medium slicks and only 10 lap races) and try get the car to point into the corner better.
Im going to throw my 16kg front springs back in as its been a pig ever since i put the 12kg springs in it. i was gona just leave the 14kg in the rear but after seeing your spring rates dallas i may go up to 18 or 20kg in the rear.
Bearing in mind i have gutted all of my rear end of my car. so the parcel tray and seat back structure etc has all been completely cut out. boot inner skin is completely gone including spare wheel well etc. rear doors are all gutted. rear window is lexan and so are door windows. carbon bootlid and wing.
Maybe thats why a slightly softer spring in the rear was working quite well for me?
Anyway since you guys all listed alignment settings i will also. -3.5deg camber front. 2deg rear. I will have to confirm the toe but i think its 2 or 3mm front and rear. caster is stock till i get my hands on some of those SSB arms and hubs
Do you know roughly your front and rear weight? Im 900/600 but should be 875/575 after this winter. That puts my NF in the 3.3f/3.55r range. So its keeping right in the middle of that 0.2-0.3hz split. I think I could even go stiffer in the rear depending how things are on concrete. But this is AX where I want the car to move because I need to yaw around element.
Track is certainly different where you need more of that throttle balance and need to keep stability to confidently push it. Similar to my Hill Climb friends setup, need to be able to push with out losing the rear.
And thats correct, no front bar. My geometry is fixed just about as good as I can get without making the car wider, and stiff enough overall that I can get to only using a bar as a trim device on the end that needs to be un-stuck. One thing we have noticed as a trend, every time we soften the front bar and stiffen the front spring, we get faster. So decided to go all the way and get that weight off the car at the same time. At first it was terrible on race tires and pretty fine on street tires. Just took more rear spring and less rear bar and things really started to work.
My rates certainly sound stiff on paper, but the car is totally composed even on our terribly bumpy lot. It just seems to absorb it all no problem to the point Im just not concerned with it anymore.
Jul 26, 2018, 06:50 AM
