CSG and RCE tag-team suspension Q&A thread! Ask us anything!

[juanjgarcia]

Originally Posted by Pat

Slightly firmer and more composed.

Thanks Pat!

[ric342]

appreciate your input, been driving the car for a week now and experience rubbing on lock out. I called the shop that did the work the the tech states that it is a caster issue. Im led to believe that it is a camber issue because it only rubs on lock out. If it is at caster issue then is there any recourse? I do have adjustability for camber through my front LCA via the ball joint, and was thinking that if I adjust the camber through that and then adjust the top hat that I might be able to get away with it. The tech also states that due to the specs of my wheels that it is part of the issue, I have TE37 17x8.5 45 offset. I took his advice and got extended studs and put on a 10mm spacer and it did make it a bit better but it still rubs. Thoughts?

Originally Posted by Racecomp Engineering

1. Forget OE specs, your car is far from OE now.
2. Aftermarket isn't always an upgrade. Those parts aren't necessarily bad but they're adding complexity that you don't need. They won't last as long as OE.
3. Understandable. Corner balancing is nice to have.

For endlinks, you want the studs to just line up with the mounting holes with the car on the ground. So don't set them with the car in the air.



This is not the final alignment right? Front is not good.

- Andrew

[Tatsu333]

Originally Posted by ric342

appreciate your input, been driving the car for a week now and experience rubbing on lock out. I called the shop that did the work the the tech states that it is a caster issue. Im led to believe that it is a camber issue because it only rubs on lock out. If it is at caster issue then is there any recourse? I do have adjustability for camber through my front LCA via the ball joint, and was thinking that if I adjust the camber through that and then adjust the top hat that I might be able to get away with it. The tech also states that due to the specs of my wheels that it is part of the issue, I have TE37 17x8.5 45 offset. I took his advice and got extended studs and put on a 10mm spacer and it did make it a bit better but it still rubs. Thoughts?

Given how you're describing the issue, your wheel specs and the fact that the 10mm spacer helped a bit but the rubbing is still there, I would tend to agree that it may just be an unavoidable consequence of your wheel & tire specs. I didn't see what size tire you're running in any of your posts here, but I'm guessing (hoping?) it's not a stretched 215 or 225 fitment, but rather something meatier in the 245-265 range.

Your current alignment specs are right in line with what folks tend to recommend around here for good performance, so rather than trying to fix your rubbing with more messing around with alignment, my suggestion would be to either a) don't turn to full lock (LOL - but seriously, it's an option), or b) install a steering rack limiter kit (like this from Verus Engineering) to make full lock less severe an angle. It's less than $30...problem solved.

[matt88]

I'm near the end of my LS swap and will tackle suspension next. I will buy coilovers soon and need your advice.

I've already got a 22mm front and 18mm rear sway bar to help with roll. However now I need to solve what I'm going to do with coilovers.

It is hard for me to get good answers because it seems everywhere I look 99% of the answers are coming from experience related to the stock car, or force fed with 50% more power and no real additional weight. It seems to be hard getting a difinitive answer when you have 100Kg extra weight and three times the power and don't want to be drifting all over the place.

My swap is much like any other with LS3 and TR6060 trans. Towards the rear I've done a few things that will likely add weight there too.

First one is my tank. Because the shape of the stock tank didn't do what I wanted with exhaust and driveshaft routing I made my own tank from aluminium. Capacity is now 78 litres so depending on how full I run theres probably some extra weight there.
Second is the diff. There are not enough ratios available here and also I wanted to use a larger diff to make sure I was satisfied with power handling so I modified my diff sub frame to accept a GM/ZF 8.6 IRS diff usually used in Commodores here in my part of the world (Queensland, Australia). I bought a new diff with 3.45 ratio. Got a 3 inch drive shaft made with 1350 joints. Along with that I made my own cv axles from Commodore inners, Landcruiser 80 birfield shafts and Landcruiser 100 CV outers and turned/milled the stubs to match the Subaru hubs. So this stuff will surely have added some weight in the rear as well. I also fabbed a dual 3 inch stainless exhaust front to rear so there's extra weight there.

Overall if I have to sniff the wind I'd say I'll end up with perhaps additional 40-60Kg up front and additional 20-30Kg in the rear. I'm guessing it will be about 1360-1380Kg all up (original weight was 1280Kg on weighbridge).

Tyres I will initially just use something easily available like Pirelli P Zero, Michelin Pilot Sport, Bridgestone Potenza etc. Perhaps I will get some better track focussed tyres with a stickier compound later on if it proves that I'm doing more track days but for now will start with something simple/easy that won't annoy me on the road. I am hoping to fit 265/35/18 on the rear and might also try and squeeze these on the front as well. If no fit I may need to go down to 255 or 245 to on the front.

I will use the car about 70-80% spirited street use, twisty mountain roads etc. on the weekend. This is a weekend toy not really a daily driver. The track days will only be a handful per year. I'm only new to this so I don't think I will be hitting 300 down the straight any time soon.

However with what I have done with the drivetrain I really do intend to stomp on it every time I drive it. I didn't want to build this thing and need to treat it lightly due to thinking perhaps my diff/axles etc weren't up to the task or "I better not push it too hard, it might break". I'll probably go through tyres like tanks of fuel.

Ok so onto the coilovers....
MCA are recommending Pro Sport with 7 to 8Kg front and 5Kg rear.

I sent Shockworks a message on their website order enquiry form and they didn't bother responding.

To be honest I am surprised about the recommendation from MCA in terms of spring rates. As stock spring rates are 2.3 front 3.3 rear I would have assumed the front/rear bias would have to be balanced. So I thought they would have come back recommending something like 5 front 7 rear.

Then I look at other vehicles with weight forward like Mustang/Camaro/Commodore etc (And yes, I know these vehicles are much heavier, I'm just raising it for the fact they have weight forward and similar power levels going to the rear) these all seem to have rear rates that are some 30-40% stiffer than the front, just as the stock 86 2.3F/3.3R are.
Looking at something like a BMW M3 they even have rates that are some three times greater in the rear than what they are in the front.

So I get it that you cant really compare across vehicle manufacturers/models because of all manner of things like weight, roll centres etc, however it does seem to me that in all instances of front engine, rear wheel drive cars that would obviously have been built/designed with large amounts of power and performance and large weight up front that they all seem to be using heavier rates in the rear, as to what they are using in the front.

I also read that due to the origins of the Japanese market of 86/BRZ and that they have limited power and trying to squeeze out an enjoyable driving experience that may be somewhat tail happy on narrow tyres, this is one reason the balance has been made as it is has in stock form. Also in the drifiting world it would seem stiffer in the front and softer in the rear is the norm, such that the car squats a little under power, steering is a little more controlled somewhat and the rear is totally tail happy. However I'm not a drifter. I rather getting through twisty roads and corners and fast track days and the back end breaking loose just when I want it to. I call it "tight and controlled" and call drifting "sloppy". I don't really want the car to squat under power.

The car is nowhere near its stock weight any more. I have some additional weight bias that has moved to the front, some additional weight throughout, three times the power and a right foot that is going to be wanting to slam that power down to the road whenever I get the chance.

All this leads me to the opinion I should be going heavier in the rear, not lighter. I'd probably be guessing something like 5 to 6 in the front and 7 to 9 in the rear.

Is there anyone out there that have gone through this exercise on a LS swap on our platforms and have similar goals to mine that can help me understand more or give recommendations on which direction I should be going?

Thanks
Matt

[strat61caster]

Stock powered and lightened cars will use 6k F/ 9k R. The car doesn’t seem that sensitive to spring rate changes imho as much as alignment, I don’t think you’ll go wrong in that ballpark with a decent damper.

[PikachuBRZ]

Originally Posted by strat61caster

Stock powered and lightened cars will use 6k F/ 9k R. The car doesn’t seem that sensitive to spring rate changes imho as much as alignment, I don’t think you’ll go wrong in that ballpark with a decent damper.

doesn't having higher rear spring rates increase oversteer? I've always been under the impression that the heavier portion of the car should have the higher spring rate to stay balanced.

[strat61caster]

Originally Posted by PikachuBRZ

doesn't having higher rear spring rates increase oversteer? I've always been under the impression that the heavier portion of the car should have the higher spring rate to stay balanced.

See:
https://www.ft86club.com/forums/showthread.php?t=9936

Edit: you could have a stiffer spring rear but when you actually do the math it's still softer then the front effective stiffness, bump stops play a part in this as well (which is why some people sell whacky spring rates that still work out) but most companies don't talk about the effects of their bump stop choices, one of the last pieces of 'secret sauce' a lot of people have.

[Spuds]

Looking for some smart folks to check my logic and understanding before jumping into suspension mods. I read a decent portion of this thread as well as general research, but reading only gets me so far. I'll try to keep the info dump brief.

TLDR? Scroll to the last "Notional Parts" section

Background and current setup: I've owned my FRS for a bit over 9 years now and am finally going to try out suspension and chassis mods. Currently suspension is stock, with Yokohama Advan sport v105 tires in stock size on rpf1s. I DD the FRS in a sense, but it's not every day and I have another car I can drive.

Motivation: 1. I want to try some new things and learn about modding suspension and chassis dynamics. 2. I got myself hooked on autocross this year, and will probably try out hpde sometime next year as well.

Goals: Buy and install the parts necessary to have a more motorsport-oriented car (feedback, response, weight transfer, balance, etc) while allowing for necessary adjustments for dialing in the geometry. Then learn things the fun way and adjust as necessary. Specifically, I want to reduce some sloppyness at both ends for predictability, prevent the car from crashing into the bumpstops on quick direction changes, and reduce understeer.

Budget: Keeping cost under $5k for suspension/chassis would be preferable. Somewhat flexible on that if there's a good reason to go over.

Tradeoffs:. Willing to sacrifice quite a bit nvh for response and useful feedback. Willing to spend a bit more for objectively higher quality parts. I wish to avoid significant compromises on reliability/durability/maintenance if possible.

Constraints:. I think I want to remain within the rules of the STX class. I want to do all/most actual installation this winter in my garage, then I can adjust things as necessary.

Notional parts (haven't picked out exact parts yet, wanted some feedback on what is needed):
-Wheels/tires:. I intend to stick with street tires for autox for at least the next year, because I feel I will learn better driving habits than with 200TW tires. Might go a bit wider at some point.
-Suspension:. I am gravitating towards RCE T2s.
-Top hats/cam plates:. Yes? Recommendations?
-Rear LCAs: Recommendations?
-Sway bars and endlinks: Just looking for adjustability if nothing else.
-Rear subframe bushings/inserts.
-steering rack bushings
-any other bushings recommended?

Wow that was longer than I intended lol... Please let me know if I'm doing it wrong, or if there's anything I forgot. Thanks in advance for your time!

[strat61caster]

If you’re not diy aligning it get white line rear lca for stx legality, I got mine through tirerack. I went with delrin steering rack bushings and noticed zero benefit, others swear by them. -4 degrees front camber is where I’d start, I don’t think you can get there without camber plates , raceseng are good but pricey. Oe rear top hats are fine imho, -2.5 rear camber. Karcepts front sway bar is great, oe rear is a fine starting point, I have a Perrin 16mm rear bar right now.

[PikachuBRZ]

Originally Posted by strat61caster

If you’re not diy aligning it get white line rear lca for stx legality, I got mine through tirerack.

Do different LCAs affect classing for STX? I want to get away from the SPC/Whiteline style since I've already had my LR slip way out and have me crabwalking home with no stability control 2 weeks after getting an alignment. I talked to the autoX tech guy and he said I could stay in STX with adjustable LCAs. I'm really liking the look of SPL's LCAs. If they send me to STU I may reconsider.

[strat61caster]

Originally Posted by PikachuBRZ

Do different LCAs affect classing for STX? I want to get away from the SPC/Whiteline style since I've already had my LR slip way out and have me crabwalking home with no stability control 2 weeks after getting an alignment. I talked to the autoX tech guy and he said I could stay in STX with adjustable LCAs. I'm really liking the look of SPL's LCAs. If they send me to STU I may reconsider.

That’s not how scca autocross classing works for mods.

The spl last I looked had a spherical bearing which is not legal in Street Touring or Street Prepared which would bump you to SM/XA or Prepared if you were to use it which is dumb but the way the rules are written.

You need a non metallic bushing that doesn’t rotate or swivel to be Street Touring legal. Right now I see Verus or RSR/Blox as threaded adjustable lca with what appears to be a ST legal bushing.

Fwiw I had a threaded adjustable aluminum lca break on me when I hit a pothole a few years ago. I’ve never had the lca slip under normal driving conditions.

[PikachuBRZ]

Originally Posted by strat61caster

That’s not how scca autocross classing works for mods.

The spl last I looked had a spherical bearing which is not legal in Street Touring or Street Prepared which would bump you to SM/XA or Prepared if you were to use it which is dumb but the way the rules are written.

You need a non metallic bushing that doesn’t rotate or swivel to be Street Touring legal. Right now I see Verus or RSR/Blox as threaded adjustable lca with what appears to be a ST legal bushing.

Fwiw I had a threaded adjustable aluminum lca break on me when I hit a pothole a few years ago. I’ve never had the lca slip under normal driving conditions.

right. it was aero that would bump me up to XSA from what I was reading. sorry I'm still new to the whole autocross thing and all of the alphabet soup is killing me right now. i just googled rsr brz lcas and ended up on csg wondering if I had a stroke because nothing seems to be words.

I can't necessarily call it "normal" driving but I was on my way home from a little mountain adventuring and had to have my steering wheel about 1/4 turn to the left to go straight and my VSC and TC lights kicked on. found out my left rear was super out of alignment and I've heard a few people have issues with the slotted LCAs. Plus I don't necessarily trust what was done to the car as it has signs of being a former stance car that I'm trying to convert into a autox daily

[Breezio]

Your on the right track, though your understanding of SCCA Solo rules isn't quite right.
For the most part, mods put you in different class 'groups', like Street, Street Touring, Street Prepared, etc.
Chassis puts you within the specific sub-group, like STX, STS, STR, STU (IE: Street Touring whatever)

The Verus RLCA with STX legal bushing works great. Only annoying part is how close the adjustment bolt is to the subframe.

RCE T2's are a great option for the price.
Definitely want front top hats with camber adjustability. I have Vorshlag top hats. I like them a lot, but pricier then others.
Front Sway bar is needed, rear isn't initially. Many people run the Perrin 22MM. I run a Hotchkiss 1" hollow bar
Rear subframe and diff bushing inserts are nice (not needed). Whiteline makes a good set.
Wheels, lightest 17x9 +35mm you can reasonably find.

My build for non-consumables was a bit over 5K I think.

[Racecomp Engineering]

Originally Posted by matt88

I'm near the end of my LS swap and will tackle suspension next. I will buy coilovers soon and need your advice.

I've already got a 22mm front and 18mm rear sway bar to help with roll. However now I need to solve what I'm going to do with coilovers.

It is hard for me to get good answers because it seems everywhere I look 99% of the answers are coming from experience related to the stock car, or force fed with 50% more power and no real additional weight. It seems to be hard getting a difinitive answer when you have 100Kg extra weight and three times the power and don't want to be drifting all over the place.

My swap is much like any other with LS3 and TR6060 trans. Towards the rear I've done a few things that will likely add weight there too.

First one is my tank. Because the shape of the stock tank didn't do what I wanted with exhaust and driveshaft routing I made my own tank from aluminium. Capacity is now 78 litres so depending on how full I run theres probably some extra weight there.
Second is the diff. There are not enough ratios available here and also I wanted to use a larger diff to make sure I was satisfied with power handling so I modified my diff sub frame to accept a GM/ZF 8.6 IRS diff usually used in Commodores here in my part of the world (Queensland, Australia). I bought a new diff with 3.45 ratio. Got a 3 inch drive shaft made with 1350 joints. Along with that I made my own cv axles from Commodore inners, Landcruiser 80 birfield shafts and Landcruiser 100 CV outers and turned/milled the stubs to match the Subaru hubs. So this stuff will surely have added some weight in the rear as well. I also fabbed a dual 3 inch stainless exhaust front to rear so there's extra weight there.

Overall if I have to sniff the wind I'd say I'll end up with perhaps additional 40-60Kg up front and additional 20-30Kg in the rear. I'm guessing it will be about 1360-1380Kg all up (original weight was 1280Kg on weighbridge).

Tyres I will initially just use something easily available like Pirelli P Zero, Michelin Pilot Sport, Bridgestone Potenza etc. Perhaps I will get some better track focussed tyres with a stickier compound later on if it proves that I'm doing more track days but for now will start with something simple/easy that won't annoy me on the road. I am hoping to fit 265/35/18 on the rear and might also try and squeeze these on the front as well. If no fit I may need to go down to 255 or 245 to on the front.

I will use the car about 70-80% spirited street use, twisty mountain roads etc. on the weekend. This is a weekend toy not really a daily driver. The track days will only be a handful per year. I'm only new to this so I don't think I will be hitting 300 down the straight any time soon.

However with what I have done with the drivetrain I really do intend to stomp on it every time I drive it. I didn't want to build this thing and need to treat it lightly due to thinking perhaps my diff/axles etc weren't up to the task or "I better not push it too hard, it might break". I'll probably go through tyres like tanks of fuel.

Ok so onto the coilovers....
MCA are recommending Pro Sport with 7 to 8Kg front and 5Kg rear.

I sent Shockworks a message on their website order enquiry form and they didn't bother responding.

To be honest I am surprised about the recommendation from MCA in terms of spring rates. As stock spring rates are 2.3 front 3.3 rear I would have assumed the front/rear bias would have to be balanced. So I thought they would have come back recommending something like 5 front 7 rear.

Then I look at other vehicles with weight forward like Mustang/Camaro/Commodore etc (And yes, I know these vehicles are much heavier, I'm just raising it for the fact they have weight forward and similar power levels going to the rear) these all seem to have rear rates that are some 30-40% stiffer than the front, just as the stock 86 2.3F/3.3R are.
Looking at something like a BMW M3 they even have rates that are some three times greater in the rear than what they are in the front.

So I get it that you cant really compare across vehicle manufacturers/models because of all manner of things like weight, roll centres etc, however it does seem to me that in all instances of front engine, rear wheel drive cars that would obviously have been built/designed with large amounts of power and performance and large weight up front that they all seem to be using heavier rates in the rear, as to what they are using in the front.

I also read that due to the origins of the Japanese market of 86/BRZ and that they have limited power and trying to squeeze out an enjoyable driving experience that may be somewhat tail happy on narrow tyres, this is one reason the balance has been made as it is has in stock form. Also in the drifiting world it would seem stiffer in the front and softer in the rear is the norm, such that the car squats a little under power, steering is a little more controlled somewhat and the rear is totally tail happy. However I'm not a drifter. I rather getting through twisty roads and corners and fast track days and the back end breaking loose just when I want it to. I call it "tight and controlled" and call drifting "sloppy". I don't really want the car to squat under power.

The car is nowhere near its stock weight any more. I have some additional weight bias that has moved to the front, some additional weight throughout, three times the power and a right foot that is going to be wanting to slam that power down to the road whenever I get the chance.

All this leads me to the opinion I should be going heavier in the rear, not lighter. I'd probably be guessing something like 5 to 6 in the front and 7 to 9 in the rear.

Is there anyone out there that have gone through this exercise on a LS swap on our platforms and have similar goals to mine that can help me understand more or give recommendations on which direction I should be going?

Thanks
Matt

Can't look at spring rates from different cars with different suspension set ups, they usually don't translate directly.

Also don't worry too much about stock suspension spring rates, they're very bumpstop active with different design goals.

I would get final corner weights and try to hit spring natural frequencies around 2.0 front and rear. That's a start.

See https://www.instagram.com/p/B6TKG6Un..._web_copy_link

- Andrew