Chassis reinforcement for race slick use.
 

Hi there.

I plan to start using Michelin WEC race slick soon.

This guy :

http://www.apr-europe.com/pneus/24-6...rt-gt-s8l.html

http://uploads.tapatalk-cdn.com/2016...87fafc9f02.jpg

I was wondering if any of you used slicks without chassis reinforcement and how well the body reacts to the abuse ?

Or which reinforcements are critical ?

I ran Hoosier A6's for an autocross season on an otherwise stock car. No chassis issues whatsoever. Don't be surprised if you start picking up the inside rear more.

We are blessed with a pretty stiff chassis.

Is your intention to run the stock suspension? You will not run into big chassis flex issues until things get very stiff. Generally chassis stiffening is the last step you take, and only when it becomes a significant percentage of total flex in the system.

I use 3 way JRZ 12-32 at the moment with 10/12k springs, full SPL arms and Powerflex Black.

Thanks for the feedback guys :)

Have you done anything regarding improved suspension bushings? Energy Suspension makes a polyurethane set.
http://www.ft86speedfactory.com/ener...ings-1436.html
http://www.ft86speedfactory.com/ener...ings-1435.html

While CSG makes a crazy spherical bushing set for your entire drivetrain and suspension.
http://counterspacegarage.com/produc...-kit-gt86.html

The tradeoff would be increased NVH. Probably a lot of increased NVH if all of the bushings were spherical.

Yes mostly everything is spherical or Powerflex Black.

I have a set of MCS singles and recently purchased all of the spherical bushings in the kit from CounterSpace Garage (I bought them à la cart, because I already had all of the Whiteline and Perrin driveline bushings installed). I'm currently working with MCS and Vorshlag Motorsports to select springs and my car will be used as a daily driver nine months a year. Prior to my decision to run spherical bushings @CSG Mike and I spent a lot of time discussing whether or not they'd be suitable for daily use - once I get everything installed, I'll let everyone know if they're tolerable or just too brutal to live with every day. I also have every SPL Parts suspension and steering piece made, so it's going to be a real test - especially here in the suburbs of Chicago.

RJ, do you have a build thread? I'm very interested in your results. We have a milder, less corrosive environment here and I'm keen on dailying with sphericals.

Hey @Ultramaroon, thanks for the shout out. No, I don't have a build thread, but maybe when I get some time I'll put something together. I'm not trying to hijack this thread, but here's my list of modifications - I thought it may be of interest to you:

- ACE 4-2-1 Type-A 350 equal length header (ceramic thermal coated)
- Motiv catted front pipe (ceramic thermal coated)
- Blitz Nür Spec stainless steel exhaust
- EcuTek Pro ECU programming and datalogging kit
- Delicious Tuning - ECU reflash/stage 2
- 4.56:1 ring and pinion
- Axle-Exchange aluminum driveshaft
- OS Giken 1.5-way LSD
- Rays Gramlights 57Xtreme 18" x 8.5" +42 wheels
- Rays Duralumin black lug nuts
- Raceseng cam plate
- Raceseng CasCam caster and camber plates
- Raceseng Shock Top rear upper shock mounts
- MCS single adjustable coilovers
- SPL Parts Titanium rear lower camber arms
- SPL Parts Titanium rear traction arms
- SPL Parts Titanium rear toe arms w/eccentric lockout
- SPL Parts Pro rear endlinks
- SPL Parts Titanium front lower control arm assembly
- SPL Parts bumpsteer adjustable front tie rod ends
- Cusco rear upper control arm (front) spherical bushing
- Cusco rear upper control arm (rear) spherical bushing
- Whiteline polyurethane differential outrigger support bushing
- Whiteline polyurethane differential bushing
- Whiteline polyurethane transmission bushing
- Whiteline polyurethane crossmember bushing
- Perrin polyurethane steering rack bushing
- Perrin polyurethane shifter bushing
- Perrin engine mount set
- Perrin front control arm brace
- Perrin front endlinks
- Perrin steering rack lockdown
- Project Mu Racing999 brake pads (front & rear)
- TWM Performance short shift kit
- Spiegler braided brake lines
- Spiegler braided clutch line
- MTEC clutch spring
- MTEC shifter springs
- Cosworth drop-in air filter
- Radium master cylinder brace
- Radium strut bar
- Radium dual catch can kit
- Fumoto Quik Valve drain pan bolt
- JMP Coachworks Alcantara steering wheel
- JMP Coachworks Alcantara speaker grills
- JMP Coachworks Alcantara shift boot
- JMP Coachworks Alcantara knee pads
- JMP Coachworks Alcantara coin tray liner
- JMP Coachworks Alcantara rear center armrest
- JMP Coachworks Alcantara instrument hood
- JMP Coachworks Alcantara hand brake boot
- JMP Coachworks leather upper armrests
- JMP Coachworks leather lower armrests
- WeatherTech floor liners
- FR-S engraved plates on WeatherTech floor liners
- Millers Oils CFS 0W20 NT
- Millers Oils CRX 75W90 NT
- Millers Oils CRX LS 75W90 NT
- Torque RT700 brake fluid

Like I said in my prior post, once I get the MCS coilovers and spherical bushings installed, I let you know how they work out on a daily driver - wish me luck...

Definitely, best of luck to you. I'll be following.

The New Zealand Racing series uses Slicks. Maybe see if you can contact some of them. Though our people running Hankook Z221's probably aren't that far off slicks to be honest in terms of grip.

I think the NZ cars are fully caged, no ?

This one :

http://www.speedhunters.com/2014/01/...ce-mode-engage

I had axle issues with my hoosiers. So did the FRSPORT car. although both cars are being built for Street Mod. So that may explain of of it.

Thanks for the feedback.

What failed specifically - the inner or outer joint, the splines, or the shaft itself?

Yes, they are fully caged.

Inside on one. And spectacularly on the other. I am supercharged but i had a massive boost leak when the failures occured.

When you're running slicks and serious suspension...it's time to think about a roll cage or at least a roll bar with proper seats and safety equipment.

Just my opinion...and Myles, Dan, Larry all here in the office nodding in agreement.

- Andrew

Yes, I'm looking at the options at the moment.

I need to go safely from home to the track on the road.

My number one option is to use the future Gspeed bolt in half cage. Schroth ASM 4 point harness with added points 5 and 6.
Plus HANS at the track.

According to Schroth user manual it supposed to work with both track safety and oem airbag system.
As it's HANS compliant and still provide torso movement on the road.

If you have other idea, I'm super interested :)

For the record, I live in a non civilised country regarding building track cars.


Other options are still using the oem belt.
With a Tillett bucket seat that's made for oem belts or with a Bride reclining seat.

I'll take any serious advices and experience.

You live in France! Your delicious wine, food, and women make up for a lot of things. :)

For a serious car (and in my opinion a car with slicks and badass JRZs is a serious car) I would recommend a HANS, HANS compliant FIA approved fixed back seat, HANS compliant 6 point harnesses, and at least a half cage.

This does make street driving a little more complicated. Theoretically you can keep your OEM steering wheel and airbag and keep the OEM 3 point belts in the car for street driving.

- Andrew

:D

Do you know a FIA approved seat that can be used with OEM seatbelt receiver ?

I mean with a large enough lap belt opening.

Thanks for your time. It's really appreciated.

Hmm...that I'm not sure about.

No problem!

- Andrew

Recaro has a street legal (ABE) bucket seat that can be used with OEM seatbelt. Check here: https://www.recaro-automotive.com/de...arbon-abe.html


Unfortunately, you will not find the appropriate rails and seat bracket for our car. You'll have to import them from Recaro Japan (did this sometime ago) or order something inferior from the US that might need some kind of modification ...

Only the leather one got the big opening for seatbelt receiver ?
It can't be used with 6 points and is not FIA :/

All the seats have the big opening for seatbelt receiver. Probably in the leather there is less material around the opening. Yes, they are not FIA approved. Just for occasional track usage.

OK, thanks

Would a front fender brace help the car? I don't know how much flex is there. https://ramotorsports.ca/collections...z-fender-brace

I’ve heard the differential input shaft bearing can get damaged from super sticky tires, but just something I heard.

I've ran the car for 6 years with racing tires and so far none of the suspension or differential components have broken.

(The gearbox broke but this was more due to the turbo than the racing tires).

Yeah I’m not sure what caused my diff bearing to get all weird. Shop said it was most likely from tires but I’m not sure. 160k miles when this video was taken, have since replaced the diff with the oem 4.3

https://www.instagram.com/p/B016KMKH...um=share_sheet

I think he probably figured out a lot of things in the 5 years since the post you're replying to :bellyroll: