The Autocross thread. Got questions? Get them answered here!

[cjd]

Originally Posted by BR-ZED

Yeah but I'm still trying to see if that piece (shift lever retainer) in the diagram below even attaches to the body.

It seems to only attach to the transmission. Am I missing something?

The highlighted part is bolted to the frame and allows some forward/back movement but restricts side to side movement/rotation. People replace that bushing to stiffen things up.

[BR-ZED]

Originally Posted by cjd

The highlighted part is bolted to the frame and allows some forward/back movement but restricts side to side movement/rotation. People replace that bushing to stiffen things up.

So are you saying the IRP removes both the bushing (highlighted) and the shift lever retainer? Since it is modifying a transmission "mount", its not STX legal?

I don't remember that bushing being removed in ft86sf's install video of the IRP, but it was hard to tell.

[cjd]

Originally Posted by BR-ZED

So are you saying the IRP removes both the bushing (highlighted) and the shift lever retainer? Since it is modifying a transmission "mount", its not STX legal?

I don't remember that bushing being removed in ft86sf's install video of the IRP, but it was hard to tell.

That's the line of reasoning, yup. Far as I can tell, it's sound reasoning as well so... Technically the IRP isn't the problem... it's the dual duty part it has you remove.



FWIW once you remove the shift lever retainer, you're removing the part that actually connects the transmission to the mount. I don't think it matters if you remove everything or not and that may not be specifically covered in the install video.


I'd have to dig in a bit to sort out whether the shift lever retainer could be swapped for an alternative piece that still handles the 'transmission mount' duties, but not the shift lever mount duties. Since it's only metal, it might actually be legal (and relatively simple) to replace (no metal content issues to worry about). Might help with some of the floppiness I've observed in videos of the IRP.

[BR-ZED]

Originally Posted by cjd

That's the line of reasoning, yup. Far as I can tell, it's sound reasoning as well so... Technically the IRP isn't the problem... it's the dual duty part it has you remove.



FWIW once you remove the shift lever retainer, you're removing the part that actually connects the transmission to the mount. I don't think it matters if you remove everything or not and that may not be specifically covered in the install video.


I'd have to dig in a bit to sort out whether the shift lever retainer could be swapped for an alternative piece that still handles the 'transmission mount' duties, but not the shift lever mount duties. Since it's only metal, it might actually be legal (and relatively simple) to replace (no metal content issues to worry about). Might help with some of the floppiness I've observed in videos of the IRP.

Thanks. Yeah if a substitute bracket was available that would be awesome! Let me know if you find something.

This seems like a classic example of a rule blocking people from making a pretty standard modification. I really wanted the IRP for enjoying the car more on a daily basis and at the track. It will make me no faster in autocross. Really frustrated I can't have it in STX :-/

[cjd]

Originally Posted by BR-ZED

Thanks. Yeah if a substitute bracket was available that would be awesome! Let me know if you find something.

This seems like a classic example of a rule blocking people from making a pretty standard modification. I really wanted the IRP for enjoying the car more on a daily basis and at the track. It will make me no faster in autocross. Really frustrated I can't have it in STX :-/

The rule is also blocking pretty accessible cheating in some cases. Probably. But it's a pretty simple rule your upset about, and it's also pretty easy to see some of the potential consequences.


STS civics once mounted huge wings at the top of the windshield...


If you're not after national level events, talk to your local competitors. They may be fine with it.

[whataboutbob]

Originally Posted by BR-ZED

Thanks. Yeah if a substitute bracket was available that would be awesome! Let me know if you find something.

This seems like a classic example of a rule blocking people from making a pretty standard modification. I really wanted the IRP for enjoying the car more on a daily basis and at the track. It will make me no faster in autocross. Really frustrated I can't have it in STX :-/

If you're a SCCA member, you can always write a letter to get some clarification if you think it should be allowed: https://www.crbscca.com/?page=submitLetter

[Shadotracker]

Question, are the Koni Yellows allowed in C Street or are they still banned? If so, what are other options for 1-way adjustable struts?

[Twinz]

I ran Koni yellows in CS for the 2017 season. You just have to make sure you install the centering washers. (Or whatever those things are called)

Without the washers, the struts have a lot of slop beyond the stock struts that would allow for more camber. (If they don't come with your shocks, Koni will send you a set if you ask)

[ConnorJ]

Hey everyone! I'm very new to the activity and I have some questions about car setup as I prep for the upcoming season. My goal is to get the car set up better before the season begins and leave it alone to better focus on developing my skills as a driver. If this post is better placed elsewhere, I apologize. Please direct and I will correct my error. First, a little background for you:


I race in the Tennessee Valley Region and last year (2018) was my novice season. I drive a 2015 Series.Blue BRZ in STX. The mods on the car currently are a Tein Flex Z suspension, Perrin exhaust with a high flow cat, header that I'm not sure what exactly it is, 20mm Whiteline front sway bar, 3/4" spacers on the front hubs and 1" spacers on the rear. Other than the sway bar, all of these mods were present when I purchased the car. I ran the season on 7" wheels with 225 BFG Rival 1.5 tires.



1) Tires. STX is allowed up to 265 on a 9" wheel. I've not found anyone yet who runs 265 so I'm guessing they rub up front. I see a lot of people run 245 and a bunch who run 255. Can someone explain to me the deciding factor on choosing between 245 and 255? Is there a reason I haven't seen people running 245/255 in front and 265 in rear? NOTE: I'm planning on pulling the spacers off next time I'm working on the car.



2) Ride height. How do you determine where to set ride height? Is it essentially as low as you can go without rubbing?


3) Odd classing question. I've seen notes about limited run models sometimes getting bumped into different classes. As the Series.Blue is the only model to come stock with the aero kit, does this actually bump the car into SM or since it was with it from the manufacturer can it still play in STX?


Thanks!

[cjd]

Originally Posted by ConnorJ

Hey everyone! I'm very new to the activity and I have some questions about car setup as I prep for the upcoming season. My goal is to get the car set up better before the season begins and leave it alone to better focus on developing my skills as a driver. If this post is better placed elsewhere, I apologize. Please direct and I will correct my error. First, a little background for you:


I race in the Tennessee Valley Region and last year (2018) was my novice season. I drive a 2015 Series.Blue BRZ in STX. The mods on the car currently are a Tein Flex Z suspension, Perrin exhaust with a high flow cat, header that I'm not sure what exactly it is, 20mm Whiteline front sway bar, 3/4" spacers on the front hubs and 1" spacers on the rear. Other than the sway bar, all of these mods were present when I purchased the car. I ran the season on 7" wheels with 225 BFG Rival 1.5 tires.



1) Tires. STX is allowed up to 265 on a 9" wheel. I've not found anyone yet who runs 265 so I'm guessing they rub up front. I see a lot of people run 245 and a bunch who run 255. Can someone explain to me the deciding factor on choosing between 245 and 255? Is there a reason I haven't seen people running 245/255 in front and 265 in rear? NOTE: I'm planning on pulling the spacers off next time I'm working on the car.



2) Ride height. How do you determine where to set ride height? Is it essentially as low as you can go without rubbing?


3) Odd classing question. I've seen notes about limited run models sometimes getting bumped into different classes. As the Series.Blue is the only model to come stock with the aero kit, does this actually bump the car into SM or since it was with it from the manufacturer can it still play in STX?


Thanks!

STX legal for the series blue.



265 is only available on a rather tall size in 18" and 2x the cost, and 18x9 are far and few between... And very costly. 245 tends to work better for most. 255 is showing up on some 17+ to help offset the diff change. Generally 245 is the fast setup on 13-16. 17x9 wheel.



And square on wheel/tire size is fastest by far. Also brake compounds.


Ride height, 1.5"-2" depending on things. Spring rates, seats, alignment, etc. Start at 1.5" or so.

[strat61caster]

If you daily drive your car set the ride height to what you're comfortable with so you don't beat up your car, as above -1.5" is probably a good starting point (iirc top of the wheel well edge of fender to ground is somewhere around 26-26.5" so somewhere around 24"-25" with a few people being more extreme but it's not all that necessary).

Agree with @cjd about the tire advice, if the car isn't doing what you want there's a plethora of suspension changes available, alignment, springs, sways, dampers will all have a bigger impact on drivability than the precise tire choice. Almost all performance setups for this car are designed with equal tires F/R so going your own way will have repercussions to your setup. And for RE71R's a set of 245/40/17's is $80 cheaper than 255/40/17 and $390 cheaper than a set of 265/35/18's.

[KevBRZ]

Hey guys i have been reading thru this thread some to learn up on this car, I have autocrossed in the past (S2k in BS, 08 Si in STX) but have been out of the game for a few years and looking to start this car in DS for now, i already got wheels with Z2s on them that i bought used, looks like crash bolts and a front sway bar will be next. Any thoughts on front sway bars who likes what and why? Looks like Perrin and the Strano bar are up on the list from what i read so far. And if i think i may be going the SSC route in the future, how bad would it be to put on the Eibach bar to start? Iv'e only got a couple hundred miles on the car to start and its pretty fun out of the box!