Got a track related question? I'll try to answer.

[gramicci101]

Replace the mirror with a tablet and a rear view camera?

[CSG Mike]

Originally Posted by DatApex

I've tried that. It's the factory home link, so adjustability/visibility isn't the best on it to begin with.

Sent from my Nexus 5 using Tapatalk

Hmmmm you might need to adjust your side mirrors differently then...

[DatApex]

Originally Posted by CSG Mike

Hmmmm you might need to adjust your side mirrors differently then...

Was really just looking to see if anyone went aftermarket and how they liked it. I have the APR side mirrors, which do fine on track. Looks like no one has done replacement mirrors, so disregard.

Sent from my Nexus 5 using Tapatalk

[fatoni]

Originally Posted by CSG Mike

But what size tire?

great question. i dont have an answer though. on a miata, a 225 on a 9" rim is about as fast as you can get on a road course. 205 on an 8" rim is faster at wsir for slower miatas. i dont know how that data translates to a much bigger car but i imagine a pyrometer and a couple sets of wheels would help figure it out. im not fast enough to need that info. i only cooked my 205 re11 on 7" rims once but i think it was my driving. i havent driven in the heat since the original azenis was new.

if i ever feel that im faster than my miata (or just get bored of it or if i decide to make my brz cool anyways) ill probably just copy the csg car. im trusting you to do all the heavy lifting.

[Doozer]

Hey Mike,

Our car is developing a push on a mid-speed righthand sweeper and a righthand 90. Not sure if this is a tire issue or set-up. Last 2 races were run on Toyo R1R (Treadwear 140) and Maxxis RC-1 (Treadwear 100) both 235/40/17

Set-up
Ohlin DFV's
550lb springs front 3/20 stiffness
500lb springs rear 5/20 stiffness
LF camber= 3*12'
RF camber= 2*30'
Rear camber= 2*15'
OE front swaybar
Disconnected rear swaybar
3mm toe out front
2mm toe in rear

Ride Heights (from ground to fender)
LF 64.5cm
RF 65.5cm
LR 66.5cm
RR 67cm

Weights(with driver)
Total= 2830
Left%= 52.05
Front%= 56.86
Cross% (RF-LR)= 49.21

Tire temps
LF= 98, 88, 80 (Outside, Middle, Inside)
LR= 80,80,80
RF= 90,80,81 (Inside, Middle, Outside)
RR= 72,72,73

Any ideas? Do you think we need to stiffen the front or try to transfer more weight to the rear of the car?

[CSG Mike]

Originally Posted by fatoni

great question. i dont have an answer though. on a miata, a 225 on a 9" rim is about as fast as you can get on a road course. 205 on an 8" rim is faster at wsir for slower miatas. i dont know how that data translates to a much bigger car but i imagine a pyrometer and a couple sets of wheels would help figure it out. im not fast enough to need that info. i only cooked my 205 re11 on 7" rims once but i think it was my driving. i havent driven in the heat since the original azenis was new.

if i ever feel that im faster than my miata (or just get bored of it or if i decide to make my brz cool anyways) ill probably just copy the csg car. im trusting you to do all the heavy lifting.

I'm... acutely aware of what Miatas run locally

Keep in mind, aero and rolling resistance are a larger factor for the FRS/BRZ, than miatas.

Now I'm curious as to what your handle is on the other forums...

[CSG Mike]

Originally Posted by Ring Leader

Hey Mike,

Our car is developing a push on a mid-speed righthand sweeper and a righthand 90. Not sure if this is a tire issue or set-up. Last 2 races were run on Toyo R1R (Treadwear 140) and Maxxis RC-1 (Treadwear 100) both 235/40/17

Set-up
Ohlin DFV's
550lb springs front 3/20 stiffness
500lb springs rear 5/20 stiffness
LF camber= 3*12'
RF camber= 2*30'
Rear camber= 2*15'
OE front swaybar
Disconnected rear swaybar
3mm toe out front
2mm toe in rear

Ride Heights (from ground to fender)
LF 64.5cm
RF 65.5cm
LR 66.5cm
RR 67cm

Weights(with driver)
Total= 2830
Left%= 52.05
Front%= 56.86
Cross% (RF-LR)= 49.21

Tire temps
LF= 98, 88, 80 (Outside, Middle, Inside)
LR= 80,80,80
RF= 90,80,81 (Inside, Middle, Outside)
RR= 72,72,73

Any ideas? Do you think we need to stiffen the front or try to transfer more weight to the rear of the car?

Pure setup.

Your static load balance is way off.

Assuming motion ratios of 0.95 front, and 0.75 rear, look at this ratio:

Front effective spring = 550
Rear effective spring = 500 * 0.75 = 375
Front effective spring % = 59.45
Rear effective spring % = 40.54

Keep in mind that motion ratio in the rear is probably lower than 0.75, so my numbers are off.

Now add the fact that you're adding MORE spring to the front with the front sway, and no rear sway, and you're overloading the fronts, causing the fronts to always wash out before the rears, short of a massive driving error or forcing the rear to come out.

Now, because you have this static understeer, you're trying to fix it by adding front toe-out, which helps initial turn-in, but hurts static grip, making the front understeer even more.

The rear toe-in, I'd guess, is to help stabilize the car, because any oversteer that occurs with your current setup is violent.

Proposed Solution:

Increase front camber to -3.4 on BOTH sides, and increase rear camber to -2.35. Your inside pyrometer readings are higher because you have too much toe.

Soften your front springs, or add rear springs, and re-connect that rear sway bar.

Then, zero out your toe, front and rear. The car will be "looser", but far more progressive. If it's too loose, then add 1/16" total toe-in. If it's still too loose for your taste, then add more rear camber.

[Doozer]

Originally Posted by CSG Mike

Pure setup.

Your static load balance is way off.

Assuming motion ratios of 0.95 front, and 0.75 rear, look at this ratio:

Front effective spring = 550
Rear effective spring = 500 * 0.75 = 375
Front effective spring % = 59.45
Rear effective spring % = 40.54

Keep in mind that motion ratio in the rear is probably lower than 0.75, so my numbers are off.

Now add the fact that you're adding MORE spring to the front with the front sway, and no rear sway, and you're overloading the fronts, causing the fronts to always wash out before the rears, short of a massive driving error or forcing the rear to come out.

Now, because you have this static understeer, you're trying to fix it by adding front toe-out, which helps initial turn-in, but hurts static grip, making the front understeer even more.

The rear toe-in, I'd guess, is to help stabilize the car, because any oversteer that occurs with your current setup is violent.

Proposed Solution:

Increase front camber to -3.4 on BOTH sides, and increase rear camber to -2.35. Your inside pyrometer readings are higher because you have too much toe.

Soften your front springs, or add rear springs, and re-connect that rear sway bar.

Then, zero out your toe, front and rear. The car will be "looser", but far more progressive. If it's too loose, then add 1/16" total toe-in. If it's still too loose for your taste, then add more rear camber.

Thanks Mike,

Greatly appreciated. We'll give it a shot and let you know the results. Next race will be mid June.

For reference:

[fatoni]

Originally Posted by CSG Mike

I'm... acutely aware of what Miatas run locally

Keep in mind, aero and rolling resistance are a larger factor for the FRS/BRZ, than miatas.

Now I'm curious as to what your handle is on the other forums...

can you explain what you mean by that? oh and im fatoni everywhere i think. this has been by far my most active forum since its a new car and there has been a lot of learning.

[Thongpocket]

So i've been looking into a competition seat due to a need for about 2" of headroom with my helmet on and I like the Sparco Evo 3 seat. Has anyone found alot of headroom with any particular aftermarket seat? I would like it to have provisions for anti-sub belts as I plan to cage and harness as well. I looked in the interior forum and didnt find much help.

[ddeflyer]

Originally Posted by Thongpocket

So i've been looking into a competition seat due to a need for about 2" of headroom with my helmet on and I like the Sparco Evo 3 seat. Has anyone found alot of headroom with any particular aftermarket seat? I would like it to have provisions for anti-sub belts as I plan to cage and harness as well. I looked in the interior forum and didnt find much help.

I setup some cobra seats on a planted base in my car. I hard mounted the seat and was able to get a nice upright position with about half an inch of clearance where before I was having to recline the seat a substantial amount just to get in while only rubbing the headliner with my helmet (I'm 6'). Further drop would have been possible if I had used steel mounting plates instead of the thicker aluminum ones or if I didn't like such a upright position. If you were needing more and were willing to modify the floor pan then you could probably get quite a bit more drop but that would involve alot of work.

[7thgear]

Originally Posted by CSG Mike

Keep in mind that motion ratio in the rear is probably lower than 0.75, so my numbers are off..

actually it depends on where the car sits, and is around 0.8-0.82 according to my measurements from OEM height through 30mm of compression


see my notes starting on post 120 and on
http://www.ft86club.com/forums/showt...t=26661&page=6

[CSG Mike]

Originally Posted by fatoni

can you explain what you mean by that? oh and im fatoni everywhere i think. this has been by far my most active forum since its a new car and there has been a lot of learning.

The Miata doesn't see the speeds the FRS/BRZ sees, and it can't afford to "tuck in" the wheels.

The FRS/BRZ can "tuck in" the wheels for better aero, without giving up any motion ratio or tire width.

Also, we have more tire options. Different tires make a HUGE difference depending on the track. Stock tires will show a 15 mph differential at ACS Roval, versus sticky 255 tires on low offset wheels.

[CSG Mike]

Originally Posted by 7thgear

actually it depends on where the car sits, and is around 0.8-0.82 according to my measurements from OEM height through 30mm of compression


see my notes starting on post 120 and on
http://www.ft86club.com/forums/showt...t=26661&page=6

We used 0.83 when we did our car... with a 35mm drop.