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

[Lynxis]

I've got some marks there too but not nearly as many. Run 17x8 with 225 RS3s. Added mud flaps late last year so they've only been used for like 2 autocross events so far. Track semi-regularly, ~4 track days per year for the last 3 years with around 6-10 autocross events a year too. Car is WRB, maybe that has something to do with it?

[Icecreamtruk]

I've got a question regarding corner balance. A bit of prologue to the question, everyone I talk to seem to be of the idea that corner balance is of very high importance. Corner balance is done by adjusting the ride heigh on the 4 corners of the car to distribute the weight as close to 50/50 (cross weight) as possible. But if you change the ride height all that goes out the window, right?

So my question is, changing my ride height at the track to change the mechanical balance of the car is something I've started doing with great results, sometimes getting as much as over 1sec of lap times just because of a ride height change, but all of this supposely destroys my corner balance, so if corner balance is so important as everyone says it is, why do I feel like it amounts to a lot of snake oil? I dont mean that it doesnt affect anything of course, but that having a car that turns the same way on left and right turns isnt important at all? Even while perfectly corner balanced, no car will turn left and right equally (tire temps, different radius and speeds on different turns), so why even bother then at a club racing / time attack scenario then?

Maybe im not good enough, but I give 0 damns about the car turning similar to the left or the right, I'll just go slightly over the limit of grip and deal with a loose rear on every turn, whatever speed that loose rear is at is mostly irrelevant in the way I drive the car (but not lap times of course).

[strat61caster]

Originally Posted by Icecreamtruk

But if you change the ride height all that goes out the window, right?

Think about it like balancing a table, a corner balanced car is a flat table, but not necessarily a level one. Put a ball in the center and it should roll off one side dead center, not head towards a corner.

If you take a table and lift one side of it equally (adding or subtracting rake is likely what you're doing) you only changed the 'levelness' in one direction. Since corner balance is a balancing of cross weight (RF+LR or LF+RR) lifting one side (say by shimming two legs equally) of the car/table doesn't change the 'cross-balance' of the system.

tl;dr if you're moving one side of the car evenly (i.e. raising the rear by X turns) your crossweight shouldn't be drastically changed.

[Icecreamtruk]

Originally Posted by strat61caster

Think about it like balancing a table, a corner balanced car is a flat table, but not necessarily a level one. Put a ball in the center and it should roll off one side dead center, not head towards a corner.

If you take a table and lift one side of it equally (adding or subtracting rake is likely what you're doing) you only changed the 'levelness' in one direction. Since corner balance is a balancing of cross weight (RF+LR or LF+RR) lifting one side (say by shimming two legs equally) of the car/table doesn't change the 'cross-balance' of the system.

tl;dr if you're moving one side of the car evenly (i.e. raising the rear by X turns) your crossweight shouldn't be drastically changed.

Well, the table analogy makes perfect sense and I've heard it before many times as well, except tables rest on solid legs, not springs. So while not having perfect cross weight would mean effectively one wheel is in the air if the car had no suspension, it means just a little less load on one wheel relative to the rest.

For the ride height change, I changed the rear, lifted it up by 1inch to get more rake and more oversteer. But then I raised the front left side because I had an issue where my tire was rubbining on the top of the fender inside enough that it ate all the plastic, the paint in the metal and polished shiny. It was enough to lock the steering wheel in whatever position it was while it was rubbing (turn one on Mont-Tremblant for those who know the track, right hander with big elevation change at the end of a straight, taken flat out at around 110mph, scary moment to have your steering locked in place, since it is followed by a blind drop into a turn, wrong position and you are along for the ride to the barriers).

So anyways, everything you say makes sense in my head, and I took it for granted, until 2 weeks ago when I was at Mont-Tremblant, makes changes that should've made the car worse but I had to do them to save tires and fenders ended up making the car better and faster. Im sure there are other things at play, but it seemed to me like cross weight mattered little to nothing there.

[strat61caster]

Raising the LF would affect crossweight, how much depends on how much you raised it. If you pay someone to corner balance the car and want to save a few bucks raise the RF the same amount you raised the LF and I'd bet you'd be within half a percent of 50/50 all else being the same.

except tables rest on solid legs, not springs

Everything is a spring, some are just stiffer than others.

[CSG Mike]

Originally Posted by Icecreamtruk

I've got a question regarding corner balance. A bit of prologue to the question, everyone I talk to seem to be of the idea that corner balance is of very high importance. Corner balance is done by adjusting the ride heigh on the 4 corners of the car to distribute the weight as close to 50/50 (cross weight) as possible. But if you change the ride height all that goes out the window, right?

So my question is, changing my ride height at the track to change the mechanical balance of the car is something I've started doing with great results, sometimes getting as much as over 1sec of lap times just because of a ride height change, but all of this supposely destroys my corner balance, so if corner balance is so important as everyone says it is, why do I feel like it amounts to a lot of snake oil? I dont mean that it doesnt affect anything of course, but that having a car that turns the same way on left and right turns isnt important at all? Even while perfectly corner balanced, no car will turn left and right equally (tire temps, different radius and speeds on different turns), so why even bother then at a club racing / time attack scenario then?

Maybe im not good enough, but I give 0 damns about the car turning similar to the left or the right, I'll just go slightly over the limit of grip and deal with a loose rear on every turn, whatever speed that loose rear is at is mostly irrelevant in the way I drive the car (but not lap times of course).

My question to you would be, why did the ride height change make you faster?

[Icecreamtruk]

Originally Posted by CSG Mike

My question to you would be, why did the ride height change make you faster?

Very good question. Let me split the answer into two different parts, since I changed the ride height twice during the day. The first change was lifting the rear (both sides) by around 0.5". Why did I do the change? Two things, I wanted more oversteer, and I wanted to see if rake would do anything worthwhile now that I have a flat floor. This dropped my times by around 0.5s on a 2min (right under it) track. I dont know if the extra oversteer (which it did have a lot more of) or the rake is responsible. I think it is the change in mechanical grip that helped more.

The second one is easy to identify and see, since my wheel wasnt locking because the tire was rubbing on the upper inside of the fender (on the metal, not just barely grazing the plastic), I was actually able to stay flat out thru that, suddently, there was no more turn 1 and 2, it was a straight all the way, reaching up to 118mph where I had reached only 105mph before the change. That neeted me 0.8s on that sector alone. I expected the rest of my sectors to suffer since the car should be "out of whack" at this point. But my times did not change for the sector 2 and 3 (not by much at least).

Before comments on the consistency of a driver, as it is a very important thing in this kind of measurement (as it should be when talking laptimes). Im not consistant in line or inputs. I dont drive the same line every lap, braking at the same point and hitting all of the apex. I try to drive the car slighly over the limit at each turn. I try to keep a slip angle big enough that I can feel it on the butt but that cant really be seen by looking at the car go on the track. I can drive this way within a tenth on a 2min lap every lap, but every lap is different and has mistakes in different places, some of which are the direct result of a setup change.

So all of this is basically me trying to get some confirmation or denial of it corner balance is actually something important for lap times, or is it more of a driver preference towards a car that is consistant.

Edit: also, Im working with what I got (feeling, laptimes, sector times, lateral acceleration, etc...). Im not trying to prove a point here or anything, Im trying to get educated in something that is somewhat of a dark art for me (corner weight, which was the reason of my main question). Because I believe I have got it wrong, or at least not the whole picture.

[CSG Mike]

Originally Posted by Icecreamtruk

Very good question. Let me split the answer into two different parts, since I changed the ride height twice during the day. The first change was lifting the rear (both sides) by around 0.5". Why did I do the change? Two things, I wanted more oversteer, and I wanted to see if rake would do anything worthwhile now that I have a flat floor. This dropped my times by around 0.5s on a 2min (right under it) track. I dont know if the extra oversteer (which it did have a lot more of) or the rake is responsible. I think it is the change in mechanical grip that helped more.

The second one is easy to identify and see, since my wheel wasnt locking because the tire was rubbing on the upper inside of the fender (on the metal, not just barely grazing the plastic), I was actually able to stay flat out thru that, suddently, there was no more turn 1 and 2, it was a straight all the way, reaching up to 118mph where I had reached only 105mph before the change. That neeted me 0.8s on that sector alone. I expected the rest of my sectors to suffer since the car should be "out of whack" at this point. But my times did not change for the sector 2 and 3 (not by much at least).

Before comments on the consistency of a driver, as it is a very important thing in this kind of measurement (as it should be when talking laptimes). Im not consistant in line or inputs. I dont drive the same line every lap, braking at the same point and hitting all of the apex. I try to drive the car slighly over the limit at each turn. I try to keep a slip angle big enough that I can feel it on the butt but that cant really be seen by looking at the car go on the track. I can drive this way within a tenth on a 2min lap every lap, but every lap is different and has mistakes in different places, some of which are the direct result of a setup change.

So all of this is basically me trying to get some confirmation or denial of it corner balance is actually something important for lap times, or is it more of a driver preference towards a car that is consistant.

Edit: also, Im working with what I got (feeling, laptimes, sector times, lateral acceleration, etc...). Im not trying to prove a point here or anything, Im trying to get educated in something that is somewhat of a dark art for me (corner weight, which was the reason of my main question). Because I believe I have got it wrong, or at least not the whole picture.

I completely understand the relative terms in which you're speaking. You're correct; the data doesn't need to be perfect, because you've already collected enough data (and frankly, more data than 99.99% of people who ask me something and give me nothing to work with).

Now, I'd have to raise the front the same you raised the rear, an see how it affects the sectors you've mentioned, as well as general lap time and feel.

Perhaps, your car was too low, or perhaps the rake is what works well for your specific setup. This is how we find out.

[Icecreamtruk]

Originally Posted by CSG Mike

I completely understand the relative terms in which you're speaking. You're correct; the data doesn't need to be perfect, because you've already collected enough data (and frankly, more data than 99.99% of people who ask me something and give me nothing to work with).

Now, I'd have to raise the front the same you raised the rear, an see how it affects the sectors you've mentioned, as well as general lap time and feel.

Perhaps, your car was too low, or perhaps the rake is what works well for your specific setup. This is how we find out.

Thanks, I missed more time to test that out but I was certainly going to try a couple more changes, the first of which is see how changing ride height at the front only (thus reducing or increasing rake while keeping the rear where it is) affects the balance of the car and the lap times. I have the impression that my car might be too low and whatever negative effet I might get from a whacky ride height is being outweighted by the suspension geometry changes. I might report back once I have a better understanding of how it all relates.

[strat61caster]

Bumpstops might be playing a part too. Getting out of a stiff bumpstop might give your suspension the extra compliance it needs to give you a big boost in confidence.

[Turbo]

CSG: Have you driven the Tein Mono Sport coilovers on track? How about the Skunk2 racing coilovers? Interested in your thoughts on both!

[CSG Mike]

Originally Posted by Turbo

CSG: Have you driven the Tein Mono Sport coilovers on track? How about the Skunk2 racing coilovers? Interested in your thoughts on both!

What's your goal?

[Turbo]

Originally Posted by CSG Mike

What's your goal?

The car is being built to be a lapping/HDPE car that I will drive to & from the track. If I had to break it down, I would guess 15%-20% street use, the balance on the track or driving to/from the track on the highway.

I'm fine giving up some comfort for increased on-track performance. The Tein Monosport & Skunk2 are within my budget and caught my interest. Sticking with a solution at their price point will allow $$ to be budgeted for other mods like sways, bushing upgrades and cooling upgrades (Mishimoto rad & coolant hose kit?).


My FR-S has a low pressure turbo setup currently running ~250 RWHP. Skunk2 was on my radar because I'm running their oil cooler and think it's a quality piece. I also thought about the Tein Flex A, but the Monoflex might be a better fit for me. Car will probably get a back half-cage & race buckets put in next winter.

I'll be running 17x9 rims (720Form GTF1 - 16.8lb ea) with either 245/40R17 or 255/40R17 R-compound tires. AD08R if I can still find them, otherwise I'm looking for suggestions. Maybe VR-1 or RS4's? 255's may be "too much tire" though.

I was going to upgrade the front & rear bars (Hotchkis?) but don't know if they're a good fit with the coilovers.



My on-track experience is limited - a few hours seat-time lapping SN95 Mustangs over the last 2 years where I had an absolute riot, plus some open lapping sessions in a 4WD Sport sedan and race-prepped rally car (which I drove as a summer car for a few years - lol). I'm planning on somewhere around 2 lapping days a month (a full day at one track and 2 evenings at another) but budget for consumables like brakes and tires could change this (either way).

[CSG Mike]

You don't need sways with a good coilover setup.

You don't need bushings with entry level coilovers such as the models you've mentioned (and anything within that price range).

Mishimoto cooling "upgrades" are not upgrades.

I think you need to track first, and determine what you want to change, rather than blindly throw parts at the car.

I can't make a recommendation for you when you can't tell me what you want, other than "parts".