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-   -   How to screw up your cars handling and ride - step by step! (https://www.ft86club.com/forums/showthread.php?t=67345)

Racecomp Engineering 06-04-2014 03:06 PM

How to screw up your cars handling and ride - step by step!
 
I remember the first time I drove a BRZ a little before it hit the streets and thinking....damn....Subaru/Toyota got serious.

Anyway, this is a list of things that I see owners doing to their 86's...often with good intentions and parts bought hoping to improve things, but they end up chasing more parts to get things right. All of these on their own are detrimental, but can sometimes be "worked around" to some extent. Unfortunately many cars check off multiple boxes and sometimes all of them...resulting in a car that is a big step back from the factory.

I'll skip "stanced" cars (slammed, stretched tires, massive camber)...I don't think anyone does that expecting not to sacrifice function for what they think looks good. Different strokes.

These are some of the common things I see:

1. Staggered wheels/tires

It's a good look and definitely makes your car look like it has a lot of power. Unfortunately our cars don't have a lot of power.

It's also a great way to build in some extra understeer that's difficult to tune out. Staggered wheels are common on cars with a lot of power but are not necessary MOST the time here.

This one CAN be worked around but there's just no need to complicate things.


2. Big ass heavy wheels

Even if you got a great deal on a buddy's 18x9.5 wheels, it may not be a great idea to use 27 lb steamrollers at each corner. Most of us don't need that much tire either. Keep it light and it'll feel like your dampers are much more capable. You'll stop and go faster too.


3. Big drop on lowering springs

If it looks a racecar then it must handle like one, right? Unfortunately, it doesn't exactly work like that. A little drop can improve things with proper spring rates, but past an inch or more and you start making big compromises and riding the bumpstops before you even hit a bump. It's a sure way to downgrade your handling. Aftermarket shocks may help in some ways, but don't solve the travel problem.


4. Big drop on coilovers

With some coilovers you don't need to worry about bump travel as much, but geometry is still a concern when lowering 2 inches. A big change in roll center height and changes in the dynamic alignment can be felt from the driver's seat...and it feels sloppy.

I know what you're thinking. There are a ton of cars on here that hit the track and handle well with a lowered ride height. If you must have that really low center of gravity than you must use very firm spring rates (and then quality dampers to match) or use geometry correction parts. That's what the fast guys and girls at the track are doing....not slamming their crappy coilovers to the ground and expecting all to be well.


5. Poor or mismatched dampers

Whether it's running very stiff springs on the stock shocks (or riding the firm bumpstops), or turning your adjustable dampers up to full stiff, damping that's not matched to the springs won't feel good. Underdamped will feel bouncy, floaty, and generally crappy in transitions. Overdamped will feel harsh, crashy, and might hurt your back. None of this is good for ride quality or handling.

Sometimes an adjustable won't have a "good" setting because the quality of the valving is just plain bad. This is more noticeable with firmer spring rates.


6. Alignment

Anything less than -1 degrees camber up front is a recipe for understeer. I still see people trying to get their camber "back to 0" after lowering. Don't do this! Tire wear isn't really a concern until you get to -2, so don't be shy...add a little camber and enjoy. Most enthusiasts will get BETTER and more even tire wear anyway. Toe is the tire killer.


7. Tire choice

Really stiff springs with all season or OEM tires can reduce grip as you'll be quickly/easily overloading the tire. Match your spring rates to your tire choice.

Running sticky tires on soft OEM springs is a problem too, but you will still gain grip from the tire. It'll just feel sloppy and move around a lot.


--------------------------------------------------

Follow all of these steps and you can turn your well tuned factory BRZ/FRS into a sloppy, numb, slow reacting, pig of a car. Please don't though, it's too much fun when set up right.


- Andy

Racecomp Engineering 06-04-2014 03:07 PM

I know that sometimes there are extenuating circumstances like budget, timing, significant others, looks, class rules, etc.

Please don't take the list as an insult or a shaming thing. These things happen to all of us. Sometimes when you do one mod it means you really should do another and there's some overlap there. :)

The point is to do your research and plan carefully. And be honest with your goals, budget, and timeline.

- Andy

mokinbird87 06-04-2014 03:20 PM

#7 seems to get overlooked A LOT.

OrbitalEllipses 06-04-2014 03:30 PM

So like, what 90% of this board does?

:lol:

fooddude 06-04-2014 03:31 PM

Does running low offset wheels have any negative/ill effects for track? (excluding aero and extra bearing load)

Let's say if I wanted 8"et5 or 8.5"et10....





.

Racecomp Engineering 06-04-2014 03:37 PM

Quote:

Originally Posted by OrbitalEllipses (Post 1778271)
So like, what 90% of this board does?

:lol:

:lol:

It's not just this board. People love the look.

EDIT: and to be fair a lot of people are new to this. I've made my sure of mistakes too. I'm not trying to call anyone out or make anyone feel bad.

- Andy

husker741 06-04-2014 03:38 PM

Say that the alignment is good, dropped on RCE Yellows, square setup, and everything else is up to par, what wheel size would you recommend? I'm looking at 18x8 or 18x8.5. I know going 18's compromises a bit, but I would think 18x8 square is much better than 18x9.5 with the car being NA.

More of a DD, but tracking sometimes.

s2d4 06-04-2014 03:39 PM

I should have tried harder.

Racecomp Engineering 06-04-2014 03:39 PM

Quote:

Originally Posted by fooddude (Post 1778279)
Does running low offset wheels have any negative/ill effects for track? (excluding aero)

Let's say if I wanted 8"et5 or 8.5"et10....

That would also be a bad idea.

- Andy

Racecomp Engineering 06-04-2014 03:42 PM

Quote:

Originally Posted by husker741 (Post 1778304)
Say that the alignment is good, dropped on RCE Yellows, square setup, and everything else is up to par, what wheel size would you recommend? I'm looking at 18x8 or 18x8.5. I know going 18's compromises a bit, but I would think 18x8 square is much better than 18x9.5 with the car being NA.

More of a DD, but tracking sometimes.

It comes down to weight and budget. Yes you can a nice light 18x8.5 wheel but it's gonna cost a heck of a lot more than a 18x8 (which we ran on our car). Same idea with a 17 inch wheel.

One thing I was thinking about putting down was massively overtiring the car. Even if it can increase cornering speeds, it may not lower laptimes and it's sometimes just not as fun.

- Andy

husker741 06-04-2014 03:46 PM

Quote:

Originally Posted by Racecomp Engineering (Post 1778320)
It comes down to weight and budget. Yes you can a nice light 18x8.5 wheel but it's gonna cost a heck of a lot more than a 18x8 (which we ran on our car). Same idea with a 17 inch wheel.

One thing I was thinking about putting down was massively overtiring the car. Even if it can increase cornering speeds, it may not lower laptimes and it's sometimes just not as fun.

- Andy

Yup, I would definitely look at the weights of the wheel. The reason I've held off so long on wheels and tires is so I can spend the money to get nice, light wheels once, and do it right. I have no problem spending more, as long as I am choosing the best wheel for my car.

What size tire did you run on 18x8? What would you recommend for 18x8.5? I'm looking into Michelin PSS because it's a daily more than a track car, and we get a ton of rain down here.

Thanks for all your posts. I have learned SO much from reading your info. The RCE and CSG guys on here are BY FAR the best, most knowledgable posters on the site.

7thgear 06-04-2014 03:51 PM

the number one mistake people make is bothering to upgrade the car at all


upgrading for the sake of upgrading shows outright ignorance and stupidity


if you're going to change something on a car you better damn make sure it will actually change some characteristic for the better and not for the worse.


I think the vast majority of the tuning industry is fueled by the willingness to express oneself.. which isn't a bad thing... if only it wasn't so heavily masked in the assumption that all of these upgrades are for a net performance benefit... que in the initial post ^^

Racecomp Engineering 06-04-2014 03:56 PM

Quote:

Originally Posted by husker741 (Post 1778340)
Yup, I would definitely look at the weights of the wheel. The reason I've held off so long on wheels and tires is so I can spend the money to get nice, light wheels once, and do it right. I have no problem spending more, as long as I am choosing the best wheel for my car.

What size tire did you run on 18x8? What would you recommend for 18x8.5? I'm looking into Michelin PSS because it's a daily more than a track car, and we get a ton of rain down here.

Thanks for all your posts. I have learned SO much from reading your info. The RCE and CSG guys on here are BY FAR the best, most knowledgable posters on the site.

245 Michelin PSS on our 18x8 BBS CH-R. Great combo. You could go to a 255 with an 8.5 but you probably don't need to do that. Compound is more important than width and if you're new to the track you'll learn more if you don't have super wide sticky tires.

For the money a 17 inch wheel is the way to go. But....the BBS wheels were just too good looking and still pretty light. :)

Thanks for the kind words!

- Andy

bee-jay 06-04-2014 03:58 PM

All good points. I've seen this so many times in motorcycling. Well intentioned modifications making things way worse.
Sometimes you can't outsmart the engineers who built it.
They (manufacturers) spend years and large sums of money to get it right. (or pretty darn close)
And the average Joe thinks he can improve on it, most often with negative results.


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