Suberman's guide on how to make the car fix his inability to drive correctly.
 

First, cut one half inch or so out of the rear bump stops. I cut this out of the hard end between the taper matching the shock dust boot and the middle section. Doing it again I'd just cut off the soft end. Once you do this your rear suspension will more or less stop hitting the rear bump stops in normal fast street driving which will make your BRZ/FRS much quicker in the corners.

Second, and if you can combine this with the above for economy since you need to take out and dismantle the rear coilovers to cut the bump stops, fit better rear shocks. I recommend Bilstein B6 (HD in North America). You don't have to do the fronts as well, as more than 75% of the improvement in grip will happen at the rear of the car.

Third, fit better front struts. I like the matching Bilstein B6. These inverted struts firm up the steering feel and front suspension rigidity in corners. Koni makes a good one also that will fit the stock suspension travel. There is no need to increase the spring rate or shorten the springs because this chassis has lots of grip on stock springs and with stock ride height.

Fourth, if you don't like the idea of reducing the rear roll stiffness then fit a slightly larger front bar instead, though I'd cut the rear bump stops and fit the correlating 16 mm rear bar as well if it were my car.

Finally, get better tires either in 215 or 225 width on stock sized rims or maybe 17 x 7.5. I fit Michelin Pilot A/S 3 but there are lots of choices out there, many of them much cheaper than Michelin especially if you don't need cold weather grip. If you want maximum grip buy the best high performance summer tires you want to afford but any improvement in tire grip improves the feel of this car.

Don't do any of this if you like to drift this car.

@CSG Mike @Racecomp Engineering @ZDan

Thoughts gentlemen??

For everyone else, I wouldn't go cutting your bump stops on stock springs. This guy claims to know more than the suspension engineers at Toyota. There is absolutely NOTHING wrong with cars using the bump stops as part of the effective spring rate, especially when they're designed to do so. Most cars on the road are designed like this because it gives a more comfortable ride.

He also contradicts himself, even in this thread.

He claims you need to cut the bump stops to reduce rear spring rate, but then suggests adding a stiffer rear bar.

Tires first, second, third, fourth

=/=

:word:
I've cut bumpstops before. It's not a terrible option, if your budget/willpower/available aftermarket options are limited.

The main difference you'll notice is with the transition from spring-controlled to (spring+bumpstop)-controlled. Instead of having a progressive transition... it will be more "flop and plant" operation.

I noticed it most when doing slaloms. Weight transfer was not exactly smooth. Effective, but not elegant.

I use the bump stops as part of the rear spring rates. The car is designed to do so from the factory (yes, we know there is short travel, and so do the Subaru engineers... hence why the bump stops are part of the suspension).

This is also why the spring rates seem so "off" from the factory; the springs alone don't tell the whole story.

Clutch grab adjustment should be one of the first mods done.

Which tire should I do first? I feel like the front right...

The OP should go to Toyota or Subaru and teach all those engineers a thing or two about suspension tuning. Maybe even Bilstein since they designed the B6 and B8 dampers to be used with full length bumpstops. Guess they were wrong too.

Suberman is that you????

Sent from my Nexus 5 using Tapatalk

^^ this.


The bumpstops are part of the suspension. They are there partly to protect the damper but also to increase spring rates when the coilover assembly compresses enough. They are even progressive for that reason. Hell aftermarket spring companies design specific bumpstops in some cases and even include that in their spring rate calcs with a specific deflection %. I've cut them *when needed* but I wouldn't on the stock rates/stock springs.


The OEM dampers are also quite good for street driving. They aren't perfect but they are fairly well matched to the stock springs, which is the point... They don't have fancy valving, but neither do Bilstein HDs (and I like the Bils).


Then to suggest those tires... when tires make the most difference..


I guess he never specified what difference he was trying to achieve though.

It most definitely is.

Thanks!! That made me laugh out loud.

So, replace the rear struts, but not the front struts. Ok.

Then replace the front struts. Didn't you just tell us not to replace them?

And why replace the struts at all? The OEM struts are fine. Replace the springs and keep the OEM struts.

Shorten the springs? Like, cut them? Might as well, since you're cutting the bump stops already.

Stop trying to reinvent the wheel, dumbass. There are plenty of people who know a whole lot more than you who have already designed much more effective systems that don't require hacking bits of the OEM suspension off or replacing two out of four struts at a time. Quit trying to sound like the authority when you have no idea what you're talking about.