How to screw up your cars handling and ride - step by step!

[churchx]

Not that familiar with FHI500, but some of turn-in sharpness might be enhanced with tires of stiffer sidewalls. Eg. something from UHP tires, like Michelin PSS & PS4S/Yokos AD08R/GY Eagle F1 supersport/Conti sportcontact 6/Vredestein Ultrac Vorti/Falken Azens FK510/GT Radial Champiro SX2 and so on ..
Of course also keep an eye on tire pressures not too low.
Possibly i'd also install steering rack lockdown and maybe rear subframe inserts.
Also if it's due alignment .. what alignment camber/toe wise you have now?

[Will BRZ]

Originally Posted by Bluefire98

Neat thread. I just replaced my stock wheels that had cheapo all season tires installed from the dealer (bought my car used at 42k miles) with some 225/45r17 firehawk indy 500's on some 17x8 +35 tsw's. I don't feel I've overtired the car but some response was lost a bit compared to the old tires even after a few hundred break-in miles. My car goes in for an alignment hopefully next week so I think that should help (installing the oem crash bolts too) but I'm kinda worried that alone won't get the response to the level I want. Seems like some people say springs are the answer? Just curious what methods are out their to increase the steering response of this car with some grippier tires.

That’s interesting. How exactly has the responsiveness changed? Does steering feel “numb” or do you just feel less connected? I’ve heard lots of good things about those tires and it sounds like you have a decent setup so it’s kind of odd you’d lose responsiveness. Those tires are certainly grippier than what you had before so maybe it’s just something to get used to What’s the suspension setup?

[Bluefire98]

Originally Posted by Will BRZ

That’s interesting. How exactly has the responsiveness changed? Does steering feel “numb” or do you just feel less connected? I’ve heard lots of good things about those tires and it sounds like you have a decent setup so it’s kind of odd you’d lose responsiveness. Those tires are certainly grippier than what you had before so maybe it’s just something to get used to What’s the suspension setup?

I'm on stock suspension. The improved grip is really wonderful but the turn in is not quite as sharp. I still feel connected but it seems like there's a slightly larger on center dead spot than before. It's mostly noticeable during in town speeds around 35mph. It's actually not too big of a difference but for autocross having quick steering inputs is important to me. Otherwise the car feels really good with this setup and I'm very excited for the next event

[StraightOuttaCanadaEh]

Originally Posted by Bluefire98

I'm on stock suspension. The improved grip is really wonderful but the turn in is not quite as sharp. I still feel connected but it seems like there's a slightly larger on center dead spot than before. It's mostly noticeable during in town speeds around 35mph. It's actually not too big of a difference but for autocross having quick steering inputs is important to me. Otherwise the car feels really good with this setup and I'm very excited for the next event

Increase tire pressure?

[strat61caster]

Check toe or newfound steering rack bushing deflection with the heavier/grippier setup.

I've got a set of bushings I've been slacking on installing for a long time, hoping they'll go in soon...

[Impureclient]

Originally Posted by Bluefire98

I'm on stock suspension. The improved grip is really wonderful but the turn in is not quite as sharp. I still feel connected but it seems like there's a slightly larger on center dead spot than before. It's mostly noticeable during in town speeds around 35mph. It's actually not too big of a difference but for autocross having quick steering inputs is important to me. Otherwise the car feels really good with this setup and I'm very excited for the next event

Since you're already going down on this path before you get the alignment done, I'd also be doing the springs(TRDs are nothing too low and always recommended highly in here) along with those crash bolts and steering rack lockdown before.
No point in getting an alignment if you are needing to do it again later after springs/coils. If you do get the lockdowns, check on Ebay as there is a copied version of the Perrin ones for a fraction of the price. I've done everything above
including the same Indy 500s but GTF1 17x8 wheels and wouldn't have changed a thing now.

[Bluefire98]

Thanks for the replies. Yeah I've been debating just springing for springs already but I'm pretty much out of money for car mods this month and I'd like to get the alignment done before the event anyway. I was thinking rce yellows instead of the trd's for the extra ground clearance and if I remember right softer spring rates (still my daily so I'd like to not die from train tracks). Sounds like I'll have to look into steering rack bushings as well. Also these indy 500s are proving to be a deal considering the grip/comfort/tread life you get for the price. 375 for all 4 after a rebate. Probably not ideal for any track junkies but perfect for the occasional autocrosser that can't afford to blow all their money on the hobby.

[FeRS]

Originally Posted by Bluefire98

Thanks for the replies. Yeah I've been debating just springing for springs already but I'm pretty much out of money for car mods this month and I'd like to get the alignment done before the event anyway. I was thinking rce yellows instead of the trd's for the extra ground clearance and if I remember right softer spring rates (still my daily so I'd like to not die from train tracks). Sounds like I'll have to look into steering rack bushings as well. Also these indy 500s are proving to be a deal considering the grip/comfort/tread life you get for the price. 375 for all 4 after a rebate. Probably not ideal for any track junkies but perfect for the occasional autocrosser that can't afford to blow all their money on the hobby.

I run Indy 500s. They're American branded Bridgestone Potenza RE003s, they seem like a good tire. I don't know about the TRD spring rates, but RCE Yellows are a better fit for stock dampers than any other aftermarket spring I've seen

[Spacemane969]

Originally Posted by Racecomp Engineering

I still see people trying to get their camber "back to 0" after lowering. Don't do this!

- Andy

Why not do this? Is it because the geometry has changed after lowering? I'm always afraid of losing steering feel due to camber.

[EndlessAzure]

Originally Posted by Spacemane969

Why not do this? Is it because the geometry has changed after lowering? I'm always afraid of losing steering feel due to camber.

When you corner under load, your car's weight transfers, causing wheels and tires to lean over. If you have zero camber, you have no margin when the leaning occurs, essentially causing you to lose good contact on the inside part of the tire (meaning less grip, leading to understeer). In track cars that don't have sufficient camber, there is a telltale sign: more wear on the outside half of the tire vs inside half of tire.



Having negative camber will counteract this and actually improves steering feel (since your car has a better contact patch under loading).



(Too much) negative camber also has some side effects. Obviously, the outer edge of the tire will not be doing much when you're traveling in a straight line and result in uneven tire wear. Camber also cause the car to steer into natural divots and banking of the road due to increased grip bias (the tire that is leaning will pull more).

[George Rosebush]

What's the stock camber front and rear?

[churchx]

For these cars? Click.
front: 0 camber, 0 toe
rear: -1deg12' camber, slight +0deg10' toe-in.
With understeer-ish bias and monstrous +/- "passing" ranges (eg. rear toe from toe in to toe out), at extremes of which car might be PITA to drive and not even track straight or have other handling issues (eg. nervous oversteery rear, if to toe-out).
Even if buying it new, even if deciding to stock alignment, worth checking and evening it out if needed, at least once.

[biggie]

This is my current setup: OZ Alleggerita HLT 18" J8 ET48 + Federal RsR 225/40 + SPC camber bolts (-1.2 front camber), the rest is stock. I also have header/catback/stage2+ and good brake pads and fluids (NED's oil cooler is also on it's way). I'm using the car as DD but also for more than 10 trackdays per season and few mountain runs.

This is my problem: after switching from MPSS to Federal I gained about 1 second on a 2 minutes track but the grip loss is way less progressive/predictable and the front end is more prone to understeer. Fun factor is down a lot.
In the long run I'm planning for coilovers but for now I'm looking for a "quick fix" for this (other than going back to MPSS). Based on what I've read on this topic I'm thinking some RCE yellows could be the fix I'm looking for (along with powerflex bushes for camber adjustment that should add an extra -1 degree front camber for some -2.2 in total). What do you guys think?

Note: weight (vs stock wheels) with MPSS is about -4lbs per corner and about +1lbs with Federal.

[Racecomp Engineering]

Originally Posted by biggie

This is my current setup: OZ Alleggerita HLT 18" J8 ET48 + Federal RsR 225/40 + SPC camber bolts (-1.2 front camber), the rest is stock. I also have header/catback/stage2+ and good brake pads and fluids (NED's oil cooler is also on it's way). I'm using the car as DD but also for more than 10 trackdays per season and few mountain runs.

This is my problem: after switching from MPSS to Federal I gained about 1 second on a 2 minutes track but the grip loss is way less progressive/predictable and the front end is more prone to understeer. Fun factor is down a lot.
In the long run I'm planning for coilovers but for now I'm looking for a "quick fix" for this (other than going back to MPSS). Based on what I've read on this topic I'm thinking some RCE yellows could be the fix I'm looking for (along with powerflex bushes for camber adjustment that should add an extra -1 degree front camber for some -2.2 in total). What do you guys think?

Note: weight (vs stock wheels) with MPSS is about -4lbs per corner and about +1lbs with Federal.

That is what I would expect with that change in tire for your car. You need more negative camber in front. RCE Yellows will help overall but more camber would make a very good difference.

- Andrew