How to get tighter handling like my friend's BMW 3-series?

[JCH13]

Doesn't a stiffer rear help reduce understeer, which is probably an issue for the tC?

Yep, you'll get more weight transfer in the rear which will reduce the rear's grip faster than the front's. Similar to the way a sway-bar works.

 

[soccerballtux]

I'm not changing cars. I got such a killer deal on this one (rebuilt title at 32k chassis with 12k on an '08 replacement engine) that I'd be stupid to sell it for what little $$$ I could get for it considering it's a rebuilt-- I'd have to spend 4x+ after tax as much as I paid for this one ($7k) to get what my friend has. Not to mention the maintenance on the BMWs or an older G35c...is going to be a lot more than mine will be, plus I get 28.5mpg and those. ha. don't. They get ~20-23 (his is rated at 28mpg but that's at 48mph "highway", he gets 21mpg max.)

There may be some lag in steering but it's not bad like a Corolla, what kills me is the front side of the car opposite the direction I'm turning diving after the wheels start turning.

Front sway bars are a B to install on these tCs apparently and don't help much at all according to the modding community at Scionlife, recommended is just better suspension, hence the $1k coilovers I'm considering.

So does nobody know the scionce behind what spring rates and damping config to use in a coilover? I have an idea how I could calculate something along the lines of the number I want but I thought there might be an easy formula. I'm not sure why everyone thinks I want to turn this into a 335i. Just want it to feel stiffer and to ride over bumps better.

 

[soccerballtux]

yeah man, BMW didn't just have one guy surf online and buy bunch of OEM parts to put together 335i. It's years of experience from past BMW's, hundreds of engineers designing, testing, redesigning and retesting to get a balanced overall design with good handling, power and comfort.

Wanna have driving experience of a 335i? Just go buy it already.

<--- Proud owner of 335i

BMW has no interent you say??? I can pull it off bro1!!!

 

[soccerballtux]

Bring it.

:awe:

But yeah..OP, IMHO you're best off to save for another car. He probably has a quicker steering rack too, which has a huge impact on the steering feel you're referring to. That won't be fixed with new suspension - and speaking of suspension..., coilovers typically ride pretty rough. Great performance when set up properly, but your ride will suffer. There's no way I'd run coilovers on a DD.

Start with sways and see if that helps - then start saving for a 3 series.

you might be right about this, but I'm willing to take the $1k gamble; I think I'm able to separate while I'm driving what the steering response is in mine vs the roll, and I'm fairly confident with better shocks it would feel much nicer. If I have to get a different car to get something like a 335i feel, I'm simply not doing it. Too many stu[dent]pid loans.

 

[soccerballtux]

I just noticed this:

Rear springs are stiffer than the front?

That's 448lb/in and 560lb/in - for reference, Tein HT coilovers for a Mk2 MR2 are 224/504 respectively. Your car is about 100lb heavier than mine...I'm going to guess that those coilovers at that spring rate are going to ride like shit.


1) Run 'em till they need a rebuild.
2) That'll likely depend on the quality of the coilover- I've never looked into them, so I don't know how long they'll last. Once they're worn out, you can typically send them to the manufacturer for a rebuild (not sure if there's a DIY solution available or not).
3) No.
4) !!!
5) Absolutely.

Ok thanks. Yeah I can get the springs switched out no charge for something softer, I just have no idea what it should be.

A stiffer rear rate shifts the car more towards oversteer. The rears are stiffer than the fronts to make up for the FWD (FWD lends itself to understeer).

 

[soccerballtux]

pass on the coil overs they will ride like crap and be dead in a year your best bet to improve handling without suffering ride quality. is by going with a quality lowering spring. i use eibach on most everything i drive or any cars i happen to work on *coughjleecough* for your car i would honestly go with the eibach pro plus kit. its a set of eibach pro kit lowering springs 1.2" drop and a pair of there front and rear sway bars. this will give you a great improvement in handling over stock but not suffer on ride quailty and dont have to worry about them having to be rebuilt in a year cause they were cheap china crap! not to mention at $460 from tire rack it will save you money! and even with install and alignment youll still be undercost of just buying the coilovers.

thanks that sounds good will look into it

 

[soccerballtux]

To get better handling out of your tC you have many options. It will not turn it into a BMW 3xx because of the many reasons already mentioned, but you can certainly make it more fun to drive.

To preserve much of the stock ride quality I would keep the stock springs and not lower the car any. I would buy Koni 'yellow' Sport shocks for all four corners, on 'soft' they should be pleasant, but will get very aggressive and fun when you dial them up (free lifetime rebuilds too). Then I would get something like Hotchkis front and rear sway bars, should be stiffer than stock, and are adjustable so you can change them to balance the car the way you like. Then I would get the lightest set of wheels with the best set of 'extreme performance summer' tires I could justify buying. Dunlop Z1 Starspecs on a Kazera KZ series wheel would be a great setup.

To pick a priority:
-sway bars
-shocks
-wheels/tires

I'm confused, I thought shocks were the springs? What's the point of replacing the shocks but not changing springs? Sorry, I'm pretty new at this.

 

[soccerballtux]

^This.

The original poster specifically mentions "roll".

Stiffer sway bars in front and back will make the biggest improvement in the "feel" he is looking for without compromising ride quality or wasting money. They are a very cheap and easy mod.

Assuming his stock shocks/struts are in good condition, I would look for a good set of performance tires next.

After that I would learn to drive the car to the absolute limits of the stock suspension before spending any more money on modifications.

I watched some youtube videos of some before/after comparisons with front + rear swaybars and honestly it barely made an impact at all it looked like-- the side opposite the turn was still dipping way low and the chassis rolling....?
edit: found it: http://www.youtube.com/watch?v=ltiwTj7cbAs

 

[JCH13]

I'm confused, I thought shocks were the springs? What's the point of replacing the shocks but not changing springs? Sorry, I'm pretty new at this.

Shocks, more accurately named "dampers," work in conjunction with the springs to control your suspension. The shocks dampen the suspensions oscillations. The point of changing the shocks and not the springs is to control the car better. The stock shocks are likely valved as a compromise between comfort and handling, with adjustable valving and stock springs you can tune your suspension more towards performance without sacrificing too much ride quality, which is a decent trade-off for a DD imho.

A good rule of thumb for picking new spring rates is to keep the ratio of your front/rear springs the same. So if your stock springs are 6f/8r you should up it to 9f/12r to maintain the same 3f/4r ratio as the stock springs to maintain the stock's balance. If you want more understeer increase the fronts or reduce the rears, if you want more oversteer increase the rears or reduce the fronts. If you know the total unsprung mass on each suspension corner you can pick springs to maximize your suspension response (check out wiki for the equations, but it's basically freq = sqrt(spring rate/mass)). <1hz is a comfortable ride bordering on performance, ~1.5hz or higher is a race/track setup, the FSAE cars I used to drive were tuned for 3hz, so they were super-responsive and very harsh.

Lighter wheels/tires will improve your suspensions response because the mass in the aforementioned equation goes down, and therefore the freqency goes up. Increasing the spring rate will have the same effect. However, softer springs will generally result in a grippier, more tolerant car to drive at its limits except when the spring rates are sufficiently soft as to compromise your suspension geometry, i.e. let camber change too much during cornering.

I know this is a lot, but I am more than happy to explain how these things work in principle, and you can then make a more educated decision about what you want to do.

I watched some youtube videos of some before/after comparisons with front + rear swaybars and honestly it barely made an impact at all it looked like-- the side opposite the turn was still dipping way low and the chassis rolling....?
edit: found it: http://www.youtube.com/watch?v=ltiwTj7cbAs

Not all sway bars are the same, stiffer sway bars will keep the car flatter than softer ones and have a more profound impact on its handling balance.

 

[disappoint]

I was going to say Eibach springs but someone beat me to it, so I'll 2nd it.

I also suggest first checking if the sway bar links and bushings need replacement. Shouldn't be too expensive for that.

 

[jlee]

Yep, you'll get more weight transfer in the rear which will reduce the rear's grip faster than the front's. Similar to the way a sway-bar works.

Oh, right...derp. I saw rear spring rates stiffer than my MR2 (which has an engine on top of them) and went WTF.

Stock Scion tC spring rates are 146 / 268. Going to 448 / 560 is going to be like driving on bricks.

I would highly recommend a Koni Yellow / Eibach Pro-Kit combination. I am confident it will provide a far superior ride, and for what you're looking for, you really don't need coilovers.

$489.94 for Konis and $202 for Eibach Pro-Kit springs (or $460 for springs and sways. You'll be much happier with that than with coilovers.

 

[soccerballtux]

not a fan of the KGB

 

[soccerballtux]

Oh, right...derp. I saw rear spring rates stiffer than my MR2 (which has an engine on top of them) and went WTF.

Stock Scion tC spring rates are 146 / 268. Going to 448 / 560 is going to be like driving on bricks.

I would highly recommend a Koni Yellow / Eibach Pro-Kit combination. I am confident it will provide a far superior ride, and for what you're looking for, you really don't need coilovers.

$489.94 for Konis and $202 for Eibach Pro-Kit springs (or $460 for springs and sways. You'll be much happier with that than with coilovers.

After some research into this product of yours I think you logic is sound and, personally, I like you. It would be bad to get something to tinker with 20x [coilovers], and those progressive spring rates are ++++. I think I will do what you recommend. Good day sir.

 

[MiataNC]

I watched some youtube videos of some before/after comparisons with front + rear swaybars and honestly it barely made an impact at all it looked like-- the side opposite the turn was still dipping way low and the chassis rolling....?
edit: found it: http://www.youtube.com/watch?v=ltiwTj7cbAs

You can setup a car to be perfectly flat, but if the tires lift/unload because there is no roll (or not enough) then you end up with worse handling/control than you started with.

Being perfectly flat in a turn is not the goal. Maximum grip and smooth/controlled transitions as weight shifts is what you are looking for.

 

[alkemyst]

few other questions:
1. What's the maintenance on coilovers? Change oil like in bike's suspension?

Coilovers usually need attention paid to the locknuts time to time. Depends on brand...almost all will be sealed units so no oil maintenance.

2. How long will they last? Do they need replacement, or would I just replace the springs?

Same or less as a regular strut/shock...some are rebuildable, some aren't...figure every 40-50k.

3. Will lowering my car 1" make me more likely to get pulled over?

Shouldn't, that'd be hardly noticeable to a cop.

4. ???

You may not get the BMW feel...steering feel is hard to change. Sometimes better tires/alignment can help...sometimes rack bushings can help.

 

[alkemyst]

You can setup a car to be perfectly flat, but if the tires lift/unload because there is no roll (or not enough) then you end up with worse handling/control than you started with.

Being perfectly flat in a turn is not the goal. Maximum grip and smooth/controlled transitions as weight shifts is what you are looking for.

lifting a tire isn't bad on many cars.

 

[JCH13]

lifting a tire isn't bad on many cars.

Lifting a tire is always bad. It means you have 100% weight transfer and are getting less-than-optimal grip on that axle. Some cars can handle it just fine structurally, but it is very bad from a performance standpoint.

 

[Arkaign]

I'm going to just put it out there one more time that investing in a FF vehicle in the pursuit of improved handling with a BMW 1 or 3 series as the inspiration is a venture that can only lead to disappointment.

At best, you'll have limited gains in responsiveness while still having the host of FF weaknesses.

At worst, you'll have a less comfortable, more expensive to maintain, and out-of-spec vehicle that chews tires/suspension parts more quickly. The TC is about 3000lbs, and that's a lot of weight on the front tires when you're asking them to do pretty much everything. The bulk of the braking, the turning, and the power application is all being forced on those two little patches of grip up front.

 

[alkemyst]

Lifting a tire is always bad. It means you have 100% weight transfer and are getting less-than-optimal grip on that axle. Some cars can handle it just fine structurally, but it is very bad from a performance standpoint.

You have no idea what you are talking about. The outside rear tire on many cars is nearly unloaded anyway in hard turns.

I'd read a basic suspension book, Fred Puhn's is dated but accurate and cheap.

 

[Arkaign]

You have no idea what you are talking about. The outside rear tire on many cars is nearly unloaded anyway in hard turns.

I'd read a basic suspension book, Fred Puhn's is dated but accurate and cheap.

On a possibly related note, I noted that the last time the Stig took the UK Focus RS around the track, it did a 3-wheel turn, and they had nothing but praise for the handling. I thought it was odd, but it did turn in a great lap time considering the relatively low power of the RS (contrast to other cars on the leaderboard).

 

[JCH13]

You have no idea what you are talking about. The outside rear tire on many cars is nearly unloaded anyway in hard turns.

I'd read a basic suspension book, Fred Puhn's is dated but accurate and cheap.

I went with RCVD, or if that's too technical for you, read page 95 in How to Build a High-Performance Mazda Miata MX-5 where it says: "And that's the big lesson. Weight transfer will cost us total grip. That's bad for braking and cornering."

 

[Arkaign]

http://www.youtube.com/watch?v=cPNwmoFAap8

Stig Focus RS lap, note the inside back tire is off the ground quite a lot. What's up with that?

 

[JCH13]

http://www.youtube.com/watch?v=cPNwmoFAap8

Stig Focus RS lap, note the inside back tire is off the ground quite a lot. What's up with that?

The suspension in the rear promotes a lot of weight transfer to try and eliminate under steer from the chassis. The rear axle is saturating it's weight transfer capability before the front axle, and so the rear inside tire is lifting as the front axle starts to handle more weight transfer.

 

[Arkaign]

Design flaw, or just what happens with that setup when driven 10/10ths a la Stigness? The lap time was quite decent.

 

[JCH13]

Design flaw, or just what happens with that setup when driven 10/10ths a la Stigness? The lap time was quite decent.

I wouldn't call it a design flaw, that's too strong, it's just a compromise. The extra weight transfer in the back does limit the car's ultimate lateral grip, but the reduction in under-steer is worth it because I do not think many drivers will be traction-limited when they drive their Focus RS, but they will notice understeer, which (needless to say) isn't fun in a sporty car.