I have had mine for about two weeks (TC 5spd). I got out on the highway and desided to let it go a little. At 85+ mph it seamed to get a little loose and at 95 I shut down because it did not feal stable at all. What would be the fix, and have others felt the same thing. I ahve had alot of cars and trucks that I could do over 100 and not be to worried.

 

I've had mine since just after thanksgiving and it feels fine on the highways. I drive 90 on a regular basis and it feels smooth and stable, my girlfriend can't even tell! I haven't tried to take it to 127, but I feel it should be fine, the fastest I ever drove was right around 127 in my integra, and that felt fine too. If you don't think the car feels stable enough you could try to lower it.

PS you would definately lose your license if you got caught going 100+, and if you go double the speed limit that can be counted as reckless driving, which you can go to jail for.

 

I've been told that it's more beneficial to put only a rear sway on the car, as opposed to both a strut bar and rear sway... can anyone validate this claim or explain why exactly having only a rear sway on the suspension setup can be better?

 

If you are talking about ride quality then the sway bars should be felt very little so i disagree with:

Swaybars are felt in the turns only, or when one side is higher/lower than the other. When you hit a speed bump the bar just goes up and down with the rest of the suspension. We have 2 tC's one with trd sway bar and one without (both with no other suspension mods) so I speak from experience here. Stiffer shocks will greatly affect ride harshness, especially in the rear. Springs will slightly harshen the ride, but you have the TRD springs which are progressive so they are a good compromise between comfort and performance.

Also, with springs and shocks you will get some degree of roll control, but if that is your goal then that job is much better handled by the sway bars for reasons of ride quality (and internal organ health).

An old rule i heard was the more air you put in the more traction you get, up to a point. On the civic forums that point was 45psi regardless of what it said on the sidewall of the tire. Adjusting tire pressures should be done as a final fine tuning change since you can only go so far with it or else you will have uneven wear on the tires. And just arbitrarily choosing a pressure may just do that, hence the old shoe polish/chalk on the sidewall to see just how much the tires are rolling over.

The front strut bar will sharpen up steering response, if it is sloppy to begin with. But since the strut towers are practically part of the firewall, there is little improvement to be had on the tC.

 

tire pressure will allow for alittle better handling.. as long as you do not run too much pressure.. for example.. running 45psi on a tire that reads 35psi max.. may cause unwanted problems... uneven tire ware..for one... however.. running the pressure at max or close to it will work fine..

the reason for better handling with higher pressures is due to the fact the your sidewalls especially in taller tires will stiffen alittle do to the higher pressures and not flex as much.. but the contact patch will remain the same... (too much pressure however and the patch may actually decress).. and too little pressure.. think about when you get a flat and how the car feels...

you must also remember.. any tire when new.. will feel skirmy compared to one that has half it's life/tread gone, due to tread block flex... thats why alot of racers will buy new tires and have them shaved down.... not that im advacating taking your new tires and having them shaved.. but just something to keep in mind when you talk about handling.. and how the car feels..

 

i'm worried the stockers will hydroplane even worse at half tread than full. wish 16" alloys were stock and 17"+ was options ;P

 

I was a part time suspension guru aka hack on a few other boards. Increasing sway bar stiffness makes a car corner flatter at the expense of ultimate grip, complete non-sense that a sway bar allows you take turns a higher speeds. There is no magic, sway bars make a car flatter but at LESS grip. In general for racing purposes you would tune the bars for a neutral car AFTER the rest of the suspension is sorted.

Since this a a FWD, there is moderate understeer (front end plow), increase the RSB will bring the car to a more neutral altitude. A dangerous thing for most people in most situations. Hence the factory design moderate understeer into the car to begin with.

My last car a VW Jetta I ran with a true autoX suspension that as an aside does not lower the car, I ran NO front bar at all and a very large RSB in addition to the OEM stock sway bar. My car did behave in a true neutral design. IE all four wheels would break away in a linear fashion. This setup is perfect for ultimate adhesion and with a competent driver will remain safe. But if I should do something like brake in a turn the car could easily swap ends, even mild braking would cause the rear to wiggle out. Ask yourself how many times that you needed to scrub off a little speed while in a turn that you were pushing it. Well in a true neutral setup, you would be at best in a ditch.

I’m sure the TRD bar brings the TC more toward neutral, say maybe mild understeer.

I’m sure that the Hotchkiss bars make the car handle flatter, but as I’ve stated above it does it at the expense of ultimate grip.

I plan on showroom stock racing the TC in the autoX and can’t change out the factory bars, I can only do dampers, and I intend to wait for Koni to come out with a set.

If I did not plan to AutoX, then the TRD bar to my mind would be the best at the COMPROMISE improving the flatness of the car, bring the car to a more neutral handler with the cost being less ultimate grip on the rear of the car. To my mind I would never upgrade a front bar on a FWD with 60% of the weight on the front tires. Just because a company makes a bar does not mean that it is needed.

On the last note, many companies go to progressive “performance springs” these have a bad habit of soggying up initial steering response. The “fix” for the soggy steering is to go for a fatter front bar, all good now the buyer can have cushy progressives and still have a tight turn in, BUT this is achieved by compromising ultimate front end grip. IE the car will feel a whole lot flatter and precise till the tires skid out far early then they would with an OEM stock setup.

I've been to a lot of races and I've seen a lot of "performance" setups slide out while a show room stock car easliy dominated.

Of course I have lots of data, and experience to back up the above claims. There is no FREE lunch if there was every car in the world would just leave the factory with MENGUS sway bars.

 

great post oldman, everything is a compromise with cars but dumping more money into it will lessen the trade-offs sometimes as you mentioned. just depends how far one wants to go for a street driven car.

 

best way to get the best of both worlds is a good set of tires, the trade off there is "only" money.

 

unless you're talking about the RE92's then it's more money for less tire

 

true dat

 

I did want to say some things
First I have not tried nor do I know of anybody with the F&R sway bar, so I’m only saying theory which is NOT where the rubber hits the road.

Second I should have mentioned that the stiffer the suspension, the less movement and hence the less applied bar. So a good stiff set of springs and shocks will need MORE bar to a lot MORE bar to have the same amount of applied bar. If you are going to tune a car with a stiff performance suspension, then yes I could see a need for a front bar depending on the type of spring and shock.

That said, progressive springs owners are cautioned about too much bar, this is NOT a band aid to cover sloppy turn in caused by progressive, in the case there is lots of applied bar due to the soft progressive setting and going to a bigger bar will reduce ultimate grip, possibly by large amounts. Of course there are many progressive springs that are stiffer then stock even on the soft non-set portion of the spring. So you really have to work with a shop that has done the work and knows their stuff like full stack vs open progressive rate vs stock rate, vs the jounce and rebound of the damper (stock, TRD or coil over for now).

Just to clear the air as blanket statements about a product are just that.

 

i read a while back that the miata, which happens to handle quite well stock maybe more so due to 50/50 weight distribution?, looks like it is almost going to flip over when cornering hard due to the amount of body movement but that obviously hasn't hurt it's abilities.

 

right, nothing wrong with movement, especially in something like the massive unequal arm rear which also has a toe out rod to give some steering while being moved.

The front of the TC is still a strut and in general a strut works best with the arms parallel to the ground and a very stiff spring. Honda up to a few years ago used A arms up front so you could lower a Honda and use progressive springs too, but as Honda has gone back to strut for this one gen, the are stuck with the same compromise, struts work best with arms parallel and minimal movement. Depending on things like roll centers etc.

The most basic thing to know is when the lower arm forms a 90 degree with the strut, the camber change goes + (bottom of tire pushed in) and the tire will have a tendency to roll over the side wall. I don't know the Scion specs and this autoX season lots will come to light. My gut feeling is toyota put a lot of movement into the suspension cause the knew Gen Y likes to tuck the tire.

A general rule of thumb is a strut can't be lowered and improve performance it is in the basic design of the strut. Some are just more tolerant. Yet in all cases the OEM height is near optimal from a performance stand point.

Don't go to the lower CG as the roll center (the tendency for the car to roll about the center line) decrease far faster then CG of the car. So yes lower means a lower CG IF the pickup points of the arm are also lowered, it really means the car will roll more if in an OEM setting. Few AutoX setups lower the car much and the AutoX is flat, bump steer never happens on an auto X so stiff springs can be used on a lowed suspension to control any more movement. On the street stiff suspension causes the tire to lose contact with the road and the skips across the pavement, NOT a good thing.

What to know what a really poor handling car is like? Stiff springs, large heavy wheels and a bumpy road. The tires will just skip across the turn yield little steering and a quick trip into the ditch.

I’ve stepped up to 17x8 OZ Titanium alloy Superleggera rims with gum ball 225 x45 tires, these are about 2 pounds rim and tire lighter then stock! This has increase the stock Scion handling to phenomenal levels. I should have done 235x45 but acceleration would start to suffer in order to give even more in corner grip.

I could say that this setup Bone Stock with wide ultra light rims is easily equal to what you would get with sway bars, dampers, springs, strut bar etc. A light strong rim and good tire is probably the most overlooked suspension improvement.

I’ve also run the Kumho 700 full race tire to “heat cycle” them down the back roads. The grip is phenomenal and now I can see I may need a race seat to hold me in at the next autoX. About where my full prep 1 LE LS1 Camaro was about .94 g, smooth surface.

The absolutely BEST news today is that SCCA has class the Tc into H stock or “HS” this means that the Scion will be a competitive package!!!! Sure it is all in fun but if the Tc went to GS where Mini plain and Integra, Celica play, it would have been SPANKED. Now it can be somebody… a contender.

 

'the next time someone's teaching why don't you get taught'

 

I think there is going to be whole lotta learning on the autoX this season, and we whould know how well the stock Scion TC with dampers work vs a full setup Scion, there is a T3 SCCA division that has already spec the Tc with OEM Supercharger!, this class go some BIG guns, but it would be fun to see a prep Tc with Supercharger really pushing it.

At the end of this season, I think we will know what setups "work". I'm waiting for Koni on my damper. The TRD suspension setup looks good and I can see that on the Tc Supercharged in T3 where suspension mods are OK, and I thinkk any rim upto 7.5 inches ride, once again racing will show what is the otimal rim size, gut feeling 17 or 16 inch diameter will prove optimal with a 235 or 245 tire. If any of you guys are intrested in T3 you can do a search and see if T3 will be run in your area. Mainly in the North and on both coast.

HS SCCA is starting this month so you guys should check your local region, almost every city has a SCCA and you gut need a helmet most clubs have loaners. Open face helmets are safer and you don't want to die of heat stroke. So a dirt bike helmet or Kart helmet is good.