Thought I'd make this post here because I think this is the forum with the most qualified people to answer me.

I mean, maybe I'm exaggerating but... my car doesn't seem to handle as "sharp" as it used to. I remember running into this problem when I went from 18" to 19", but then when I dropped the tire pressure to a dangerous (for streets) 32-35psi, it usually helped.

However, I've been at 35psi lately and it still handles kinda slow. There's a little bit of "lag"... that scalpel turn isn't there anymore... it feels sluggish.

There are no suspension mods on my car currently. The tires & wheels are ADR M-Sport 19" with 8.5" front and 9.5" back, Dunlop Sport 9000 tires on front 245/35/19 and 275/35/19.

I don't really want to drop the pressure anymore because I'd probably get bent wheels if I did so and went over a pothole. Any input here ?

Oh and I know the Greddy TT relocated the power steering reservoir but I don't think this would affect handling & response...

Suggestions ?

 

Well you did add an awful lot of weight to the front of the car with the TT kit... probably around 100 pounds worth. That will significantly impact the handling of the car.

 

Since your ADR 19s weigh so much, you've added a significant amount of unsprung weight to the car. The more unsprung weight you have, the sloppier your handling is going to be... that's my best guess...

 

Different tires = different sidewall stiffness. That could have a big effect. And of course more unsprung weight.

How does dropping tire pressure help performance? Seems that would just make it 'sloppier'. If you're running 19s....naughty naughty...tire pressure becomes more critical. You'll need to keep that PSI up. Those short sidewall tires don't like the heavy loads.

 

INCREASE tire pressure in front. I'm not sure what it should be for your 19 Dunlops, but I'm sure it should be higher than 35 in front!

For my 17 Toyos for the racing I pump it up to 53-54 front, 35-36 rear (measured when hot). And you have so much more weight there in front...

 

The best tire pressure is the one that creates the best contact patch to the road. Too much and you'll bulge the center of the tire. Too little, and you'll be riding more on your sidewalls. Finding that optimum psi can be tough though... I normally run 33 cold on my S03s. Anything higher, and the center of the tread wears prematurely (did it on my RE040s and my S03s).

 

Thanks for the input fellas, I'll play with my tire pressure

 

Get a temp tool to read your tires - you'll know when you have too much up front, the center will be hot compared the rest of the tread. Sounds like good starting point to push the front pressure up.

50+ psi sounds high to me, but everything you said points to front end feeling heavy and/or soft - you may need to think upgrades, i.e. sways and possibly shock/springs. Stock shocks are short on dampening IMHO. Springs are stiff compared to shock rebound and too linear.

If you're overloading the front sway bar (likely with your tire/wheel change), handling will also start to feel like you're scrubbing the front tires (soft feel or less than sharp steering response feel) - not quite the same as bad understeer, because you'd feel it almost all the time. With your extra weight and traction up front, that's almost a given. Stock sway rubber bushings are crap, too - could be worn and/or splitting - look at the sway bar mounts.

 

Steve, thanks for the informative post.

As of right now, I have 44psi in my fronts, and about 36psi in the rears, COLD. Now the front sway bar is under the hood right ? What do these "bushings" look like ? Because when they put the Turbo kit in they had to remove this sway bar... I'm not sure if they put it in correctly, if that's even possible ?

I basically feel soft steering response... I don't feel as comfortable going high speeds anymore because it just moves sluggishly... and I hate that about the car. I need to get this resolved. What would an aftermarket sway bar do for me ? Also, is it possible to play with the tightness setting on the factory sway ? How do I narrow this problem down ?

 

They probably took out your strut brace up top, under the hood, with the turbo install. The car it probably stiff enough w/o it. Probably not enough room for it.

Anti-sway bar (front) is under the car, goes across the width of the car, stock is pretty small diameter. Front sways are not usually adjustable. The bushings are just rubber between the clamp and surrounding the bar where it mounts to the car (other than at the ends). Aftermarket you typically upgrade those to harder and more durable polyurethane, preferably with ports for lube (Hotchkiss has this in theirs). Good set front and rear runs ~$300. If you end up upgrading, I recommend both, because the rear is 3-position adjustable and you can balance front to rear - I only do one-bar upgrades on front wheel drive, i.e. rear only because they usually have a lot of body roll and plow with a lot of understeer. RWD get a pair, so you can match stiffness and get closer to neutral.

I'd take it to a good tuner shop before you spend $$$ on suspension upgrades - once you change one area, you really have to ensure you keep balance. W/o driving the car, it's really hard to tell whats going on - but part of the problem could just be you've got a lot more rubber up front now, with a car that had a little tendency toward understeer to start with.

When did the sluggishness start? After or before wheel upgrade? Same with turbo - after or before?

BTW, nice slip with that 60' launch time - I agree you should be able to drop into the low 12's no problem. What are you using for a clutch? Stock? I have found the stock clutch slips badly when it gets hot, could be part of your 60' time...that and diff (viscous LSD)

 

Steve, thank you for the informative response as always.

The strut brace is still there, that's what I actually thought was the sway bar in the first place. The sluggishness started, as far as I can remember, after the wheel upgrade and then after the turbo. But the wheel upgrade got better in a week because the tires settled in, and it started handling good again. Not really so after this latest mod (turbo).

Anyway, I'm using the stock clutch. And it hasn't really slipped on me except the one time immediately after a 2nd gear burnout. Never during a launch/drag though. My rear axles are also going to get replaced because of that "clicking" TSB.

So what kind of "tuning shop" should I take it to ? Heh.

 

Hi slay2k. Figured I'd say hi since I grew up in Paramus.
A set of sways would help stiffen it up. I don't know about such high tire pressures but with a temp guage you can figure out a good pressure.

 

350ed, Paramus ? You know that's exactly where I live right now, right ? Or just a coincidence =0

I'm like 2 blocks from Bergen Community, hehe, on Paramus Rd.

Anyway, how's Cali man ? That's my dream destination...

 

slay2k, I know from your Cardomain listing
Yep, I know where that is. I grew up between Stony Lane and West Brook in the side streets. PHS 93' Still visit yearly.
I really love California. Expensive as hell, but Bergen Co ain't cheap either. I came here via Virginia and Texas but am most happy here.

 

Ahh cool man, what do you do there ? Heh. I'm hijacking my own thread.

 

www.350EV0.com

 

You run 53psi in the front for autocross? On the stock 17" RE040s I ran 36psi and they are wearing perfectly at the AutoX, right on the wear indicators. I wonder what it handles like with an additional 20psi!

 

Oh my god I just realized something...

Someone tell me, what does the STOCK front sway bar look like ? Is it silver/metal in color or is it black ?

Because when the test-pipes were installed recently after the turbo was put on, there was a connecting bar underneath the car that no longer fit and was left off the car for now. It's primarily because of the aftermarket test-pipe/exhaust combo.

I'm thinking, if this is in fact the sway bar, my crappy handling makes perfect sense... it bolted on near the cats.

Can someone show me a pic of what the stock ones look like ?

-slay

 

Oem sway bars on all Z's and G's are black.

Is the part your talking about this front brace assembly sitting on the floor jack in the pic?

 

No, I think he's referring to the U-shaped piece that connected the cats to the tranny housing.