I've got a '93 touring with a strut bar and all stock components on the suspension. I've got a set of Koni Yellows, Eibach Pro Kit and a Pettit launch kit with the hard bushings ( 1 set for diff 1 set for trailing arms) but not installed. I want to get my car straightened out before I start modifying things. I'll explain.

When I'm driving on level road, the car tracks straight so I'm pretty sure my alignment is ok. I'll know for sure when I get the alignment done this weekend. The best way I can describe it is that the car feels "Darty" when I pass over imperfections in the road and it gets worse the faster I go. The strut bar helped some but I've still got issues.

When I change lanes on the interstate, the grooves where the trucks have worn the road present an issue. The lane change starts fine but then the car tries to pull to the shoulder and I have to fight it to stay in the intended lane. When I'm on back roads, the car is all over the road and doesn't feel planted at all.

I've searched the forums for a week now and can't find the answer or a description of my problem.

Everybody says that the rear bushings that I have will help but it really feels like the problem is slop in the front of the car. If that's the case, what should I replace or check? The car has 78k on the chassis and I'm sure that some of the components are worn out. Any help would be greatly appreciated. I've never had an FD before so I'm not sure if this is just the nature of these cars or not because my car has always handled like this.

 

What are your alignment specs and what size tires are you running?

Larger tires up front (ie 285/30/18's) will be more "darty" and follow imperfections in the road than let's say a 255/35/18.

My car with approx -2* front and -1* out back with 285/30/18's was all over the place like you mentioned... however not changing the alignment and only the rim/tire to a 255/35/18 the car was much more enjoyable on the street. I simply change to the larger tires when racing now. I believe this changes the overall alignment as well as the tires are different overall heights.

 

What terms did you use to search for?

Lots of talk on this....there is a lot more to an alignment than just the car tracking straight. Camber, toe, and caster will all affect stability and steering feel. Completely aside from that, wider tires and certain types of tires tend to tramline more than others (follow road ruts). To some extent this behaviour will always be present in a sports car...

 

I'm runnig stock wheels with 245/45/16 s all the way around. As far as I know, nothing on the suspension has been tampered with, it's all stock.

To address the sports car thing, I've had several sports cars and driven a lot of cars and none of them have been this bad at speed. I'm pretty sure something is out of whack.

 

What's the most likely thing to be worn out on the front end?

Should I upgrade my sway bar or would that not be the problem?

 

Did you read my post? It has nothing to do with your sway bar.

 

+1
read here
http://www.tirerack.com/tires/tirete....jsp?techid=47

my suggestion is to just go ahead with your upgrades. the bushings may indeed help. stiffer suspension may hurt. check your tire pressures. too stiff will increase tramlining as well. unfortunately, increased tramlining often goes hand in hand with certain modifications.

 

Sounds familiar

https://www.rx7club.com/showthread.p...ight=alignment

 

What kind of tire are you running?
Some tire models are more prone to tracking grooves...

Also, if you want to mess with the alignment (got your current alignment specs?), you might want to dial in some slight toe-in up front...like 1/16".


-Ted

 

IME, the 'darty' thing has been pretty consistent. The bigger/slower/more mushy the vehicle, the less darty it will feel on a slightly bumpy or uneven road. So the FD is always kinda darty, and moreso when running higher tire pressures. As Rynberg mentioned, different tire/wheel sizes will also make it more darty.

Running toe-in or toe-out will stabilize the car, but at the cost of grinding up your front tires. I run 0 toe, which is a good compromise for street, autocross, and track driving, although it's more darty this way.

Dave

 

In general: Toe-in makes the car less darty. Toe-out makes it darty, but gives faster turn-in.

For the OP, you might have some worn bushings that need to be replaced. But even if they check out okay or you replace all the ones that need it, I think your situation could be improved substantially by adjusting the alignment. As others have pointed out, alignment isn't just about making the car go straight. Different alignment settings can make the car feel stable, darty, change how much grip you have in turns, etc.

-Max

 

install all the stuff you have, get an alignment, then see if it still has the problem. chances are your alignment is off, and you'll need one anyway after lowering/bushings.

 

Wider wheels makes the car feel a ton better to me. 18x11 is the width I would go. 285/30/18 tires would be the tires I choose. the strength of the wheel matters and having a slightly stretched tire does wonders for confidence and grip. I also suggest the shorter 28/30/18 tire because the grip to stiffness of the tire is better then a taller sidewall tire.

When I really push my rx7, I also own an rx8, the thing that scares me the most is pushing really hard and deep into a corner where you trail brake and losing the rear end. Granted I was pushing my friends rx7 and I am not as used to his car, but I would recommend doing this.

Go wide wheels and get some grippy tires after you have a bunch of seat time.

Get a good alignment. I like -2+ degrees front, get around .5 degrees less in the rear or so.

If you like slow speed autox, get some FF cheap brake pads. (FF = grip of the brake pads, just get some wagner thermoquiet ceramics). if you do more high speed 100+ mph on track courses get higher friction level pads to bring the speed down quicker. go after GG type pads or some high friction level whatever.

I also think little rear bar is good and getting a bigger front bar would be worthwhile on the slower speed courses. the faster you push the car with higher grip brake pads the more the rear end dances all around and you really need to be careful trail braking.


the rx8 with the longer wheel base and higher motion ratio suspension feels a lot more stable to me then the rx7. I actually perfer the rx8 handling over the rx7.

 

Wow, you just revived a 13 year old thread, but glad you did, my fd is very darty, seems to be some good info contained in this thread!

 

I’m not a suspension guru but not sure what a “shorter 28/30/18 tire” is. And don’t think just adding tire width automatically reduces the “dartiness” of a car.
Intuitively a more neutral caster and/or camber would, as would more aspect ratio (sidewall) and more compliant suspension and bushings. Of course all those things will negatively impact handling. Wheel base and track width also come into play.
And if the road surface is grooved or sunken from heavy traffic there’s not much you could do to minimize “darty”. This is a sports car...not a GT.
Cars are kind of like a fighter plane...the more inherently unstable the more maneuverable.

 

How many miles on the chassis? Any records of bushing replacement? I just purchased another Fd (been 5 years since my last one) with 60k miles. All original. Refreshed engine and turbos. Now going through all suspension and bushing components. You need to know what's going on in this realm before blaming it on tires and so forth.