Racing Logic Please help!

[feelio]

1993 Type R, 235/45/17 (Front) 255/40/17 (Rear)
I\'ve bought some racing Logic coilovers and am having problems with the set up. The car was fine on the standard shocks and springs but I wanted a lower firmer ride.
The Racing logic seems too soft, even on the hardest setting the back end bottoms out when exiting roundabouts too hard (for example). Also the car has developed a distinctly unsettled feeling at speed and through corners, not cool!
I\'ve been to a suspsension specialist and they recomend changing the springs. The racing Logic are 10kg ( I think) does anyone know what spring rate would suit? My brother has a tein set up ( I have no idea which one) which is quite firm but the spring rate doesn\'t seem to be printed on the spring.
Any help advice or suggestions welcome.

[AtomicRex]

For track racing, we run an 800/600 combination.  For fast road it would be 550/500
 
These are in lbs

[Macer]

Not that I\'m an expert (far from it!!) but I\'d say 10kg springs are more than firm enough for road use, so I doubt that\'s your problem. In fact, that\'s not far off what Atomic Rex has just mentioned for their road setup:

10kg/mm sq. = 559lb/in sq.

I have Aragosta\'s that are 10.3kg front and 7.8kg rear and they\'re definitely firm enough!!

Maybe it\'s the preload setting?...

[TonyC]

10kg springs are too firm for race use. I also run a 800/600  and that was what Ohlin recomend for racing. Max in the nippon has also moved away fromhis orignal 10k rears to the same rate as myself.

I\'m not too sure the car is bottoming out - it may be so bleeding hard it feels to be bottoming out but is either just stupid stiff or so low there is no more suspension movement.
Both of those (too stiff, or no travel) will make it feel very unsettled as well, as suspension needs to move to allow it to work.

I would check the suspension travel to see if has any - and if not, give it some travel, then back off the dampers and see how it feels.

You need a compliant spring, with firm damping, not a piece of scaffold tube masquerading as a spring, for good handling.

[Macer]

10kg springs are too firm for race use.

I take it you meant road use?

I\'ve read before (on this thread http://www.rx7club.com/showthread.php?t=723617) that 8kg/6kg is a decent spring rate front to rear, for both street and track, with 10kg/8kg being the outer limit, for street use at least.

In your experience, would you say that sounds reasonable. If not, what rates would you suggest?

[feelio]

I would check the suspension travel to see if has any

I had set it up fairly low to begin with, but not so bad the wheels were inside the arches. Probably about a 20mm gap front and rear. After experiencing the bad.....I raised it up a fair amount to see if it made an improvement. I think there was a bit but there is still the distinct feeling that it\'s trying to kill me when I turn the wheel!
I also tried different settings on the damping with little success.

I\'ve gone and had a proper look and it says 180mm 10kg (front) and 180mm 6kg (rear)
According to what you have said this should feel stiff......to me there is very little difference from the standard setup when it comes to body roll and general stiffness. It\'s like a limo compared with my brothers on the Tein setup which I consider to be a firm but not ridiculous. :2Confused

I am certainly no expert (You may have guessed!) but I know the basics of coilovers, is there something I\'m missing on these?

[RobMatthews]

have you had the tracking and wheel alinment set up?now you\'ve changed the suspension and height it all has an effect!

[bwillbond]

That\'s very well said, I\'d check the tracking and wheel alignment! (I\'ve been saying this for how long??)
I reckon you should finish painting your living room, clear the garage out and get the car in there so we can get wheels off and start over.......
Like it was said earlier, it might be a travel issue too or the preload. The shocks have so many settings and general concensus is that the springs are plenty hard enough for fast road application.

[feelio]

I guess that is a starting point, I do need to check the wheel alignment and that nothing has changed, although having said that the car had 4 wheel alignment set up by a local racing team with the racing logic on. The only change I have made is to change the tyres.
I\'m fairly sure the travel is more than adequate, not only was it never that low, certainly not as low as yours bro, but I raised it up to see if that would make any difference.
The preload is an issue, I\'m not 100% on what changes affects what?
Maybe I will just have to spend the money and get the whole lot (Ie ride height, preload and damping) setup professionally. Something I really didn\'t think was necessary just so that I could feel like I can drive the car with confidence.
Although you have all said that the spring rates I\'ve mentioned should be hard enough I can\'t get out of my head that it feels no firmer than the standard setup I took off the car. :3Confused