Red-Rx7

Hey all.

I have looked through various suspension questions, and understand some of the basic concepts / designs differences of the coilover setups.

I would like a more advanced system to play with. I was thinking of the JIC FLT-A2 system, or the Tein RA, or something greator.

Cost is not really a factor, if justified.

Background:

1) 1995 RX-7 / 20B conversion. Will produce over 500 at the wheels, and up past 1k on the special days.

2) The car is a weekend/night/track warrior. My intentions are to drive it on the street on the nice days, while doing some 1/4 mile play. Also, I will be doing road-racing HPCCC events once per month in the good weather season (about 5 times a year).

As you can see, most of the time will be on the street.

3) The car will have either a 4pt or 6pt cage.

My questions:

A) How can the suspension components directly assist in the traction department? I know the logic for tires, etc. But specifically looking here.

B) If I go with a setup like the JIC, when drag racing on the street / track, do you set the rears for as tuff as you can get? Whats the logic?

C) Is there any good sites that I can read up on for various driving conditions, and in reference to setups for coilovers?

Thanks!

Mike

SpeedRacer

1. Well in general, the softer your springs/anti-roll bars and struts are the more mechanical grip you will have. Although not necessarily, because softer suspension means more body roll/pitch. This causes changes in camber and toe that once again reduce your mechanical grip. So you want to compromise. You want a suspension setup that is stiff enough to reduce body roll and pitching under accel/brake, but not so stiff as to reduce mechanical grip to the point where your car is simply skating over the rode and feeling very skiddish, especially on not so smooth roads.

2. Now bearing in mind what I said about softer suspension giving more mechanical grip, still applies for a drag racing setup. You will want a softer setup in the rear for drag racing then you would want for a street or road track setup. A stiff setup will cause you to get wheelspin, and hop more easily than a softer setup. The reason why is becaue the softer setup allows the weight transfer to go to the rear under acceleration more slowly and gradually instead of all at once. If you have adjustable struts, that is the key, you will want a softer bump setting in the rear, with a stiff rebound setting so the rear end won't pop back up after the initial weight transfer to the rear. If the rear-end pops up quickly, you are decreasing the load on the rear-tires and therefore traction as well. In the front, you will want a softer rebound setting to allow the front end to unload more quickly under acceleration to allow that load to transfer to the rear. You will want the front bump setting to be stiffer so it takes longer to unload the rear weight after the initial load transfer.

I hope that makes sense, i suck at explaining things. And also, I don't do any drag racing, and I have never setup a car for drag racing. The info above is simply information that I know from personal experience of setting up cars for road racing, and my own on-track experience, and simply applying that information to drag racing. So if anybody knows that I am wrong, please let me know.

ARD T2

iTrader: (22)

What he said. I guess figure out what you'll be leaning towards most, drag setup or roadcourse. You could always buy another set of springs for the rear to get as close as possible to both setups.

I'd be happy to work with you on customizing the JIC's or even offering you the RA's. I don't believe the RA's will be suitable for your kidneys on the street.

Have you done any lightening of weight on the vehicle. specifically in the front. THis will help me interpolate ideal spring rates for you. I will also do some more research into the additional weight of putting the 20B in the FD.

Rishie

The JIC's are definitely the best bang for the buck and can be further customized in the future should you decide to lean towards one purpose only, Drag or Roadrace.

Red-Rx7

I appreciate the responses.

It makes sense on having some softness in the suspension. I appreciate the clarification.

As far as weight reductions go, I am not sure how the engine weight will pan out. As it progress further, I can get an idea.

I have most of the items in the front still:
- Super large FMIC
- Super large Radiator
- Large IC piping
- 20B engine
- Single turbo Manifold
- Single turbo & Wastegate
- Powersteering pump
- ABS unit

The rest of the stuff has been pitched. The batery has been relocated to the middle/rear (storage bin).

It is difficult to choose one option or the other. But I do see the reasoning. So, here:

Drag racing...................... with the ocasional road racing?

It is tuff, because I will do both. I can say that I will street race/drag race more often than road racing. I will road race about 4-5 times a year... depending on weather.

So, the majority of the harshness will be from street / drag racing.

Thanks (both of you) again!

Look forward to hearing from you soon.

Mike