Thought this could be an interesting thread:
Does anyone know of a good guide, or can give some details on setting up the suspension on performance cars in general, and particularly the rx7. Purely out of interest really; I\'ve rebuilt engines so know a little about them but have never played with the suspension setup and would like to know more. Also from a driving perspective as one of my ambitions with buying the rx7 is to learn more about performance driving. Sort of thing I was thinking about was the ideal setup for track, ideal for road,etc also what effect on the cars handling different tweaks would have.
I\'m considering looking at coilovers for the rex to be adjustable for trackdays, but don\'t really know anything about it.
Thanks in advance,Dave
Hi Dave,
First thing I would say is that I was very pleased to find when I first saw the suspension on an FD how "race car like" the suspension system was, with its double wishbone set-up front and rear and the extensive use of alloy for all of the arms to keep the unsprung weight down, and providing you keep the wheels at 16"or 17" diameter so as not to upset the geometry of the suspension you actually have a very very good handling car as standard and in stock form with good tyres it is more that capable of pulling 1G in a corner!.
This means that just by having a good set of coil over adjustable with a good damper setting range is all most FD drivers will ever need, be it for the road or the track.
You will find if you really want to find out about suspension that you will find you normally end up with more questions than answerers and that some even term "race" suspension as a black art, yes there are lots of do\'s and don\'ts but there are soooo many variations on how to make the same car even with the same suspension handle.
For instance when I raced I realised there are two distinct schools of thought, one will tell you to set a car up on the poundage of spring sometimes even with different springs across the same axle dependant on for the particular track you are racing on, but then another school of thought is that "the springs just hold the car up" and you adjust the car on its anti roll bars. However I have seen the same two models of car set in these totally differing fashions and yet produce the same lap times!.
One constant though is a good damper system because this is the most important part of any suspension system as this is what keeps your tyre in contact with the road properly
Even if you have your suspension system fully sorted as regards type and geometry and set off around the track you will then find that you can alter the car dramatically by tyre pressures, stiffening the front or rear of the car by roll bars and springs or damper settings ,adjusting the toe in or out at the front of the car, ( tracking) or even shifting weight around in the car either physically or by adjusting the height of each corner individually ( this is called corner weighting)
Then of course you have the driver, where you can put two different drivers in the same car and yet one may complain of understeer ( this is when the car wants to go straight even though the wheels are being turned) and yet the other complains of oversteer ( where the back of the car wants to break away and slide).
So why is this, I have know one driver be "cured" of understeer just by fitting a slower steering rack ratio to the car ( so there are more turns lock to lock) and this was because he just kept turning the wheel too much into a corner and thus inducing understeer.
See I said you could end up with more questions than answerers, but if you really want to find a good book on how suspension works and can be altered etc a very good start to learn the basics would be the "How to make your car handle" book which has been updated many times over the years.
Hope this waffle helps!
Not something I profess to know much about, but I picked up a really good book on eBay - might be for sale through the vendors on the site as well.
Mazda RX-7 Performance Handbook by Mike Ancas ISBN 0-7603-0802-0
Covers pretty much everything to do with performance improvements for road and racing rotaries - Suspension, Brakes, Wheels, Tyres, Exhaust, Engine, Electrics, Tuning, Fueling.
Cheers,
Prof :cheers
Thanks guys theres lots to get my head round there! I decided the best way was to take the car for some \'spirited\' driving to research the ideas :)
I was going so much faster round the corners than in my zed on the twisties. I couldn\'t seem to reach the limit of what the car would stick to. I can drive my zed hard enough to make it under/over steer depending on the situation but the rex just sticks on in there way furthur than I have the skill or bottle to push it. Its such good fun to drive. I think an airfield day is the answer to throw it out a bit and see where its limits are. I\'m so happy to have found such a quality handling car !
Dave