To preface this, I have searched quite a bit through the suspension forum, race forum and also read Howard Colemans suspension FAQ. If I have missed this covered somewhere I apologize.

I'm thinking about upgrading the stock suspension on my 93 touring. I seldom drive the car but I have recently gotten into autocross. I will not be turning my car into an all out autocross machine. I'd like to keep it stock looking and not kidney pounding because it is in very good original condition and when I do drive it occasionally or to/from autocross I'd like to not to feel like a go-kart or be dragging in/out of gas stations. I also would like to stick with a conventional spring/shock setup rather than coil-overs. That decision is mostly based on simplicity and cost. If I get very serious about autocross I'll find another car, mine is too nice to go Mod crazy on. I know that the best mod for autocross or any racing for that matter is the Driver Mod, and I will be doing as much of that as possible. I'm in the ASP class so I figured I might as well utilize the freedom I have and make the car a little better suited. Please feel free to educate/correct me if I have the wrong idea about anything. My current inclination is to do the following....

Springs - Racing Beat is what I'm leaning towards, Seems to lower the car the least out of the springs I've seen. I know the proper ride height is important. Should I consider another brand? Are these a good compromise for comfort vs. sport.
Racing Beat sway bar mount brace, I've heard the OEM sway bar mounts are weak and this is the cheapest fix I believe for the weak mounts.
Front sway - Racing Beat, I know there are many different available. I'm afraid I don't want to drop the money on the tri-point. Is there a good compromise out there? Should I be looking at another brand?
Shocks - Konis, as listed on the Racing Beat website.
Rear strut tower brace, not certain if this is necessary.

I do have a greddy front strut tower brace so I've got that covered.

I'd really appreciate insight from any of you guys who have autocross experience and those of you who own or have tried some of the products I listed above. Thanks in advance!

Adam

 

I've heard a lot of complaints about aftermarket bushings. I think Mazda makes some bushings that are stiffer but expensive. Something to consider on an older car, both for street and autocross use.

 

It seems to me like you've already answered your own questions, and know what you want, but I'll give you from my experience. It's very hard, if not impossible to come up with a combination for both if you're aiming to be any kind of competitive in the auto-x.

I've never auto-x my FD, haven't had it for that long, but I auto-x for a pretty long time in an e36 m3. Now of course the M3 is heavier than the FD, but mine was basically stripped so the weight wasn't too far off a stock FD. The biggest thing to most stock cars is body roll, and you're not going to fix that with just sport shocks and springs. They simply have too much travel to compensate for the weight transfers.

If you want to be more competitive, you can get yourself a soft set of adjustable coilovers. There are plenty out there that you can use springs that are the same stiffness as regular sport springs. You will however be giving up ride comfort in the streets because of the much shorter travel of coilovers. If you have pretty smooth streets where you drive your car around, I'd say go with that.

I would also skip the sway-bars and strut-bars until after you upgrade the suspension and see how it feels. The bars don't make that huge of a difference from my experience.

And remember, just because certain suspensions are softer, doesn't mean it's more comfortable. There's a whole mess of combinations that contribute to that. I've ridden plenty of cars that were more comfortable on coilovers than regular sports suspensions when setup of properly.

 

I realize that I will certainly be giving up some ride quality and I'm okay with that, I'm just saying with respect to springs and the sway bars, that if there were 3 choices, but all were a worthwile improvement over stock, that I would probably go with the less aggressive options. I have not decided to buy anything, I'm just listing what I thought I would do if I had no other advice. I don't want to upset the car and open a can of worms. It seems like there can be a simple upgrade path that might achieve 50-75% of what a dedicated autox setup could give. Maybe it's impossible for somebody to tell me what that would be. If possible I'd like to avoid trial and error and buy the right parts the first time.

 

1. Good Tires
2. The right brake pads
3. Seat time

Once you have those nailed down move onto parts of the suspension you feel lacking. Tackle one area at a time. ZeroG put it very well and I would take his advice before just throwing parts at the "problem." Some coilovers will ride better then stock and I can attest to this first hand.

Springs/shocks/coilovers are a great first step, next question is what's your budget? You will get 100 different opinions on what springs/shocks/coilovers you should run, analyze each and determine which best meet your needs.

In my opinion, you should at least take a look at Ground Control. They offer a kit to turn regular shocks into coilovers with readily available Eibach springs. This setup will give you the ability to not only try out as many spring rates as you want but also the availability to both revalve your shocks(koni/Bilstein/etc..) to match your spring rate(s) but also easily rebuild when required. Rebuilds or revalves may not be easily available on certain shocks/coilovers from companies such as Greddy and Apexi.

Don't rule out a used set of nice coilovers as over the past few months I have seen some great deals on used Ohlins in the for sale section. If you go used, just factor in the cost of rebuilding the shocks if available.

 

The RB brace will probably work for street tires. But if you ever move to R compounds you'll probably need the reinforced versions or widefoot mounts.

Don't forget to get your own helmet but I wouldn't go crazy for all the latest CF technology etc. Just a decent helmet of the latest SNELL rating that clears your headliner.
Our local SCCA always provides loaners but...........?

 

If you are looking for a conservative build, just start with Koni shocks and a set of stock-size Eibach or Hyperco springs around the 400 lb range. Also, change your tires to a 140-200 treadwear brand. You could go with a stiffer front sway, but I never did until much later.

Concentrate on learning how to drive the car fast as it is before doing anything else.

 

My car runs in ASP with relatively few mods. I use stock touring struts under Eibach Pro-kit springs, stock swaybars, bushings, and wheels. Alignment per Pettit's short track setup. Kumho v710 R-comps in 225/50/16. I think that for the buck, this is a great setup. But it's not uber fast and a tauter setup would steer better and wiggle through slaloms more tightly. For rain and less serious days I run stock wheels with RE-01R tires.

That said, it's a highly drivable setup on the street or on the course. The build and release in traction is very good. While Howard's suspension suggestions are very much toward road course, the Pro-Kits on stock dampers are cheap and very good performers. I think my next mod will be an adjustable front swaybar and widefoot mounts. After that, maybe coilovers that have a wide range of settings.

Other things which really help speed in ASP but may not be what you are willing to do with your car:
- Coilovers (Lower, stiffer)
- Wide, fresh R-comp Hoosiers or v710s on light wheels
- Aggressive alignment with more negative camber and toe out in front
- Light flywheel for quicker acceleration
- Lightening the car
- Basically, you have to do a lot to an RX-7 to make it really competitive at autocross. At the ProSolo level they only play in SSM anymore.

Note: brake pads/brakes almost don't matter. Stock or performance street pads are ample for autocross usage, in fact some top drivers prefer cheap pads with less bite because they can modulate more easily.

Another note: there is nothing about a stock RX-7 that needs to be addressed to autocross except for the regular cooling mods, because autocross tends to resemble drag racing between red lights and waiting a long time to move again. Just air up the tires extra and bleed down until your tire wear just approaches the edge of the tread block.

David

 

Good point there, The biggest performance difference you'll get from a car, is switching to R-compound tires.

 

I have the cooling mods taken care of. Pettit fan switch, koyo n-flow, aluminum AST, and I replaced all the lines with oem hoses. I don't think the oil will every get hot enough to require R1 duals or an aftermarket dual setup.

I bought a new Bell M4 2005 snell rating for $210 because it was discontinued. I never wanted to share a helmet, mine was sweaty enough the first time I used it.

My tires are V rated dunlop direzzas that are almost new but not very good. I figure if I'm going to be sliding around and learning I might as well put some wear on them before I get new ones.

My current front end ride height is 26 1/8". I believe I need to be at 25" or at least closer to it.
Does anybody have racing beat springs? I've had good luck with their products on my past FC so it seemed like a logical choice.

I've seen a few people mention running eibachs so I guess they'll be high on my list.

 

jkstill replied in another thread regarding oversteer. I asked about his autocross setup and here is his reply. I wanted to share it because I thought others might be able to gain something from it....

Post #28
https://www.rx7club.com/showthread.p...4#post10841674

Shocks are Koni Yellows all around
They are mounted with a Ground Control coilover kit.
Springs are lbs - front/rear = 700/550
in kg/mm that is 12.5/9.8

Front swaybar is a Tripoint with .120 wall bar
and Widefoot mounts.
(nice bar, but if your car is lowered you may have to shim
the mounts to keep the tie rods from hitting the bar)

Rear swaybar is stock

Replaceable bushings are LubeGroove delrin.
All new pillow *****.
All other bushings replaced with new mazdaspeed pieces.
( Only two of them IIRC - one in each of the lower control arms)

Improved Racing trailing arms to clear the tires.

Wheels are 18x10 +50 Forgestar all around.
18x10 +45 would have actually fit better in the rear, and would still clear the front.
I know they would fit in the front because I am using a 5mm spacer due to some interference with rotor hat bolts.

Tires are Hoosier A6 285/18/30 all around.

 

My impression of the "oversteer" thread is that oversteer is a relative term. In autocross you will find yourself understeering and oversteering at different times, and it's mostly a matter of how you drive that makes one happen more than the other.

Dunlop Direzza (the star spec model, specifically) is a very good street/autocross tire. One thing I like about street tires is the auditory feedback. It's been said by some very fast autocrossers that street tires teach speed much better than race tires, and I generally agree. Get out and drive, drive, drive.

 

My tires definitely make some noise.

I'm not looking to correct anything with a suspension upgrade, I just would like to have it setup a little more suited to autocross than street as it is now.

http://www.youtube.com/watch?v=moTX5Yg9QPE

 

go get some soft coilovers

 

How about the ground control setups? They seem like an affordable option. Otherwise I'm just going to get some eibach springs and try them out with the stock dampers

 

If you really want to retain the ride, but improve the handling, then start with swaybars. They will reduce the body roll, but won't harshly affect the ride quality...

I race an fb in CSP, and have done pretty well with the stiff swaybar/lightly sprung approach.





.

 

I've been happy with mine. Several years, no complaints. Height adjustable and varying spring rates are available. But as mentioned above, stock springs and shocks are fine, especially for a novice.

 

understeer: If you do that you are going too fast to turn - there simply isn't enough traction available to go as fast as you would like. Varies with suspension/tires/aero of course. ( I know of course that you know this, but many reading this thread in the future may not)

oversteer: Slightly less simple I know. My post was based on autoxing an FD starting with 100% stock through SSM prepared. While driver experience (knowing when to keep my big foot out of the the throttle) definitely plays a part in this, suspension setup and the Carbonetics diff made a big difference in how much throttle could be applied at corner exit, and how soon.

That said, I am still not patient enough sometimes and get a little sideways.

That's how my last co-driver beat me - he was patient where I was not.


I would agree with that. Street tires are more forgiving than race tires - when you can go fast on street tires, switch to race tires.

Wish I had taken that advice several years ago...

 

I'm thinking about just getting a set of springs to start off with. I've heard mixed reviews of the Eibachs and Racing Beat springs. H&R seems to be popular but they're progressive and may not be as best suited for autox. Would the H&Rs be a mistake to run with the stock dampers? I think my shocks are fine, only 42k miles and they seem good.

I'll be sticking with stock 16" wheels indefinitely

Does anybody know if the Eibach kit listed on their website as part # 5525.140 is the same as the "Pro Kit" that is in the HC suspension setup thread. I've found a set through Advance Auto Parts but I want to make sure it's the right thing for me.

 

From the suspension arhives by the former moderator:
https://www.rx7club.com/suspension-wheels-tires-brakes-archive-112/h-r-springs-r1-shocks-justification-194635/

You'll be fine with Eibachs, H&R, Tein springs. I think the RB springs are thought to be too soft.

 

i would do this setup too, and play with the alignment. its simple and you can work on your driving instead of the car.

the next step is better tires, better shocks and stiffer springs. basically the tires dictate the spring rate.

http://farnorthracing.com/autocross_secrets6.html

 

That is the exact direction I am heading. I've ordered the eibach pro kit springs and that is all I'm going to do for now. I think that the tires are probably a weak link, however I am probably a weaker link so I'm sticking with the V rated direzas for a while.

 

that's probably fine. the more traction you have the stiffer springs you need, so the eibachs probably work really well with the direzzas.