Suspension Recommendations for '99C2 DE/AX

[juddtaylor]

I'm looking into suspension upgrades for my '99 C2 coupe. I've looked through the posts on this forum, and I haven't quite found anyone looking for something that exactly fits what I'm looking for. I think I'm at the point in my driving that the stock suspension is beginning to limit my speed (or it will soon).

Please provide any suggestions/experiences/advice.

Car info:

It's a tip (yes, I'm serious about using a tip for racing), with the GT3 aerokit.

All of the suspension stuff is stock base-model stuff.

It looks like I'll be using 18x8's and 18x10's for the track.

Engine is stock 3.4L, from MY99, aged 8/1998 (50k miles)

Brakes are stock, but I've been using the new BHP pads (I like them a lot!)

No PASM or PSM

Desired uses of the car:

Daily driver on the rough Dallas area roads

I'm becoming a DE junkie, with a crazy goal of getting to instructor level in 2 years (going well so far...)

I haven't done any AX or club racing yet, but given how nuts I am for DE's, I'm sure it won't be long before I'm doing those as well.

Plans:

First priority is getting a set of track tires and wheels. Since I've already got the light Carrera III wheels in 8" & 10" sizes, I think I'm going to stick with those wheels for the track. I'm looking at getting some 17" wheels for street use, to help offset for the future suspension. I'm looking at the Hoosier A06 or R06 tires (and I can't figure out which)

I don't think I'll get much farther without needing a harness. I move too much in the cockpit while driving, and it's hurting my consistency. This will likely mean getting a couple of harnesses, the sparco bar (or the factory roll bar, if I can find one cheap), and a couple of seats.

After the wheels, I'm looking at working on the suspension. I'm not sure what to do here. The ideal situation for me would be to get adjustable coil-overs, and get to the track, lower the ride, and race. Then before driving home, jack the ride height back up. Is that realistic, or is it just not feasible to make that adjustment at the track?

I've been looking real hard at the JIC/Cross coil-overs, as they seem to be very adjustable (with height separate from everything else), and pretty well priced. Other alternatives would be the PSS9, or the H&R setup. The next tier up in price appears to be JRZ and Moton. Would it be worth it to spend double the $ for either of those setups? The JIC setup has been suggested in place of the JRZ already, so are those any better?

It looks like I'll need new sway bars when I upgrade the coil-overs. I've been looking at the H&R adjustable setup, as well as the GT3 bars. Am I correct in thinking I'll need the adjustable drop-links to use either of those?

I'm happy to do whatever is cheaper, since I don't think there's much difference between the two brands.

More Questions:

1. For track adjustments to the suspension, what special tools will I need to do ride height and camber adjustments at the track? Am I pipe-dreaming thinking I can do this at the track, and then set it back and drive home?

2. The GT3 seats are pretty expensive. What other alternatives are there without needing a adapters (I need the seat pretty low)?

3. What are the differences between the 5 & 6 pt harnesses?

Thanks!

Judd

[juddtaylor]

Man, I must be pretty unpopular, no responses to this post after all these months!

Anyways, I've done some stuff to the car since then, got a lot better at the track, and I still have some questions. Hopefully, I can describe what I want to correct better and get (at least) a (single) response to this post.

I've done the seat/harness/rollbar/track wheels, but I'm starting to look really hard are upgrading the coilovers and maybe sways in the near future. My current stock (not M030) shocks are going bad, and the ride is pretty gnarly on the roads here.

When on the track, my car rolls pretty far, but I'm still not having to wait very long for it to set. It's a tip, so I can get a pretty quick set by left foot braking, but is this (waiting to set) the problem that stiffer sway bars are supposed to solve, or is there something else they provide?

What am I supposed to be looking for in a coil-over setup? It looks like the main features are the spring rates, number of tubes, and damper adjustability (both compression and rebound). Some models incorporate camber plates in the top mount, but others don't really say whether they do or not (does the PSS9?)

I've talked many people who have gone through many sets of coilovers to get to where they are now. I figure someone out there must have had expierence with the different setups now available. I'm mainly looking at the H&R clubsport, regular H&R coilovers, JIC/Cross, and PSS9 systems. Please report on any of there, especially if you've had experience with more than one of them.

How important are upgraded bushings in the suspension?

[pat056]

If you don't get your answers here, try the race forum on Rennlist. They will have lots of experience here and a lot of those guys are DE only.

Pat

[Ranger]

Man, I must be pretty unpopular, no responses to this post after all these months!

Anyways, I've done some stuff to the car since then, got a lot better at the track, and I still have some questions. Hopefully, I can describe what I want to correct better and get (at least) a (single) response to this post.

I've done the seat/harness/rollbar/track wheels, but I'm starting to look really hard are upgrading the coilovers and maybe sways in the near future. My current stock (not M030) shocks are going bad, and the ride is pretty gnarly on the roads here.

When on the track, my car rolls pretty far, but I'm still not having to wait very long for it to set. It's a tip, so I can get a pretty quick set by left foot braking, but is this (waiting to set) the problem that stiffer sway bars are supposed to solve, or is there something else they provide?

What am I supposed to be looking for in a coil-over setup? It looks like the main features are the spring rates, number of tubes, and damper adjustability (both compression and rebound). Some models incorporate camber plates in the top mount, but others don't really say whether they do or not (does the PSS9?)

I've talked many people who have gone through many sets of coilovers to get to where they are now. I figure someone out there must have had expierence with the different setups now available. I'm mainly looking at the H&R clubsport, regular H&R coilovers, JIC/Cross, and PSS9 systems. Please report on any of there, especially if you've had experience with more than one of them.

How important are upgraded bushings in the suspension?

Judd, this won't answer all your questions, but it might help. I started fighting this battle in the same timeframe, with the same car, and with the same objective. I've done ~25 track days since embarking on this effort to make my car a better track car, while remaining reasonably streetable. Some of my mods have worked, some have not.

1. Suspension. The problem was that the car was understeering like a pig. I went with ROW M030 and stock alignment. That helped. Then I went with GT3 "Street" alignment (-1deg camber F, -1.5deg R). That helped even more. Now I'm about to dremel the front strut mounts to try to get a little more neg camber. My tires are wearing very badly on the outside corners, a good indicator that more neg camber is indicated.

If I had to buy a suspension again, I'd buy something that dropped the car more. The would require that I pour some cement so I could get into my garage, but that would be a small price to pay to drop my center mass another 10 or 15mm, and the additional neg camber that would result.

When you say M030, it's important to distinguish between US and ROW.

I have read postive things about putting monoballs in the shock mounts, but I've heard that it can be tricky. I've read about ball "fit" problems and increases to "height" that were unexpected. I'd certainly buy the monoballs from the same outfit that I got the shock/struts from.

If you would like to do any SCCA "Solo" or NASA "Time Trial", be sure to understand the impact of your mods. External reserviours and adjustatibility, for example, can count against you in Time Trial.

2. Seats. I did a lot of research on this. I'm curious as to what you ended up getting and how well it worked. I ended up concerned about the width of the seat narrow enough. I think that the OEM seats were ~18" and most of the seats I found on line were 21 or 22". Note that I had to get seats that folded forward. I ended up with Corbeau A4 "Narrow", w/ anti-sub slot. They worked out ok, but not without warts. They are a very tight fit against the central tunnel, they don't slide far forwards or backwards, and the headrest pushes my helmet forward akwardly. I also had to get the butt and lumbar pads removed and replaced with much softer foam.

3. I ended up putting in a harness bar and 5pt. This was a huge step forward in holding me planted in my seat. But I'm going to be less excited about the 5pt if the car rolls and the roof pushes in and breaks my neck.

4. Tires and wheels. I've spent most of my track days on Yoko AD07's 225/285, but I've just bought an extra set of wheels and put on Yoko AO48's in 235/295. I spent a lot of time trying to figure out how to go to a wider tire, but in the end I was defeated by the cost of wheels with GT3 offsets and some uncertainty whether or not wider would work. By a narrow margin I found a consensus that GT3 offsets would be necessary to wider. And that consensus was amid a heck of a lot of contradictory or amibiguous info from well informed sources. So in the end I decided that the lower cost (996 offset) and more "sure" solution was the smart way to go. Hence 235/295.

5. Even tho it's easy to drive a street/DE car to a distant track, start thinking about trailering it. I blew my motor 7hrs away and having no way home didn't make things any easier.

6. Is "dual use" the way to go? I'm starting to think that turning my street 996 into a street/track 996 just makes it crappy for both. I'm thinking about getting into Spec E30 and putting the OEM seats back into the 996.

Edited July 23, 2007 by Ranger

[juddtaylor]

Man, I must be pretty unpopular, no responses to this post after all these months!

Anyways, I've done some stuff to the car since then, got a lot better at the track, and I still have some questions. Hopefully, I can describe what I want to correct better and get (at least) a (single) response to this post.

I've done the seat/harness/rollbar/track wheels, but I'm starting to look really hard are upgrading the coilovers and maybe sways in the near future. My current stock (not M030) shocks are going bad, and the ride is pretty gnarly on the roads here.

When on the track, my car rolls pretty far, but I'm still not having to wait very long for it to set. It's a tip, so I can get a pretty quick set by left foot braking, but is this (waiting to set) the problem that stiffer sway bars are supposed to solve, or is there something else they provide?

What am I supposed to be looking for in a coil-over setup? It looks like the main features are the spring rates, number of tubes, and damper adjustability (both compression and rebound). Some models incorporate camber plates in the top mount, but others don't really say whether they do or not (does the PSS9?)

I've talked many people who have gone through many sets of coilovers to get to where they are now. I figure someone out there must have had expierence with the different setups now available. I'm mainly looking at the H&R clubsport, regular H&R coilovers, JIC/Cross, and PSS9 systems. Please report on any of there, especially if you've had experience with more than one of them.

How important are upgraded bushings in the suspension?

Judd, this won't answer all your questions, but it might help. I started fighting this battle in the same timeframe, with the same car, and with the same objective. I've done ~25 track days since embarking on this effort to make my car a better track car, while remaining reasonably streetable. Some of my mods have worked, some have not.

1. Suspension. The problem was that the car was understeering like a pig. I went with ROW M030 and stock alignment. That helped. Then I went with GT3 "Street" alignment (-1deg camber F, -1.5deg R). That helped even more. Now I'm about to dremel the front strut mounts to try to get a little more neg camber. My tires are wearing very badly on the outside corners, a good indicator that more neg camber is indicated.

If I had to buy a suspension again, I'd buy something that dropped the car more. The would require that I pour some cement so I could get into my garage, but that would be a small price to pay to drop my center mass another 10 or 15mm, and the additional neg camber that would result.

When you say M030, it's important to distinguish between US and ROW.

I have read postive things about putting monoballs in the shock mounts, but I've heard that it can be tricky. I've read about ball "fit" problems and increases to "height" that were unexpected. I'd certainly buy the monoballs from the same outfit that I got the shock/struts from.

If you would like to do any SCCA "Solo" or NASA "Time Trial", be sure to understand the impact of your mods. External reserviours and adjustatibility, for example, can count against you in Time Trial.

2. Seats. I did a lot of research on this. I'm curious as to what you ended up getting and how well it worked. I ended up concerned about the width of the seat narrow enough. I think that the OEM seats were ~18" and most of the seats I found on line were 21 or 22". Note that I had to get seats that folded forward. I ended up with Corbeau A4 "Narrow", w/ anti-sub slot. They worked out ok, but not without warts. They are a very tight fit against the central tunnel, they don't slide far forwards or backwards, and the headrest pushes my helmet forward akwardly. I also had to get the butt and lumbar pads removed and replaced with much softer foam.

3. I ended up putting in a harness bar and 5pt. This was a huge step forward in holding me planted in my seat. But I'm going to be less excited about the 5pt if the car rolls and the roof pushes in and breaks my neck.

4. Tires and wheels. I've spent most of my track days on Yoko AD07's 225/285, but I've just bought an extra set of wheels and put on Yoko AO48's in 235/295. I spent a lot of time trying to figure out how to go to a wider tire, but in the end I was defeated by the cost of wheels with GT3 offsets and some uncertainty whether or not wider would work. By a narrow margin I found a consensus that GT3 offsets would be necessary to wider. And that consensus was amid a heck of a lot of contradictory or amibiguous info from well informed sources. So in the end I decided that the lower cost (996 offset) and more "sure" solution was the smart way to go. Hence 235/295.

5. Even tho it's easy to drive a street/DE car to a distant track, start thinking about trailering it. I blew my motor 7hrs away and having no way home didn't make things any easier.

6. Is "dual use" the way to go? I'm starting to think that turning my street 996 into a street/track 996 just makes it crappy for both. I'm thinking about getting into Spec E30 and putting the OEM seats back into the 996.

For the seats, I ended up finding a used seat from an '05 cup car on ebay. That is a Recaro SPG Hans with a $1400 porsche patch sewed on (that's the markup for getting the same thing new from Porsche Motorsport). On the passenger side I got a new Recaro SPG XL seat. These don't fold, and getting the street seat belts mounts was a problem.

There is plenty of room with the SPG Hans seat between the seat and tunnel to get the buckle through there, but I did CNC some aluminum brackets to sit under the seat rails to give be a good mounting point to attach the recepticle. The problem is that you can't mount it to the seat bracket, as it will be too far forward to provide any protection at all. This bracket moves the mouting point about 2-3" back from the end of the seat bracket to give me the proper distance. It works, and I can either use the belt through the hole or above it, but there were some problems... but I can provide detail if you want it (I'm not going into great detail since I CNC milled this bracket, and that's not a real viable solution for most people... I just happen to work at a manufacturing facility). One other thing I don't like is that I need to pay serious $$ for a new cushion with a longitudinal slit for the anti-sub opening, as the porsche motorsport cushion has a slit running front to back, which just doesn't work with a 6pt).

The SPG XL see it too wide to get the belt around the outside, so you have to go though the hole. I was able to just drill the bracket for the recepticle here, but it doesn't fit perfectly, as the recepticle still sticks out of the hole a little bit, and if you're not sitting just right, it can be real annoying. That being said, I don't typically have passengers on the street while I have the race seats installed.

I have team-tech 6pt harnesses, and they are mounted to an autopower roll bar, and then directly to 4 points on the chassis. It is _really_ tricky to get these things mounted "properly" where all angles and distances are correct according to manufacturer specs.

I have no carpet or seats in the back. Removing the carpet paid for the roll bar in weight (It's shockingly thick and heavy... I'd estimate at least 60+ pounds).

I use 18" Carerra III wheels (8"&10") with Hoosier R6 tires. 225/245 in front and something around 295 in the rear (yes 295 fits a 10" wheel). I buy used tires for super cheap (4 cycles on them, for like $25-50 each!). I use 17" (7"&9") wheels with super cheap Kuhmo tires for the street (they seriously suck, however, but I couldn't care less on the street).

-Judd