Hi there, newbie user here, posting from New Zealand.

I have done an LS1 conversion on my NA MX5 here, and by accounts this is the only one like it down here, so it's a bit hard for a reference point.

I am just trying to figure out what a good spring rate is for my car, we have put it on the scales and it weighs in at 1155kg (2546lbs) with a weight split of 52% in the front and 48% in the rear. Was looking at putting in 12kg (700lb) springs on the front and just trying to work out what is going to be the best for the rear end, tossing up between 9kg (500lb) or 8kg (450lb). The car is going to be used for track days, but also for driving around occasionally and scaring the locals.

Anyway, just thought I would put it out there and see what other people are running in their conversions when they are using the car for a bit of track work.

 

I guess it depends on if you used coilover shocks or not. I did and have 450lbs in the front and 350 lbs in the rear. On the track I tend to rub in the rear but the front is fine. Great fun car.
Carlisle

 

Originally I used a Spec Miata suspension in mine and it worked REALLY well. I race it with SCCA and ran on both 205/50/15 R888's and also 275/50/15 hoosiers.

 

HSVMX5 what did you decide to do on your spring rates and how do you like it?

I'm also considering springs and I feel the 700 F and 450R you mentioned is probably about right but from what I have seen in the market not many folks run that stiff.

Would appreciate your feedback on how it came out for you. Thanks!

 

Fat Cat Motorsports put together two track/street suspensions for cars I built using 500 pound fronts and 325 rears. Currently I'm running a hobbled -together setup with Konis and 500 pound fronts and 275 rears. The 275 rears are way too soft. I need to get FCM to build me a suspension for this car as well.

If my car was track only I'd bump it up from the 500/325 proportionally. My car weighs in at about 2700 pounds (full interior, AC, iron heads, etc.).

Hope that helps ,
-Jason

 

Thanks Jason.
I've looked at fatcat stuff and would love to have him build me a set up. But $1900 bucks would kill my project. At the moment my top choice is the Flyin Miata V-maxxx track pack with 504 in the front and 336 in the rear at $900 but I think that is going to be too soft. I shot them a note last night asking if they had stiffer options for the V8.

Sway bars is another issue to wrestle with. Have you ever seen this video?

It will turn what you think about sway bars up side down!

 

Did FM ever get back to you about stiffer springs for the V-maxxx? I'm thinking of going the same route but getting the "topless" ones and making up my own NB top hats with FCM's bushings. This, I hope will get me the best of both worlds. I could always sell the V-maxxxes later and go with a full FCM setup or try a 600/400 on the V-maxxxes and hope they don't blow.

-Jason

 

Yeah I talked to Keith Tanner and he said the V-Maxx will not support a higher spring rate then the track version. (504F 336R) He recommended AFCOs with 750 front and 450 rears but that is even farther out of my budget then FMCs so no help there. I might have to just toss some ebays in it for the first year.

 

I ended up running with the 12kg front and 9kg rear (sorry, can't be bothered converting to imperial, we use metric down here) and finally did a track day session on them last week.

I haven't had the shock's re-valved as yet, so they weren't really able to control the spring I don't think. I was playing around a lot with the damping on it, trying to get it all balanced out, as it was going from oversteer to understeer wth adjustments, was eventually getting close to getting it right, when I completely boiled the fluid in my brakes coming into a hairpin, and got spat off the track, so that was the end of my day there (really need to get my brakes sorted out, but I guess that is another post)

Anyway, thinking about getting a set of Xida from 949 Racing, as people have said those are the ones to get, so rather than spending the money on the re-valving, putting it towards a new set of shocks.

 

I was really torn between the Xidas or a non-adjustable set of FCM shocks. Both are right in that $2000 range. Finding out I'm having a second child in October sort of changed by budgeting a bit. I'm pretty sure my wife would be "slightly upset" if I dropped $2k on shocks right now.

I'm hoping the "Track Pack" can get me 80% of the performance of the other two options at 40% of the cost. If they do I'll be happy for a few years until I can upgrade again and unload them for $500 or so.

In the mean time I'm selling off my set of Koni Yellows with ground control 500/275 springs if anyone wants them. $550 + s/h (or pick up in Allentown, PA).

-Jason

 

I just pulled the trigger on a V-Maxx Extream track pack. I'll let everyone know how it goes (sometime in April).

-Jason

 

Wow didn't see that one coming! I figured you'd bump the spring rates on your Konis. You really think the v-maxx 504 F and 336 R is enought for a V8 track car? Auto X too? That's a wash in the fronts and just a little bump in the rear for you. Are you going to run their bars too?

I'm a little foggy on the advantage to making your own NB top hat. Or are you planning on using the hats from your old ones?

Well I really look forward to hearing how this works out. These were my first choice for quite a while too and if you like them they should be more then good enough for me. It just seems so light for a proper V8 track car....

 

Here's my thoughts and reasons for going with the above.

Problem:
#1-I currently have NA Koni yellows that someone tried to match up with a set of NB mounts. To make this work they deleted the upper shock bushing which is causing the shocks to make an irritating squeaking noise. I need to match the shocks with the proper mounts. This means swapping NA mounts on it which I'd have to buy and would reduce my travel or swapping NB Konis on which would cost over $500. The GC sleeves I have are not compatible with any other shock brand.

#2-The rear springs are only 275 pound springs. To make them work I have the adjustments almost to the top. There is only about 1/4 inch of thread left above the GC mount on the sleeve. I need a stronger rear spring.

#3-The car spends 80% of its miles and 99% of its time on the street, not the track. I tend to think it as a "Grand Touring" car more than a full-blown track machine, much like the Vettes that are with me on the track. The suspension has to be comfortable enough for daily driving.

-----

Buying new NB Koni shocks or new OEM NA mounts would both cost about 60% of the cost of the track pack. In the latter case I'd have a suspension that does not have as much travel as I do now and in both cases I'd still need to locate a stronger set of rear springs. These springs would cost at least $100 which brings the cost even closer.

The mounts I have can be "rebuilt" for much less than the $100 FM charges for a set on the shocks. I can pick up new rubber mounts for about $9 a corner from Rock Auto. The NB ones that FM includes are only rubber as well so this is saving me $60. What I plan to do is later purchase the necessary parts from FCM to upgrade the NB tophats to his spec. This will cost about $145 and give me a solution even better than had I purchased the Track Pack with mounts.

What I really would like is a custom set from FCM or EXID's. My wife informed me last week that we will be having our second child in October. I can no longer spend $2000 on shock absorbers for my toy car. My wife didn't make this stipulation, I personally can't justify it. If I can down the road I can unload this package for $500 or so and upgrade to one of those options at that point.

I'm about to sell off what I have for $550 which brings this whole venture down to under $300. I can justify that.

As far as spring rates go, the 500 pound fronts were not that bad. It was the rear squat I didn't like. I'm hoping this will help solve that issue.

-Jason

 

Humm I might just follow in your shoes on that Jason. I like your plan a lot. Well except for the 2nd child cuz my 2nd is about to graduate from college. (Side note congratulations and please enjoy them while you can. College, the military and empty nest all stink big time!)

My only concern is in the dozen Mustangs and Camaros I have set up over the years it always seems the more I do to prepare it for the track or auto x the more fun it is to drive to work. I will say with my last couple of cars I did go too far for my wife and she won’t hardly ride in with me anymore due to excessive coolness. (noise, cam, harsh ride etc) But for me even riding all day in a fiberglass racing seat just adds to the joy of the machine. After 30 years I’m starting to think there is little hope for me growing out of this…

But maybe with your idea on the V- Maxx I can find a happy middle ground and use the car for date night again. It certainly is much more attractive price point and your point about V-Maxx resale is spot on. I very much look forward to hearing how yours works out for you.

FYI another interesting thread on the subject that speaks very well to the V-Maxx track pack.
http://forum.miata.net/vb/showthread...10#post6202110

 

I've heard a lot of good reviews of these coil overs, even on V8 cars. My only concern is that when you actually read the reviews most of them were written by people who had very poor suspention systems to begin with, most of them worn out stock suspentions.

I'm really hoping that it's at least on par with the Koni suspention I have. Again, if I was not faced with ether buying a set of NA mounts or a set of NB Konis to make what I have work properly I'd be completly happy with the setup I have (other than the need for higher rear springs).

We'll see how it goes,
-Jason

 

I just received my set of four NB shock mount rebuild kits from Rock. At about $8 each you can't beat it. Once the ship arrives I'll use these rubber isolators to build my existing NB mounts up correctly. If they seem too stiff I'll later pick up the same parts from FCM and replace the OEM rubber parts from Rock with FCM foam isolators.

-Jason

 

Hey Jason did you get your V-Maxxes rolling yet? Just wondering what you think of them. Also what are you running for sway bars? I'm kind of thinking I will go with the full kit and get the FM bars too.