EvanB
EvanB SuperDork
5/31/11 10:21 a.m.

I am thinking about future modifications I want to do for my Miata to be more competetive in RallyX. I need some thoughts/opinions on a suspension setup.

What I am thinking now:

Some kind of better shocks (what would hold up best to the abuse?).
Ebay coilover sleeves to raise it back to stock height, maybe gain 1/2" or so but I don't need too much more clearance.
Aftermarket springs (what rates would be good?).
NB tophats to gain more travel in the rear.

Maybe just shocks, tophats, and springs in stock length from a circle track supplier?

nderwater
nderwater Dork
5/31/11 10:27 a.m.

What's your budget? What rules are you bound by? You're probably going to want greater than stock height.

Josh
Josh Dork
5/31/11 10:32 a.m.

I'd talk to Keith about FM's V-maxx budget coilover kit, the rates seem like they would be appropriate for rallyx, and the secondary springs would be useful where other spring setups might unseat at full droop. The whole kit is barely more than a decent set of shocks would cost otherwise.

EvanB
EvanB SuperDork
5/31/11 10:35 a.m.

For budget I would like to stay under $700. Cheaper the better but I want it to work fairly well.

It is for M2 class, according to the rule book:

7. Any suspension may be used. This allows changes to all components and geometry.

I did my first event in the Miata on Saturday and didn't have any clearance issues with the stock height, slightly more may be desirable though to get a bit more travel.

EvanB
EvanB SuperDork
5/31/11 10:38 a.m.
Josh wrote: I'd talk to Keith about FM's V-maxx budget coilover kit, the rates seem like they would be appropriate for rallyx, and the secondary springs would be useful where other spring setups might unseat at full droop. The whole kit is barely more than a decent set of shocks would cost otherwise.

I thought about that but I don't know what the longevity of those would be on the rough surface.

Josh
Josh Dork
5/31/11 10:38 a.m.

Also, who do you rallyx with that allows convertibles?

EvanB
EvanB SuperDork
5/31/11 11:10 a.m.

scca, only allowed with a factory hardtop.

Josh
Josh Dork
5/31/11 11:15 a.m.

Do you have a rollbar too? I am pretty sure I got turned down by NER even with the hardtop. It was a while ago, I may be wrong.

cghstang
cghstang HalfDork
5/31/11 11:15 a.m.

Evan, check out this thread and maybe send actualsize a pm. He'd the one person (in the US) to run a stage rally Miata. I thought I had seen the actual spring rates he ran at some point.

EDIT: Found the article I was thinking of on miata.net.

SCCA RallyCross allows convertibles with factory hard tops in place.

SCCA said:

A RallyCross event is open to any fixed‐roof production based vehicle (including convertibles with a factory hardtop attached, targa‐types with factory panel in place, t‐tops with factory panels in place) that can pass safety inspection. If the Event Chairman after consultation with the Event Safety Steward determines at his discretion that a vehicle cannot safely negotiate the course, it may be excluded.

bluej
bluej Dork
5/31/11 11:49 a.m.

Keith did a bunch of shock testing IIRC for FM and himself for the Targa Newfoundland miata. I think it was afco he mentioned working with to get a good setup for the variety of terrain he would see there. good reference either way.

www.targamiata.com

Keith
Keith SuperDork
5/31/11 12:07 p.m.

Yeah, the AFCO setup is the dog's danglies. But it's not $700. Well, not if you want it on more than one wheel.

We did have a couple of Miatas run the Targa Newfoundland last year with the V-Maxx setup, partly to prove (to us and everyone else!) that they'd survive the pounding. They did, and both cars are going back again this year with the same shocks. So it's probably a good bet, and I don't think you'll do any better for the price. You might want the extended front springs depending on your targeted ride height, they're a $50 option.

actualsize only ran one stage rally with his car, but he did a lot of rallycross with the car. If you can get an answer from him (he's a busy guy), it might be some good info.

amg_rx7
amg_rx7 HalfDork
5/31/11 1:34 p.m.

I'd probably look into a set of revalved Bilsteins. Call Bilstein down in so-cal and see if they still have the specs they used for ActualSize's shocks. Then pair with the same length and rate springs. You probably don't need to use different top hats given that you'll be on taller springs at higher ride height. I'd maybe skip those if you are on a budget and see how the setup works.

Woody
Woody SuperDork
5/31/11 3:01 p.m.

Where are you going to put your head?

EvanB
EvanB SuperDork
5/31/11 3:05 p.m.

I'm short

cghstang
cghstang HalfDork
6/13/11 12:01 p.m.

I'm a hair under 6' and found a seat position that was surprisingly comfortable: youtube rallycross miata in-car action

EvanB
EvanB SuperDork
6/13/11 3:24 p.m.

The options I have been considering so far:

V-Maxx coilovers from FM

FM Stage 1 kit with the addition of GC sleeves

Bilsteins with springs from Speedway Motors - from the ActualSize Miata article:

“I was on a first-name basis with the Bilstein guys,” says Dan, “so I bought a set of stock Miata Bilsteins from Mazda Team Support, converted them to coil overs myself and sat down with Bilstein to figure out how to re-valve them for rallying.” Once again, this was new territory. After a bit of research, they settled on valving that was based on the European Ford Escort, the closest small rear-wheel drive rally car they could think of. Springs were long - 10" in the front and 12" in the rear with fairly soft rates of 225 lb/in and 130 lb/in. “Between the tires and the taller Eibach springs, the car sat about 1.5 inches higher than stock”, explains Dan, “It didn’t need to be real stiff, because Treeline is tight, technical and doesn’t have big jumps.”

Any opinions?

EvanB
EvanB SuperDork
6/14/11 8:57 a.m.

Noone? I guess it isn't the usual Miata question

cghstang
cghstang HalfDork
6/14/11 9:27 a.m.

My vote goes to the Bilsteins with coil over sleeves and springs similar to those used by ActualSize, maybe a little higher rate. Add some good bumpstops (FM, FCM, etc) and the NB top hats for good measure.

The V-Maxx coilovers would be way too stiff (with the supplied springs) in my opinion for rallycross around here. You could change out the main springs if they're a standard diameter but then they'd be overdamped.

The FM stage 1 kit with FM springs and NB upgrade for early cars is noted as sitting up to 1/4" higher than the normal 12.5"F/13"R ride heights. Maybe you could add a spring spacer to get the ride height up a touch without having to go to sleeves? Those springs are great on the street but are probably a bit stiff for rallycross, though not as extreme as the Vmaxx rates. With this option you do get adjustable shocks which would be nice if you want to autocross too.

EvanB
EvanB SuperDork
6/14/11 9:38 a.m.

What kind of rates would you recommend on the Bilsteins?

Maybe these in 300/200 or 300/175? http://www.speedwaymotors.com/AFCO-Yellow-2-5-8-ID-Coilover-Springs,24517.html

EvanB
EvanB SuperDork
6/14/11 10:23 a.m.

Found some pictures of a Miata rally car in Australia on another forum, I'm going to PM him and see if I can get some more info on his setup. The only info I have found is Bilstein shocks and "King" springs.

cghstang
cghstang HalfDork
6/14/11 10:28 a.m.

Those shots are awesome! And E30 wheels to boot

King is just a brand of springs as far as I know.

I'd probably start with 250 or 275 lb/in front springs and 150 lb/in rear. I think 2.5" is a more standard diameter than the 2-5/8" you linked to.

EDIT: The stock NB Mazdaspeed Miata springs are 215 F/158 R. A set of these + some NB Bilstein HDs + FCM 36/46 bumpstops + NB shock mounts would probably be a good starting point that would gain you some ride height too without having to buy coilover sleeves and dealing with rusty adjusters.

Keith
Keith SuperDork
6/14/11 10:35 a.m.

You can pretty much interchange 2.5" and 2.625" springs. I do all the time. Check out the AFCO silver springs, they're usually a couple of bucks less expensive than the yellows and carry the same lifetime warranty.

The rally that Actualsize (aka Dan Edmunds) ran was a very slow, very rough one from what he's told me. But he did have a lot of rallycross experience with the car before that. This was a long time ago so it's possible we've learned a few things since, of course...

NGTD
NGTD HalfDork
6/14/11 12:16 p.m.

Threadjack - What is that Co-driver doing???

Holly crap would you get in trouble in NA for sticking your hand out the window at a rally!

It is a 10 min penalty alone for having your window down more than 1".

Our Preferred Partners
L6KOQ3bDXt0C8m7izqtYfPIWCroll2W5AGSwYitjd79ePpSauB1nLWK63t32ks80