Is Miata really the answer for everything?

So I got another Miata.  They just fit right and feel good.  After fresh tires and a new radiator, I finally got some miles and smokes out of it.

So how would you build it to really do it all?  Turbo, supercharger, V8 swap?  What about suspension?  Potential rallycross a few times a year means stock ride height and max travel.  So what's the best suspension to do that?  And dead stone reliable.  I'd want to be able to drive cross country in it with AC and cruise.  The car currently has weak AC making a funny noise and no cruise.  What kind of chassis reinforcement is needed for this variety of events?  And lastly since it would be an all purpose car, the ultimate in performance isn't necessary.  I've always wanted a cobra like V8 roadster though.  Budget isn't a big issue since it'd be part of a fleet reduction effort.  
 

I'd want to be able to autocross it, so HPDEs, rallycross it, hillclimb it, and drive it anywhere.  Heck it'd be fun to see if I can hit 1 million miles with it before I'm done.  
 

As it sits I have a truck, Subaru and Miata as fun cars.  I'd like to reduce it to the truck and Miata. Since the truck will be LS swapped, and my wife's daily is a Tahoe, it could be an LS all things scenario.  

Turbo BPs really like to blow up on track, unless you add an additional $7000 in reliability mods. 

low budget/low effort recommendation: one of the older s/c kits, be happy with 180whp

high budget/high effort: Camaro V6 swap. 300whp isn't out of the question. Conveniently you can see the GRM build on just such a car!

For suspension probably your best bet will be stock replacement performance shocks like konis or bilsteins, with a coilover conversion kit running stiffer springs but at stock or nearly stock ride height. Stock travel should be fine for all but the worst rallycross venues. Extended ball joints to get camber for track and autocross at stock ride height. Aftermarket swaybars, hopefully adjustable because you're going to want at least one of them softer (but probably not disconnected) for rallycross. Rallycross requires a hardtop, track might not require it but it's a good idea for both safety and aero reasons.

With hill climb, rally cross, and HPDE, I can't see how you'd be able to it without some sort of rollover protection, and ideally, you'd really want an RHT (removable hard top) to go along with it too.

If you are looking for off the shelf roll bars, you can't go wrong with what Blackbird Fabworx has to offer.

Traum said:

With hill climb, rally cross, and HPDE, I can't see how you'd be able to it without some sort of rollover protection, and ideally, you'd really want an RHT (removable hard top) to go along with it too.

If you are looking for off the shelf roll bars, you can't go wrong with what Blackbird Fabworx has to offer.

This is already part of the plan.  What other chassis bracing is needed?  I figured a skid plate may come in handy for rallycross.  If I'm doing an engine swap it's a k24 or an LS with a TKX behind it.  I hate V6 sounds.  That may be a silly reason to some but that's just my preference.  
 

I have Koni's.  I thought about GC coilovers conversions since I can get stock ride height with them.  

calteg said:

Turbo BPs really like to blow up on track, unless you add an additional $7000 in reliability mods. 

Nah.  Turbo system making low 200s will be fine all day long at the track, so long as you have a decent cooling solution (good radiator with ducting and a thermostat reroute) and a proper ECU with a good tune on it.  You will definitely need a brake upgrade as well.

For suspension, if your budget stretches beyond stock-style shocks then I'd talk to either Keith about the Fox system or 949 racing about their Xida XLs.

calteg said:

Turbo BPs really like to blow up on track, unless you add an additional $7000 in reliability mods. 

low budget/low effort recommendation: one of the older s/c kits, be happy with 180whp

high budget/high effort: Camaro V6 swap. 300whp isn't out of the question. Conveniently you can see the GRM build on just such a car!

Key to making a turbo BP last on track: maturity and mechanical empathy. I have yet to hurt one, but I'm conservative with boost levels and I react to my gauges. 

I don't think the GRM V6 can be held up as a paragon of reliability quite yet :)

I can tell you an LS-powered car can be an anvil, and Fox suspension lets you do pretty much anything. BTDT. But it's a big step to get there, you can't build it but by bit. 

My lesser Miata is a turbo BP with a butterfly brace, Fox suspension and a mild brake upgrade. It's competent on track, comfy on the street and while I haven't rally crossed it, I have lifted it for winter use in the past. It's been perfectly reliable. 

If you're looking at NB roll bars, the big names are Blackbird and Hard Dog. The latter is just as effective but looks a little more utilitarian. Both are constrained by having to fit under the top. 

My wife just bought one with the Hard Dog bar. The roll bar makes it a hard no for me. By the time I get the seat back enough for my legs my head is resting on the bar. 

In reply to Toyman! :

That would be A Hard Dog bar. They come in different geometries. You have to trade off vertical clearance for horizontal clearance due to the shape of the top. So they can either be tall or they can be far back, but not both. All Miata bars have this limitation. 

Keith Tanner said:

My lesser Miata is a turbo BP with a butterfly brace, Fox suspension and a mild brake upgrade. It's competent on track, comfy on the street and while I haven't rally crossed it, I have lifted it for winter use in the past. It's been perfectly reliable. 

This would be my pick.

In reply to Keith Tanner :

Tell me more about the Fox coilovers?  What is the adjustment range on height and recommended spring rates, damping etc?  If I pare the fleet down the budget is way open.  

Full write up and dyno charts: https://flyinmiata.com/products/fox-suspension-for-nb-chassis

Weird, the reviews are missing. I'll look into that. I have a pic on my work computer showing max recommended right height for the standard springs, I'll try to post that tomorrow. It's not monster truck high, but it's at least stock height. If you swap in longer springs you can go higher. 

In reply to Keith Tanner :

Read it all and noticed the missing reviews too.  Stock ride height works at the rallycross venues I've run so far.  I've seen Miata's run at both.  I've seen lowererd Miata's at both but would prefer stock height and max travel.  
 

Anyone ever fit dust boots on the Fox coilovers?  

Reviews are 5 stars, I'll import them off the old site.

I've not heard of anyone using dust boots on them. Fox knows how to build seals (they actually have calibrated dust at their factory for testing) but it certainly wouldn't be a terrible idea. I'd probably just put on a set of spring bags.

Following...

Keith Tanner said:

In reply to Toyman! :

That would be A Hard Dog bar. They come in different geometries. You have to trade off vertical clearance for horizontal clearance due to the shape of the top. So they can either be tall or they can be far back, but not both. All Miata bars have this limitation. 

Hers is tucked up under the hard top so it's neither tall nor far back. 

Keith Tanner said:

In reply to Toyman! :

That would be A Hard Dog bar. They come in different geometries. You have to trade off vertical clearance for horizontal clearance due to the shape of the top. So they can either be tall or they can be far back, but not both. All Miata bars have this limitation. 

Keith - has FM ever looked into a 'convertible' rollbar for NA/NB, similar to the HardDog Transformer for the NC PRHT?  Low bar that's safe for the street, with a tall bar to switch out for the track?  

Toyman! said:

Keith Tanner said:

In reply to Toyman! :

That would be A Hard Dog bar. They come in different geometries. You have to trade off vertical clearance for horizontal clearance due to the shape of the top. So they can either be tall or they can be far back, but not both. All Miata bars have this limitation. 

Hers is tucked up under the hard top so it's neither tall nor far back. 

 

Hard top clearance is basically the same as soft top clearance, the main difference is that the hardtop has an extra set of latches on the sides that get in the way of the Hard Core bar. There are ways to work around that if you want it. You have a legitimate complaint about the geometry of putting a roll bar in a Miata, but not about a specific brand of roll bar.

Sales numbers for the NC Transformer bar have not made an NA/NB version a high priority.

In reply to Keith Tanner :

There is a another way :)

Of course, taking the whole top off isn't really an option for most people :P

...and also not legal for rallycross.

I had Fox coilovers with standard rates on my NA Miata for a few years with no boots.  I four seasons daily drove the car, and had about a mile of driving like a jackass on a curvy gravel road to greet me at home every day.

I'd reckon they'd be fine for the occasional RallyX.  I used them for AutoX, and the car's next owner did Time Trails, truly a do it all suspension.

I had the exact almost. A 2000 NB in Chaste White (PT) along with Advanti Storm S1 wheels. Very fun cars. 

Two things you cant do despite what the internet says (in my opinion)

1. Long Highway drives. Without ear plugs you'll eventually damage eardrums
2. Real winter driving. Interior fogs up in 1 second if you have any snow/moisture on your coat/body/clothes.

Provided you don't do that its golden :)

When I was getting into motorsports I Megasquirted and turbocharged my NA Miata, tuned to about 200whp. It was fine when I was learning but as I got to be a better driver, it became a neverending cycle of (mis)managing heat and breaking things. If I were to do it all over again I would leave it stock, but if I HAD to have more power I would K swap it.

In reply to ShinnyGroove (Forum Supporter) :

I probably gotta have more power, but that's just me.  I guess I'm saving for Fox coilovers pronto.  I wonder if anyone wants to buy zero mile Koni's, FM lowering springs and new bump stops...  I guess I will put them in FS soon.  I have a ton of stuff that needs to go in FS since we've moved and the entire fleet has been changed.