'90 Mazdaspeed Miata Rallycross Project

The car is doing quite well and proving to be fully competitive on the local MR scene when driven properly

RallyCross video from this past weekend: youtube

cghstang wrote: The car is doing quite well and proving to be fully competitive on the local MR scene when driven properly

As you can see, MR means Mazda Rear-wheel-drive around here.

The engine bay was a bit dusty after the last race, it is cleaner now but I didn't take any after pictures.

It's always good to see the red and white Miatas in action.

I need a turbo...

Hey Evan and cghstang, how do you like manual steering for RallyCross?

a. Would you see any benefit to running power steering instead to reduce steering effort?

b. How about going the other direction by running a quickened manual steering ratio (i.e. depower a Miata PS rack)? Do you see increased steering effort (vs. a stock manual rack) being an issue?

I have the option to go either way with my build, and your Miata is about as close of a comparison as I will get.

For me, the effort level and feel of the manual steering is perfect for rallycross.

If it had a quicker ratio with the exact same effort and feel, it would be even better.

Having driven Knurled's RX-7 equipped with a depowered FC rack, the effort level is acceptable but the feel is not the same. That said, I'm not sure what method he used to depower his rack. I think, in terms of driving enjoyment, I'd rather have a slightly slower rack that feels perfect than a slightly quicker rack that doesn't inspire confidence.

In my fantasy land, EvanB's miata would retain the oem manual rack and add modified steering knuckles for quicker steering with the same effort and feel.

What he said.

This is the only car with a manual rack I have driven at a rallycross so I can't comment on the increased effort of a depowered rack. I do daily drive this car though and I have never felt that the steering takes too much effort, even when parallel parking. Especially on the dirt at speed it doesn't take much effort to turn the wheel.

In my fantasy land, I would learn how to drive the car quicker and not have to work on it.

Thanks for the responses, guys. I don't have a true manual rack to start out with, so I'll continue with de-powering my power rack. If it turns out to be too much steering effort, I'll hunt down a manual rack... and if I'm too much of a weenie for that, then I have my second power rack to fall back on.

Finally got around to covering the holes in the hood I cut for ventilation. Electrical tape and mesh gutter topper.

Also painted the wheels in preparation for the rallycross national challenge next week.

Love the wheels. They look proper in white.

If all goes to plan, you will have competition in MR at next year's nationals

Does that mean I will have no competition this year? I'm not that good.

Are you building the Spitfire for MR? That would be awesome.

Nah, we'll both have plenty of competition from the RX7s. I just meant that I intend to be there... in the Spitfire.

cghstang wrote: Having driven Knurled's RX-7 equipped with a depowered FC rack, the effort level is acceptable but the feel is not the same. That said, I'm not sure what method he used to depower his rack.

Knurled's RX-7 also weighs about 1350lb on the front axle. Yes, it's a porky car. There may be steering geometry issues involved comparing a Miata to a strut suspension that has two camber bolts in it (screws up included angle and scrub radius) and a bit too much positive caster.

I just cut the two "ram" lines, spun the unit back and forth a few times to clear the fluid out, and connected them to each other with a piece of fuel line. Everything else got plugged off. Well, I like it anyway, but I might re-power it so I can use a quickener. More nose weight...

Another successful weekend for Evan and the Miata. Evan drove it 900 miles to Tulsa, the car performed great with two drivers, and drove 900 miles home without incident. Now we just need to keep working on learning how to drive

Good on you guys for making it down to Tulsa (and back!) in the first place. I'll be there next year.

That's an awful lot of squat in that pic... are you planning any suspension changes based on feedback received at nationals? If so, please share because I need some setup tips for the RallyX Spitfire/Miata.

That's not 'just' squat in the pic. The terrain at the site was very undulating and the car moves around quite a bit, especially front to rear. Check out some of the other pictures at gotcone.com; lots of cars were less than composed over certain sections of the course(s).

Evan's Miata could probably use a bit stiffer springs and definitely would benefit from better damping. Mostly we need to work on the loose nuts behind the wheel.

This photo shows that there isn't always squat (this may have been in the section right before the above photo was taken).

I wish I could have made it to nationals, I will one of these days. Looks like you guys had fun, and yes MR class does mean Mazda RWD lol. I'm pretty sure my rx7 squats more than your miata.

and that was a few months ago, it has gotten worse.

In reply to fidelity101:

At least part of your airfilter made it there zip-tied to the RX-7s antenna.

EvanB wrote:

cghstang wrote: The car is doing quite well and proving to be fully competitive on the local MR scene when driven properly

As you can see, MR means Mazda Rear-wheel-drive around here.

seeing all the rotary power makes me less interested in coming to visit Ohio region next season. Already sick of the two rotaries I have to run against every week here, lol....

EvanB wrote: Finally got around to covering the holes in the hood I cut for ventilation. Electrical tape and mesh gutter topper.

I expect my copyright royalty check to be in the mail pronto

Winston wrote: Love the wheels. They look proper in white. If all goes to plan, you will have competition in MR at next year's nationals

pending finances and TIME, we might roll up there with a couple of the local MR e30s as well. Also depending on where nationals is (do they ever do it closer east than freakin Oklahoma or Nebraska??)

fidelity101 wrote: Looks like you guys had fun, and yes MR class does mean Mazda RWD lol.

them be fightin words 'round these parts (though we do have 2 RX7s running in MR as well, who are the defending MR and PR champions)

Though in the last few events, it has also started to mean "MR2"

What is it about the RX-7 that makes it so good at rallycross compared to other RWD options? Is it the combination of low torque (less wasted energy due to wheelspin), high redline (allowing you to stay in each gear longer), LSD (duh), and IRS (better contact over uneven terrain)? Clearly the Miata and E30 have the latter two features (or at least the potential to have them) as well, so is it the rotary engine that makes the difference?

Locally, Shawn is probably beating me because of the driver rather than the car (albeit he has about 40% more power than my M10 beast). But put him in one of the M42 or 6cyl e30s that run out there with the same tires and I'm betting he could put up similar times to what he does in the RX7. I've been running even with the other RX-7 out there all season (and we're both first-year guys with pretty good motorsports experience).

Could just be that in RWD cars that are cheap enough and tough enough to rallycross, there just isn't that much selection - e30s, RX7s, Miatas....what else? Maybe older Z cars? Most other RWD cars that are "older" tend to either be muscle cars or larger sedans, or are verts, or are rare/expensive. Maybe an AE86, but those all seem to be snatched up for drift...MR2's....I would think they'd be pretty quick, but the two that have come out this season (one is a V6 swapped) haven't been quite as quick as the RXs and e30s so far.

Besides, e30s, RX7s, and Miatas are some of the best all-around cars for any kind of budget motorsports, IMO.