CS miata question

[Colin Langeveld]

Hi everybody,
I've got a few questions regarding CS class for my miata. I've got a hard dog hardcore roll bar for the car (isn't installed yet). I was wondering how specific the rules are on taking out seat foam in my seat. At 6'1 I'm not comfortable with my head so close to the bar (i've got SFI 45.1 padding there..still I want to get as far away as possible) and so I wanted to do the foamectomy to get myself lower. Will I get bumped into STS2 because of this? Would me bolting the seat directly to the floor of the car altogether take me out of CS too?

Lastly, I'm on the verge of ordering some KYB AGX's to replace the factory dampers (at 80k miles) and would like to replace the bump stops with fat cat motorsports units and dust boots. To my understanding I can replace the dampers but not the springs and stay in CS, what about the bumpstops (even if they are similar to factory?). Thanks in advance. I'll be either at the August or September run. Take care!

-Colin

[Steve Ekstrand]

Sounds like a no go for stock class.

[Bob Beamesderfer]

The foamectomy is definitely out. Not sure about the bump stops.

Mr. Isley?

[Leonard Cachola]

Will I get bumped into STS2 because of this? Would me bolting the seat directly to the floor of the car altogether take me out of CS too?

Next step up from CS is CSP as no Miatas in CS (99+) are allowed in STS2. But, yeah, bolting the seat would be a no-go for CS.

[Colin Langeveld]

oh man oh man. CSP is a pretty crazy class, but I guess it doesn't matter so much where I get placed, just as long as I have fun, right? And I gotta be comfortable and fit in the car.. guess I have no other option to gain clearance while staying in CS. thanks everybody!

[Bob Beamesderfer]

Don't forget that you can't use racing-style shoulder harness with a roll bar unless it clears your helmeted head.

[James Wilson]

Comfort and Convenience and fitting a safety rule = okay by me. I seem to recall several National Miatae racers of years past doing the same thing... I won't name names, but it is not as uncommon as you'd think. You are not removing weight and not making a performance modification. I say do it, but it is just IMO.

[David Avard]

Comfort and Convenience and fitting a safety rule = okay by me. I seem to recall several National Miatae racers of years past doing the same thing... I won't name names, but it is not as uncommon as you'd think. You are not removing weight and not making a performance modification. I say do it, but it is just IMO.

Lowering the CG of the driver would have a performance advantage, no matter how small.

And with Koni's available, I don't know that I'd waste my time on AGXs. Koni Sports should only be about $200 more than AGXs. They are also potentially rebuildable, although not quickly.

If there is one thing I've learned in 18 years of doing this it's that if you go cheap, you will later regret that you did. Save you money up and buy the best (reasonably-speaking...no one expects you to go out and buy $1000+ shocks... and that's apiece).

If nothing else, good parts usually have real value as used parts, if you want to sell them later (anyone priced a 15 x 7.5 SSR lately vs. what they were new?).

[David Avard]

<snip> would like to replace the bump stops with fat cat motorsports units and dust boots. To my understanding I can replace the dampers but not the springs and stay in CS, what about the bumpstops (even if they are similar to factory?). Thanks in advance. I'll be either at the August or September run. Take care!

-Colin

Cut from the SCCA 2008 Solo Rules

A bonded shock bushing/plate assembly is considered a shock
mount assembly and not a bushing. It may not be replaced with
an aftermarket performance part. It is not permissible to replace
the bonded bushing material.
D. A suspension bump stop is considered to be performing the
function of a spring. Therefore, the compressed length of the
shock at the initial point of contact with the bump stop may not
be increased from the standard part, although the bump stop
may be shortened for the purpose of installing non-standard
shocks. Bump stops installed externally and concentric with the
shaft of a shock may be drilled out to fit a larger diameter shock
shaft. Bump stops may be substituted for the purposes of installing
non-standard shocks.

WIthout knowing exactly what the bumpstops look like and their dimensions, it's hard to say. Since most stock Miatas corner on their bumpstops, changing them could have a profound effect on the behavior of the car.

[Colin Langeveld]

Hm, interesting David. Although I'm still confused now if I'm allowed to use after market bumpstops provided they are only used/modified to fit an after market damper to physically fit into place?

I get what you're saying about buying the cheaper stuff and regretting it later. Would Bilstein Sports be comparable to the Koni's? They are non adjustable I believe but I don't feel like I'd be missing out on my much with that, I need to learn how to become a faster driver first!

I don't have harness, although the rollbar comes with harness tabs, but yeah, i know about the broomstick rule and am positive I won't clear it with the factory seat. Quite frankly I won't drive the car with my head sticking above the rollbar, so I'm going to have to at least cut out the foam in the seat and if that doesn't work, either buy an after market seat or use the factory seat and bolt it to the floor. Is this dangerous? Thanks again for the tips and help everybody!

[David Avard]

Carroll Smith made a mention in one of his books comparing Bilsteins and Konis. Maybe someone with the book can find the passage, but basically, the Bilsteins are better than a poorly adjusted Koni, but ultimately, the tune-ability of the Konis would let you go faster. Bilsteins would be cheaper than the KYBs, and work better. Try shox.com ($359) or Tirerack ($364).

[Colin Langeveld]

Wonderful! I will definitely pick up the Bilsteins then. I've always heard great things and have been in a few race cars in Germany (on the Ring as a passenger) that had them equipped but what kind they were, how they were dialed in, etc. was all above and beyond my comprehension. They seem like quality dampers though.

Since I will be in CSP then, I'm thinking about going just with an after market seat all together. Mine has a huge hole in the middle of it and while it still functions, it's kind of gross to look at, plus the leather hasn't been treated since I've gotten it. In the end, I'm just making excuses not to work on the factory seats and am looking for an excuse to get a cool after market one Are there some big do's and don'ts with after market seats? I don't think I want to go as extreme as the kirkey stuff, it's still my daily driver. I don't need it to be adjustable as I'm gonna be bolting it to the floor anyways, it just needs to comfy enough for some 2-3 hour traffic drives (4 hours at most). For the most part, I was considering the MOMO Start seat, its dimensions fit the miata but I'm certain it's a fiberglass shell, should I be looking strictly at Carbon fiber shells? Generally how does the ranking for seat safety go; tube steel, fiberglass, carbon fiber, carbon kevlar? As you can tell, I'm pretty clueless about seat safety/integrity.

I've read that FIA approval doesn't necessarily mean it's approved in crash testing, only in fire retardation. Is this correct? I'd like to keep things as safe as possible. Lastly, is it alright to run the factory seat belt in an after market seat?

Phew.. So much to talk about! Thanks again everyone, I really appreciate it.

[Bob Beamesderfer]

I don't know how I let the KYB thing get past. You don't want those in the long term. They're not rebuildable and will lose damping ability after awhile. Bilsteins are good; have them on my Toyota Pickup. Konis offer the advantage being revalved and shortened. Koni also sells a threaded perch, or at least used to.

Momo or Sparco seats are good. Cobras are nicer, but more expensive. A Kirkey or similar might not be that comfortable day in, day out. I have Sparco Revs in my car and I find the seat pretty comfortable, even driving down to San Diego.

You've got the right idea about seat safety vs. materials. Not sure how far the FIA tests go; it's partly a homologation thing. I use my stock belt with my seat. I'd recommend a side-mount seat, which means you also buy the large L brackets. The shape of those can interfere with getting the seat where you want it. I have the Sparco brackets and they bulge out just above the 90-degree bend. That made it harder to install the seat. I plan on replacing them with these or something similar/cheaper: http://www.pegasusautoracing.com/produc ... RecId=1070


I have the belt fed through the belt slot on the outboard side. You'll need to fashion a bracket to hold the receiver, which normally bolts to the inboard seat bracket. I used 6061 bar stock, inch by 3/8ths.

Bill Schenker should be able to provide advice on mounting a seat in the NB. You'll most likely have to fashion a bracket unless the L brackets can bolt flush to the floor. They couldn't in my car, but I'm 5'8", so the seat's further forward.

[Aaron Goldsmith]

You know.. if you're just going to do local events, I'd probably just tun CS anyway. As long as you don't start beating Ryan, which physics has shown us is like trying to go faster than light, you're probably not gunna get protested.

National events you better REALLY have your comfort and convenience argument down pat.. and it probably won't fly.

[Mako Koiwai]

We (Karen and myself and I would think Tim also) CS mortals would welcome the added competition. Misery loves company ...

[Leonard Cachola]

I would join you guys in CS, but I haven't figured out a way to transport R-comps to and from events.

[Mako Koiwai]

Trailer them like Karen does ...

[Leonard Cachola]

Don't have any room to store a trailer - studio apartment, no garage.

[Christine Grice]

Ken Motonishi used to put one in his trunk, one on the package deck (top up) and two in the passenger seat.

They all fit but it was a very snug ride

[Leonard Cachola]

Ken Motonishi used to put one in his trunk, one on the package deck and two in the passenger seat.

They all fit but it was a very snug ride

Done it before for short distances as they do all fit - just can't see out the passenger or rear view mirrors...

[Christine Grice]

I never said it was a perfect plan, it's just been done before.

Sooner or later you get desperate enough to run on R-Comps and then this idea seems more feasible

[Mako Koiwai]

How about a storage facility that has those opening to the outside storage rooms ... get one on the shady side of the building. Unfortunately they tend to be the bigger "rooms," ie. expensive. The fellow next to me (mine opens to the inside corridor however) has a dragster in his. Next to him is a Motul dealer's store room. My facility has a few "just the right size for a small trailer" rooms with roll up doors right next to the entrance/exit, on the cool AC'ed inside, that would be perfect ... use to be around $200/month ... but those are hard to get.

On the other hand ... Gary Thomason always drives to the event on his 710's. Doesn't Steve Abbott also ...

[Leonard Cachola]

S'ok. Been looking at my options and I'm getting there... it won't happen this season, though, as I've still got another set of Falkens to go through before this happens. Considered a tire tail, but I don't like the idea of putting that much load on the rear shocks for the 110 mile round-trip.

I've thought about a storage room, too, but I can't justify $200/month for tire/trailer storage!

A few other things may happen that could change things for me, but it's wait-and-see at this point. I've thought about driving on them as well - I think the Lynches do this, too, right?

[Bob Beamesderfer]

Ken Motonishi used to put one in his trunk, one on the package deck and two in the passenger seat.

They all fit but it was a very snug ride

Done it before for short distances as they do all fit - just can't see out the passenger or rear view mirrors...

I used to put one in the trunk, one behind the passenger seat and two on the passenger seat. Wait ... I still do something like that.

[Bob Beamesderfer]

S'ok. Been looking at my options and I'm getting there... it won't happen this season, though, as I've still got another set of Falkens to go through before this happens. Considered a tire tail, but I don't like the idea of putting that much load on the rear shocks for the 110 mile round-trip.

I've thought about a storage room, too, but I can't justify $200/month for tire/trailer storage!

A few other things may happen that could change things for me, but it's wait-and-see at this point. I've thought about driving on them as well - I think the Lynches do this, too, right?

$200 for a small storage room? That's what I paid for one almost as big as a single car garage.

So how about two on the Tire Tail, one in the trunk and one on the parcel shelf?