SCCAForums.com

gripfreak89:

Kart seat. This is clearly my ignorance making you all worried. I used to race karts, so i had a perfectly fitting seat, the kart puts out more g force than the miata will and I find them comfortable.

 

I too have driven shifter karts and know their capabilities. However, there is no comparison between a kart and a car.  The dynamics are very different for the driver.  In a kart, the roll center is right at the driver's butt and the CG is only an inch or two above that.  So the moment arm is very short therefore the driver doesn't experience much effect.

In a car, the roll center is well below the driver, the CG is significantly higher and the chassis has many times the karts body roll.  Therefore the driver experiences infinently more side to side pitching than a kart.  The kart seat is not designed for this environment.

Also, the kart seat isn't intended to restrain the driver in the event of an accident.  In a severe accident, the driver is ejected from the seat/vehicle.   The kart seat is not designed, nor capable, of restraining the driver in an accident. 

Thanks for using the Kirkey

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Steve Hoelscher
#27 DP - Toyota MR2
http://www.terriehoward.com

Kart seats do not have provisions for secure lap belts...

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Keith
'90 Miata with a really big roll bar
www.chaserace.com
www.tightntidyracing.com
www.vorschlag.com

motoring:

Kart seats do not have provisions for secure lap belts...

 

Bah...just cut some slots in the side!!!! 

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Tracy Ramsey
Team Blenderblaster
2000 MR2 DP Spyder

Zauskycop:

motoring:

Kart seats do not have provisions for secure lap belts...

Bah...just cut some slots in the side!!!! 

Or just put on enough weight that your body sticks out past the sides of the seat.  Problem solved!

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Steve Garnjobst
#75 XP
'99 Mazda Mutant

I should really rename this thread to "lots of questions from a prepared newbie about DP"

Here come the next:

Camber, my car still has 2-.8 front -3.1 rear from STS2. I'm hearing less about half of that for the slicks. So would about -1.3 f and -1.5 rear be a decent starting setting? Spring rates are 750 - 450 or so (i have a few spring sets to mess with, fronts from 500 to 750 and rears from 325-450) I'd want to go with highest rates due to the big sidewall of the 22x10-13 and overall softness of bias ply's sidewall. anyways, Camber, does that seem about right?

Now for toe, im assuming it'd remain the same as how I liked it with the STS2 setup, I think it was 1/8" toe out front, 1/32" or 1/16" toe in rear. RB tubular front sway bar, on and off stock rear swaybar depending on conditions. Caster was always 5 degrees or so i believe, close to max.

 Wheel backspace. I know there's a lot of talk about this, but i havent heard numers for a 13x10 wheel. CSP guys using 15x10's were running as much as 6.25" backspace, but im afraid with so much the 13's will scrub control arms. Does 5.5" backspace all around sound reasonable for my 13x10's or can I go more, or less?

Thats it for now.

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German Tabor
#46 STS2 1991 Miata - Future DP car
STS2 or STS wheel/tires for sale (RE-01r):
http://sccaforums.com/forums/276012/ShowThread.aspx#276012

I'll leave most of these questions to the DP guys, as my settings are quite a bit different than the DP cars - due both to my car's additional power and DOT tires.

However, I wouldn't exactly call the sidewalls of Hoosier bias-ply slicks "soft".  I ran a LOT lower pressures on my slicks, versus my A6's. 

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Steve Garnjobst
#75 XP
'99 Mazda Mutant

Anybody?

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German Tabor
#46 STS2 1991 Miata - Future DP car
STS2 or STS wheel/tires for sale (RE-01r):
http://sccaforums.com/forums/276012/ShowThread.aspx#276012

I run the 13" canteliver slicks, so I have no experience with the big tires.  But your alignment settings sound like a good place to start.  I'm running about 1 -1.5 degrees of camber, toe out in the front and toe in in the rear.  I *think* my spring rates are 750/425.

 

Can't help with the big wheels. 

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Steve Hudson
DP Miata

Update:

There's really nothing to update.

The car's gonna be in the garage for a couple weeks while I do some headwork, brakes, and put back in the race suspension (sent shocks to koni revalving). Still debating alignment settings as I know some people dont want to go over 1 degree neg. camber when using cantilever slicks, plus mine and 9.8" wide.

I wish I could get some more alignment tips and feedback.

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German Tabor
#46 STS2 1991 Miata - Future DP car
STS2 or STS wheel/tires for sale (RE-01r):
http://sccaforums.com/forums/276012/ShowThread.aspx#276012

gripfreak89:

 Still debating alignment settings as I know some people dont want to go over 1 degree neg. camber when using cantilever slicks, plus mine and 9.8" wide.

I wish I could get some more alignment tips and feedback.

 

Well, actually, you got some feedback.     Seriously, since you are a little outside the setup of the other Miata guys here,  you're not going to get a lot of direct information on your setup. 

I think your existing setup is a good starting point. From there, its what works best for you and your particular car.    It has been my experience that camber is a direct function of the specific tire and the amount of body roll your car has.  It doesn't matter what kind of tires you have, if you are rolling over onto the shoulder they aren't working at their maximum potential.   So start with what you have, pick the end of the car that isn't hooking up and try adding/subracting camber until you see improved grip.  Then go to the other end and duplicate the process.  That will get you where the camber needs to be.

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Steve Hoelscher
#27 DP - Toyota MR2
http://www.terriehoward.com

You're very right with what you say. Besides I have noticed that this forum is overall not super-active and there aren't too many people using it, just not a lot of people in Prepared classes even. I didnt realize that I was going to be a minority trying out the 13x10 wheels and the different sizes that can be put on it.

The buildup has been slow.... my brother is taking up the garage to install and tweak with a turbo in his SM2 miata, so all the work I can do for now is with the car remaining outside in under-30degree weather. . . Not fun, but I've got the suspension still apart and currently working on brakes.  

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German Tabor
#46 STS2 1991 Miata - Future DP car
STS2 or STS wheel/tires for sale (RE-01r):
http://sccaforums.com/forums/276012/ShowThread.aspx#276012

I havent given any updates for a while and sadly there's a good reason why.

December 29th I was coming home from work when a BiG BROWN UPS truck hit me in driver's front side, or shall I say I hit it (it was both mine and his fault, but FWI I was driving the speed limit). Frame is bent and I wont attempt to repair it. A couple days ago I drove to Pennsylvania and trailered home a red 92' miata with no engine. Hopefully I can get everything transferred and ready quickly but this takes a hit on my budget and it's not gonna be as nice as I planned (for now).

Oh well. I will put up some pics when I get stuff done.

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German Tabor
#46 STS2 1991 Miata - Future DP car
STS2 or STS wheel/tires for sale (RE-01r):
http://sccaforums.com/forums/276012/ShowThread.aspx#276012

Sorry to hear about the wreck.  At least you're OK and ready to resume the build!

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Steve Hudson
DP Miata

Sorry to hear about the car.  Hope you weren't hurt. 

Such is the risk in driving your competition car on the street.  Its tough to recover from such a loss of time and money.  Many years ago, when I was a poor, starving college student, my daily driver/autocrosser was totaled by an uninsured driver in an RX7.  It set me back probably three years as it wasn't until I was out of school that I could afford to get back to where I was with that car.

Good luck with the new build.  It speaks well of your determination that you are sticking with it. 

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Steve Hoelscher
#27 DP - Toyota MR2
http://www.terriehoward.com

Oh yeah. I was not hurt at all so and that's definitely 1st priority.

At least all the expensive stuff in the car can be transferred to another (except the brand new paintjob done over the summer)... but suspension, engine, exhaust, brakes, etc can be moved.

and I got a good deal on the "new" car. . . I covered 1160 miles in 36 hours! that was quite a trip, and with a trailer...

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German Tabor
#46 STS2 1991 Miata - Future DP car
STS2 or STS wheel/tires for sale (RE-01r):
http://sccaforums.com/forums/276012/ShowThread.aspx#276012

gripfreak89:

...Wheel backspace. I know there's a lot of talk about this, but i havent heard numers for a 13x10 wheel. CSP guys using 15x10's were running as much as 6.25" backspace, but im afraid with so much the 13's will scrub control arms. Does 5.5" backspace all around sound reasonable for my 13x10's or can I go more, or less?

 

On my 13x8.5 and 13x9 Panasports C8s, I couldn't go more than 5" backspace.  This is on a CSP car, but it should be the same for yours. 

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Bill Schenker
CalClub & S.D.R. #14 CSP 10AE Miata

On a practical note, the majority of commonly available 13x10 wheels are only offered in a 5" backspace, which is probably all you are going to be able to fit anyway. 

-Chris