Spec Miata - Dying to run

K

kcbhiw

What "Lifestyle"?

Contributor

:

64 Valves, 16 Cylinders, 7.2L, 622 HP

• Nov 4, 2003

• #1

I've got the itch. Had it for over a year now. I can't wait until the day comes where the budget allows such a venture (maybe within the next year). I'll probably end up buying another Miata to set up and keep the current one for auto-x and what not.

(courtesy of www.specmiata.com)

 

D

Darin

Member

• Nov 4, 2003

• #2

Somebody is selling a spec miata on miata.net classifieds

Ya know? Some of those guy are getting 120whp???

 

C

chri3

Member

:

91 miata

• Nov 5, 2003

• #3

Theres too many things that spec miatas aren't allowed to do for me to do that to my only miata. Now if i had a few spares...

 

K

kcbhiw

What "Lifestyle"?

Contributor

:

64 Valves, 16 Cylinders, 7.2L, 622 HP

• Nov 5, 2003

• #4

Darin said:

Ya know? Some of those guy are getting 120whp???

Click to expand...

Kinda makes ya go HMMM, doesn't it? Considering engine modifications are goverened by the same rules as showroom stock.

 

K

Keith@FP

• Nov 5, 2003

• #5

It's a matter of tuning the engine to run well under a narrow range of conditions at the expense of others.

SM is a great deal. I'd love to try it myself if I was closer to a series.

Keith

 

R

rx7gslse

Member

• Nov 5, 2003

• #6

SM cars are amazing track cars... The guys at Import-Motorsports (i.e Shannon McMasters) are here locally and always have a fleet of spec cars in their shop.. (they did start the whole thing afterall)

As far as budget racing goes, you just cannot beat it.... Highly reccommended.
http://www.specmiata.com/

 

D

Darin

Member

• Nov 7, 2003

• #7

kcbhiw said:

Kinda makes ya go HMMM, doesn't it? Considering engine modifications are goverened by the same rules as showroom stock.

Click to expand...

One example of how they find every last HP -

SM teams have been known to buy bunches of Air Flow Meters. They take the car to a dyno, and dyno the car with a new AFM until they find the one that gets them the best power. They could go thru FIFTY - they do the same things w/ exhaust components...

And some fo them just plain ol' cheat.

 

K

Keith@FP

• Nov 7, 2003

• #8

Yes, we get a lot of calls from Spec racers looking for an advantage Almost nothing we sell is legal in Spec - which is why our race car is built for a totally different class...

I believe the most common way to get more power is to play with the adjustment of the AFM itself. Lean the car out at high rpm and you'll pick up power. Sorting through stacks of OEM parts to find the ones that are closest to the ideal spec is a common way to optimise a "stock" engine.

Keith

 

C

cortez

Member

:

WTB: Protege MP3 in SE area

• Nov 11, 2003

• #9

There are Spec Miata "stock" 1.6 liter cars putting down MORE power to the wheels than they are rated from Mazda at the crank (116hp). These are motors that pass technical inspection and all components meet the specs published by the factory workshop manual.

That should give you guys an idea of the level of money/development/competition involved.

 

K

Keith@FP

• Nov 11, 2003

• #10

Keep in mind that they are allowed some modifications. SM isn't a stock class, it's a spec class. Free exhausts, timing and intake do allow for some power to be found and for the powerband to be moved to a more appropriate level for racing. You wouldn't necessarily want to drive one of these motors on the street.

Plus the careful tuning of course. I've heard the 1990 motors are the ones that do best, thanks to a more aggressive cam.

Keith

 

K

kcbhiw

What "Lifestyle"?

Contributor

:

64 Valves, 16 Cylinders, 7.2L, 622 HP

• Nov 11, 2003

• #11

Keith@FP said:

Plus the careful tuning of course.

Click to expand...

Don't forget that they are allowed to follow the showroom stock GCR. That allows them to do a "parts-bin balancing". That alone will add a little advantage. Other than that, I beleive nothing else can be done to the motor. However, as mentioned already, there's a lot of tuning that can be done with stock parts. It's quite an amazing science, heh.

 

C

cortez

Member

:

WTB: Protege MP3 in SE area

• Nov 12, 2003

• #12

Keith@FP said:

Keep in mind that they are allowed some modifications. SM isn't a stock class, it's a spec class. Free exhausts, timing and intake do allow for some power to be found and for the powerband to be moved to a more appropriate level for racing. You wouldn't necessarily want to drive one of these motors on the street.

Plus the careful tuning of course. I've heard the 1990 motors are the ones that do best, thanks to a more aggressive cam.

Keith

Click to expand...

Come on, Keith! A 1.6 Miata with an intake, an exhaust and advanced timing not being a car you'd want to drive on the street? Your car has a lot more work done than that!

Yeah, these motors get a lot of little things done and may not be the longest lasting motors, but they behave just like a stock Miata motor, except with about 20hp more. They are not very peaky or "race like".

When I said "stock" motor, I meant that the motor itself is supposed to be stock. Yeah, they can put an intake and an exhaust (with stock manifold), but every part of the long block itself has to be within the dimensions specified by Mazda for that part.

The trick in Showroom stock and in SM, and the reason why these 1.6 motors are making so much power is in what Mazda DOES NOT give dimensions or specs for in the manual. Like, for example, the factory manual does not give any specs for how things look like inside the flow meter. Only a procedure for verifying that it works. Same thing for the differential. They give specs for the ring and pinion, etc., but not for dimension of the internal parts inside the diff.

These motors also get build based on what the tech inspectors can measure and detect and what they can't, if you know what I mean. There is a lot of "parts bin blueprinting", but there's also quite a bit of plain old machining that can't be detected too. In the end, you end up with a 1.6 motor that is supposed to put less than 100hp to the wheels and you end up with more than 110 hp to the wheels (some with a LOT more than that) and still are "stock" motors in that their components meet the dimensions given by Mazda for each part.

 

K

Keith@FP

• Nov 12, 2003

• #13

Yes, my own street motor has a lot more work done than a Spec. But it's also not limited by running stock components. It was my understanding that the Spec boys are getting their hp increases primarily by fooling with the setup of the AFM. You can use that to tweak the A/F ratio at high rpm (it's fairly rich above 4000) but you'd end up with poor tuning down low. Thus my comment. I'm not sure if they can tweak cam timing or not. There's definitely a lot of blueprinting going on.

I'm not a Spec racer, I don't work on Spec cars. My street Miata's probably faster around a racetrack, being lighter with more power So I can't speak from experience and I could certainly be wrong.

Keith

 

M

maitai92

Member

:

92 Miata,93 Miata 03 P5

• Nov 17, 2003

• #14

I remember Grassroots had a horsepower recipe for Sms few months ago. If I remember, they dynoed a 1.6 w/ i/e close to 120whp
by adjust the AFM and advancing the timing to 20btdc.

 

K

kcbhiw

What "Lifestyle"?

Contributor

:

64 Valves, 16 Cylinders, 7.2L, 622 HP

• Nov 17, 2003

• #15

maitai92 said:

I remember Grassroots had a horsepower recipe for Sms few months ago. If I remember, they dynoed a 1.6 w/ i/e close to 120whp
by adjust the AFM and advancing the timing to 20btdc.

Click to expand...

If it's the article I'm thinking about, it was one of OPM's former cars they were toying around with. They got quite a significant increase by screwing around with the VAF.

 

C

cortez

Member

:

WTB: Protege MP3 in SE area

• Nov 23, 2003

• #16

I've been trying to find that article. Do you guys know which issue of GRM it was? (Date or cover?)