Show & Tell: My new track car
09-23-2007, 12:14 PM
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Show & Tell: My new track car
Some of you may recall that four years ago I sold my K04'd B5 S4 to go spec miata racing. It's a hoot and I've got no regrets: I can't imagine having more fun at the track than being in the middle of an SM race. But for non-competitive track days an SM is, to be blunt, a weakling. Fast in the corners, but with nothing to give on the straights. How about all that light and nimble spec miata goodness (and low costs!) with twice the power? Thus was born my Mazdaspeed Miata track car project, which is now 'complete'. (Is any track car project ever really finished?).
<img src="http://pictureposter.audiworld.com/29808/front_corner.jpg">
The Mazdaspeed Miata was the swansong of the 2nd gen miata line, notably more powerful than its predecessors due to the inclusion of a small turbo from the factory. Factory power spec was 178hp (crank) with 7.25 lbs of boost, but the car is well known to be heavily air restricted.
The starting point was this insurance auction special with only 2295 miles on the odometer, $10,500 including delivery and broker fee. There was no frame damage.
<img src="http://pictureposter.audiworld.com/29808/prebuild.jpg">
Said to be a dealer car that had a rough test drive, it came with the window sticker listing a $27,125 Total MSRP. The front had been smashed in, and there was a clean cut/tear though the convertible top, which frankly looked a lot like someone put a knife through it, perhaps a little insurance fraud to make sure the car was written up as totaled (the soft top is a $3000 part). For my purposes the damage was largely inconsequential - radiator and intercooler upgrades were part of there build plan as was bolting on a hard top.
The car was completely stripped and a custom cage installed, with Nascar bars on both sides.
<img src="http://pictureposter.audiworld.com/29808/through_door.jpg">
By SM standards the cage is 'illegal', as it has extra mounting points on the firewall and A pillars. Driver and passenger each get a kirkey seat, 6 point harnesses, and window net hardware. We also installed a quick-release steering wheel.
<img src="http://pictureposter.audiworld.com/29808/dashboard.jpg">
Power upgrade comes solely from better breathing, with a new intake and larger intercooler (each from Flyin Miata). Boost is regulated to ~12lbs peak.
<img src="http://pictureposter.audiworld.com/29808/motor.jpg">
Some custom piping was used to simplify the air pipe routing, as we had removed the AC unit and thus didn't need to route around it. An open exhaust was also fabricated and installed. We also put in a competition radiator, since these cars were known to have cooling issues. Brakes are stock. Our starting point on suspension was the Mazdaspeed spec miata kit, with dampers revalved (as per an apparently common SM cheater spec). For wheels and tires, I'm just using old competition tires from my SM (Toyo RA1, 205 50 15). The current dry weight of the car is ~2100 lbs.
While this was supposed to be plug and play, of course it was not. Initial testing had the car overheating after just a couple of hot laps, and the car was repeatedly overboosting and then cutting out. Plus it had heavy understeer. The overboosting was eventually traced to a faulty wastegate diaphram. Understeer was dailed out by changing spring rates and swaybar settings.
<img src="http://pictureposter.audiworld.com/29808/front.jpg">
The intercooler hogs most of the airflow. To solve the cooling issues we fabbed ductwork so air cannot bypass the radiator, and added some extra openings in the bumper cover to allow more air in, above the intercooler and directly in front of the radiator.
On the track
This Saturday at NHIS I ran the car in this `final' form for the first time. Wow! It's very fast and involving, and clearly retains the light nimble neutral chuckableness of an SM, but with great power (~200 rwhp on a dyno dynamics dyno @ ~12 lbs of boost). The extra power means much more active throttle steer than an SM, and later corner entries to account for the much more aggressive powering out of turns. The close spaced stock 6-speed means near constant gear changing. The shift pattern for NHIS chicane-chicane, starting with the run out of the final corner, is 3-4-5-6-4-3-4-5-3-4-5-3-4-5-4-3. My 1.6l SM (5-speed), in contrast, is 3-4-5-4-3-4-2-3. It's incredibly involving to drive with the extra power and shifting, and takes much more energy than piloting an SM at a track day. I left the track really tired! Running on SM spec wheels and tires (as per my plan), it's under-tired, but I'll probably just live with that.
There was no lap timer in the car, but it's clearly got several seconds on a SM and it easily outpaced the Elises on track (this was the instructor group, so one would hope they were well driven). I think it can hang with or out run just about anything at NHIS, although at a place like the Glen it won't have the top speed of a big power car.
Towards the end of the session the brakes were going soft. We'll try ducting through the fog-lamp openings for starters, but bigger brakes may be required (which might mean bigger wheels, too). Or I could just brake less!
<img src="http://pictureposter.audiworld.com/29808/side.jpg">
Total cost? Under 30K, including labor. All work was done at DWW Motorsports.
<img src="http://pictureposter.audiworld.com/29808/front_corner.jpg">
The Mazdaspeed Miata was the swansong of the 2nd gen miata line, notably more powerful than its predecessors due to the inclusion of a small turbo from the factory. Factory power spec was 178hp (crank) with 7.25 lbs of boost, but the car is well known to be heavily air restricted.
The starting point was this insurance auction special with only 2295 miles on the odometer, $10,500 including delivery and broker fee. There was no frame damage.
<img src="http://pictureposter.audiworld.com/29808/prebuild.jpg">
Said to be a dealer car that had a rough test drive, it came with the window sticker listing a $27,125 Total MSRP. The front had been smashed in, and there was a clean cut/tear though the convertible top, which frankly looked a lot like someone put a knife through it, perhaps a little insurance fraud to make sure the car was written up as totaled (the soft top is a $3000 part). For my purposes the damage was largely inconsequential - radiator and intercooler upgrades were part of there build plan as was bolting on a hard top.
The car was completely stripped and a custom cage installed, with Nascar bars on both sides.
<img src="http://pictureposter.audiworld.com/29808/through_door.jpg">
By SM standards the cage is 'illegal', as it has extra mounting points on the firewall and A pillars. Driver and passenger each get a kirkey seat, 6 point harnesses, and window net hardware. We also installed a quick-release steering wheel.
<img src="http://pictureposter.audiworld.com/29808/dashboard.jpg">
Power upgrade comes solely from better breathing, with a new intake and larger intercooler (each from Flyin Miata). Boost is regulated to ~12lbs peak.
<img src="http://pictureposter.audiworld.com/29808/motor.jpg">
Some custom piping was used to simplify the air pipe routing, as we had removed the AC unit and thus didn't need to route around it. An open exhaust was also fabricated and installed. We also put in a competition radiator, since these cars were known to have cooling issues. Brakes are stock. Our starting point on suspension was the Mazdaspeed spec miata kit, with dampers revalved (as per an apparently common SM cheater spec). For wheels and tires, I'm just using old competition tires from my SM (Toyo RA1, 205 50 15). The current dry weight of the car is ~2100 lbs.
While this was supposed to be plug and play, of course it was not. Initial testing had the car overheating after just a couple of hot laps, and the car was repeatedly overboosting and then cutting out. Plus it had heavy understeer. The overboosting was eventually traced to a faulty wastegate diaphram. Understeer was dailed out by changing spring rates and swaybar settings.
<img src="http://pictureposter.audiworld.com/29808/front.jpg">
The intercooler hogs most of the airflow. To solve the cooling issues we fabbed ductwork so air cannot bypass the radiator, and added some extra openings in the bumper cover to allow more air in, above the intercooler and directly in front of the radiator.
On the track
This Saturday at NHIS I ran the car in this `final' form for the first time. Wow! It's very fast and involving, and clearly retains the light nimble neutral chuckableness of an SM, but with great power (~200 rwhp on a dyno dynamics dyno @ ~12 lbs of boost). The extra power means much more active throttle steer than an SM, and later corner entries to account for the much more aggressive powering out of turns. The close spaced stock 6-speed means near constant gear changing. The shift pattern for NHIS chicane-chicane, starting with the run out of the final corner, is 3-4-5-6-4-3-4-5-3-4-5-3-4-5-4-3. My 1.6l SM (5-speed), in contrast, is 3-4-5-4-3-4-2-3. It's incredibly involving to drive with the extra power and shifting, and takes much more energy than piloting an SM at a track day. I left the track really tired! Running on SM spec wheels and tires (as per my plan), it's under-tired, but I'll probably just live with that.
There was no lap timer in the car, but it's clearly got several seconds on a SM and it easily outpaced the Elises on track (this was the instructor group, so one would hope they were well driven). I think it can hang with or out run just about anything at NHIS, although at a place like the Glen it won't have the top speed of a big power car.
Towards the end of the session the brakes were going soft. We'll try ducting through the fog-lamp openings for starters, but bigger brakes may be required (which might mean bigger wheels, too). Or I could just brake less!
<img src="http://pictureposter.audiworld.com/29808/side.jpg">
Total cost? Under 30K, including labor. All work was done at DWW Motorsports.
09-23-2007, 02:35 PM
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No plans to race it
It's just a track day toy.
It could run in ITE, and maybe even be competitive at handling tracks (but not a power tracks). It might even have a bright future as an ITE enduro car with additional brake and cooling work. I don't want to subject it to the brutalities of endurance racing though.
yea, it was one of Ian's days. I would have liked to go today but other commitments intervened
It could run in ITE, and maybe even be competitive at handling tracks (but not a power tracks). It might even have a bright future as an ITE enduro car with additional brake and cooling work. I don't want to subject it to the brutalities of endurance racing though.
yea, it was one of Ian's days. I would have liked to go today but other commitments intervened
09-23-2007, 05:03 PM
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My fingers are crossed that it's all worked out
Saturday at NHIS was about 75 degrees, and the sessions were only 25 minutes. The issues could resurface on a hotter day and/or longer sessions and/or a track with a greater % of WOT time. Given how quickly it heated up when we first ran it, and the simple airflow work we did to solve that, my guess is that there isn't much buffer in the system right now.
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09-23-2007, 06:12 PM
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looks great... glad to hear you finally are getting it out there.
the front looks a bit like the solstice with those two metal grilles ;-)
are you going to get rid of the SM?
are you going to get rid of the SM?
