Budget Street/Autocross/Track 2.5 NC Project!

[Brian]

For packaging reasons we have tried some shapes that are round on the sides and flat top/bottom and it doesn't work easily, too much resonance of any flat section of the piece. You end up doing internal ribs to keep any flat bits from resonance, not an issue with round shapes. Thus, round shapes are superior for strength.

[MitchC635]

Not sure a diffuser is necessary, but getting rid of the drag generated by the rear valance scoop in the rear bumper cover is something that could be done on this car. It should also help with cooling flow under the car and cost little, although some racing rules might restrict such a mod.

I've seen the attached mod as well as a video where the entire lower dark grey valance was removed - somewhere in between may be the sweet spot. Would like to see what affect the mods would have on track, and it would allow the world to see the true art of your exhaust creations as well as honor Ryan Passey's proven fast assless Miata form in a more street acceptable look. Know you would find a way to do it right and make what looks like a useful mod less scary for those of us unwilling to do raw experimentation on our NCs.

Although you haven't seen enough demand for a center exit muffler to justify going that way yet, if you perfect this valance mod to make it easy, you should be able to generate significant demand for a center exit muffler and create a signature GWR look in the NC community in the process. Center exit single would look significantly better than off center exit IMO. The attached double center exit exhaust shows a little different way of reducing the rear valance drag and gives a hint of how good a center exit single could look.

[Brian]

Stage 1 of updates is on the road and SO MUCH BETTER!

Started with our very popular Progress Springs and KONI SPORT SHOCKS plus a prototype set of new PROTOTYPE NC sways that are less serious than our Progress Sway Bars. On the stock 16 inch wheels and tires this was enough to get the car nicely flat in the turns and yet ride is just cleaned up and stable now (it was sloppy on blown out shocks before). Got the KONI shocks set to full soft and damping is plenty for these mild springs, smooth and fast compared to before. I am thus reminded how good these Progress Springs are for regular street fun, they are not for ultimate track/autocross times, but around town and freeway ramps they are a ton of fun and don't beat you up.

[ptr622]

light weight battery kit, like for the ND? would be cool!

https://www.good-win-racing.com/Mazda-Performance-Part/61-1950.html

[Chuck H]

For packaging reasons we have tried some shapes that are round on the sides and flat top/bottom and it doesn't work easily, too much resonance of any flat section of the piece. You end up doing internal ribs to keep any flat bits from resonance, not an issue with round shapes. Thus, round shapes are superior for strength.

Good point. I hadn't even thought about that. There are already some folks sensitive to resonance on the round HH midpipe resonator, and it would definitely be worse with any flat sections to really sing at certain frequencies.

[erikv]

light weight battery kit, like for the ND? would be cool!

https://www.good-win-racing.com/Mazda-Performance-Part/61-1950.html

As much as I'd like to loose some weight from under the hood, be mindful that some sanctioning bodies and now some tracks are disallowing aftermarket lithium batteries -- mostly from the "we can't handle a lithium battery fire hazard" respect. Some lithium battery manufacturers cut corners and don't put in sufficient protection circuitry. I don't expect that the safety crew at the track wants keep a running list of mfr A is OK and mfr B is not.

FYI: Optima Search for the Ultimate Street Car series disallows lithium batteries -- for obvious reasons

[Brian]

Project NC Up on the Exhaust Creation Lift for the Entire Week!

Going to start with finishing off the Helmholtz version of the Race muffler I showed previously. With the addition of the Helmholtz the result is super mellow. Since it ends up being much like ND SuperStreet we are going to add the nice tip here too, go to next prototype with it as "Helmholtz SuperStreet Single." Prototype so excuse fact not all polished up, etc. Remember, this is does not mean it actually gets made, just one for further testing by the entire crew here. So far everyone here loves it on otherwise stock NC.

[MitchC635]

Desired parts/tune seem to be exceeding the stated budget on this project, so it looks like one or both may need adjustment to meet performance and cost goals on this project. The stated evolving budget NC 2.5 initial parts list follows using GWR current advertised and estimated costs (no tax):

2.5 used motor ~$300
Hypergram 17x9 wheel set $716
MotoEast E85 Tune (xerolimit website) $199
Progress Sways (initially, RoadsterSport sways will be developed at lower rate/price) $319
RoadsterSport end links $42
RoadsterSport Race Springs (to be developed on this car) 400 lb/275 rates ~$178
KONI SPORT shocks $596
Bumpstops $79
RoadsterSport Competition Motor Mounts $149
Triple Pass Radiator $499
NC Aluminum Coolant Expansion Tank $224
RoadsterSport MAX Power 1.8 Inch Header - Ceramic Coated $549
RoadsterSport HighFlow Stainless MX5 Miata Midpipe with HighFlow Converter $399
RoadsterSport new Helmholtz Muffler (to be developed on this project) ~$439
Offset Bushings (much more ideal camber numbers) $89
SuperPro Differential Center Support Bushing Kit - 70 Durometer $105
Initial total $4882

Adds from Miata.net, forum & basic knowns:
Air valves, hub-centric rings, lug nuts $151
GWR Hi Perf Street Brake Kit? $579
MotoEast 1.5 Cam set? $599
235/40-17 Tires? ~$400 to 800
Front Splitter?
Master cylinder brace?

Any ideas on items you plan to go used, a little less expensive, or just skip initially?

[Brian]

Desired parts/tune seem to be exceeding the stated budget on this project, so it looks like one or both may need adjustment to meet performance and cost goals on this project. The stated evolving budget NC 2.5 initial parts list follows using GWR current advertised and estimated costs (no tax):

2.5 used motor ~$300
Hypergram 17x9 wheel set $716
MotoEast E85 Tune (xerolimit website) $199
Progress Sways (initially, RoadsterSport sways will be developed at lower rate/price) $319
RoadsterSport end links $42
RoadsterSport Race Springs (to be developed on this car) 400 lb/275 rates ~$178
KONI SPORT shocks $596
Bumpstops $79
RoadsterSport Competition Motor Mounts $149
Triple Pass Radiator $499
NC Aluminum Coolant Expansion Tank $224
RoadsterSport MAX Power 1.8 Inch Header - Ceramic Coated $549
RoadsterSport HighFlow Stainless MX5 Miata Midpipe with HighFlow Converter $399
RoadsterSport new Helmholtz Muffler (to be developed on this project) ~$439
Offset Bushings (much more ideal camber numbers) $89
SuperPro Differential Center Support Bushing Kit - 70 Durometer $105
Initial total $4882

Adds from Miata.net, forum & basic knowns:
Air valves, hub-centric rings, lug nuts $151
GWR Hi Perf Street Brake Kit? $579
MotoEast 1.5 Cam set? $599
235/40-17 Tires? ~$400 to 800
Front Splitter?
Master cylinder brace?

Any ideas on items you plan to go used, a little less expensive, or just skip initially?

Thanks for adding it up, it sure does add up fast! I don't count tires any more than I count gas and oil, expendables are constant with or without the build. I expect the Race Springs to come in something like $249 range, RoadsterSport sways about the same retail. Inspection on the lift yesterday at exhaust factory found diff bushings old and hard but not cracking at all, going to leave those alone for now since their 'aged' durometer likely about equal to poly and no sign of failure in those yet. Going to skip brakes for now too, brakes feel really good on this car, inspection suggests those were done pretty recently by last owner, so no need to change for autocross 'top time' on budget goal, will do simple brake cooling ducts for track days. Starting front splitter effort with the $99 item from Carbon Miata, which should fill the gap to simple black spray painted cut plywood extension we add under that to local SSM class limits (6 inches if I recall).

[erikv]

Save a few bucks and go with PowerStop TrackDay pads ~$112 on Amazon (ships direct from PowerStop). Search for PST-1179 and PST-1180 (autox/track) or ~$163 for PSA-1179 and PSA-1180 (advanced track day spec). Upgrade your fluid and get the stainless brake lines. Everything else you can leave OEM (including rotors).

I run the PSA-1179/1180 and have zero issues even on heavy braking tracks like Road America or Blackhawk Farms.