Budget Street/Autocross/Track 2.5 NC Project!

Miata Parts, Intakes, Superchargers, Headers, Exhausts, Shocks, Springs, Sway Bars, Brake Kits, Autocross and track mods.
JimP159
Posts: 2
Joined: Mon Jan 16, 2017 7:27 am

Re: Budget Street/Autocross/Track 2.5 NC Project!

Post by JimP159 »

08, NC, 2.5, Garret Turbo, tuned down to 325hp
Sounds like a ton of fun. I found the Act 6 puck rated to 500/600ft lbs to be the best. Burned up others on the dyno-despite their rating.
I have 4 hard track days w NO issue. Curious on the front splitter from Blackbird..let me know if it will become a running line item. Thanks, Jim in Dallas
Ryan @ GWR
Posts: 497
Joined: Fri Oct 17, 2014 11:37 pm

Re: Budget Street/Autocross/Track 2.5 NC Project!

Post by Ryan @ GWR »

JimP159 wrote:08, NC, 2.5, Garret Turbo, tuned down to 325hp
Sounds like a ton of fun. I found the Act 6 puck rated to 500/600ft lbs to be the best. Burned up others on the dyno-despite their rating.
I have 4 hard track days w NO issue. Curious on the front splitter from Blackbird..let me know if it will become a running line item. Thanks, Jim in Dallas
Sounds like a very fun car for the track!
Will be working on the splitter/aero second half of this month, once the drivetrain is sorted.
Brian
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Re: Budget Street/Autocross/Track 2.5 NC Project!

Post by Brian »

Yes, though we have been racing our Supercharged 07 with 18x10.5 levels of grip and over 320 hp for a decade with our only rear upgrade being the OSGIKEN limited slip, we plan to take the budget turbo NC even further on torque. Customers racing beyond 400 hp tell us the rear NC bits start to fail in race use as you approach 400 hp. To get ahead of that and go for max safety and reliability we are upgrading rear with uprights and axles from RX8. What you see here came from automatic RX8 at local junkyard, everything under $200 delivered.
Attachments
RX8-REar.jpeg
RX8=rear.jpeg
Brian Goodwin
Good-Win Racing
www.good-win-racing.com
JimP159
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Joined: Mon Jan 16, 2017 7:27 am

Re: Budget Street/Autocross/Track 2.5 NC Project!

Post by JimP159 »

What's your thoughts on the rear diff, Manual trans, and drive shaft for 300-350 wheel HP.
Any other good recommendations? I just ordered another set of the R41 pads..love those for track and all around use
Brian
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Re: Budget Street/Autocross/Track 2.5 NC Project!

Post by Brian »

We have a built Walter Motorsports transmission already added, and differential built by Walter getting added with the RX8 axles and uprights.
Brian Goodwin
Good-Win Racing
www.good-win-racing.com
FFwizard
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Joined: Wed Apr 03, 2019 8:38 am

Re: Budget Street/Autocross/Track 2.5 NC Project!

Post by FFwizard »

Can you show us a picture of the stock NC parts or maybe explain why the new parts are better?
MitchC635
Posts: 42
Joined: Sun Feb 25, 2018 10:06 pm

Re: Budget Street/Autocross/Track 2.5 NC Project!

Post by MitchC635 »

Pretty good thread on the NC to RX8 rear hubs on Miata.Net here: https://forum.miata.net/vb/showthread.p ... light=axle
Ryan @ GWR
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Joined: Fri Oct 17, 2014 11:37 pm

Re: Budget Street/Autocross/Track 2.5 NC Project!

Post by Ryan @ GWR »

Worked through the RX8 Rear Hub/Bearing/Spindle conversion today. Our donor parts came from a 2005 Automatic RX8.

RX8 Spindle (Left) and NC spindle (Right).

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RX8 Bearing (Left) and NC bearing (Right). Both are 80mm OD, but the RX8 bearing is 5mm longer, with larger ID for the larger axles (45mm vs 42mm):

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RX8 axle stub, 31 splines (Left) and NC axle stub, 28 splines (Right):

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RX8 hub (Top) and NC hub (Bottom). Tried to take this picture a couple different ways, it's kind of hard to tell in the photo but the radius between the hub flange and the shaft is much thicker on the RX8 unit i.e. stronger:

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RX8 spindles with fresh bearings pressed in and our ARP extended studs swapped over from the previous NC hubs, ready to go in the car:

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The NC axles won't work with the RX8 hubs. The trick is to remove the outer CV joints of the RX8 axles and swap them on to the NC axles. Straightforward process; remove the CV boot and then hammer the outer end off the axle shaft with a brass hammer. It will go all at once when it pops past the C clip. The RX8 end goes on the NC axle shaft the same way, just hammer it on. The boots on the NC axles work on the RX8 ends.

Removing the end:

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RX8 outer CV end (top) NC outer CV end (bottom):

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Finished NC/RX8 hybrid axles:

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And finally, we used the RX8 ABS sensors (left) instead of NC sensors (right):

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Weights:

NC:
Hub + Bearing 5.25 lbs
Spindle 8.55 lbs
Axle CV end 3.65 lbs
Total 17.45 lbs

RX8:
Hub + Bearing 5.90 lbs
Spindle 9.40 lbs
Axle CV end 4.25 lbs
Total 19.55 lbs

Net weight gain just 2 lbs per side.
Ryan @ GWR
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Re: Budget Street/Autocross/Track 2.5 NC Project!

Post by Ryan @ GWR »

Also installed our fresh differential today. 3.63 final drive to stretch the 6 speed's ratios out a bit, OSGiken LSD, assembled by the fine folks at Walter Motorsports with their upgraded race bearings, and topped off with SuperPro diff bushings:

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jboemler
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Re: Budget Street/Autocross/Track 2.5 NC Project!

Post by jboemler »

Any problems due to the difference in number of teeth on the ABS wheel? Wondering if it could confuse ABS or speedo, maybe even change what gear the ECU thinks the car is in.
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