NC endurance (ChampCar) questions

couple of comments...  I don't care how many points...  put the 2.5 bone stock low mile junkyard engine in it with 2.0 head swap and will do WAY WAY better than any modded 2.0.

You can marry the axle parts together... not hard... It can be done.... Have done it several times.....

The MX5 rear hubs are junk.....  They fail from heat and nothing else.  Nothing you are going to do, even with slotted rotors will solve that..... They last 13 hours and no longer..... We've won the VIR 13 hours a couple of times and the hubs NEVER made another session....

couple of comments...  I don't care how many points...  put the 2.5 bone stock low mile junkyard engine in it with 2.0 head swap and will do WAY WAY better than any modded 2.0.

How much power did you make with this combination? I don't think we'll be able to run this combination in ChampCar (too many points), but I'm curious how it performs.

The MX5 rear hubs are junk.....  They fail from heat and nothing else.  Nothing you are going to do, even with slotted rotors will solve that..... They last 13 hours and no longer.....

We were going to run RX8 vented rear rotors and stock NC hubs, which should significantly cut down on heat at the hub. However the RX8 parts aren't much heavier, so we're switching to those. The RX8 wheel bearing is also a good bit larger and should last longer.

I'm told the way to make RX8 hub adapter axles work is to remove the outer CV joint from an automatic RX8 with smooth (no bumps in the shaft) axles. Then put those on the end of a NC shaft. I haven't tried this yet because the supposedly-automatic axles I bought off ebay all had the larger-diameter manual shafts with bumps in them. I'm not sure if this is a model year thing, or I was just being sold manual axles.

Any recommendations on oil to run? I'm looking for maximum longevity, not power, no I'd assume a 30 or 40 weight Motul 300V?

While the roll cage fab and covid really delayed things, we've been testing and racing for the last six months. The NC has been a fantastic car for us. We've had four starts (two at VIR North, two at NCM), four FTDs, two wins and one second place finish. We might've had three wins if we hadn't of shown up to VIR with no crew, just me and my co-driver (0/10 do not recommend).

We'll be at CMP with it in two weeks, then PBIR, then Sebring. Next year we're really hoping to run in the SCCA's national enduro series.

The car is about 1950 lbs full of gas, and makes 167whp. Stock motor, we ported the intake (removed the butterflies), 1.8" GWR header, custom ram-air intake, and my tuning. 255 tires on 17x10s. We've tested a few different compounds and so far our favorite are Cooper RS3-Rs.

We also tested 225/45-17s on the stock wheels at Daytona, and oddly found them to be barely any faster in the straights. We repeated the same test at the Firm and got the same result. Baffled me, but the data doesn't lie? At the Firm the 17x10s were worth 0.65 seconds, though with different compounds (255 V730s vs. 225 RT660s). I thought the RT660s handled the heat better.

The only failure we've had was a fuel pump (the original one from 2009) at VIR. The car started to lean out to 16:1 AFRs. Remarkably the car lasted for hours like this and took the win, with no signs of engine damage. We still haven't even popped the valve cover off.

We were going to run GP1 in WRL, but they changed ownership a while back and no longer allow cars without windshields. We tested a makeshift windshield with no roof at Daytona and it was awful, lost 7 mph! I think we'd need a factory-shaped windshield + hardtop to make it work.

Could a mod move this thread to the endurance section? Thanks!

Should have had 2 wins at NCM. 

While the roll cage fab and covid really delayed things, we've been testing and racing for the last six months. The NC has been a fantastic car for us. We've had four starts (two at VIR North, two at NCM), four FTDs, two wins and one second place finish. We might've had three wins if we hadn't of shown up to VIR with no crew, just me and my co-driver (0/10 do not recommend).

 

We'll be at CMP with it in two weeks, then PBIR, then Sebring. Next year we're really hoping to run in the SCCA's national enduro series.

 

The car is about 1950 lbs full of gas, and makes 167whp. Stock motor, we ported the intake (removed the butterflies), 1.8" GWR header, custom ram-air intake, and my tuning. 255 tires on 17x10s. We've tested a few different compounds and so far our favorite are Cooper RS3-Rs.

 

We also tested 225/45-17s on the stock wheels at Daytona, and oddly found them to be barely any faster in the straights. We repeated the same test at the Firm and got the same result. Baffled me, but the data doesn't lie? At the Firm the 17x10s were worth 0.65 seconds, though with different compounds (255 V730s vs. 225 RT660s). I thought the RT660s handled the heat better.

 

The only failure we've had was a fuel pump (the original one from 2009) at VIR. The car started to lean out to 16:1 AFRs. Remarkably the car lasted for hours like this and took the win, with no signs of engine damage. We still haven't even popped the valve cover off.

 

We were going to run GP1 in WRL, but they changed ownership a while back and no longer allow cars without windshields. We tested a makeshift windshield with no roof at Daytona and it was awful, lost 7 mph! I think we'd need a factory-shaped windshield + hardtop to make it work.

 

Could a mod move this thread to the endurance section? Thanks!

Grant, your car looks great and is clearly very fast. (Haven't seen it in person yet.) We are currently building an NC for Champ and you're car appears to be the benchmark. Looking forward to getting on track and duking it out.

Should have had 2 wins at NCM. 

Tell me about it. I was having motion sickness problems so we had to put another driver (Troy from Biohazard) in who'd never driven the car before. When I did get back in the next day I was still not doing well. The car has lost 65 lbs since then (it's now 1945# with 12 gallons of fuel), and I think I've got the motion sickness sorted.

Grant, your car looks great and is clearly very fast. (Haven't seen it in person yet.) We are currently building an NC for Champ and you're car appears to be the benchmark. Looking forward to getting on track and duking it out.

It's a great platform. The only weak point is the LSD, which I forgot to mention above. Mazda Motorsports is said to be developing a "factory replacement" LSD that will last.

This year our plan is to run CMP (this weekend), PBIR, maybe AMP, VIR North, and Sebring.

Depending on what the SCCA Enduro ruleset looks like, we may switch to a longtube header. I hear Burns Stainless designed the header for the NP01 which appears to use our motor, so I was going to see if they could provide the specifications.

Tell me about it. I was having motion sickness problems so we had to put another driver (Troy from Biohazard) in who'd never driven the car before. When I did get back in the next day I was still not doing well. The car has lost 65 lbs since then (it's now 1945# with 12 gallons of fuel), and I think I've got the motion sickness sorted.

 

It's a great platform. The only weak point is the LSD, which I forgot to mention above. Mazda Motorsports is said to be developing a "factory replacement" LSD that will last.

 

This year our plan is to run CMP (this weekend), PBIR, maybe AMP, VIR North, and Sebring.

Good lord! Where are you finding even MORE weight to take out?

Good lord! Where are you finding even MORE weight to take out?

36 lbs of that was brakes; we went from heavy RX8s to light Wilwoods with 12.88x0.81" rotors. Headlights were also 11 lbs. Then a bunch of random stuff; 2.5 lbs of plastic bracing off the front bumper, shortened some coolant lines, brake dust shields, etc.

I hope to test a longtube header this week. I'm hoping it picks us up some area under the curve.

We won Saturday at CMP, but on Sunday our exhaust fell off. Doh. Titanium is not a great material for endurance racing unless you can ensure it doesn't hit anything when you go off. I think it's too notch sensitive, i.e. prone to fatiguing once a crack develops.

The car was great in the wet! At least until standing water developed, where its light weight, 255 wide tires (on backwards, lulz) turned it into water ski.

Fun fact: you can flip the rear bumper support upside down to gain about 2" more clearance for bumper cutting / diffusers. The rear fascia will still bolt right on.