Robbo's Clubbie Racer

GR124 · Postby **GR124** » Tue Jan 24, 2017 10:23 pm

Hi guys thought this may be of some interest to some of you.
I love the idea of fabricating my own race car, was going down the track of the Sports Sedan, but a little too expensive. So I ended up tacking up some SHS so I'll end up with a clubman style race car.
I purchased a NB8A write off for the running gear. I'll be running the stock engine with ECU for now. Has a 4.44 subaru suretrac LSD. Using the MX5 uprights and brakes.
Most of the build diary is on the OzClubbies Forum.

93_Clubman · Postby **93_Clubman** » Wed Jan 25, 2017 9:41 am

Great project!

Ned Loh · Postby **Ned Loh** » Wed Jan 25, 2017 11:18 am

Subscribed.

Went to ozclubbies to have a further look but it appears you have to be a member.

GR124 · Postby **GR124** » Wed Jan 25, 2017 11:44 am

yeah Ned Loh wasn't sure if you have to be a member of OzClubbies to view. sorry about that.

Thanks 93_Clubman, it is a great project. It makes it a lot less hassle if you build one for the track as opposed to a road registered version.

93_Clubman · Postby **93_Clubman** » Wed Jan 25, 2017 11:59 am

Indeed, especially in NSW of late!

manga_blue · Postby **manga_blue** » Wed Jan 25, 2017 12:29 pm

Thanks for posting. It's looking good. I was going to ask about the 124 in your name. I used to have a 1600 BC - great car but fragile. Much of the time it looked like yours.

GR124 · Postby **GR124** » Wed Jan 25, 2017 12:37 pm

MB I am into Fiat 124s and Alfas I purchased the rust bucket Fiat in the photo for the clubbie running gear. But after a visit to Wakefield and talking to the Clubbie guys I scrapped that idea, went to the MX5 donk.
I've always had Fiat 124 CCs.

Jeo · Postby **Jeo** » Thu Jan 26, 2017 9:14 am

Book chassis, or presumably a little bigger?

GR124 · Postby **GR124** » Thu Jan 26, 2017 7:28 pm

After much deliberation I went with the book chassis dimensions. Talking to a few guys most of them said if its a race car keep it small you don't need the room. However I probably should have made it a bit higher to accommodate today's modern engine.

GR124 · Postby **GR124** » Tue Jun 06, 2017 10:21 pm

bit of an update. Currently fully welding the chassis and adding bracing.

GR124 · Postby **GR124** » Tue Jun 06, 2017 10:40 pm

Hoping to get some input into track preparation of the engine. I have a stock NB8A with 100,000km on it. At this time I want to keep it stock and get some time on the track before I start looking for more horses. What do I do to the unknown engine so it don't fall apart and keep it reliable. Don't want to spend a lot of coin on it yet.

My thoughts are
* timing belt and water pump kit would be the first thing.
* I have a concern about the harmonic balancer. It has some small pieces missing around the serpent pulley area, like some chipped bits. I believe this needs replacing?

your thoughts welcome

93_Clubman · Postby **93_Clubman** » Thu Jun 08, 2017 11:39 am

Build is coming along well - the NB8A motor is fairly bullet proof - so as you say replace timing belt & water pump, & anything else you'd normally do when recommissioning an unknown quantity motor that's been sitting for a while.
Re harmonic balancer, not having visibility of it, I'd probably replace it unless it was very minor chipping & I could establish it was not uncommon & could be run safely. The big forum (miata.net) <https://forum.miata.net/vb/> might have posts on this, or it might get a mention in the miata.net garage: <https://www.miata.net/garage/garageengine.html>

GR124 · Postby **GR124** » Thu Jun 08, 2017 1:17 pm

Thanks for your response 93 clubman. I like your comments that "the NB8A motor is fairly bullet proof" I figure If I keep it under the 7000 RPM mark I should be safe? with it being standard.
When I get to it I'll take a pic of the harmonic balancer so I can get some more informed opinions of whether it should be replaced or not. I may just purchase a new OE factory one as some reassurance.

Cheers

manga_blue · Postby **manga_blue** » Thu Jun 08, 2017 2:21 pm

x2 on the bullet proof bit. If you end up going beyond around 7400 or with high lift cams then the cam buckets become a weak point - they throw the shim out - so you need to replace them with shim-under lightweight buckets.

If you're just after a tough dependable tractable N/A motor then the best performance gains come with a decent aftermarket ECU and a good 2 1/4" exhaust system. Minor porting helps too. Also lighter flywheel and lightweight wheels. Harmonic balancer failure is not particularly common - as long as the pulley runs true and there are no nicks to damage a belt then I wouldn't worry too much.

93_Clubman · Postby **93_Clubman** » Thu Jun 08, 2017 5:14 pm

GR124 wrote:I figure If I keep it under the 7000 RPM mark I should be safe?

No probs as manga_blue says - if you're initially running factory ECU, then AFAIK, NB8A factory ECU is rev limited, although there might be differences in that limit between JDM & ADM MX5s as there has been in the past. Mention this as we don't know if your motor has come from a JDM or ADM MX5.
Re mods, in addition to manga's suggestions, 5x Racing & a few others in the US do a replacement timing wheel which allows advancement of timing: http://5xracing.com/i-6330020-5x-racing ... miata.html
Intake setup on a clubbie should be fairly free anyway, but if not then factor in so that it is. Again, if you're initially running factory ECU, then NB8A MAF isn't generally considered restrictive.