More boost...

Time to add more boost to my built motor so here is what I know:

Stock pulley:
3.3" diameter
0.64" keyed shaft (not press fit)
0.4" offset
6 rib
nut torque spec: 45 ft-lbs
Magnuson part number: 58-90-06-033

Stock Cosworth belt:
Gates Micro V-AT K061040= 6rib 104"

The supercharger is rated at 16000 rpm so I cant exceed that.
I decided to go with the cheapest pulley I could find for testing purposes as I could not find any formula that would determine boost output. I went with the smallest readily available pulley which wouldn't overspin the blower. The charts to the side are from Magnusons web site for this blower.










I bought a 2.8" pulley from PulleyBoys.com Install wasn't too bad, there is only one bolt to remove (do this before you loosen belt tension or use an impact wrench)then i used a cheap pulley puller ($5) from AutoZone to pull the pulley off. They say that a puller is not needed but as it was my crappy puller barely was strong enough to get it off, so don't believe the hype. I put the new pulley on with some anti-sieze lube and torqued the nut.

The ne w smaller pulley required a new shorter belt so I got a Gates Micro V-AT 061031= 6rib 103.625"OD. This is for sure the shortest belt one could go with for this app as it was a tight install but that is what I was looking for.

so here is the pudding...14psi! at a little under 15k rpm at redline. NICE!

idle time

So my car would not idle for the first 50 miles or so, upon startup it would but if you revved it it would simply die. That made for some tricky intersection work as I found I needed a 3rd foot to keep the car running.

Now with 200 or so miles on it is has really stabilized and seems fine. I'm hoping for another beautiful day tommorrow so I can put a hundred or so miles on the car. I want to have at least 500 miles on it before Pat at Sniper/Delta gets his hands on it next Monday the 15th.

Engine Break-in

Cosworth tips for break in:

Adam,

Here are some general break in guidelines.

Let us know how it turns out.



Before Starting

During the break-in process, we recommend using a high quality API SJ or newer mineral 20W-50 engine

oil. We also recommend using a genuine Mazda oil filter. Do NOT use a synthetic or synthetic blend

during the break-in process. We also strongly recommend priming the engine’s oil system before starting.

To do this, make sure there is no fuel or spark by disconnecting either the ECU or by removing the

appropriate fuses. Then crank the engine for 30 seconds or until there is oil pressure registering on an oil

pressure gauge.

Engine Break-in

Upon initial start-up hold the engine at 2000rpm for 10-15 minutes for proper camshaft break-in. If the

engine will be broken in by driving the car, then drive the vehicle at various loads, speeds, and throttle

positions while keeping engine speeds below 4000 rpm for approximately 1000 miles or 1660 kilometers.

The longer the engine is broken in, the better your results will be.

The engine should be calibrated to achieve an air fuel ratio rich enough for
the type of fuel you are using. Consult with a professional tuner if you are unsure of what air fuel ratio

you should be running.

More fried brakes anyone?

Putting my car together, going through everything and found some more toasted brakes from the last track outting...I think I am done with these Maruha pads now.

From blown engine

From blown engine

Header install tip

If you have changed the headers on an NC or are planning on doing so here is a little tip that will save you 30mins and a pocketful of change from going in the cuss can.

The heat shield on the NC MX-5 is a real pain to remove and install. there are fastening points, one nut on the firewall (easy) and 2 bolts running longitudinally on the car. Them middle bolt isn't so bad, but the front one is a bastard as it is right above the alternator.

Here is my tip, slot the bolts with a Dremel or similar and just unscrew them from the top. Once you have the shield out, notch the mounting holes so that you can partially install the bolts then slide the shield in or out without having to remove the bolts totally in the future. Once the shield is in place just screw the bolts tight from the top, then snug them from the underside.

From blown engine

From blown engine

From blown engine