Hi all,
Not really started many posts on here but have been lurking for a while.

A few months ago I bought a 62.5mm nose pully for my jrsc kit along with a 150mm crank overlay. Neither are fitted yet.

I was recently at a friends garage who has a slightly later mx5/miata than me. I showed him the pully i have to install (from Track Dog). He said that it wont fit on the earlier jrsc kits. Is this true?

I have the original kit I think as the oulet from the charger has no markings. It looks like it has a domed nut on the end. I didn't realise the older charger nose pully couldn't replaced or is he telling me a load of bull....?

Car is a 1990 mk1 1.6 currently running standard boost but I have an A/A intercooler installed. When I put the crank overlay and pully on (if I can) I will be installing a dual fuel rail and larger injectors. I am installing my megasquirt install this weekend. Preparing for the questions.

 

No one replaced a nose pully on an old charger then?

 

I have heard that the round nose ones cant have the pulley changed and all you can do is use the overlay pulley. I have no idea why though.

 

Damn, not what I wanted to know.

 

They can be changed, but the flat pulleys that seem to be the only upgrades available won't fit so it can only be changed for another domed style one. If you have a 1.6 kit there is the possibility to swap it for the one from an early 1.8 kit if you can find one.

The other options are a custom machined one, you might find one or two other people that wouldn't mind being able to upgrade so maybe a mini group buy possibility there if you can find a friendly machine shop.
I also read that swapping the charger nose section is also a possibility

 

So is the early 1.8 kit pully smaller than the 1.6 kit pully then?

 

72.5mm 1.6L pulley vs the 67.5mm 1.8L version

 

Don't still have your old one do you Martin? Your 1.8 one.

 

Actually, you have a later charger kit than me so it wouldn't work.

 

The older pulley style can be changed with a similar type. If you can find a pulley from an older 1.8 kit, that would work. There was a custom run made back in the days of SSCOR (Sebring Superchargers Owners' Registry) of 1.8 pulleys, also known as the "Tony pulleys".

But if you install both the crank overlay and the smaller nose pulley, you will be spinning the m45 beyond it's rated efficiency. Thats why I just opted to run the crank overlay.

 

As my car is a daily driver I have decided to settle for a little less power and stick with the crankoverlay now. If it was a weekend toy I wouldn't mind spinning above its efficiency.

Driver training is needed now the rest is sorted Track days here I come.

 

I run 10-11 lbs on my 1.6 JRSC. I'll get the name for the pulley and let you know.

 

If you install both the overlay and smaller pulley, you will be spinning well past the max blower speed recommended by Eaton. If you install the overlay only, you will be spinning near the max when at redline if you keep the 73 mm supercharger pulley.

From what I have heard, this should be god for 8-9 psi.

 

I get 8psi from my 150/62.5 setup on my NA8, I only go a gain of 8kW (now 129kW ARW) but a 51Nm increase in torque (now 380Nm 440Nm ARW@3000rpm). With the torque peak now lower in the rev range I don’t need to take the engine above 6000rpm in fact I have set my red line to 7000rpm, the limit for the M45 (approx. 15000rpm) is a continuous rating not a peak RPM. I wouldn’t bother with the fuel rail. Good luck with it all, and you will love the new pulley set up, I’m still smiling.
Ted

 

Holy poop. What's your setup? Do you have any dyno's? I'm just running stock 6lbs.