The difference between 5 and 8PSI

[Miatamad]

As per my other post the turbo is in and running. I started a low boost until I was sure that there was no knock etc before winding it up slowly.

I started with at 5psi - you could feel the difference - although to be honest, whilst happy to have the additional power I was a bit underwelmed. I guess I had higher hopes.

So I would it up to 8PSI - bl00dy hell - its like a hammer in the face. The difference is like night and day. ...... and I like it ..... I like it a lot!

I still have the fuel tuning to go - so I know that there is a lot more power at the same PSI rating. A new clutch is going in very soon (1.8 size with a lightened flywheel) and then Ill run her up to 12 PSI. This thing is going to be a monster.

[SLYDIT]

what sort of clutch are you going to get?? im running and 1800 flywheel with an "xtreme" brand clutch its a 700kg clamping plate and a stock 1800 disc..for your application a 6 puck sprung disc in either kevlar or ceramic would be a good choice...Try to avoid clutches that you think may be ok and get something that is PROVEN to work. dont want to have to keep swapping clutches out all the time.Especially as high performance clutches arent that cheap.

[VIKING RACING]

That gave me something to think about, had planned to continue on 6psi
but now I want more
If I buy Bipes build the Older guys Ox clamp together with existing AFPR
would it be possible to run 8psi without problem, or what else is needed?
I do not want to buy any aftermarket computers...and spend time trying to get it work. Want to keep it simple.
John

[SLYDIT]

A bipes and an o2 clamp may get you to 8 psi but the problem will be your fuel pump....heres why.
The stock greedy AFPR raises you fuel pressure 12 psi for every 1 psi of boost so if youre at 8 psi then it will be trying to push 96 psi ON TOP of your 40psi standard pressure!!!! OUCH the standard pump cant cope with that so
to run 8 psi you may need a better high pressure fuel pump such as a walbro 190LPH high pressure pump...you gonna need the recalibration disc kit for the fuel pressure regulator as it comes stock with a 12:1 disc and at 8 psi youll need around a 6:1 disc in it.
the 6:1 disc will see your fuel pressure at around 100psi at 7-8 pounds boost which is as much as you want to run..if you need more fuel then some 1800 injectors are needed.
Have a look on this site below,as it will give you an idea on what setups people are running with the greddy...you may even find some stuff for sale as people are upgrading.
http://www.miataturbo.net/forums/