How much boost can i run??
 

Just wondering how much boost 660cc secondary injectors can be tuned for?

Supporting mods extend port, 500hp fuel pump, 44 tial wastgate with 10.8 psi spring, microtech lt-8, front mount, to4 front cover on serie 5 turbo.

After run in i would like it to be tuned for 10.8 wastegate but not sure if i have to upgrade injectors again

Thoes injectors and an S5 turbo aren't going to let you go above about 12lbs. The turbo is the main limiting factor as it looses a lot of efficiency above 12psi. I think you'll find yourself at most of your injector dutycycle at 12lbs anyway.

On another note, why would you run an external wastegate on an S5 turbo? Port the internal wastegate and it will do just fine.

I'm guessng he means a hybrid turbo - so the Hitachi back end and core with a t04 compressor wheel at the front end.

Kind of agree on the injectors, although I made 317BHP with this kind of turbo setup (but ported wastegate) using the top mount intercooler and the stock 550's all be it with a little more pressure on the fuel rail. Boost was kept below 0.7 Bar because of the intercooler. Initial tests with the turbo suggest it will flow to 1 Bar with ease, but you must port the wastegate or you'll get crazy boost creep. I'm going with 800's for the secondarys and leaving the primaries alone. There is about another 45% duty you can get from those in any case.

so its possible that i wont have to upgrade tyhe injectors at this stage? I dont really want to go to 1680cc yet because they may not atomise the fuel as well being a bigger nozzle?

I went with an external so I could upgrade the turbo later and wasnt hard to make up a custom manifold.

My wastegate has a 0.7 spring in it which is about 10.8lbs so might be ok with current injectors and a retune?

According to the 2nd Gen Injector Calculator:

http://www.rx7.com/cgi-local/2ndgencalc.cgi

You could get 330BHP at about 85% duty - but that would be pushing those injectors close to the limit, and you'd need push the duty up on the primaries. You may as well go for larger secondaries and let them have an easier life !

will big injectors still atomise the fuel correctly? because i would rather go all out and get 1680cc in secondarys and a fuel pressure reg then just upgrade slightly.. i would like to have room to move..

You need something control the 1600's. I'm not sure if an Rtek is precise enough to do it, you will probably need a Haltech, Microtech, Power FC, etc

in my first post i said i have a microtech