single turbo to4z dual ballbearing
stock motor
pfc
full fuell system upgrade 1600cc and 850cc
front mount intercooler
what psi should i tune it to and to be safe.

 

depends on fuel pump and octane at this point..

 

Yep.

 

93 octane
255 walbro

 

15 psi.. probably want to run dual walbros

 

15-17, but i think one walbro is sufficient

 

i should brake the 400whp mark at 15psi..?

 

id use a supra TT pump. walbros are ok but I've had a bad experience with one personally and my tuner and rotary mechanic that's worked on these cars for 20+ years has seen many motors blow up due to a walbro failing and not one supra pump failure had occurred during that time. you just cant beat OEM quality parts sometimes. its a very reliable pump. i have the non ball bearing T04R and i made 385 @15psi on pump gas and stock ports. you should see the 400 mark.

 

We have done around 440 RWHP at 15 psi on a street port.

Jason

 

although ive heard many say its risky going much over 400 without putting dowl pins in

 

You need to dowel till at least 475 or better..

 

as long as i break 400 im happy.

 

will consider getting a more reliable pmp..

thanks for the imput 13bturbofc

 

I do 430rwhp on 16psi running very rich so you will def break 400rwhp on 15psi

 

What is your turbine A/R?

 

1.00 A/R

 

whith stock ports it may be a little laggy but it will have a nice top end

 

let us know how it does

 

That's bad info. No need to dowel until you're well over 500 rwhp.

 

Defo go with a Supra TT pump or a Apexi BNR33 pump, 15psi will be nice and safe and will get you over the 400rwhp all day long

 

Add a nice meth kit and tune for 20 psi.

 

i have a meth kit instaled on mine but im always scared to bump the boost up to 20 for fear of the meth system failing. and having to rebuild.. i guess im just paranoid

 

ooooooooh meth kit where can i buy that kit?

 

coolingmist.com

 

Aren't the S4 TII blocks known for cracking the rear irons once you start to go 400+? I'm pretty sure if you do a search on here you will find a few who have.
http://www.rotaryresurrection.com/2n...ron_break.html
Mazda started to make some improvements to the S5 TII irons and then FD Irons. So you're right for the FD and some late S5 blocks not needing it till well over 500 rwhp. But for an S4 or S5 that doesn't have the thickest casting like the FD Iron, dowel\studding is probably not a bad idea if your looking for 500+ rwhp with one of those blocks.