Essentially I have...

S4 turbo II engine. but with s4 n/a higher compression rotors. no porting done.

stock s4 turbo. (I will be upgrading to a s5 stock turbo for better waste gate.. s4 turbo over boosts like crazy I can only give it half throttle. even spikes past 8 psi in 1st gear if I try going full throttle)

I have un-catted 2.5" exhaust from turbo back to a rear can

I have the factory 4 550 cc injectors and the s4 turbo II fuel pump.

I retarded the timing a couple degrees for safety and plugged in a boost cut defender

so my question is now knowing my setup should I have to upgrade my fuel system to support 8psi on this engine?

 

its only a matter of time before u blow your motor with thouse rotors because u didnt mention any standalone

 

firstly....why does it have high compression rotors in it? that will make you HAVE to run less boost.

for whichever turbo you chose, i still suggest you port the WG as much as you can without putting a new flapper on (if youre cheap). you need to tell us what PSI you are planning on running on average OR peak. are you going to be using a boost controller? what are your HP goals. if you are planning to port the WG and run stock ish boost with these mods, the stock injectors and fuel system should be fine.

 

Yes.



-Jack

 

a standalone isn't required for 8psi on high compression rotors.

 

better out of boost performance is the reason.
An s5 turbo's stock waste gate without modification will be adequate to maintain the >>>>8psi<<< I stated in the last sentence.

 

would you like to elaborate on that comment? What's your reasoning? do you have one or are you just trying to build up posts?

 

OR you could toss a real cat on that and be done with your problems. Did you really think a non-ported wastegate w/ open exhaust isn't going to give you problems?

 

Or you could stop assuming things and making an *** of yourself. I said stock s4 turbo that doesn't mean i didn't port the dam thing. My s4 gate is ported as big as it will get. Still no I didn't think i'd get away with it but I had it, its ported so why not try it and if the waste gate wasn't enough then go from there. and I don't need a cat where I live nor do I want to add restriction to my exhaust... Not so genius solution to a problem i didn't even ask advice over.

Now seeing as how this reply had nothing to do with my question. Will someone please give me your input on what i actually asked about?

 

I say the only way to tell is to put it on a dyno/wideband and see if your leaning out. You may not even need to change your fuel system, maybe just a piggyback to add fuel in certain areas.

 

i would at least port the wastegate a ton(even if you have to weld on a new flapper, its not hard). and get an SAFC and a wideband at the very least.

 

Time to port that wastegate. http://www.aaroncake.net/rx-7/s4wastegate.htm

What ECU are you running? If you have the TII ECU, you should be trouble free at 8 PSI. If you want to up the boost, then you'll want to upgrade the secondaries and go with a piggyback. At 8 PSI you probably don't need to worry about timing either.

Sigh.


Best advice. If you don't have a wideband or dyno and have been running the car for a while on the street, pull the plugs and check for signs of detonation. Chipped or pock marked electrodes are a good indication.

 

alright thanx guys i'll probably purchase a wide band. I'd need it in the future eventually anyway. Yes i could go a bit bigger on the s4 waste gate i know this. but the other reason I need a different turbo is because the hot side has a lot of blow by. every time im in boost I burn oil. which is another question.. can i salvage this turbo? is there a fix?