nillviod

Can someone please explain to me the problem with boosting psi levels above 12 on the stock motor/stock turbos. I know that fuel injection is one problem when it cuts off? What are the other problems... because couldn't I just add new injectors/bigger injectors (like 700ish cc prim and 1050ish cc sec?) the stock i understand to be 550cc and 850cc (prim sec)

sorry if i sound like a moron im just trying to get a grasp on what the dangers of psi boost are

OneBadRx7

You would need an aftermarket stand alone ecu to control the larger injectors since the stock ecu cant. Plenty of people run over 12psi on the stock motor and twins, me being one of them. As long as you have the proper mods to run 13 or 14psi the stock twins and motor can handle it but of course wont last as long if you ran more conservative boost.

nillviod

Can a PFC alone compensate for the 13-14psi boost with regards to the fuel injection??

(I get 13-14psi on full throttle too - just cause of the dp, m2 cold air intake, and the damned cold weather)

nillviod

Or I could just get a boost controller that limits it at 10psi :\ But where's the fun in that... Plus - ill need the pfc for future mods

T88NosRx7

iTrader: (1)

you can limit the boost with a boost controller, but the pfc would probably be the better choice.

911GT2

When Steve Kan tuned my car for 12 psi, my stock injectors were damn near maxed out at redline. Like 94-95%. So with a PFC and bigger injectors (1300cc even) you'd have no problem running more than 12 psi, 13 or 14 would be no problem.

The only issues you'll run into at that point would be the limits of the stock fuel pump, which can be upgraded rather cheaply (~$250 for a walbro 255lph unit) and the efficiency range of the stock twins, which most people say is in the neighborhood of 16-17 psi.

911GT2

I and many other PFC owners recommend another boost controller, as the Power FC is inconsistent at best at controlling boost. The GReddy Profec B or Profec B Spec II are the best choices IMO, cheap, easy, and simple. And they work.

nillviod

Err.. I'm a little confused GT2... Are you saying that the stock fuel pump can handle up to 16-17psi? Or that the upgraded on you mentioned can... What type of psi can the stock fuel pump handle? Thanks for the replys btw very helpful

nillviod

btw how much will new injectors run me? $$-wise

OneBadRx7

He was referring to the stock twins effeciency.

OneBadRx7

And no I dont think you would want to run above 12psi on the stock fuel pump, at least I wouldnt. You can pick up the walbro for like $110 on eBay.

clayne

I've hit 100% INJ @ .75 kg/cm^2 @ 30C IAT.

Only seen it once.

I say the stock twins are good up to 1 bar - and that's it.

911GT2

Sorry if that was unclear. I'm not sure how much the stock fuel pump can put out, but if I had to guess I'd say probably not more than enough to handle 14psi. If you're looking to run more than that, or run that consistently, I'd upgrade the pump just to be safe.

nillviod

Ok, I'll pick one of those pumps up ASAP. Then I'll move on to the PFC and injectors. (BTW i still have that question about the pfc -- can it compensate for the fuel injection by itself? or will i have to upgrade the fuel injectors + the pfc to handle 14psi. i understand that i can juts adjust the boost once i have the pfc but id like to run as high as i can get)

clayne

When you order the PFC at the same time schedule an appointment with a reputable tuner. If you're going to be replacing injectors and raising the boost the PFC is more than capable of handling these modifications. But without proper tuning you're playing with fire.

nillviod

mm anyone know of a reputable tuner near maryland?

911GT2

You will need the Power FC and higher flowing injectors to run more than 12 psi. Thats about where the stock injectors max out.

But, like clayne said, you'll need a tuner to tune the maps for your car. Don't assume you can plug and play the the Power FC, it needs to be tuned before you can get on it at all.

clayne

Seriously. Don't slack on it. Get it tuned right at the same time you do those modifications.

nillviod

Understood.


I'm asking all about this now for a reason. I won't have the money to purchase this stuff for at least a couple weeks .. so I'm making sure to learn all about it before I make the investment. If getting a tuner is an appropriate thing to do, given my situation, I'll gladly do it.

I'm actually writing up a sheet right now on what I'm buying, what it does, why I need it, costs, etc. I've got a ways to go - but I've also got a few weeks to do it.

Again- anyone have info on a reputable tuner near the dc/maryland area?

911GT2

KD Rotary in PA should be able to do it.

nillviod

sweet ill check that out thanks