Interesting Idea for a Modification

[NZLego_See]

I was having a brainstorming session the other day, thinking of ways to increase performance after the boost. and i came up with the following idea..

 

I want to Add a fuel (118 Octane AV Gas) via a spray injector to the Charge air from the turbo for what i imagine to be a performance increase somewhat.

 

I am able to compress av gas into a custom gas bottle (which ive already tried and done sucessfully) i just havent been keen enough to plumb it in with the appropriate valves switchgear etc etc..

What do you fellow subaru enthusiasts think? a viable idea or a waste of time?

[evolutionmovement]

Did you up boost and are you running dangerously lean or NOS? If the car runs fine, you'll lose power running rich unless this is a temporary fix for a lean condition from too much boost or to compensate for NOS. Either way, though, it's improperly managed fuel delivery and should be tuned for optimal use as long as you have the air to match. Plus where are you going to add the injector? Just centering it in the manifold, say, would be inferior to just fitting larger injectors since SPFI pools fuel around the manifold in parts, unlike MPFI which fires right into the cylinder (well, at the intake valve anyway). I'd say increase boost, add bigger injectors, and either get a computer to tune it right or maybe some cheater to fool the stock ECU into delivering less fuel off boost to avoid running really rich. The other issue, at least on the USDM Legacy turbo, is that the MAF sensor can only measure so high before it throws the injectors at 100% IDC anyway.

 

Steve

[firedawgs]

Almost sounds like a afterburner on jets.

[NZLego_See]

Well i kinda expected 'evolutionmovements's answer

 

The car isnt running rich nor lean (how to tell if its running lean?) the only time it runs a lil bit rich is on start up with a small puff of black smoke and thats it.

 

As to my idea, i had kinda only thought about it for a wee while, but i had considered the charged air temp to be too high and things like this (and may ignite the AV gas?).

Also steve if possible explain what kinda of stsyem my 91 legacy has in it if possible : either spfi (huh?) or mpfi (huh ?).

Usdm? Note im not a car newb, but this is my first Subaru, there are many systems i am unfamiliar with o.O

[evolutionmovement]

Does sound just like an afterburner, but the car isn't propelled by thrust.

 

You have the overseas model and my familiarity is more with the USDM (US domestic market) model, which is a single overhead cam 2.2 liter while yours is a double overhead cam 2.0 liter model but both are arguably the strongest blocks Subaru has made. Both cars use MPFI (multi-port fuel injection) with an injector at each cylinder (aiming at the intake valves). SPFI or Single port fuel injection is a single injector located centrally in the manifold to supply fuel to all cylinders. You might want to check bbs.legacycentral.org or the liberty site that I can't think of the name of right now for our old cars.

 

Steve