Adding a 5th injector(car Q)

[Hellmund]

Well I figured this'd be the best forum to ask. My brothers basically has done up his car, it's a 98 mitsubishi mirash, lowered,bodykit etc....

He wanted to add a hobbes pressure to switch to turn on the 5th injector when the boost reaches a certain level, now I've been trying to get some reasonably precise diagrams etc on wiring it up. It seems people talk about doing it on most of the sites I see but am having a real hard time getting something really useful. Anyone got an any reasonable links....or Cadman and the other wise-ones of cars be able to assist. Looking for wiring instructions to apply the pressure switch....I might just research the switch itself work it out.....

[bigblue77]

Have you looked into Nitrous system diagrams? Some NOS systems use a pressure switch to kick on the NOS similar to the way you need the injector to. Sorry, I don't have any links for you , just suggestions.

Jer

[caddmannq]

Thanks for the vote of confidence, Helmund, but I've never even seen a Mitsubishi Mirash! I wouldn't know one iif it bit me in "my rash" (so to speak.)

The only advice that comes to mind is that the extra fuel will probably be useless, unless the boost pressure is raised above normal. Unless you have extra intercooling, the extra heat may quickly push you into the area of diminishing returns. I'm assuming this is a turbo-charged machine with a bypass valve that vents excess boost.

As I said, I've never even seen one here. Is this like a non-US version of the 3000GT?

[Toadman]

Wouldnt it be easier to get larger injectors and re-map the ECU?
Or maybe get an Apexi PowerFC or Haltech?

[Hellmund]

The mirage is a standard 1.4ltr and this one is reconditioned and overbored to 1.5. Basically it needs more fuel in the high-range of the boost. He's just looking to setup a pressure switch too see the boost and say open up and get the extra injector going at a certain level......I think about 16 pounds is when the mixtures too lean. It's not the BEST way, but it's how he wants it.

Cad: Just basically a smal corolla hatchback kind of thing. Small engine but the whole frame is light. Fuel-injected, turbo from a mazda RX-7 and running thru a intercooler.....just if u have had any experience or have any knowledge on just how to fit it.....

[caddmannq]

Ohhh...A Mirage!

You said Mirash!

Is that some "down under" humor? ...or just a late nite typo?

Anyhoo, I do know what a Mirage is & I've even owned a Mitsu 1.4 powered car (Plymouth Champ) waaaay back when.

As far as the wiring, that depends on the exact components you plan to use. I don't think that there's any good solution that's as simple as what you want to do.

Properly speaking, the signal to the injector needs to be mapped to a whole bunch of parameters, boost pressure being only one of them. That's why modern fuel injection has so many sensors, and a dedicated processor to read them and signal the injectors..

[bigblue77]

I assume you are just looking for a way to do a raw fuel dump once the turbo gets done with spin-up. I can think of various good reasons to do it, like it will drop the turbo-temp, thus helping lower intake air temps. That is one trick I've seen done to hopped up Cats(1000+ horsepower ones).

Jer

[Hellmund]

Nah cad....this is what happens when most of your posts occur at 1-3am......

Hmmm, I think I know what u mean, the computer will see when the excess injector came on from the sensors if it was solely mapped to boost pressure and it'd compensate by reducing the fuel output of the other 4 injectors......