Stand off Injection
Turbo Mini Forums

Ok I am thinking of running Injection on my Daily Hack mini I am sick of Carbs and there in tune ability.

Now the engine I hope to Inject is a 5 port N/A 998 with 10:1 compression 286SC cam 12G940 and a 2" LCB.

I hope to use Mega Squirt on this one

I have seen Stand off injection used to great effect on big cam race Bike engines and the likes of F1 engines. So I got to thinking could this work in a Down draft setup on a 5 port.

I have attached a crappie 2D sketch of what I mean.

This Idea is similar to the SPI but broke up over the Two ports so maybe the best of two worlds IE SPI easy setup and the better fuelling that straight pre port runs give you.

I would not be after super Accurate AFR on inner and ousters just nice would do as this is a came engine which will have to run the richer side anyway imo.

Any way what’s peoples taught good bad or indifferent?

Again sorry for crappy sketch but I am learning and just haven’t the time to spend hours and hours at CAD to make a pretty one.
Thanks
Paul

Edited by PaulH on 22nd May, 2009.

Would such a system still suffer from the problems of port injection ?

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Is it not just effectivly a single point injection. Would there be any advantage doing this way over controling a single point injector setup?

Well It would be simlar to the Single point but there will be one per port.

Steve I think this will still some what suffer from the Age old 5 port problam I just hope it will be acceptable,

I'm not familiar with "stand off" injection but I assume from your sketch, the injector is a long way away from the valves (even before the throttle plate in the sketch).

If you then had one injector per port then I would have thought you lose the simplicity of SPI and lose the "wet manifold" continuous mixing of fuel air (as the two ports individually don't have a continuous airflow) and you have everything bad about port injection, ie, far too far away from the valves, hence wall wetting and no control of what goes to inners and outers.

But as I'm not really sure what "stand-off" means, I may be completely wrong.....

Any links to something where stand-off is used ???

Schrödinger's cat - so which one am I ???

I think by stand off, he means running an injector at a distance, as opposed to pointing at the valve.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

http://www.youtube.com/watch?v=AKyP19ky_W0&feature=related basically as per the diagram :)

Edited by evolotion on 23rd May, 2009.

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

I had a feeling it might be like the video from the description and sketch....

I think what I said stands then,,,,, all the siamese port issues, worsened by the distance and without the simplicity and uniform mixing of SPI.

Looks highly dangerous for a road car too - suppose there was a glitch and the injector operated against a closed throttle plate !!!

Schrödinger's cat - so which one am I ???

I don't know about stand off, but I would not hesitate to recommend a couple of Jenvey or bike TBs with the latest MS2/extra code that I'm using.

My 998 loves the EFI.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Sorry I thought you meant one single TB with 1 injector replacing a single carb. Are there any bike TB's that lend themselves to mounting car injectors?

I would tend to agree with Rod on this.

And I would think that the best results from the Jenvey or bike TBs would be with a very short intake to put the TBs as close to the head as possible.

Jean

http://www.jbperf.com/

Well I would have no worries about the safety of this on a road car since at no point will you ever have a totally closed throttle butterfly,

I see what you are saying about continues air flow but looking at this a little more deeply

1300 RPM is what this motor Idles at, So that’s
1300/2=650 so that’s 650 sucks per port per Rev per minute. so what does that mean,
Well as I see it is the Air passing trough each butterfly will be pulsating but never stopping. So in essence not having any really effect on wall wetting, for the good or bad. What it does allow is cheep easy injection which gives good fuel air Emulsification in a high lift cam situation.

Maybe I am barking up the wrong three but I think, if we always do what we always did, we will always get what we always got.

I have another Idea I will post a sketch up of In a short while

There would only be a safety risk if the fuel was being sprayed with no enclosure...

WHich wouldnt work too well in a boosted application lol

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

You can pick up a standard factory fit SPi manifold on fleabay for around £20.

More than enough for a 998.

You will have to run Alpha N on the ECU though with a 286 cam