Extra injector in supercharger intake and blow off valves

[quadcam boat]

I got one of Jordys manifolds and a M90 Eaton. If my standard injectors are not up to scratch (not sure what size mine are) I was thinking of relocating the cold start injector to the inlet of the supercharger and adding extra fuel there. Would I need to put a blow off valve into the plenium to protect from a backfire? the plenium is somewhere between 3 3.5 litres I think?

 

[Cobra]

Does anyone know how long the cold start injector actually works for at start up?

 

[Lexurious]

I would assume it stays on till at operating temp which may explain the extra performance I have when cold, but im just guessing.

 

[Miles B]

"Cold start injector" ?

 

[1UZ-HZ]

Yeh, the thing that sits underneath the top half of your intake manifold

 

[Miles B]

Oh I thought you meant an extra *fuel* injector...

 

[Zuffen]

When we look at supercharging we all assume the stock injectors will feed up to 6lb of boost. This is true for an SC400 but Crown engine have much smaller injectors anf this should be taken into consideration when planning the upgrades required to make it all work together.

 

[Cobra]

I have been doing a lot of asking around. The Crown and Soarer injectors are both one in the same.
Also the cold start injector is only in operation whilst the starter motor is cranking. It does not flow enough to be used as a 9th injector.

 

[Lextreme II]

I know for a fact the US Spec. 1UZFE has 251 cc/min. I also have heard that Crown has smaller injectors. Anyone know what size of injectors does Crown has?

 

[quadcam boat]

I guess I could check the flow of the cold start injector by measuring how much fuel it puts into a measuring jug in 1 minute. I have 2 of them sitting here doing nothing so I could mount 2 of them together if neccessary. I though it would be a good idea because they are really easy to mount, just drill a hole to fit it in and 2 more tapped holes to hold it down. Also sprays fuel in 2 directions, 180 degrees apart which means I can mount it in the middle of the supercharger inlet and it will spray into both rotors.
To test measure it, all I have to do is connect 12volts onto the 2 wires? That should be right shouldn't it?
But will I need to have a backfire protection blow off plate? I can remember someone telling me that that if the injector is set up to work only under boost, I should be right. The idea was that a backfire shouldn't occur under boost. Is this right??

 

[Zuffen]

I'm not too sure the blower will like raw fuel being fed through it.

I don't think they are designed for that.

You could mount the extra injector under the blower in the valey of the engine.

 

[Zuffen]

Guts,

If you do a search of this Forum under "Crown Injectors" you will find six answers.

According to KDog (who has a measuring rig) Crowns flow 205cc and SC400 251cc.

This would limit the crown to no more then 325hp or so.

I have a set of 251cc I will probably use, but it looks like I can get onto some 350 or thereabouts which I would instal for supercharging.

 

[Dreamkiller]

Zuffen,
Most carbied blown v8's are suck through setup, so I dont think that raw fuel through the blower is that bad.

Ive also seen a few articles with the 1UZ fitted with sprintex superchargers and they have an extra injector mounted in the back of the charger. I think "Bullet supercars" do this as well.

 

[quadcam boat]

Yep, yella terra use extra injectors on the inlet of the terra-charger (eaton) supercharger kit that they fit on the holden 5ltr V8.

 

[Zuffen]

Dreamkiller,

I think you are right but why risk fuel being forced into the gears and bearings of the blower?

There's plenty of room under the manifold to fit a couple of injectors.

Quadcam Boat,

How do you plan to fire the extra injectors. Do you plan on an aftermarket ECU to do the job?

 

[quadcam boat]

Anyone know the flow rate of the cold start injector?

 

[quadcam boat]

Zuffen,
You could run into fuel distribution problems with putting injectors under the manifold - some cylinders getting too much and some running lean. The engine is in a boat and running an Autronic SMC. I have a spare output left to run the extra injector.

 

[quadcam boat]

Measured the flow of my cold start injector and it flowed 115cc in 1 minute. That was with the standard fuel pressure regulator. Would 2 of these have enough flow to supplement my standard injectors?

 

[Lextreme II]

I got one of Jordys manifolds and a M90 Eaton. If my standard injectors are not up to scratch (not sure what size mine are) I was thinking of relocating the cold start injector to the inlet of the supercharger and adding extra fuel there. Would I need to put a blow off valve into the plenium to protect from a backfire? the plenium is somewhere between 3 3.5 litres I think?

3.0-3.5 liters per what (minute or hour)? I would like to know...

 

[Gazzasore]

That is the size of the chamber
as in how much water it would hold if you filled it up