why 4 injectors on rg turbo

[MCIVER]

maybe someone can answer this for me. why can't we just put 2 larger injectors in and use a rising rate of gain regulator that you can adjust the gain on (1:1-7:1). I would think if you put 2 larger injectors in lowered your base fuel pressure down to make them flow the same as stock off boost, then set your gain at above the 1:1 ratio on boost, till you find the sweet spot you could get away from using a 4 injector setup. in fact you wouldn't have to run a control box all together although it would aid in tuning. oh and of course you need a larger fuel pump aswell.

Maybe I'm way off here and someone can fill me in.

 

[snowmanx]

You're way off.......J/K lol

Sorry, I couldn't resist...but what would be the benefit? Cost?

 

[MCIVER]

yep cost no more extra injectors, or throttle bodies, fuel rail, extra wiring harness, also less to go wrong.

 

[Comp 670]

If you turn the fuel pressure down enough to try to get a clean idle with a large injector the spray pattern out of the injectors goes all to hell.(the fuel just dribbles out and the engine coughs)The injectors need a certain amount of fuel pressure to operate properly.Also hard to get the fuel pressure to go up and down quick enough to make that work.

The race cars I have been working with are starting to go to a system that uses a small injector for idle and part throttle then a bigger injector comes online as the boost come in.

 

[Snowstar]

Larger injectors dont atomize as well as smaller ones. Then lowering fuel pressure on top of that would make it worse. The result would be poor fuel economy and drivability. Injectors are designed to work in a certain range or duty cycle, when they go out of that range performance suffers. There are a number of other issues like connector plugs, high impedence or low inpedence, proper sizing and fuel curve. If you got time and money try it, it wouldnt be the first time traditional theory has been wrong.

 

[MCIVER]

has anyone tried this on a sled setup ? I've done it on several cars before and it worked great.

 

[Snowstar]

Thats alot easier on like a L4 V6 or V8 motor where you have more cylinders to spread the fuel across to double the hp a RG Turbo does. You would have to double the stock injector size to have the same fueling the dual injector gives. For example what would give better throttle response and drivability on say a V8, A big one barrel carb or a properly sized 4 barrel.

 

[MCIVER]

snowstar,

what is the stock fuel systems problem, is it the injectors or the pump, which one can't meet the demand first. and thank you for answering to my questions.

 

[Snowstar]

On a M1000 motor the fuel pump and injectors max out at about the same hp range 220hp. The M8 motor seems to get away with more boost but probably the same hp range.

 

[bholm87]

don't the polaris rg turbos just use two?

 

[mtn_extreme]

I think polaris comes with 4 stock injectors.

 

[Snowstar]

don't the polaris rg turbos just use two?

I have heard some kits rely on only 2 of the 4 injectors in the Poo kit.

 

[product tester]

If we had better fuel control (ecu) then just a bigger injector would work great up to a certain point.

 

[Mseven]

How much pressure can the injectors take reliably? What fails with to much pressure the body or nozzle?

 

[MCIVER]

I've ran over 80psi through a set of injectors on my turbo car before, that was at 31 psi of boost. no problems ,failures, or leaks.

 

[hatchers]

apples to oranges

 

[MCIVER]

not really apples to oranges.

an injector is still an injector and a fuel system is still a fuel system.
I think I provided a bit of answer to his question. Granted I didn't tell him the limits at which a part will fail due to psi, cause I never have made something fail yet, but I'm sure I was close.

 

[Mseven]

not really apples to oranges.

an injector is still an injector and a fuel system is still a fuel system.
I think I provided a bit of answer to his question. Granted I didn't tell him the limits at which a part will fail due to psi, cause I never have made something fail yet, but I'm sure I was close.

Not really, in a diesel common rail system the pressure is in excess of 23,000psi. It is still an injector and fuel system. I know your comparison is much closer, but I would assume an auto app would have more durable parts since cars are made to last much longer than snowmobiles. I am sure someone has tested the limits of our systems.

 

[hatchers]

not really apples to oranges.

an injector is still an injector and a fuel system is still a fuel system.
I think I provided a bit of answer to his question. Granted I didn't tell him the limits at which a part will fail due to psi, cause I never have made something fail yet, but I'm sure I was close.

wrong, but what do i know

 

[MCIVER]

Hatchers,

rather than the short answers like "apples to oranges" or "wrong" explain the difference and fill us in on what the limits of the injectors and fuel system are, when do they leak or break down ? this way you can tell us "what you know".

Maybe I should have stated that I was talking about efi systems that were similar, one automotive one sleds, not diesel, carb, mechanical gas injection ect... I did leave that wide open.