5th injector with stock injector??

[frostburner]

I have a question.. do i need a cold start injector in order to add a 5th injector or can i just drill ahole in a pipe and stick one of my old stock ones.. put about 1 inch of it in teh pipe.. and tap that into teh fuel line and have it come one when i flick teh switch.. would that be too hot and ignite the fuell.. or what if i got a fitting that extended the tip of the injector so it wouldnt be directly in teh pipe..???

[artur_p]

the stock injector flows to much fuel. your better off using a cold start injector or a mustang/corvette/camaro injector which flow 19lbs/hour. also use a pressure switch to turn the injector on, i wouldn't recommend using a toggle switch .

[frostburner]

ok... so where can i get a pressure switch.. anyone know??? also which cars can i get a cold start from if i go to the j-yard... years and what to look for.... thanx guys

[artur_p]

local parts store should be able to get you the pressure switch. i dont remember the part# but Hobbs makes a pressure switch set to 15psi. for the cold start injector look under the hood of turbo diesel VW's and Saab's.

[frostburner]

k thanx.. so they wont have one for sale at the store does eveyrpla e have to order it.. or are tehre some palces that have them.. which other cars can i get them off of(injectors) i know of those two but i dnot see them very often.. thanx again

[LeGweg]

Hobbs pressure switch #76052

I also beilieve stock injectors pulse, and that wont work for the 5th injector install. The cold start injectors put out a constant flow of fuel.

So the stock ones wouldnt work......am i wrong?

[artur_p]

stock injectors pulse because the computer makes them pulse if you apply 12V to a stock injector it will put out a constant flow.
i had one running on a work bench for 2 hours with no problems. it never overheated like some people would think.

[GLHS#116]

Quote:

Originally posted by artur_p stock injectors pulse because the computer makes them pulse if you apply 12V to a stock injector it will put out a constant flow. i had one running on a work bench for 2 hours with no problems. it never overheated like some people would think.

Well, 525s don't blow up for most people when you put twice the rated amount of torque through them. Then again a lot of them do. If people have the opportunity to put a stouter gearbox in a high hp car they generally take it.

The stock injector is designed to be pulsed. If it isn't pulsed it doesn't get to cool its coil properly. When testing injectors the FSM doesn't recommend more than a few seconds of continuous voltage. Does this mean it won't live if you keep it open for more than that? Maybe not. But I know I'd rather have an injector like the Bosch cold start injectors that was actually designed not to pulse.

If your 5th injector cuts it will blow up your engine NOW. You are already needing more fuel than your stock injectors can provide and running higher boost or the injector wouldn't be on. When it fails you will be lean at WOT with a lot of boost.

A lot of people will argue that if you make a run down the strip you are only over 15psi boost and running the 5th injector for a few seconds at a time. Well, fine. But tell me that one night you're not going to find a nice open stretch of road and put your foot down for a few minutes or hours. That's when you don't want a pulsed injector that might blow.

There are any number of parts that can fail on a car without causing catastrophic failure. This isn't one of those parts. I wouldn't take that chance on my car unless it was a drag strip-only race car never driven on the street.