7th injector?

[Adam Connell]

So the 7th injector setups were before my time. I understand they were used to add fuel because 0f the lack of high flow injectors back in the day, but with alky injection now being a staple in the TB community and E85 gaining popularity with just about anyone who tries it I think there could be some merit to the old 7th injector setups once again.

I am not familiar with how the old 7th injectors were wired and fired, and honestly I don't know anything about them so this idea may be way out in left field. Would there be any benefit to adding a 7th injector running e85 from a charge cooling standpoint?

Would it make more sense to run a mechanical style constant flow injector similar to the alky injection kits with a pressure regulator or cutoff so it doesn't run at idle? It would basically be the business end of an alky injection setup tied into the car's fuel system.

I don't know if e85 has enough cooling capacity to make it worth it like methanol does, but I figured I'd throw this out there.

 

[Adam Connell]

A little searching netted me this: http://www.yellowbullet.com/forum/showthread.php?t=624201&page=2

Looks like the parts are already out there thanks to the nitrous guys!

 

[ITSAV6]

the ATR one plugged into the inj harness and had a adjustable turn on point. It just followed the pw of the injectors.

 

[WFO]

I've run an old ATR 7th injector in this exact way.

The 7th injector harness wires inline to the injector harness and pulses the injector at the same rate as one of the injectors. Once the rpms are up at all the injector puts out a pretty healthy fog of fuel. My car has been sitting for a while but it ran pretty good with it.

 

[JayC]

Kirban used to sell a 7th injector setup I designed using NOS parts and a control box. You could use a Hobbs switch for turning it on.

You'll need to stay small on jet sizes.. I think I included a 15, 20 and 25 with the kit. Bob Armstrong ran 10.50 with 40# injectors and my 7th back in the 90s.

Looks like Yellowbullet is about 20 years behind me. Go figure.

I dont know that it still exists but at one point NOS had an unpublished part number for my whole kit. Could be worth a call although my contact there has been gone for years.

Red Armstrong had a pretty nice 7th too at one point. I dont know how many were sold. The ATR one was junk but it looked nice.

 

[WFO]

I don't have experience with any other than the ATR but it did exactly what it was supposed to do.

I have 60# injectors in the car and put another 60# in the 7th to add basically 10% more E85. The injector sprays in at the vacuum block so the fuel travels through the intake manifold similar to how alky injection would. Plus since it's pulsing along with an existing injector it's progressive. So far so good.

 

[JayC]

The problem with the ATR unit is that the fuel just dribbles into the intake track.. other than that, its a quality piece.

 

[WFO]

I remember looking at the design when I put it in and wondering about the 90° turn the spray had to make.

It would be easy enough to TIG one of these bungs in to the up pipe in front of the TB. Or maybe into the back of the plenum?

http://www.diyautotune.com/catalog/weldin-injector-bung-for-ev1-and-ev6-injectors-p-505.html

 

[JayC]

The Armstrong one Terry Houston made had the injector in the up pipe.

 

[Steve]

The Armstrong one Terry Houston made had the injector in the up pipe.

I had the Red Armstrong unit back in the day. I remember that Red was very negative on the way the ATR set up injected the fuel into the intake.

 

[JayC]

For once, I agree with Red. Thats probably a first.

 

[MNwe4]

To bring this topic back up, I had similar thoughts to Adam's. Instead of only for air cooling purposes what about adding it for extra fuel? Say you've maxed out your injectors, but are looking to run only a couple more psi of boost and you know the fuel pump is up to the task. Adding an extra injector would be much cheaper than getting a new set of injectors and then needing a modified ecm or an aftermarket one.

Assuming you've got it mounted in a good orientation, couldn't you just pull fuel from the end of the stock rail by the regulator and activate it with a Hobbs switch? At that point it's basically a non progressive alky kit, right? Removing the extra tank and pump from a traditional alky kit would mitigate some risk.

I guess I'm hung up on how to make it progressive. Following the duty cycle of only one injector leads me to think that the fuel pulse would only be optimized for one of the cylinders and slightly off for the other five. To be ideal wouldn't you need it to fire every time one of the main injectors fires, essentially resulting in it being on all the time?

 

[troyk]

I'm not sure I'm reading this thread correctly, but this is what I posted before & I got shot down for my idea, but I don't think your talking an aftermarket ECU either.
http://turbobuick.com/threads/is-it...tage-of-after-market-ecu-capabilities.424718/