Re: HFS-4 Q&A, application for your engine...
 

Is the cobalt a diirect injection engine?

If it isn't, you only need to tap one wire into the fuel injector (-). Very simple wiring job. If you have a colblt ECU pin out diagram, I can make a special diagram for you.

Re: HFS-4 Q&A, application for your engine...
 

Question:

I have a stage 3 2001 (C5) A6 2.7T, I am currently running a vast w/m setup. Is the setup of the HFS-4 the same. What all do I ? What injector size is recommended? Do I need 2 nozzles or 6 for direct injection? How does this work with nitrous?

http://desmond.imageshack.us/Himg65/...jpg&res=medium

Re: HFS-4 Q&A, application for your engine...
 

The Cobalt is a direct injection engine.

Here is the ECM diagram: http://www.reachingoutministries.com/temp/LNF.html

Re: HFS-4 Q&A, application for your engine...
 

I believe the Vast w/m setup is a progressive pump speed system (PPS) and based on boost?

The HFS-4 is PWM-valve system (same as fuel injection), based on fuel flow and manifold pressure. You can use two nozzles (simplier) or 6-nozzles direct injection (complicated).

Questions:
1. What is the fuel injector size
2. Is your nitrous a dry or a wet type.

Once I have these answers, I can advise nozzle size.

Re: HFS-4 Q&A, application for your engine...
 

1. #52 injectors
2. Not purchased yet, will be a wet setup though.. 50-100 shot

Re: HFS-4 Q&A, application for your engine...
 

This is great help.

The HFS-4 has a dedicated input for Di injectors. Just wire the red and green wire of the green harness to anyone of the DI injectors. If the ECU is easily accessible, you can wire them there.

Do you have a back view of the ECU?

Re: HFS-4 Q&A, application for your engine...
 

Thank you funatnight for posting that info. I am looking at getting an SS/TC when I get back the states, and wanted to use the HFS-4. Didn't know where to find a pinout, so I didn't post.

Re: HFS-4 Q&A, application for your engine...
 

I do not have a back view. Let me hunt it down and take a picture tonight. For some reason the Cobalt community has not taken advantage of injection very much at this point. I am thinking that this car would really benefit from it though.

Re: HFS-4 Q&A, application for your engine...
 

I normally make a drawing showing the backview of the ECU. This way, people cannot make a mistake.

It will be great with you can take a picture of the ECU pin out. plase go for a hi-resolution wioth flash so that I can see the pin allocation moulded on the connector. My email is [richard@aquamist.co.uk).

Is modification such as wmi popular in the Cobolt community?

Re: HFS-4 Q&A, application for your engine...
 

I am going to be setting this up on a 1.9 litre M44 BMW engine with stock internals and compression with a Downing Atlanta Supercharger running approx 10-11Psi Max boost. It will have a custom ECM tune configured to run 93 (USA) octane petrol through a set of 42Lb/hour injectors and flowing through a 3" MAF. The tune will not depend on the water/meth for safety so I can run without the Aquamist running without danger, but I want to add the water/meth to lower operating temps in the supercharger and to add the extra safety factor of increased effective octane of the water/meth. I know there will be a performance increase running the Aquamist as the cooling effect and increased volumetric efficency.

I am curios as to where best place the injectors, I am leaning towards pre-supercharger but wonder if pre throttle body or past is best and if maybe the injector should be placed very close to the supercharger as I can get a nozzle to spray directly at the end of the rotors in this setup. Any suggestions?

I am also curious as to the proper size for the nozzles? The basic system should put out around 210HP at the rear wheel and about 250-270 at the crank and I want to have a system that adds that safety margin and power and also shooting for any possible improvement in fuel economy as well in conjunction with dropping from a 3.46 to a 3.25 rear gear.

Who do I talk to about tanks? I am wanting to get two 4qt tanks with one setup as a surge tank with baffle and the other as the primary, just like Howerton uses in the twin tank system, just without the enclosure as I will be custom building an enclosure and a pump mount to suit my boot.

Thanks,
Dave Ellsworth

Now to go and put my name down for the group buy.