hey guys, im thinking about when i go to larger injectors and ditch my FMU. if i get the aeromotive adjustable fuel pressure regulator will i be able to adjust the air fuel mixture without any pcm tuning? i dont have tuning capabilities and nobody near me does either.

id like to have more control over AF ratio tuning without getting LT1edit/tunercat, or doing dyno pulls then sending out my pcm for tuning......

here is a link to the regulator im thinking about, its the AEI-13106http://store.summitracing.com/defaul...=egnsearch.asp
thanks guys

 

you can't swap injectors or switch from a FMU to a FPR without tuning.

if you swap to bigger injectors without tuning, you will dump way too much fuel in.

if you swap from a FMU (which increases fuel pressure, say 6 psi per 1 psi of boost) to a FPR, which only increases fuel pressure 1 psi per 1 psi of boost, you will run the engine way lean under boost without tuning.

 

alright, thanks. i dont have a laptop yet to use tunercat. will a hypercrap work for tuning AFratio???

 

nope... :/

 

didnt think so...

 

If you are that hard up for lack of tuning, just get a mail order through www.madz28.com or www.pcmforless.com. A couple hundred bucks and your are done. Both of these guys are supporting vendors here.

 

The 13106 is the reason I popped a head gasket back in the day. I'd stick with the stock regulator until you're ready to upgrade the fuel system for real.

 

When would you upgrade the FPR? If you do a dual intank setup and get bigger injectors with tuning, would you also not want to upgrade the FPR to an AFPR?

 

if you're running the stock lines, keep the stock regulator -- there are a LOT less problems with the stock regulator than with aftermarket ones. I would only upgrade the FPR if you are putting big lines, and really want to flow some fuel.

the dual-in tank is a really good setup, but not with the stock lines. Regardless of how much pressure you put behind it, you can only flow so much fuel through a 3/8" outside diameter line -- that's about 1/4" inside diameter.

Think of it like a garden hose vs a fire hose. At the same pressure. Set both up at 60psi and fill a swimming pool. Assuming the pump is big enough to actually keep up with flow, which do you think will fill up the pool faster?

 

I thought the consensus was that the stock lines would be fine for a dual in tank setup feeding a 900FWHP engine?

 

900 might be stretching it... Personally, I wouldn't run the stock lines past 500rwhp. Also keep in mind that turbos eat more fuel than supercharger and superchargers eat more than NA, so the combo really affects the power potential of a 3/8" OD line.

Going overkill is a little added insurance. The fuel system is one of the cheaper parts to a build. The last thing you want to do with a boosted motor is run it lean.

But back to the topic at hand... Unless you replace the fuel lines or need to turn up the fuel pressure, there's no need to replace the stock FPR. The stocker flows plenty to not be a problem and it works pretty darn good.

The only reason I would mess with the fuel pressure is if I barely went over what my injectors could flow. For example, I'd increase the pressure by 10 percent and pull fuel by 10% across the board in my tune. Any more than that and I'd upgrade injectors.

 

Jered, I think that s/C cars eat more fuel than turbo, because of parasitic loss. The engine needs to turn that supercharger which requires more fuel comsumption since its more work. The turbo uses the exhaust, despite the backpressure, the A/F requirements in the combustion chamber wont be too affected.

We did a calculation back in college on a roots charged jaquar (factory supercharger) and we calculated that it took and aditional 40hp to run that S/C. thats extra fuel consumptin there.

I agree with the regulator, use it if our injectors are at the hairy edge.

Jon

 

I used stock lines, rails, and regulator back when I was making "only" 700rwhp.

Rich

 

I was reading up somewhere that the BSFC for S/C engines is around .55 and for turbo was .6-.65

-- could've been some mis-information too...

And I wasn't saying that stock lines couldn't be used to make 700rwhp... I just said I wouldn't do it.

 

I dont know. I remember the jaguar example because it was advertising 300hp @ crank with supercharger, but the fuel comsumption needed was to feed 340hp in order to get the 300hp output. I'll see if I can find the question in my old notebooks.

Jon