Whats the difference/ benefits to each one, and how does each one affect the fuel delivery system.
I know that for turbo applications an FMU is recommended, but for NA I have seen people recommend a FPR.
Also, how does each one work,
Thanks, just trying to expand my knowledge.
http://www.j-body.org/forums/read.php?f=40&i=83909&t=83909
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Madjack wrote:Like I said before, building an engine like ours (2.2 or 2200) is a painstaking chore , since there is so few custom made parts. It's frustrating to me too, but that's what I like about doing this engine, it's the challenge.
ahh, thanks, didnt think this topic would be in the boost forum.
one more question about fpr, it says it is regulated by the amount of vacuum created by the motor, how does the motor create this vacuum?
also, does anyone know the equation for calculating the proper AFR?
your motor sucks in air, unless you are boosted your going to have a vacuum, the piece of tubing that connects to your FMU is hooked up to your intake manifold to get the vacuum.
-Chris
gotcha. so how would it work on a boosted motor?
on a boosted motor you get positive pressure, and typically use a fuel pressure riser(cheap solution) or an engine management system(like greddy e-manage) to increase the amount of fuel as the boost increases.
also replace FMU with FPR in the previous post.
FPR would be the riser, and similar to what you have currently.
FMU would be something like an e-manage or MegaSquirt.
-Chris
an FMU can also be a mechanical device like a FPR, it doens't have to only be a megasquirt, or e-manage. Cartech sells a very good adjustable rate Fuel Management Unit. Fuel goes in one side, and out the other.
So, for example, if you have the FMU set to a 1:4 ratio, then for every one psi that is made, the fuel pressure will increase 4 psi, so normal idle fuel pressure, is around 40, so, if you're driving, and the boost is at 5 psi, in this example, the fuel pressure would go up by 5*4 =20. 20 from whatever the stock system has the fuel pressure at 0 psi, which on a N/A car is when you're flooring it.
