hybrid_944

ive just purchased an AreoMotive AFPR.. and well my car is running really bad.. im a big fan of only one mod at a time. so I can tune it and then add another variable.. well I did get my fuel rail modded to accept AN- fittings.. and then bought a AM. afpr. but at .4 bar it detonates / hesitates.. so after a bunch of "tuning" it only gets worse.. when i run 40psi at idle.. ro 70psi at idle.. it is the same problem.. did I not get the right type of fuel pressure regulator???

mike... with eternal problems..

Alan C.

Sounds like you bought a decent AFPR. I have a Weldon set at 43 psi static, engine off. If you have 40 psi at idle it is too low. Remember at idle you are in vacuum. My car runs in the 30's at idle.

How did you mod the fuel rail? Mine has -8 AN fittings welded to the rail. Out of the rail a -8 goes into the AFPR and exits with a -6. A vacuum line runs from the manifold to the AFPR to supply pressure.

Any chance it could be so simple as connections?

Here's a shot of my setup

Rob

Alan C.,

I see from your picture that you have eliminated the fuel pressure damper. Does the Weldon FPR take care of this function and are you still running a factory fuel pump? Anyone know a reason to keep the dampner when running a more generic aftermarket FPR?

Thanks,
Rob

Danno

Yes, danny951 has got it!

The standard FPR on our cars are already boost-sensitive (rising-pressure). They raise fuel-pressure 1psi for every 1psi of boost. That's what the little vacuum line that goes to the middle of the FPR does. However, this doesn't mean that you get more fuel as boost increases. The rise in fuel-pressure is to equalize the pressure-differential across the injector. If you didn't increase fuel-pressure with boost, at some point, high-boost engines would pump the gas back into the tank!

So let's say you take the case of a turbo running at 15psi. If you have a 951 with a 2.5bar FPR, starting pressure is 36.25psi. At full boost, the fuel-pressure is then 36.25+15 = 51.25psi.

Then if you upgrade to a 3.0bar FPR from the S2, you'll get 43.5psi at 0psi and 58.5psi at max boost.

What's typically called an 'adjustable FPR' in our crowd is really a 'adjustable start, rising-pressure regulator' that allows you to set the initial pressure, however, the rising-rate is still 1psi fuel per 1psi boost.

Finally, a true 'adjustable start, adjustable-rate, rising-pressure regulator' is something like the <a href="http://www.bellengineering.net/fmu2020.html" target="_blank">Bell Engineering unit (BEGI)</a>, which has TWO adjustments. One for the initial pressure, and one for the rate-of-rise vs. boost.

hybrid_944

ALAN

that is a nice looking set up.. Automotive TEC-II ?????

im lokking at the TEC-III but in a few months.. (hopefully)

<img src="graemlins/drink.gif" border="0" alt="[cherrsagai]" />

but yes my set up is hooked up similar to yours.. but. I welded my an- fittings on differently.. both of them are exiting on the passenger side.. but very similar.. except for one thing. the origional shop that I had built it NIG welded it instead of TIG.. so after instalation it had 12 leaking ... no I mean spraying holes in it.. the new company i have did a much better job

but I guess as soon as I get it on then ill be able to trouble shoot it..


thanks.. mike