rx7_turbo2

I thought this might save people some time.

If I remember correctly the stock FPR and PD have the same thread size. I replaced both and used the following fittings.

Earl's# 991945 (-6 to 12mmx1.25 Del Orto Carb)
Aeroquip#FCM1532 (-6 90 degree)

The Aeroquip fitting is a larger barbed fitting than stock, but a smaller one can probably be found.

Hope that helps

Icemark

why are you replacing them? for out board versions?

rx7_turbo2

Yup. got rid of the pulsation dampner, and am running parallel fuel rails with a Paxton rising rate regulator.

Icemark

Ah, okay... that makes sense... I thought perhaps you were another one of those "remove the PD" fundementalists that I might need to debunk.

But for your set up that makes sense.

Cory Simpson

Whats wrong with removing the PD???

Does it hurt anything???

Icemark

Yeah, can make your motor run lean (or rich) at different RPMs, can cause older fuel lines to split or crack, can cause broken and leaking injectors.

Just like if you suddenly slammed/turned off the water in your sink, you'll hear a clunk of the fluid as it stops in the pipes (or in our case the fuel rail). Every hear a cluck when the valve for your toilet stops filling the tank? its the same idea.

Well that clunk is happening once every firing of the engine... so what? about 1800 times a minute at idle, a large cluck from just one injector... well alone two happens on the fuel rail. And what happens when there is two??? could there now be pressure waves from the injectors opening and closing? yep. so maybe now, with nothing to absorb those pressure waves, one injector maybe not getting the full amount of fuel pressure...

I know what your thinking next," Whooops you mean the engine could go lean only on one injector???"

Sure can, but maybe it only goes lean at 4000 RPM to 5000 RPM or maybe only 2500-3500 RPM that shouldn't effect the motor right??? And to top it off, its almost impossible to trace down why it's going lean, unless you are looking for shock wave in the fuel rail.

there is a reason why PDs are standard on on every mass production imported fuel injected car made in the last 20 years, and every mass production domestic fuel injected car for the last 10. It's because there are too many fuel issues from lines being stressed and breaking to injectors running lean because nothing is controlling the shockwave, if you don't have a PD.

boosted1205

iTrader: (9)

[QUOTE]Originally posted by Icemark
[B]Ah, okay... that makes sense... I thought perhaps you were another one of those "remove the PD" fundementalists that I might need to debunk.

LOL

Cory Simpson

Uhhh, I think I'll buy a new PD, and put one back on my fuel rail.

I have never ran it without the PS yet, I just figured it would be better to loose the chance of a fire hazard.

wrxfc3s

What takes the place of the pulsation dampner? The RRFPR?

I don't have a PD on my WRX and I've been through the fule system and as far as I can tell it only has a FPR. None of the aftermarket Fuel Rail kits even come close to mentioning anything about PD effect.

I was looking at making a dual feed rail myself. From what I've learned w/ the WRX and then looking at the RX7 fuel delivery I see some flaws. It seems the rear rotor will get less fuel than front. Has anyone else come to that conclusion?

dr0x

Thats why you run parallel fuel rails instead of a series, like pointed out above..

j200pruf

iTrader: (4)

Is there any cheaper PD's available for our cars?

wrxfc3s

So exactly how does it fix the problem, fuel supply still stops and goes, on and on. The drastic changes in pressure are still there. I still haven't seen a Pulsatin dampner on the WRX or my Mustang for that matter or the '03 cobra. None of those are parallel fed from the factory. Actually of all the cars mentioned, The RX7 fuel supply system appears to be the best but the non-parallel issue still causes the one injector to get more pressure than the other.

BlackRx7

so running them in parallel means extacly what?

all four injectors firing at the same but only at 25% each or what?

how would you go about running the fuel rail in parallel?

DCmaestro

Does anyone have reted's fpr diagram from the fc3s-pro site cached. It's one of the pages I've been trying to find in internet archives that I can't get. Perfect explanation of parallel fuel rails and aftermarket fpr install.

Icemark

On many of the newer cars (much like the S5) the PD is integrated into the rail for initial build cost savings (and added repair costs when they fail), and unless you know what design is being used it may be difficult to locate).

Its quite common to have aftermarket PDs made for GM and ford products, but at this time none of the domestic aftermarket ones are interchangable with the FCs.

J-Rat

iTrader: (2)

I love icemark!.....

I have been preaching this all along.

Jarrett

wrxfc3s

OK, lets get some pics of these custom fuel system setup's I'm looking for idea's. I haven't installed my Microtech yet because I haven't decided what to do with the fuel rail. So does anyone have some pics?

The other thing I've heard was that some of the really new new cars have tighter control of the fuel pump; altering the voltage to alter the flow ( Irealize older cars do this too). I think the WRX, if I'm not mistaken does this as compared to the others that burn their fuel pumps up because they are constantly on high voltage. Now I'm not certain on the terminology of what I just said so don't flame me, I'm just trying to get a better overall understanding.

Now that I think about it, there was a big write-up on the nasioc.com that talked about the issues the mitsubishi guys had when changing fuel pumps and injectors and why the subie guys didn't have to worry about it. But as usual I can't remember.