slartibartfast

Hi,

Hopefully someone on here can help me. I live in the UK and have a 1984 S2 (16v) which has been fitted with an aftermarket ecu and distributorless ignition.

We found out after mapping that my injectors are flowing less than standard and so they can't map the ECU to give enough fuel. The injectors were cleaned and the report shows them all matched at about 10% less than the rated flow.

So, I want to increase the fuel pressure to compensate and I think that I can do that by replacing the Fuel pressure regulator with one from a later model. I understand that as I have 2 FPRs I should replace the other one with a second fuel damper.

Can anyone tell me what parts I would need and the options available?

Thanks.

Bart-Jan

Hi, I believe you can take a single fuel pressure regulator from an S4 and use a damper in the place of the other regulator. Two of them is overkill anyway, to my opinion.

I have Megasquirt installed on my 16V and have made my own adjustable fuel pressure regulator. I presented some images of the build of that one here on this forum. Don't have the link by hand at the moment. I run 2.6 bar pressure @ idle with vacuum hose attached.

PorKen

Two used '87 S4 FPRs (55 psi/3.8 bar) would be great if you could find them.
'87 have a hose barb return line. '88-up have a threaded connection.

Otherwise, one FPR, one damper, and plug the return line.


'87 S4 FPR, 92811019802/Bosch 0280160262

slartibartfast

Thanks for the replies.

Does anyone know the pressure rating of the various regulators fitted to the 928?

What would be the benefit, if any, of retaining two pressure regulators?

If I replace one of the regulators with a damper, does it need to be a specific one or will any fuel damper from a 928 fit?

Thanks

byrdman454

The method that has been used here in the past was using a damper (rear drivers side) from a -85/86 US 32v model and replace the Euro rear drivers side regulator. You also swap out the rear passenger side regulator on the Euro with an adjustable fuel regulator. Then you can dial in as much psi as you want. If I remember correctly, the psi on the adjustable should be high 30s low 40s. I would have to look at my Dad's Euro to be sure. It runs great.

slartibartfast

Thanks for the replies.

I've had a look on PET and a US '85 32V shows as having 2 fuel dampers. Going by the pictures, there is one at the front which has 3 connections (928 110 202 00) and one at the back which has 2 connections (930 110 602 00)

Which is the one that I should use? And does anyone know the bosch part number? It might be easier to get hold of over here using the generic bosch PN.

thanks.

byrdman454

930.110.602.00 (damper)
Damper is actually Bosch P/N 0280161021

tv

I have had 2 of the aluminum billet style rrFPR's sold by 928GT years ago on my 85 euro along with the stock front damper. I run 50% more pressure than stock as shown by the pressure guage mounted on the end of the fuel rail, supplied by Murf.

This was necessary to get my car out of its lean running condition and the 2 rrFPR's allow tuning each side of the engine. I don't agree with mixing and matching bits. It worked for my car -- runs with the right A/F mix and has basically 0 pollution numbers, sounds incredible, and ran fast! (I think some loc-tite or something might be useful on those connections, anyone have an idea?)

slartibartfast

I've finally got all the bits together and have the time to change my fuel pressure regulator so I just want to check that what I'm planning is ok. To recap, the car is a 1984 Euro S2 Manual and I need to increase the fuel pressure because it needs more fuel than the existing system can deliver.

I've followed what you nice people have said and this is what I've come up with. I'm planning to replace one of the FPR's with a later one at a higher pressure and replace the other with another fuel damper. I'm also planning to remove the fuel cooler as it's not doing anything since the air conditioning was removed (I live in the UK so it never gets very hot!).

I've attached a couple of images showing what I want to do. Any comments would be welcome.

Hilton

You have the fuel supply and return lines mixed up in the proposed. The return comes out of the Fuel Pressure Regulator.

The other question I have is are the pressure dampeners you're using from the original S2 setup rated to be safe at the higher working pressure? You might need to switch them to the S4+ variant too.

Otherwise, I can't see any reason for it not to work - its basically the same setup as the 87-95 cars have (bar the missing cooler).

robot808

Hilton is correct. Your feed goes right to the damper up front, then feeds the rails. The regulator is at the end so it can keep the pressure up on the rails.

slartibartfast

Thanks. Do you mean that I have to swap over the feed and return from the existing setup or that I have just labelled them wrong? I assumed that the feed was the one that went through the fuel cooler and connects to the two regulators at the back.

Hilton

The fuel cooler is on the return line - to remove the extra heat from the fuel rails etc. before heading back to the tank.

slartibartfast

Thanks guys hopefully I can get it up and running now. :-)

grepin

Hi, Digging up a real old thread. Was there any success with this attempt. Or has anyone else done similar.