CIS to carb fuel filter questions

[Koich]

Hello all,

I'm converting from CIS to Weber. Got most of my parts from PMO sans the carbs.
Also have PMO's fuel pressure regulator. Going with the stock CIS pump.

Instructions say to remove the stock fuel filter and accumulator. I understand those are CIS parts. I probably should run a fuel filter before the pressure regulator, and 1 each from the regulator to the Webers.

Anyone have any recommendations on the fuel filter before the pressure regulator? I understand it probably has to survive some what higher pressure?

[jkh2cpu]

I'll tell you what I did with my 1973 911 T / MFI: I incorporated
the fuel filter that came with the MFI setup. I had to plug the
hole for fuel enrichment. You won't be needing a high pressure
fuel filter here, as the webers like 3 or 3.5 pounds per square inch,
which is more than the CIS system uses. One fuel filter should be
enough. No sense in getting over complicated :-)

Good luck on your conversion.

[Koich]

Originally Posted by jkh2cpu

I'll tell you what I did with my 1973 911 T / MFI: I incorporated
the fuel filter that came with the MFI setup. I had to plug the
hole for fuel enrichment. You won't be needing a high pressure
fuel filter here, as the webers like 3 or 3.5 pounds per square inch,
which is more than the CIS system uses. One fuel filter should be
enough. No sense in getting over complicated :-)

Good luck on your conversion.

Thanks John. Though I think I will need high pressure because I'm:

1. Using the stock CIS fuel pump
2. Placing the fuel filter before the PMO Fuel Pressure Regulator/controller.

Or, should I run one after the PMO FPR and call it a day?

[Koich]

Originally Posted by Koich

Thanks John. Though I think I will need high pressure because I'm:

1. Using the stock CIS fuel pump
2. Placing the fuel filter before the PMO Fuel Pressure Regulator/controller.

Or, should I run one after the PMO FPR and call it a day?

Actually, I got a email from Richard Parr saying that a major advantage of the PCU is that the pressure never has a chance to build. so any metal canister inline 5/16 or 8mm hose barb filter will do.

Sweet!

[jyporscheboy]

are you changing the cam shafts.. i thought about doing the switch over to carbs but i spoke with people who said that i would need to change the cam shafts ,, would you want to get rid of the cis stuff? let me know if you do, thanks john young

[jkh2cpu]

CIS pistons require CIS cams. CIS pistons will collide
with valves is a non-CIS cam is used. It's the nature
of the beast.

There's lots of info on the subject.

John.

[pemz0r]

I went from CIS to Carbs, but in IMHO it's not worth the switch over, you are losing a great performance upgrade by keeping the same CIS cams and stock pistons. I have a 2.7 E cam 9.8:1 and it's a blast and reliable.

I am running filters after the regulator.

[snbush67]

Pemz0r, do those filters thread into the fuel rails? Neat set up. Where did you get them?

[pemz0r]

They are from the UK, I pick a few up when I travel there, I currently do not have any extras.

here's a link for you

Facet Fuel Pump Parts Metal Filter Union Solid State | eBay

[Koich]

Originally Posted by pemz0r

They are from the UK, I pick a few up when I travel there, I currently do not have any extras.

here's a link for you

Facet Fuel Pump Parts Metal Filter Union Solid State | eBay

That's definitely a trick setup!

I'm keeping the motor stock for now. Eventually plan to swap the motor out to a 3.0 or 3.2. The carbs are 40s converted to 46, so I'm currently choking them down with venturis, and should breath fine with the later swap.

[snbush67]

Originally Posted by pemz0r

They are from the UK, I pick a few up when I travel there, I currently do not have any extras.

here's a link for you

Facet Fuel Pump Parts Metal Filter Union Solid State | eBay

Thanks.