So... I need a fuel sample port to pass SCCA tech.
On my fuel rail ('99 996 C2) there is a steel cap as shown below in the photo.
Under this cap is a Schrader valve. The male threads appear to be M11x1.25. But I'll be damned if I can find any fittings to fit this.
The plan was to remove the valve guts and run a length of tubing back and place a fitting on the loose end for sampling.
Questions:
1. Is there an easier (better) way to provide an easy to access location for fuel sampling?
2. Does anyone have a source for an M11x1.25 high pressure fitting?

 

How about this:

 

You need a fuel sample mechanism like that shrader valve, but on a tube where you can access in Tech? so, the issue with 928 porsches, and even 911s, is the non-standard threading for all sorts of fuel sampler parts that fit on american cars. im still, after 15 years of dodging the bullet and convincing the tech guys (I promise, ill have it next year") the problem for me is i dont like having some protrusion off the fuel rail that can break off in an impact and spray fuel. i think its stupid. you wan a fuel sample, we should just stick a hose in the tank and suck out a few oz.

anyway, ill send a picture of what have bought, just haven't found a guy to make the custom part with the porsche threads to make it work yet.

Mk

 

Says it's M12 and I need M11x1.25

 

If you don't want to reinvent the wheel, I have one like this on my Spec Boxster.

http://www.bimmerworld.com/Intake-Fu...ort-Kit_2.html

 

I found an M11x1.25 Female to 1/4” NPT Male brass fitting on EBay. Will mate this to a hose via an NPT to AN adapter.


https://www.summitracing.com/parts/a...2723/overview/
The hose will then get a std Schrader valve on the end to sample.
https://www.summitracing.com/parts/mli-s-684/overview/
http://www.theraceplacepa.com/store/...ssor_Tool.html

That should do it.

 

It is not M11 X 1.25. It is 7/16-20 which is dash 4, so you can attach a normal dash 4 brake line to this port. You will also need to remove the valve core in there. That is a tire valve core.

Chris Cervelli
Cervelli Technical Service

 

Chris, thank you. I just received the -4 fittings and hose I had ordered and you are correct.
I will not have to use the adapter I had bought. I only have metric thread gauges so was not aware it was also 7/16-20.
The fitting and hose below will get a -4 to 1/8 NPT female on the other end which will accept a Schrader valve to 1/8 NPT fitting.

 

OK so for anyone else looking to do this here is the parts list:
(all from Summit)
MLI-S-684 SCHRADER VALVE $5.97
AER-FBM2721 STEEL 1/8 FEMALE PIPE to -4 AN FLARE $3.97
VPE-11954 -4 AN FLEX HOSE (2 feet) $8.93
VPE-21004 -4 AN STRAIGHT HOSE FITTINGS x2 $6.04

 

Sorry to come into this thread so late, but I'm curious how this setup has worked out for you. Also curious how you actually draw a sample. Where do you leave the end of the 2-foot hose for access? How do you secure it? Have you experienced any leaking? Can you get to it from under the car or must you remove the engine cover (and, presumably, the car top) to access? Must the fuel pump (and the car) be turned on to draw a sample? A fuller explanation of the practical use would be greatly appreciated. This setup is for a first-gen Boxster (SPB)?

 

Reach out to @turbochad he has done this on an SPB.

 

Here is a picture of the fuel line coming off the pressure test port with a motec pressure transducer and jiffytite quick connect that goes in the rear trunk. You have to wire a new switch on the dash to override the bosch fuel pump relay control so you can pump out with the ignition on but the motor not running. Mine is set up as a toggle that switches from ECU control to manual control just like a Cup car.

 

Also, you really want to use PFTE lines and quick connects with Buna-N seals because of the ethanol in fuel. I carry a spare connector in case one fails. Never had a failure. I use it all the time to pump out and verify the amount of fuel in the car when running endurance and for impound.

 

Pegasus has the fittings and premade lines off the shelf for the whole setup.

 

Sorry to revive after a bit... I've got a Boxster 2.5 (not SPB) I run in ChampCar and now SCCA Enduro. Have you used this setup to do a FULL pumpout of the system to verify capacity? I've spoken to a few folks and there was concern about the fuel system's ability to fully pump out a topped off tank. This makes sense for a sample, but any thoughts on regularly using to verify capacity?