whats this? tubing on back of air filter housing

[sj911T]

Hi!

In tracing down some fuel leaks on my 1970 911T, i took off my air filter housing and noticed this tubing on the back that has not connected to anything for the last 21 years I have had the car.

On the inside of the housing cover there are metal tubes that appear to be purposely blocked by a rubber plug on each side.

Any idea what its for?

Thanks
Chris

[Discseven]

Had this on file for '70 911T-K Chris. Not sure if this helps.

[Hi_Fi_Guy]

70T was carbureted, at least in the US (not sure about ROW).

Zenith carbs had a few different emissions and enrichment devices. If memory serves at least one of those was recommended to disconnect early on as they were causing engine fires.

Sorry, I don't remember all the details but when I was rebuilding my Zeniths I found tons of info on the threads here about it. I'll see if I can dig one up but if you search Google and limit the results to the Pelican forums you will probably find them quickly.

[Arlo911]

Looks like the cold start fuel supply for MFI.

[Hi_Fi_Guy]

Here is a photo from Rennlist. Same set-up 70/71T with Zenith carbs

[Hi_Fi_Guy]

Again, if memory serves there was an enrichment or cold start enrichment for these. I also remember old timers telling me that even in the time these cars were still new-is it was being disconnected due to engine fires. That is hearsay and I have no evidence.

Here is a thread on another forum where Ed Mayo confirms there were fuel spray bars that fed directly into the airbox...
https://www.early911sregistry.org/forums/showthread.php?99348-Need-help-1971-911T-with-Zenith-Carbs

[Hi_Fi_Guy]

Sorry I don't have more or better info. It's been a few years since I rebuilt my Zeniths. I did a ton of research before hand but just don't recall since I did not reinstall or use any of the emissions or enrichment devices.

[sj911T]

Amazing responses and help. I had no clue what to even search for. Now that i know what I am looking at, I see the topic has come up before. My 70 T does have Zenith carbs. I will leave well enough alone and leave it as is.

Thanks,
Chris