Am I missing something important?

wahoofan · 03-09-2006, 06:03 AM

I notice that some MFI cars have an extra part on the air intake that mine (and some others) do not.

MINE

OTHERS

What is that thing, what does it do, and would not having it affect the performance of the engine in any way?

reed930 · 03-09-2006, 06:11 AM

It is an emissions device. Basically, by moving a flap inside the housing it directs warm air passed over the heat exchanger into the engine thereby reducing emissions from a cold engine.

It is harmless if installed and not really necessary if missing. Most people only worry about it if they are looking for concours originality.

Rot 911 · 03-09-2006, 06:11 AM

That is for pollution control purposes. Takes heated air off the heat exchanger until the engine warms up then a flap moves allowing cold air into the airbox. Not needed.

daepp · 03-09-2006, 06:11 AM

My 72 T has it. Porsche msut have had a reason for putting it there. It might have a flapper in the end - not sure, and I can't get to mine to check at the moment.

wahoofan · 03-09-2006, 06:25 AM

Wow, thanks for the quick replies! (With good news to boot!!)

OK, now for another (slightly) related question - does everything seem to be here and hooked up correctly regarding my left exhaust? I've been troubleshooting a cold start issue and have been told to check that all the hoses to the heat exchanger are connected. What is supposed to go on that open pipe?

reed930 · 03-09-2006, 06:38 AM

Bingo. That is the connection for the MFI pre-heater. You should also see a hole in the engine tin where the hose comes up into the engine bay and connects to the pre-heating system.

By the way, there is someone on the early911sregistry selling the parts needed to restore yours to original if you're interested.

The link is below. I don't know if the parts are sold yet.

MFI Pre-Heater

wahoofan · 03-09-2006, 06:58 AM

Here's a few more pics - I don't see any unused holes in the engine tin, so where would the hose from the pre-induction heater have gone?

midlife · 03-09-2006, 07:09 AM

There is a bolt and washers in the center of your first picture that looks like it is blocking the hole.

wahoofan · 03-09-2006, 07:21 AM

Oops.....I didn't even notice that.....I was looking for some biga** opening

So I can assume that everything is hooked up just fine and that my cold start issues have nothing to do with anything exhaust-related?

Rot 911 · 03-09-2006, 07:41 AM

Quote:

Originally posted by wahoofan

So I can assume that everything is hooked up just fine and that my cold start issues have nothing to do with anything exhaust-related?

Not true. While the pre-heater will not effect cold start issues. You need to make sure your MFI thermostat is working. I see the hose is connected, but the disks inside could be sticking. That won't effect start up but will effect how the engine runs when cold. If you are having trouble starting in cold weather you probably have problems with your cold start injection system.

reed930 · 03-09-2006, 08:10 AM

Have you checked the hose that leads to the MFI thermostat to make sure that the inner cardboard liner is intact? The absence of that liner can affect cold running. It's often torn or missing altogether.

Clay Perrine · 03-09-2006, 08:25 AM

I have the flapper box for the warm air thingamagig. I couldn't use it on a 914 /6.

It's yours if you want it. Just pay for shipping.

wahoofan · 03-09-2006, 09:04 AM

Haven't checked hose-liner yet. Can I replace that hose with a similar sized rubber/coolant hose, or does it have to be the paper-lined one?

reed930 · 03-09-2006, 09:31 AM

Use the correct Porsche hose for this. It's actually a hose within a hose and its purpose is to insulate the incoming air. It's cheap and there really is no reason not to go original on this part.

As you know, the MFI system is quite susceptible to minor tuning issues. An incorrect hose could be at least part of your problem.

wahoofan · 03-09-2006, 09:37 AM

Hose available here on Pelican, or is it a "dealer-only" part?

David E. Clark · 03-09-2006, 09:41 AM

The MFI hoses are available through Pelican here.

Grady Clay · 03-09-2006, 09:44 AM

wahoofan,

Take Pelican Clay Perrine’s offer. If you don’t, Clay you can send it to me so I can use it to post functioning and adjustment. I’ll pay shipping.

Everyone is correct, it isn’t necessary for proper running. Getting your thermostat to turn off asap will do far more to reduce cold running emissions (and oil dilution).

On the other hand I think it is desirable to preserve the originality, even if it just sits in a box.

Best,
Grady

Clay Perrine · 03-09-2006, 09:55 AM

Quote:

Originally posted by Grady Clay
wahoofan,

Take Pelican Clay Perrine’s offer. If you don’t, Clay you can send it to me so I can use it to post functioning and adjustment. I’ll pay shipping.

Everyone is correct, it isn’t necessary for proper running. Getting your thermostat to turn off asap will do far more to reduce cold running emissions (and oil dilution).

On the other hand I think it is desirable to preserve the originality, even if it just sits in a box.

Best,
Grady

If he doesn't want it, it's all yours. I got lucky enough to find a set of 916 heat exchangers that had the MFI heater setup in them. (Porsche built a bunch for the 916 program. When it was cancelled, the put them into the spare parts program as 914/6 parts).They are fairly rare, and I got them cheap. But it doesn't have a connection for the warm air box.

I have to dig it out of the attic though. :-D

Anyone know where I can find the snorkel for the air filter that doesn't have the fitting for the warm air box?