MFI question

[goldsc78258]

Do you guys know how the flapper box that goes to the filter ataches to the engine? here is a picture the part is in the red circle. if you have any detailed pictures of the bracket and how it ataches plase post them




thanks

[Early_S_Man]

Three hex-head M6 bolts to left stack on cadmium-plated stamped steel bracket -- cyl 1 trumpet, illustrated on p. 6 of CMA.

[David E. Clark]

Get a copy of CMA and lots of other MFI information here.

[goldsc78258]

Thanks Guys

[goldsc78258]

Anybody have a close up picture of the area? I can't find anyway to atach it to the stack, maybe I'm missing some parts. If you do please post it

Fred

[sithot]

Here you go.

Tom

[daepp]

I will try to get you a close up photo Friday night.

[goldsc78258]

Thanks Tom, I've got all the parts I just can't figure out where that plate ataches to the stacks.I think with this picture I'll be able to firgure it out

Daepp That would be great Thanks!

Fred

[sithot]

FWIW: Porsche issued a bulletin way back (before some of you were born) regarding the suggested removal of the flapper box. The factory thought that there was a distinct possibility that the engine could ingest items pumped through the left hand heat exchanger particular to only the '72-'73 MFI cars. (Plus, it never gets cold enough here to really need it anway)
According to the owner of SSI Chuck Stoddard was questioned about this when they first began making heat exchangers and said it was useless.

That's why they don't make a dedicated left side SSI heat exchanger with the additional heater box for the intake pre-heat.

Tom

[goldsc78258]

I din't know that ,I'm finishing a 1971 E and wanted to look as stock a possible, I just won't conect it to the heat exchanger. Anyways i don't think mine have a place to conect it to.

Fred

[daepp]

Originally posted by sithot
The factory thought that there was a distinct possibility that the engine could ingest items pumped through the left hand heat exchanger particular to only the '72-'73 MFI cars.

How could something be ingested if the air filter was properly in place?

[sithot]

Here is the subject as it was discussed on the Early S Registry in 2004.
Roger Grago is with Porsche Motor-sports but was in the dealer system for more years than he cares to remember.

Note Posts #18, #20 and #24

http://www.early911sregistry.org/forum/showthread.php?t=2562&page=2


Tom

[Grady Clay]

First a ’69-’71 doesn’t use this pre-heat flapper.
This is only on the ’72 2.4 and later MFI.

Since we are discussing this ….

The ’72 picked up the air at the heat exchanger. Yes
Porsche was concerned enough to change it again in
’73. The ’73 has another thin aluminum tube going
from the pre-heat exchanger to a small grill on the
left side engine tin. This allows the air to go from in
the engine compartment down that tube to the pre-
heat exchanger and then back up the larger aluminum
tube to the flapper valve.

Here is the ’72 configuration.

"
"
© Dr. Ing. h.c. F. Porsche A.G.
"
"
© Dr. Ing. h.c. F. Porsche A.G.



"
"
© Dr. Ing. h.c. F. Porsche A.G.

1 – Fresh air flap
2 – Hot air flap
3 – Thermostat
A – Hot air
B – Fresh air



"
"
© Dr. Ing. h.c. F. Porsche A.G.

1 – Nut
2 – Spring washer
3 – Washer
4 – Lever
5 – Control box
6 - Nut



"
"
© Dr. Ing. h.c. F. Porsche A.G.

Above is the ‘72 heat exchanger and warm air tube. The
air intake is at the red arrow. In ’73 the area of the red
arrow is closed off and there is a tubular fitting similar to
the green. An aluminum tube goes over the green fitting
and over a fitting on the left engine tin.

A ’73 presented at a Parade concourse better have that tube.

Best,
Grady

[goldsc78258]

Thanks you grady, So my car being a 1971 doesn't use a flaper, what does the correct configuiration on the car look like? long intake tube? If you know( and I think you will) please let me know

Thanks again

Fred

[Grady Clay]

Fred,

This isn’t exactly the best view. Note the air intake horn goes
to the left (passenger side). There is a small paper hose that
goes from a fitting near the air inlet over to the chassis just
forward of the oil filter. This is for warm air and only functions
when you have the heaters on.

“
"
© Dr. Ing. h.c. F. Porsche A.G.

Best,
Grady

[goldsc78258]

thanks! I guess one never stops learning about the history on this things huh?

Thanks everybody that responded but I have gotten my answers and gotten a little wiser

Fred