How many different factory air boxes from 1965-73?

[stout]

Two for the experts:

-How many variations of the factory air box were there between 1965 and 1973?
-What were the differences for carbs, MFI, displacement, T, E, S, etc?

I must confess I don't know much about 911 air boxes other than there were metal ones (early) and plastic ones (starting when?), and that Porsche eventually ditched the snorkel for the SC/RS (as seen on another thread here: http://www.early911sregistry.org/for...he-air-snorkel).

Can anyone provide Cliff Notes from which to start my research, or a link that explains the variations?

I ask because I went to the dyno to do a first dial-in on my Webers and made 169.9 hp at the wheels with no air filter in place. Was pretty jazzed, and then the dyno operator said "Now watch when we put the air box back on...it'll be even nicer." We lost 20 horses. It was the end of the day, and I still need to finalize exhaust before we really dial the thing in, but we pulled the snorkel and air filter to do one more run. We gained 12 hp back, so 162~ hp at the wheels. This from a 2.2 six with E pistons, a bit of compression, Solex cams, a bit of head work, headers, a single-tip Leistritz muffler, and Webers with a factory plastic air box and a long, uncut snorkel. I'd prefer to keep a factory air box on my car, but would like to get some of that power back. My engine also feels like it's gasping for air past 6000 rpm.

I know, I know—rain hats are the easy answer, but I'm not terribly interested in going that way. I'd rather find a way to confirm I've got the right air box and/or snorkel for a warm 2.2.

Thanks!

pete

[NeunElf]

Well, I can start where I have a little knowledge: the Solex air box (which has absolutely no application on your Weber-carbureted car).

Here's the parts catalog drawing of the Solex Air Cleaner:

It's two pieces with the junction covered by a big rubber band (yellow in that drawing). You have to insert the two pieces into the engine bay separately and get them over the velocity stacks on the carbs. It's not especially convenient.

There's an aluminum plate (yellow in this drawing) over the Solex carburetor tops to which the air cleaner seals:

I understand there are two versions of the Solex air cleaner--the early version is very hard to find. I think the difference may be in the way the ends of the boxes over the carbs are chamfered.

The early Weber air cleaner is very different.

The Weber air cleaner has "buckets" (# 3) for the velocity stacks so that the main part of the air cleaner doesn't have to go around the velocity stacks.

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By the way, did you compare the performance of your engine with the snorkel and no filter element to the performance with the filter element and snorkel? It might be interesting to know which contributed to that 8 hp drop.

[stout]

Well, I can start where I have a little knowledge...

By the way, did you compare the performance of your engine with the snorkel and no filter element to the performance with the filter element and snorkel? It might be interesting to know which contributed to that 8 hp drop.

Thanks, Jim!

We tried three different setups as the day drew to a close:
-Final tuning run for carbs/ignition, with no air box: 169.9 hp at rear wheels
-Air box in place with snorkel and filter element: 150~ hp at rear wheels
-Air box but no snorkel and no filter element: 162~ hp at rear wheels

We did not try putting the snorkel back on without the air cleaner.

[stout]

Bump.

Can it really be that hood strut decal typos are more important than induction systems? I can't find a single definitive thread on the air boxes for early 911s. This sure seems like the place for it...and the Early S Registry crowd sure seemed like the crowd to ask.

Marco, are you out there?

[RSTarga]

Have you tried an 72-73 airbox? I think it is less restrictive than the earlier units.

[70SATMan]

I remember a pretty good thread on the differences between the metal and plastic airboxes 70/71 including discussions about the latches.

[71gold]

I recently saw a comment related to a box for sale on eBay from the seller that hose #7 was on pre 72.
Would also like to understand the variations.
Additional info/ comments are needed
Thanks for assistance