SMTCapeCod

Sorry, I was unclear- the elbow I was referring to is actually molded into the air cleaner lid.

Because of the way that the tube slip fits over the lid, and the likely extent of demand (probably not high)- I doubt it is worth designing to-- but thanks for considering!

As for above, I think the accordian just affords some compression and compliance to aid in repeated installing/removing.

Jerry Feather

Its about 2 3/4 inches.

Avar928

Where the intake tube mates with the air box, the tube connects over the outlet of the air box and I'm guessing seals via the accordion end (which for most of us are already kinked and probably leaking air).

Could if be better to design that end to fit into the air box opening? Basically it has a stepped design where a portion slides into the air box and seals. Should look sleeker and you don't lose air leaking out the side.

snoz

That's what I thought. That won't work for an 86.5 with the original air cleaner top. They are right about 3 inches. It probably wouldn't make sense for you to make sets for them though.

I was completely wrong. The inlet diameter on both my original and replacement air cleaner top are ~2.75".

Jerry Feather

One of the benefits of doing this development is that when it is complete for at least one style of air tube, the only thing needed for any other style or restyle of air tube is another male form. In fact i have in mind to do some redesign for the later tubes and particularly a nice looking one that will be suitable for the GTS.

Mrmerlin

NOTE on some of these tubes they only made one version,
and then fitted the rubber collar,

This tube then had two holes in it for connection to the cam cover vents.

Thus it was to fit them to either side of the intake,
by simply turning the rubber collar it would be lined up with either hole.
So only one hose was necessary.

The taper was made to reduce intake noise.

Investing the time to make a mold may be enjoyable,
However you may not have such a big base of owners wanting these spares, VS the time and expense involved.

BUT I know you like challenges Jerry, so carry on, your work is very well done

Avar928

Don't jinx it! Make them! Make them!

I was lucky to score a good set for a very nice price off a parted S3 over a year ago. Before that, I had a standing order with 928intl that went unfilled for a year. They're very hard to come without having any kind of disintegration these days.

Jerry Feather

I don't think that the induction tubes are operating on much or any ram air basis. I think the air pressure inside them at just about all rpms is lower than ambient air around them. Therefore any leakage is in and not out.

By putting the tube inside the air box opening rather than over it will just reduce the size of the opening. I don't see any advantage to that.

76FJ55

I could be mistaken, and please correct me if I am, but I think the 85-86.5 have the same airbox lid. Looking at PET they all use 928 110 230 02.

RKD in OKC

The ends of my GTS intake tube blow off if I don't slip then on firmly. The old ones the tubes actually blew apart at the seam on the bottom after I started seating them tightly on each end.

Jerry Feather

In a normally asperated engine you can never have any more manifold pressure that ambient, and most of the time much less. The only thing moving the air in the induction system is ambient air pressure. The only way to get a higher pressure in the tubes than ambient might be if there is some way to create a lower pressure in the rest of the engine compartment. I don't know of any way to do that.

Too, when the air is moving in the tubes and relatively still around the outside of the tubes, the pressure is greater on the outside than the inside.

Where do you think the "blow" is coming from that would blow your tubes off or blow them open at the seams? Maybe backfire?

Jerry Feather

I was wondering about that too, because I think the reason the openings on the 85/86 cars are smaller is simply because that is the max size that can pass along the sides of the huge intake plenums. The same should also apply to the 86.5 with the same intake system. I suspect that an 86.5 with larger air box intake openings has the wrong intake box top.

snoz

The '86.5 models may be unique in that department. I looked all over for a replacement airbox top with the same diameter inlets before finding out that Roger had some of them. The inlets are right at 3" and everything else I found was 2.75".

I was wrong again. The inlet diameter on both my original and replacement air cleaner top are ~2.75".

RKD in OKC

Nope, absolutely no possible way the air pressure could get higher in front of the radiator vs behind the radiator.

Hilton

Will it have a venturi effect and flow extra air?