slide valve photos

[vlocci]

Anyone have a few pictures of a slide valve induction setup?

I'm considering fabricating something for a 3.6 I'm working on, and am looking for inspiration. Aside from looking incredibly cool, I think a EFI driven slide valve setup could run incredibly well.

As an aside, anyone have some detailed photos of individual throttle bodies on a 3.6? This is the second consideration, but I'm leaning toward slide valve RSR knockoff.

Thanks,

Vin

[jpnovak]

I agree. Anyone have pics of a slide valve system disassembled so we cam make some drawings of them and duplicate?

[GeorgeK]

I LOVE slidevalves.
One caveat though: they get stuck. At wide open throttle. Ouch.

[Bill Verburg]

How bout this

[adomakin]

oh my god. i have got an oak tree in mypants...........


Andy

[efhughes3]

Bill: That is one of the most exquisite motors I've ever seen. Anywhere.

[David]

I built one for a 3-rotor Mazda engine. I don't have any disassembled pics.

A few tips:
You must use bearings. I used steel but I saw some with teflon ball bearings in a plastic cage and that's how I'll go next time.
They won't work very well on turbo cars (too much pressure on the slide plate).
You can have round or D shaped ports which will change the throttle response.

[911pcars]

Here's one.



Sherwood

[adomakin]

looks like a set of air horns!

[88911coupe]

At the risk of sounding stupid...what exactly is slide valve induction?

[jfpound]

Instead of a butterfly valve to control the air, there is a plate that slides in and out of the airflow path. We can't see them very well in the photos so far.

[5axis]

Originally posted by 125shifter
I built one for a 3-rotor Mazda engine. I don't have any disassembled pics.

A few tips:
You must use bearings. I used steel but I saw some with teflon ball bearings in a plastic cage and that's how I'll go next time.
They won't work very well on turbo cars (too much pressure on the slide plate).
You can have round or D shaped ports which will change the throttle response.

Has anyone tried barrel valve TBs on a Porsche motor?
Same open hole as slide valves and pivots like a butterfly to minimise the sticking problem.

[randywebb]

The big advantage is that when open there is nothing in the air path, unlike a butterfly where the flaps are hanging down, and and their support is across the entire flow path. This obsructs the flow and creates turbulence.

Slide valves have a reputation of sticking a lot see a post above). But, an experienced racer or engine builder (maybe it was Steve Wiener - not sure) told me that they really do work well on street engines.

[jpnovak]

typical throttle bodies use a butterfly valve. This is a circular section of metal that pivots around a shaft. When the butterfly is perpendicular to the airflow the valve is closed, parallel and the valve is open. The problem is that you will always have a shaft and valve in the airsteam.

Slide valves that Porsche used are based on two sliding plates. Imagine if you took two plates and cut a hole in each. the next part is like an eclipse. These plates slide across each other through the centerline of each hole. You start with two holes that are completely covered by the surrounding metal. As the holes cross, you start with a cresent shaped opening. This allows good air flow. When the two openings coincide, you have an unubstructed airflow.

There are a few other ways to make a slide valve. A tub drain pipe contains a type of slide valve. Motorcycles use a different type of slide valve. All have unubstructed pathways when open.

[mpdevelopment]

How about double slides that open like a camera shutter.

[mpdevelopment]

Sorry I lost control for a moment. The problem with slides for the street besides sticking is too much false air leaks around the plates. Very hard to get good slow syncronized idle. Also slides can be noisy if there is excessive clearence between the plates and bearings (they bang around) just like worn shafts-bushings in mfi only lowder.

[Pete000]

[Pete000]

[5axis]

cool stuf...

http://www.jmengines.com/throttle.htm

[jpahemi]