Slide Throttle / High Butterflys....
 

I've been kicking the idea around of building from scratch a "ultimate hotrod" engine for my '69 911S. Im thinking this coming winter to make this a project, and perhaps begin getting the parts together and all machining work done this summer.

Right now Im going to be doing interior (its on a diet), suspension, exhaust and other upgrades with the "R Gruppe" attitude and track use in mind. The car has a sweet running 2.7RS MFI engine in it now.... (except it pukes gas into the oil until I figure out how to fix it) but more power is always a good thing.

Im thinking a 2.8 twin plug shooting for around 275hp would be just tons of fun. I know I want MFI too, so I want to choose a configuration for which space cams exist so the MFI will run properly.

I currently have a spare complete MFI system, a 2.4 "T" core engine and lots of other bits and pieces to start from.

I would LOVE to have a slide throttle injection system. They are SOOOOOOOOOOOO cool.... but I called Andial and they quoted $7,600.00 for the slides and linkage alone. Uhhhhhh not that cool I think.

Anyone know of other sources? Anyone have the blueprint specs for this stuff? Any chance a good machine shop could build it from scratch for less? Any alternatives?

how about a high butterfly setup with tall stacks? Advantages? Sources or costs?

Am I insane?

Terry

Slides are way cool...until they stay stuck in the wide open position. It seems every slide will do that at least once; after it happens, the car is toast anyways, so the slides have time to unstick themselves during the rebuild.
Go with butterflies. Cheaper, more reliable, and not such a loss in performance.
GeorgeK

Either method you choose make sure to bring wads of cash!

Try

these guys for another source of slide throttles

http://forums.pelicanparts.com/uploads/slide2.jpg

I've made a slide valve system for a three rotor Mazda engine. If you're serious about making one let me know and I'll give what help I can. One tip I'll give you if your going to design your own, you've got to have the slide plate running on bearings. Also, the one I made had round holes in the slide. This works fine but I've heard a 'D' shaped hole gives more linear throttle response. I don't have a pic of the one I made but here's a pic of the car. It's a '58 Austin Healey Sprite, 1550 lbs with about 425 hp.

http://forums.pelicanparts.com/uploads/139em.jpg

When i was re-doing the stacks on my motor (3.5 MFI) i considered both the choices that you are. High butterflies that need a rebuild will probably still run $4000. I was told that by Matt blast at Eurometrix, who rebuilt my throttle bodies to my specs. Anyway, i ended up boring out a set of '69 S magnesium stacks and using 49mm Carrera 6 velocity stacks. It still looks stock until you look down the bore.

For space cam work you should call Hanz at H&R in New York. If you give him the info on your motor, he will custom build a pump for you. He even has core pumps that he already knows are good. 631.589.1600

Paul

While you're at it, try Injection Perfection. They're an Australian outfit that can custom make them for you. With the exchange rate the way it is right now (US$1.00 = AUD$1.85), it's a bargain!

I think it's www.injectionperfection.com.au

No affliliation, just word of mouth...