Does anyone know who makes a slide valve throttle body or where to purchase one? Any help would be appreciated.

 

Defined auto works

 

I checked their site but didn't find anything but I did find a factor MFR slide valve from an old friend but thanks anyways Grant.

 

Here's the unit I picked up for $200. It was designed for mechanical injectors but I have designed the parts to make it work with electric injectors and a TPS. I will post more as I make progress for anyone interested.

 

I just realized I posted this in the wrong section. Admins feel free to move it.

 

those are genuine MFR throttles? for $200? somehow that sounds like a steal to me. congrats.

definitely interested in seeing what you do with them.

 

The guy I got it from has had this thing sitting around since the 80's from when he used to be crew chief for Dave Kent of Kent racing. Yeah, when he told me $200 dollars I about had an orgasm since I have been looking at butterfly style TB's for close to $1000. This will take a bit of work and cost to convert but should be worth it.

 

damn, what a steal.. if you find another one for even double of that let me know!

can you take some pics of the inside?

 

I will next time I'm at my shop.

 

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Sorry there have been no updates. Been busy building engines and a run in stand, getting ready for the enduro here in Portland and the 25 hrs at Thunderhill.

 

So here are the pics of the insides.

 

And 2 more.

 

looks to be from the ages where cnc was obscure =) how much clearance is there between the silde and the lower body?

 

There's about .oo6" clearance. Are you looking at making one? I modeled it up in Solidworks. Here's what I have so far but need to add some final details.

 

I always wanted to make one but I had a different bearing system in mind. oval milled slots in the baseplate in which a piece of aluminum would precisely fit, this would hold a small roller bearing, and would have a screw on the bottomside to set the clearance..

but if it works this way its ofcourse much easier to make, but much harder to fix the clearance or to adjust when wear occurs.. I would only be a bit worried that the bearings would end up at one side? but maybe I am thinking too much :p

 

I think you're over thinking it but you could use a piece of feeler gauge material to adjust the clearance but this would only adjust the clearance between the slider plate and the upper and lower housings since the housings are machined to accept the slider plate and there would be no way to adjust this space.

 

I haven't had much time to work on the slide valve TB but I did get a little time to model some preliminary adjustable air trumpets. Haven't worked out how I will operate this yet but working on the idea. Here are a couple of pics.

 

Added a couple of jpg's

 

Nice.. is that a plenum, or is there an air filter in there? Do you think there will be enough hood clearance with the turmpets at max length?

'You dont perhaps know a 13B MFR intake manifold for a IDA lying around dont you?

 

That's just the air box. The filter will be mounted elsewhere. As far as hood clearance goes, this will be mounted horizontally on top of the engine as shown in the pic.

I'm thinking of using a stepper motor for the the trumpets and run the motor off of engine rpm signal. I'm not an electronics guy so any help with this would be appreciated.

Negative on the MFR 13b manifold.

 

Hmm, wont the intake be a bit on the long side this way? The length for peak torque at 9-10k is shorter according to the intake system from the le mans 26b.. For controlling using a stepper motor you will need some additional control system. If you want to use it in open loop you also must be sure that the motor is strong enouh and the trumpet cannot jam a bit as then then the 0 point is lost. Basicly in open loop you know how much steps there are from end to end, then at ign on you do this amount of steps to one side, this way you are sure the trumpet is at an end position. Easier might be to use a RC servo, it works closed loop and has the motor driver built in. You just need a rpm based pwm signal, this can come from an ecu or from a simple analog circuit using a f/v convertor and some opamps or 555.

 

For anyone interested, I found a couple of Slide Valve TB's. One is a used MFR part for $1000 and the other is a brand new copy of the MFR unit for $1900. Both are 48mm and have a Weber IDA bolt pattern. If your interested drop me a pm.

 

Yes you are correct. Decided to mount the TB in a different location rather on top of the engine.

 

does the mfr one come with the mfr manifold that bolts to mfr housings?