Kenku

http://photobucket.com/albums/e171/K...Solidworks/TB/

Just a little design that I was working on ever since seeing that sexy ex-MFR slide throttle pop up on ebay a little while back. It's not really 100% complete or anything but enough to satisfy myself it should probably work. Just need to find time to sit with the milling machine and carve billet... and find someone to weld bits together... ah well.

Obviously from the pic with the ubends this is for a peripheral, though I'm half thinking of making it fit up to a standard Weber type flange. Whatcha think?

pistonsuk

Looks like a highflow setup, nice.

Justin

13btnos

iTrader: (1)

Check this site out has a lot of good info on making a slide throttle for a PPort motor. http://www.rotaryeng.net/intake.html

Kenku

Interesting... but the problem with teflon is that the coefficient of friction when riding on aluminum is around .2. On aircraft engine's that's not a problem because it's not like the throttle sticking a bit is an issue... but cars play around with throttle settings a lot more. Keihin went to mounting the slide on rollers on their FCR carbs, and everyone else in racing (AFAICT) used some sort of needle bearings, so why not?

My Mk1 design (the one that's not opened up) actually does have teflon sliders inside it but... then I found a source of cheap bearings. And doing it out of sheetmetal is also not a bad idea. I'd seriously consider it... if I hadn't found my a big pile of scrap aluminum billets one day while poking around the basement of my college.

rotarygod

iTrader: (1)

I have no idea who bought the slide throttle and mechanical fuel injection off of eBay last month but I do know the history of those exact parts. Those parts were off of one of the 2 1984 Mazda Lola LeMans race cars. One of them won their class. I forget what the car number was. The parts that were for sale were from the other car. If anyone knows who bought those, tell them they own a piece of rotary racing history! I tried to buy them before they were on eBay but couldn't get ahold of the owner. The rotors that were from that engine are owned by Scott at Mazsport.

Kenku

Oh damn... as if the old school slide valve / Kugelfischer setup wasn't sexy enough...

Black91n/a

I'd think that maybe a barrel throttle would be better/easier to do. You'd be able to use velocity stacks, as the slide throttle you have there would cause separation at the inlet, which is bad for flow.

RXBeetle

Very nice.
Just nickel plate the aluminum. It's cheap, it will be slick with the teflon riding on it, and it will look good. Teflon-steel is like .04 CoF Nickel should be better yet.
Ever see this setup on one of the FSAE cars?
http://evilallianceracing.com/ipw-we...neTB/throttle2
http://evilallianceracing.com/ipw-we...TB/intake_side
http://evilallianceracing.com/ipw-we...oneTB/102_0283
http://evilallianceracing.com/ipw-we...oneTB/102_0277
I made a few similar models in solid edge (I prefer ProE/wildfire but hey SE was a free student edition). I have this terrible problem that I have all the tools and machinery to fabricate this kind of stuff but no car that could take the power without dumping a few thousand on a trans and half shafts.

Kenku

Enh, well, I figure little ball bearing units will work even better than any kind of sliders (BTW, the 0.04 figure is for teflon on teflon, from my research... AFAICT, teflon on steel is about the same as on aluminum) and be easier than nickel coating stuff. Besides, I already spent my $10 for bearings, darnit.

The cone throttle is one of those things that's a neat idea, but... just has problems. Plus, there's quite a lot involved in it. Slide's nice and easy, and... well, WOT is WOT, and both of them have more or less no restriction. No reason why I can't use velocity stacks; Mazda and everyone else did. I just changed the mounting face on the Mk2 revision so that I can be lazy and bolt DCOE air horns onto it. Barrel throttles might be a little bit better in terms of flow, but the gaps I've designed into it are pretty damned small... and having sat and figured out what it'd take to machine a barrel (or dual roller barrel) setup... slide's far easier.

'sides, I wanted to make a slide throttle.

torean

yay....fase.....im on the rutgers team....

banzaitoyota

i have a set of the MFR Slide throttles.
anyone have the link to the expired auction on the other set?

Kenku

*searches for post* Oh, you found it already.

I am kinda curious how Mazda did some of the stuff on those... have any pics of them opened up?

Michael_Rudy

If you would like to machine up a slide throttle, i would test it on my MFR PP 12a engine

banzaitoyota

just FYI, they were made by LUCAS for mazda.

no I havent opened mine up yet.

rotarygod

iTrader: (1)

The ones that were on eBay were the actual throttlebodies that were run on one of the Lola's in the '84 24 hours of LeMans! They weren't off of the class winning car. They were from the other one. I forgot the car nubmer. That shouldn't be hard to figure out though. I know how the owner acquired those pieces. That LeMans car was eventually sold to some guy in Florida. It sat around in pieces for nearly 20 years. The original owner died. Someone else came in to get rid of the parts just to clean up some space. The person who put that on eBay had no idea they were selling a piece of Mazda racing history. Whoever bought that throttlebody and mechanical fuel injection unit now own an actual Mazda LeMans raced setup. I wonder if they will read this? Scott at Mazsport in Florida owns the rotors that were out of that engine. One is on his desk. I tried to acquire that throttlebody before it went up for auction but no longer had any contact info. He only wanted $150 a year ago.

Kenku

That, in my mind, brings up an interesting question. I was already going to make one of the things out of pieces of billet I've scavenged, but if it works properly, would people actually buy these things? No reason I couldn't fiddle with things to make it bolt up to a normal IDA style manifold.

Getting ahead of myself though; still need to finish the first one.

Michael_Rudy

If it works nice, and you can build bigger sized ones, i would definatly be intrested. Just to see if there would actually be a gain, as there would be less turbulance entering the intake.