Idea: Stock-Looking ITBs

[Warsteiner]

The pic of the slides are different than the last pic with the Dbilas ITB's. I had the slides made in Thailand with the guy who used to work for Schnitzer and built the S14 motors for Ravaglia back in the day of the E30M3. I don't have the slides on the motor yet. Just finished the mating of the complete E30M3 exhaust system with SuperSprint muffler to the new header from 666 Fabrication. Next is installing the slides and tuning the MSII.

Cheers,
~Ralph

[bmwman91]

That iris concept is awesome!! I imgine they would need springs (possibly blade not coil) to bias the blades to prevent jambing.

For a non USA resident im going to ask a dumb question. Whats a smog test? It sounds more than a O2 sensor up the tail pipe but a full induction and exhaust inspectionwhere no mods are allowed? What if your mods reduce emmisions?

Good idea on the blade style return springs. I was trying to think of how to best do that. I'd just have to extend the guide slot ends so that the control disc doesn't prevent them from closing. I think that I would also put some small sealed bearings on the little guide pins to avoid having metal-metal wear issues. Then again, it has way too many moving parts I think...the throttle sort of seems like one of "those things" that you want as simple as absolutely possible! I need a second car to play around with this stuff on and not care if it breaks!

The pic of the slides are different than the last pic with the Dbilas ITB's. I had the slides made in Thailand with the guy who used to work for Schnitzer and built the S14 motors for Ravaglia back in the day of the E30M3. I don't have the slides on the motor yet. Just finished the mating of the complete E30M3 exhaust system with SuperSprint muffler to the new header from 666 Fabrication. Next is installing the slides and tuning the MSII.

Cheers,
~Ralph

Cool! Any chance you could open them up and get some pictures of the internal arrangement? I am really curious to see what the plate slides on. I can't imagine that it is just metal-on-metal in there (maybe some Delrin or nylon guides?)! I have always loved the idea of slide throttles. There's a dual-slide concept that I worked out in CAD last night that I think could improve on the original idea a little, without adding monstrous complexity (like the iris valve lol).

[lunchkrispy]

I am all about flat slide carbs, just never thought about using flat slides for ITBs before until I saw this thread. I think the combination of high vacuum at closed throttle pulling on the slides and the necessity for tight tolerances to prevent air leaks could cause issues for even a really stiff return spring if the slides are not on some kind of roller bearing. Here's a diagram of a Keihin FCR carburetor (part #20 is a roller bearing):


Now that I'm looking at this, if cost and "stock look" weren't an issue a rack of these could be modified and used just as throttle bodies.

[wazzu70]

Where the lower and upper intake manifolds meet up, the inside diameter of the runner is 44mm.

[bmwman91]

Awesome, thanks!

So did / do you go to Wazzu? IIRC the school hates people calling it that lol.

[thedguy]

For a non USA resident im going to ask a dumb question. Whats a smog test? It sounds more than a O2 sensor up the tail pipe but a full induction and exhaust inspectionwhere no mods are allowed? What if your mods reduce emmisions?

Our laws are idiotic, especially in states that follow California legislation.

The test is a visual inspection to make sure no "emissions equipment" has been removed.  That means anything between the air filter and the muffler.  If that is all there, then you get a 4 gas analyzer (sniffer) put in your exhaust pipe to check for Co, hc's, and NOs.

If you pass that then you gotta show you have no  vapor leaks from the fuel tank.

Some states don't bother with the inspection, others aren't as stringent on the testing.  Many only care that the car meets the sniffer test.

[wazzu70]

Awesome, thanks!

So did / do you go to Wazzu? IIRC the school hates people calling it that lol.

Yeah, I went to Wazzu (graduated in 2005). The school wanted to shed the nickname to sound more sophisticated. They did not want the name on any school sanctioned printing.

Of course after the announcement everyone started using the name, printing the name, and wearing shirts with it ect.

The school will never shed its party image IMO. It is a party school in the middle of the wheat fields and always will be. They just happen to have some good academic programs as well