Supercharger Dual Throttle Project
 

I'm looking for help with a supercharger project. I'm copying a dual throttle body install from the UK onto my 2000 with MP62. I have a Big Throttle Body at the charger inlet and the stock TB on the inlet. I'm trying to find a coupe of silicone tees to connect up a recirculation valve and I figured who better than a bunch of turbo experts. Does anyone know of a company that makes odd-ball sizes of silicone? Specifically I want 2-3/4" inlet and outlet with 1" side port and 2-1/2" inlet and outlet with 1-3/8" side port. My searches have found nothing so far.

(I'm in Toronto, Canada)

I think I understand your question. How about getting a metal coupler between two hoses and have your desired fitting welded to the coupler.

That would be an option but I really wanted to use the tee(s) as the "couplers" between two other pieces:

a) Outlet of AFM to BRP Sleeve (2-3/4")
b) As a sleeve over the metal cross-over pipe with a 1-3/8' hole in the cross-over pipe. (2-1/2")

Try these guys out: Intercooler Pipe Fabrication - Silicone Intake Systems Auto Parts

Yup, found them. They have silicone tees but not the right sizes and don't do custom work. But thanks for the suggestion.

I've also tried these without success.
Silicone Vacuum Hose - StylinMotors.com, StylinMotors Inc.
Blow Off Valve Adapter Hose, BOV Adapter Hose, BOV Hoses, Blow Off Valve Hose, Blow Off Valve Hoses
Turbo Hose — 90° Elbow with 1" Nipple— Silicone

You could try to make your own. I remember seeing a how to a while back but I don't remember if it was on mr2oc.com or here.

DIY Custom Silicone Couplers - DSM Forums
Here's the link

You're over-complicating your setup. There is no good reason to run dual TBs on a supercharger. I've run a s/c with the TB in front of the s/c and in it's stock location....using one in conjunction another only voids the other one being used.

Point taken.
I've been running my s/c in the normal configuration for a couple of years and I only have one goal in mind - to get rid of the idle dip which on a cool morning in Toronto causes stalls at traffic lights until the engine warms right through. Reports from the MX5nutz in the UK report the DTB WILL do this.

Great link, thanks.

Oh boy, I can see me getting into all kinds of trouble from the missus if I try to do that in the kitchen.

Plenty of evidence to the conterary in the UK....

In my experience running a charger unthrottled is deafeningly loud and extremly unplesant. Having two throttles removes this and solves all idle and throttle response issues.

You can also have any IC pipework route you like which means a DIY around the rad option is feasible.

...my wildest dream.

It's not hard to accomplish to be fair, all you need is a throttle cable and a 2nd TB :)

Got both of those - the car is away for the winter so it won't get tested until spring.

I've been following the threads on MX5Nutz and a few of us in Canada are waiting on the kit from PJB to arrive. I ordered tees from Turbohoses, not exactly the right size but I'll adapt. I'd be interested in your thoughts of using a recirc valve or just cracking the blower TB at idle.

Your time and money are better spent on a better fuel management system. Which will also cure this problem. And instead of adding an intake restriction and reducing hp, will increase your hp through optimized timing and fuel.

Ha reducing HP? That I seriously doubt.

Engine management can help for sure, but you can't kid physics, a smaller intake track is better period, end of.

Re the recirc valve, I ran without one for a bit and it was fine till I took it on track and kept blowing charge pipes off....

Regarding physics
 

"but you can't kid physics, a smaller intake track is better period, end of."

HP X 1.62 = airflow in CFM

stock miata size

55mm TB flows 317 cfm

317/1.62 = 195 hp at the crank.

With 17% drivetrain loss thats means you have a restriction at anything over 162 wheel horsepower.

Don't get me wrong reducing intake track total volume will help throttle response, but if that's your focus do it by using an air to water intercooler to shorten up the piping. Don't use a diameter of pipe or tb that is too small to flow the air you need without causing a restriction. I presume you're shooting for more than 162 whp, and this project will cost you hp.

I'm already at 220 and know someone pushing 280 ... The extra tb made no noticable difference in power, a/w I tried it's ok nut can't cope after a few laps on track , it's also still a longer intake tract...

You can band theory about all you like, in practice it works!!!

I thought you couldn't kid physics?!?

Just cuz your butt can't discern the lost 5 hp doesn't mean they're not gone.

You can't I have a short intake tract and a great idle etc ;)

is the TB. Any smaller than the dummy TB? if it is it's marginal at best.

Besides 5bhp for OEM drivability and fantastic throttle response? Nothing to think about there. As you just said you can't even tell a 5bhp loss ;)