Individual Throttle Body questions
 

Hey guys I just had a few questions about individual throttle bodies. I know the general purpose behind them and for the most part how they work. But I was wondering if someone could explain a little more in detail some of the benefits and drawbacks. I also don’t know if anything else is required once you get ITB’s not including an f-con. Any help would be great, including places to buy them.

-Thanks, Andrew

Are you talking about the dual throttle bodies that would replace a Weber DCOE or IDA carb? If you are then your way beyond using an fcon. You'll need a fuel management computer at the minumum(Megasquirt, Haltech F10, etc...). If your not talking about the dual TB's then I'm assuming a set of quad motorcycle TB's. Once again a fuel management computer at the minumum and a custom intake to mount them on.

Places to buy them:
www.ebay.com (many motorcycle TB's available)
www.twminduction.com
www.tweakit.net

More information for you

http://www.mazdarotaryclub.com/forum...?threadid=6861

http://ausrotary.dntinternet.com/for...ghlight=zch00k

They cost like $1,000+ for the whole set-up.
I doubt you can afford them.
It's a waste of time for a non-turbo or for any street vehicle.


-Ted

Individual throttles are of benefit on 4 stroke reciprocating piston engines as the flow in the intake ports starts and stops regularly. The benefit is that you do not have cylinders in the creating vacuum in the plenum robbing other cylinders so you have full atmospheric pressure available during the intake stroke of each cylinder. The column of air above the throttle plate is denser (heavier) so the ram effect is greater giving better cylinder filling. It also makes it easier to build a tuned intake to take full advantage of pressure wave or ram tuning. A good plenum system usually matches the top end power of an individual throttle system, but the individual setup has more torque throughout the low and mid range. With individual throttles on a piston engine the torque increase is so good you can run a longer duration camshaft and have the same drivability with better top end. A rotary is essentially flowing air through the ports all the time with the flow going from one rotor face to the next so most all of the benefit of individual throttles is lost. This is the theory at least. I would want to see dyno results between an optimized single throttle plenum system and an individual throttle system before spending a dime. Unless, of course, you're in it just for the bling.

One more thing. With individual throttles it's much more complicated to implement a variable length intake system. Also the cost of individual throttles on a rotary is much less than even a 4 banger as you only need one 2 bbl throttle body on the rotary. Mazda put a lot more time and effort into the 6 port intake system with a 3 bbl throttle body than would have been required on an IDA type throttle body. Ever wonder why? The 6 port system is like variable valve timing for a rotary. I wouldn't give it up.

I disagree...

Once you get rid of the primary versus secondary design, you lose a LOT of low end power.
If you study the stock throttle body, and it's progressive design, the secondary ports are staged slightly later than the primaries.

If I had the money, I would run *4* ITB's - one for each intake port.


-Ted

Why not just be cheap and run motorcycle ITB's? You can get quite a few different sizes ranging from 38mm all teh way to 50mm.

And while on that subject what would be a good size throat for a full BP N/A, I was thinking that a 38mm set from a GSXR600 would be a good fit, but I really have no idea.

Hey thanks for all your help guys, i definatly better understanding the amount of work/money its gona require if I decide to go down this route. Thanks agian for your help and keep the thread goin, I would like to know as much as possible