Throttle Body Question

[Mest30]

I have a 65mm BBK TB that I bought NIB from a member here. I know that gains from a TB, especially on a NA build, is minimal. My question is is it worth it to have the TB port matched to the plenum? I dont care about the cost vs. performace value or anything like that. I just want to know if I would get any gains (regardless of how small) by port matching the plenum and TB. Thanks.

[Blk Mamba]

Everything you do to "smooth" the airs passage is a gain, regardless of how minimal, I'm thinking of a 90 mm MAFS, and a dual 65 mm TB, but have yet to fab a 3 3/4" inlet, and the air box under the radiator. To cold in the winter. I'm going to template the air passages all the way, to limit any restrictions, this will be as close as I can get to Ram Air. (later, larger injectors).

[Mest30]

You said you're going to "fab a 3 3/4" inlet, and the air box under the radiator." I'd have to do that to add a 65mm TB?

[babbage]

Mest the plenum on an MM is only ~ 60mm - so you won't get the full effect unless you port out the plenum to 65.

[Blk Mamba]

no you dont have to change anything, but remember you are only going to get the amount of air that will fit through the smallest opening. On the MM it's the small hole in the header panal that the engine breaths through. Relieve all restrictions, as per Bernoulli's principle, the turbulence caused will decrease the air flow, and you lose more than you gain, try to keep the area between the air filter and the TB as close to the same size as you can, (high and low pressure zones don't help. BTW, a 92mm MAS, is the same surface area as a dual 65mm TB, and thats fairly close to 3 3/4". An intake spacer is also a good idea, but thats a different mod. Now the next thing is that you don't want to be fuel starved, so now you have to increase the size of the injectors, remember, lean engines have the most power, but the price for that is a terminal failure. Bet you wish you had never started this.

[FordNut]

The upper intake is going to be really thin if you open it up to 65 mm. I opened one up so it would match up with the twin 62 tb and even that was getting pretty thin. Stock tb is 57 mm, intake is between 57 & 60 but it's rough so opening it up and polishing it should be helpful. But in my experience it didn't make enough difference to be worth the time & money involved.

NA the stock injectors and fuel pump are plenty big enough. Just have it tuned and the injectors will flow plenty of fuel.

[Blackened300a]

After my TB install I gain a whole 1 RWHP and 0 RWTQ peak but gained 5 RWHP across the range on the dyno.