xr4tic

I'm giving some serious thought to a Haltech system (mainly because there is a local tuner that supports it) and it uses a Ford style Throttle Position Sensor. So I'll probably just adapt a Mustang TB to the stock intake initially.

Mustang TBs can be had in 50,60,65,70,75, and 80mm sizes (probably even bigger too)
I've got a stock 50mm TB laying around (they can be bought for $10 used) that I'd use as a template.

So the main question is, how much is too much?
The stock 1.8T TB was designed for low flow values (1.8 liters and 7psi of boost) Now that I'll be running 2.0 liters and a lot more boost, I'm sure it's too small, and may choke upper RPM breathing.
For example, a 2.0 at 24psi flows twice as much air as a 1.8 at 7psi at any given RPM.

What do you guys think?

CMH

Do you plan on making the intake manifold runners larger and opening up the head to flow the extra air.

4kq

I think you need to calculate the runner areas vs. the TB area and see where the restriction in flow area is. Obviously the TB is usually the restriction, that is why the use restrictor plates in racing.

A bigger TB gives a different "feel" to the engine's responsiveness, but usually are a 1-3 hp gain and a loss of low-end torque. The way to do this is with individual butterfly runners. feeding from a filtered manifold with the Tps sensor on the end of the butterfly/accelerator arm.

This is really common in racing and the haltech even has a mapping adjustment for it. Then you have really crisp throttle response, and all the flow the head can take.

I think the head itself flows more than either end of the system with better cams.

xr4tic

But you won't notice it, because the boost signal is sourced from behind the TB.

By getting rid of a pressure drop, you increase the efficiency of the turbo, so you'll have a cooler air charge and more air (higher density) for more power.

Lambo-Bully

1.8T stock is approximately 2.5" and the 2.8 5v is approximately 3". the 1.8T fits inside the 2.8! I drove it for a month like that, but my car had no serious mods, and no programming done for that t-body. Ask around some of the tuners, if they can program an ECU for that t-body? BTW, the bolt holes had to be bored out a little to bolt up, and I wondered if the gasket would've held under higher boost....

xr4tic

so I won't have to worry about messed up signals and chip programming

SMOKINA4TURBO

I believe ATP went with a Ford 60mm throttle bodies on one of their A4's they are putting a Tech2 in. Not sure if it was exactly 60mm. The plate looked pretty easy and sharp!
When I get back to the bay area and around ATP I may have to throw one of those on!
I'm prolly no help btw :-)

Lucas_Gchips

Size of intercooler pipes?
I haven't had a problem at top rpm with air flow with stock throttle body.

You cant compare Normally aspirtated air flow to forced induction.
Some air flow mods that may benfit NA cars, make little or no difference to a turbo/supercharged car.

Audiboy

and before the throttle body and compare what you see in the manifold. Any pressure drop you get means that thing is restrictive. At least a drop from the intercooler is expected, but not from TB.

xr4tic

it's approx 53mm, it narrows down, then opens up, so it's kind of hard to measure.

The opening in the intake manifold is 61 mm