Explain to me the benefit of a "ported" throttle body

[NicD]

Yeah, ported TBs work OK on IAC based LS1s as they were smaller dia to begin with and don't rely on that blade sweep area for idle control like all the electronic control cars. I would never put a ported TB on an ETC car and tell anybody who has to ditch it and buy a stock one especially if they are camming the car because changing the ETC scalar only solves one part of the issue with idle stability. The bigger aftermarket TBs generally try to follow the same sweep pattern (as far as airflow goes) as the stock ones to minimize the typical problems associated with ported stockers. Of course some aftermarket ones are better than others... Bigger TBs work great on PD blowers because while blowers push air very well their ability to "suck" air sucks. On turbos and superchargers like Procharger/Vortech you are pushing air through the TB which makes it largely irrelevant since most people are running no larger than 3" charge piping anyways.

[Jon]

You are exactly right, Jon. The only instances where I have seen a big bore throttle body make impressive gains was when it was placed in front of a PD supercharger.

You need to explain "impressive" in more scientific terms.

The original question dealt with 4-6 HP, which may sound impressive on a 50 HP engine, but not on a 500 HP motor, depending on the definition.

I usually avoid dyno HP as a criteria to gauge performance, because I use my car to move me from one place to another, not merely to spin a large drum. However, dyno HP is a better measurement than SOTP.

30-50+ HP with a bigger throttlebody in front of a PD blower if you are running it max effort. Part of that gain is the 1 or 2 psi extra boost you gain by opening up the inlet path of the blower.

[HOXXOH]

You are exactly right, Jon. The only instances where I have seen a big bore throttle body make impressive gains was when it was placed in front of a PD supercharger.

You need to explain "impressive" in more scientific terms.

The original question dealt with 4-6 HP, which may sound impressive on a 50 HP engine, but not on a 500 HP motor, depending on the definition.

I usually avoid dyno HP as a criteria to gauge performance, because I use my car to move me from one place to another, not merely to spin a large drum. However, dyno HP is a better measurement than SOTP.

30-50+ HP with a bigger throttlebody in front of a PD blower if you are running it max effort. Part of that gain is the 1 or 2 psi extra boost you gain by opening up the inlet path of the blower.

Now you're talking HP gains by additional boost, which can also be accomplished by the blower drive ratio. And a number alone is still meaningless without knowing a baseline. Was that 30-50 HP on an engine that previously was 500 or 1000?

Let's get back to the original question, which dealt with ported TB on NA emgines.

Here's another claim of HP from TB size, that is worth watching for more reasons than the results.

http://www.bbkperformance.com/news_item.php?nak=74

[Two Fangs]

You need to explain "impressive" in more scientific terms.

The original question dealt with 4-6 HP, which may sound impressive on a 50 HP engine, but not on a 500 HP motor, depending on the definition.

I usually avoid dyno HP as a criteria to gauge performance, because I use my car to move me from one place to another, not merely to spin a large drum. However, dyno HP is a better measurement than SOTP.

The chassis dyno is merely a tool, used to give us information about the delivered torque and horsepower. I have seen gains of over 50 horsepower through switching throttle bodies on forced induction cars. This was on an SF-902 engine dyno. And dealt primarily with 4.6 supercharged Fords making power in the 500 to 600 brake horsepower range.

Here's my TB experience. Maybe you can rank it in degrees of impressiveness.

1/4 mile test results.

2 passes for baseline - 11.92 @ 121.24 & 11.96 @ 121.17

2 passes after install - 11.90 @ 121.18 & 11.90 @ 121.05

The 60' times dropped from 1.97 & 1.97 to 1.95 & 1.94

Not entirely impressive to me. Not without knowing the ambient conditions. Looking at the HP indicator in what you did post, HP likely stayed the same or was lower with the ported TB.

[ICULUKN]

the engine is an air pump.. Air in.. Air out... The idea is if you port the throttle body, then you can get more air into the intake, resulting in additional hp. Like everyone said.. the gains are minimal at best. I would rather see port matching on the intake