Throttle Bodies... Come hither JT.

[DakotaKid]

Something to think about.

Pretend you have 10 psi of boost at WOT.
Now you have 10 psi of boost at 1/2 Throttle.

Which car is quicker? Is there a difference of 10 psi through a 52mm hole vs a 26mm hole?

[B.A.P.]

Quote:

Originally Posted by TrboVan Something to think about. Pretend you have 10 psi of boost at WOT. Now you have 10 psi of boost at 1/2 Throttle. Which car is quicker? Is there a difference of 10 psi through a 52mm hole vs a 26mm hole?

Interesting question, but not sure what you're asking...

[DakotaKid]

Quote:

Originally Posted by BadAssPerformance Interesting question, but not sure what you're asking...

Throttle Body Size.
Does it matter?

[B.A.P.]

Quote:

Originally Posted by TrboVan Throttle Body Size. Does it matter?

CFM is CFM. HP is a direct calculation of how much fuel you can burn efficiently. More air means you can burn more fuel. Larger T-Body, more CFM, more air...

[Putter]

10psi of manifold pressure is still 10psi of manifold pressure. The difference though could be a low throttle angles to get 10psi of maifold pressure you may have 25lbs of intercooler backpressure, or total 35psi in the intercooler piping and 10psi in the intake, thus doubling your exhaust backpressure.

To solve the TB size issue would be fairly simple, a pressure drop gauge one in front of TB and one after the TB in front of the transision.

My question really is going after why people always talk about such low intake tract velocity when port velocities are probably significantly higher. I'm not trying to say higher velocity is better or lower is better, I'm just curious to where these numbers come from.

[DakotaKid]

Quote:

Originally Posted by BadAssPerformance CFM is CFM. HP is a direct calculation of how much fuel you can burn efficiently. More air means you can burn more fuel. Larger T-Body, more CFM, more air...

Just because I put a bigger carb on my car does not mean it is going to be any faster.

[Frank]

Quote:

Originally Posted by TrboVan Something to think about. Pretend you have 10 psi of boost at WOT. Now you have 10 psi of boost at 1/2 Throttle. Which car is quicker? Is there a difference of 10 psi through a 52mm hole vs a 26mm hole?

Yes throttle body size matters. To extrapolate on your example. Plenum reads 10psi. You have a 52mm and 26mm throttle body. In both cases, you will achieve 10psi. In the case of the 26mm, you will need higher air velocity moving thru the 26mm to achieve this. However, this higher air velocity comes at a huge price--inefficencies in the compressor, more turbulence filling the plenum from higher tb velocities, a lot less throttle response, etc. Your engine demands a CFM. It will get that CFM up to a point. If you have too much restriction, then HP will begin to suffer because it can pull enough air into the engine... aka its eating the air in the plenum faster then the turbo can supply. A good example is that on cars with too small of turbo. They have a tendency to drop in measured boost as they increase in RPM.

Anyway, I am not saying you can't run 500chp with a 52mm, but what I am saying is that you could see a huge increase in power if you went to something like a 65mm provided the elbow on the intake can take it.


Frank

PS> In reference to compressor inefficencies, this is because a smaller tb will create a larger backpressure before the throttle body. The means that compressor on the turbo is actually operating at a higher PR then what your engine is! That means you could be outflowing your turbo and not even know it because your measured boost level at the plenum is still a below that.

[B.A.P.]

Quote:

Originally Posted by TrboVan Just because I put a bigger carb on my car does not mean it is going to be any faster.

c a r b ? Whats that?

N/A is a differnt story, but if you can build a motor to use that 1100 CFM Dominator, it will make more power than that 600 CFM double pumper...

[DakotaKid]

Quote:

Originally Posted by BadAssPerformance N/A is a differnt story, but if you can build a motor to use that 1100 CFM Dominator, it will make more power than that 600 CFM double pumper...

Ah, that is a very good statement.
Same would apply to Turbo application. For most there is no need for a larger TB.

[B.A.P.]

Quote:

Originally Posted by TrboVan Ah, that is a very good statement. Same would apply to Turbo application. For most there is no need for a larger TB.

Very true as well

[Frank]

Quote:

Originally Posted by TrboVan Ah, that is a very good statement. Same would apply to Turbo application. For most there is no need for a larger TB.

yes and no. need is a relative word! we dont need more power, we dont need turbos, but in order to make good power, then throttle bodies need to be upgraded. i dont know why everyone is so hesitant on this... well other then the needed work to cutting off the elbow and welding on a new one. anyone making over 300chp can benifit from it because their flow is being hindered by the throttle body.


frank

[DakotaKid]

Quote:

Originally Posted by Frank i dont know why everyone is so hesitant on this...

Because people have run Low 10's with stock TB's.

I made 337 Whp with a 46mm.

[B.A.P.]

Quote:

Originally Posted by TrboVan Because people have run Low 10's with stock TB's. I made 337 Whp with a 46mm.

...and they should run high 9's with a larger one and imagine how much you would made with a 52mm!

Frank, I was gonna say 300whp...

[Frank]

Quote:

Originally Posted by BadAssPerformance ...and they should run high 9's with a larger one and imagine how much you would made with a 52mm! Frank, I was gonna say 300whp...

I was going to say what you just did! LOL. Anyway, I have repeated said that you can still do make the power you want, but at what efficency costs!? So JT, you want to be the test bed?


Frank

[B.A.P.]

Quote:

Originally Posted by Frank I was going to say what you just did! LOL. Anyway, I have repeated said that you can still do make the power you want, but at what efficency costs!? So JT, you want to be the test bed? Frank

Sure, I'll test it out... whatcha want me to test?