a real answer to Throttle Body Spacers...do they work?

[Egi7]

Case closed, Throttle body spacers do absolutely sh!t. Its the same concept as the plenum stackers people put on dual runner manifolds, to increase the volume.

 

[S-spec]

I wouldn't say they do ABSOLUTELY **** (in terms of giving power, hey, agreed 100%) But, they will improve throttle responce at low RPM since the plenum is in fact bigger.

 

[Egi7]

Not always, neccessarily. Manifold design also plays a role in throttle response at lower rpms. The f23 manifold, in itself, is already designed for quick throttle response, being that it has short runners and a big plenum. I would better advocate a aftermarket throttle body, if one wanted to better throttle response, being that it allows more air to enter the plenum at an accelarated rate.

 

[S-spec]

Not always, neccessarily. Manifold design also plays a role in throttle response at lower rpms. The f23 manifold, in itself, is already designed for quick throttle response, being that it has short runners and a big plenum. I would better advocate a aftermarket throttle body, if one wanted to better throttle response, being that it allows more air to enter the plenum at an accelarated rate.

Well ofcourse! But changing the manifold design isn't exactly practical But for example, 2 identical mani designs, but one with a larger plenum than the other, the larger plenum would yield better responce. Not necessarily more power, but better responce.

Also, having a larger TB doesn' allow more air in at an "accelerated rate". Its actually slower! (Bernoulli Effect). What it does is it gives an illusion of throtle responce, because with a larger TB, opening it up 30% would yield the same effect as opening up the smaller one 50%. But in terms of MAX flow, it would have very little effect on it, because 90% of the time the TB can outflow the manifold anyway.

 

[Egi7]

Iam not talking in terms of MAX flow, iam was reffering to intake velocity and volume( "the TBS issue"). Your statement about "opening it up 30% would yield the same effect as opening up the smaller one 50%" is true being that they both end up with the same diameter and circumference..lol But if your insinuating that an aftermarket TB gives a non-positive effect on throttle reponse your wrong. Time and time again, TB's have proven to have great results in response and flow dynamics being that the manifold is a performance oriented piece itself.

 

[S-spec]

Iam not talking in terms of MAX flow, iam was reffering to intake velocity and volume( "the TBS issue"). Your statement about "opening it up 30% would yield the same effect as opening up the smaller one 50%" is true being that they both end up with the same diameter and circumference..lol But if your insinuating that an aftermarket TB gives a non-positive effect on throttle reponse your wrong. Time and time again, TB's have proven to have great results in response and flow dynamics being that the manifold is a performance oriented piece itself.

nononon....don't get me wrong! I am not saying that and aftermarket TB will NOT affect throttle responce. For sure it WILL. But its BECAUSE of the fact that opening up the bigger throttle body 30% (less throttle input) will feel like you opened the smaller throttle 50% (more input) hence the "better responce". (Mind you , I don't quite follow you when you say this holds true if the diameters and the circumferences are the same...that just doesn't make sense!)

I AM however saying that it will not necessarily allow air to enter more "rapidly" simply because of the bernoulli effect. Now if we take it a step further, a wider TB, and a well tapered wider TB at that, YES, it CAN have a positive effect on air velocity. It all depends on design, and I apologise for making it sound absolute that it would have a negative effect on velocity in my previous post.

Anywho, we are pretty much on the same page

 

[Egi7]

(Mind you , I don't quite follow you when you say this holds true if the diameters and the circumferences are the same...that just doesn't make sense!)
)

lol, I was meaning that the same "flow characteristics" were achieved by the bigger throttle at 30% when it theoretically would take the smaller TB more input. Maybe it was my choice of words but "basically" I was in total agreement with you!

 

[accordfiber]

I totally agreed with S-spec. Adding a spacer increase the plenum volume and it helped me restore some low torque end when you have an exhaust manifold like DC sports and a catback exhaust 2.5". Also, if you want to build NA, this is the way to go: remove any bottleneck from your intake to the motor and after. Throttle body same size of the intake then bore spacer and bore intake manifold then add a performance camshaft. I will try that this spring. I just got a skunk2 throttle body with a spare intake manifold. The only thing i saw is the intake manifold plenum has a couple of holes for some sensors and i will not be able to bore it the way i wanted to. Does somebody tried to bore is intake manifold?

 

[hiddengamer7]

Holy revival batman!

 

[5spdcoupe]

Holy **** this thread is ancient! But for what is worth, take it from this "physics nut", everything S-spec posted with regards to physics theory I stand by and support 100%. He hit the nail right on the head. I do however have some more input on the subject...

a TBS is best used for carburated applications, fuel injected systems typically don't see large gains. In carburated cars the fuel is injected before it enters the cylinder and the TBS will cause turbulance in the air and allow for a better mix of air and fuel opposed to just a linear air flow, hp increases of 10, 20+ are NOT uncommon. In fuel injected cars like ours however the fuel is not added in that way, but before combustion. The incoming air is already "swirling" into the cylinder due to design and allows for fuel to be mixed in easily and effectively so a TBS's effects would be very minimal. This also allows the car the use less fuel since it can be accurately added to each cylinder instead of just shooting fuel into a common tank and hoping for the best as it moves into the respective cylinders. Fuel can also be shot only when needed in each combustion cycle. And also fuel additions can be dynamically controlled with a lot more precision by the computer shooting it into the cylinder in this individual system rather than the common air tank style in carburated cars.


So TBS in fuel injected cars: minimal gains
TBS in carburated cars: big gains