JRad405

My Professional Products throttle body and plenum whistle too. However, it doesn't leak. It just happens to some. If you like it quiet then don't buy them I guess. Whistling is fine to me I just wish it was a supercharger instead of my throttle body and plenum. I don't even hear the noise unless I'm outside the car.

cliffyk

They had 2 or 3 different "fins" that were interchangeable, screwed to the underside of the top plate with button head cap screws--you could pick and choose the shape and size that tickled your crotch and allegedly "tune" the plenum to your cams/exhaust/etc.¹

One problem was as I understand that end users did not seem to understand the value of using a permanent type grade of Loctite (one of the red flavours) on the screws and a few customer's engine ate them and parts of the fins.

speed UNLIMITED welded the standard fin to the top plate and liquidated the lot of them...

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¹ - I don't know what the people at Granatelli smoke, but there are times I wouldn't mind having some.

jrp1588

Hmm, weird

cliffyk

Well you know, the whole history of the "Shark" plenum should serve as a grand example of why one should not believe the pile of BS that accompanies a whole lot of aftermarket stuff.

If someone says that bolting on their particular piece of oxenscheisse will add 20 HP, then it is very most likely a crock of the same.

As to the "whistling", a good part of the decision making process for OEM components is NVH--Noise, Vibration, and Harshness. Very often performance is a secondary criteria...

teej281

And for the aftermarket, those are reversed. I like the whistle. Mine does it a little bit now. If you clean the TB with carb cleaner to clean the gunk from the flap to make it less sticky, they will whistle a little bit. The one I might get eventually will probably whistle a lot.

Cliffy, if one had plans of forced induction not too far down the road, would you suggest one of the larger offerings on the market to prepare for it?

jayglaze

Dont know if this is correct but I purchased the 75mm stack racing combo with plans to SC one day. From why I've read 75mm is optimal for SCing but I do air conditioning and have no real idea lol

teej281

Well when forcing air into an area, you create pressure. Now, moving air into a larger space will create less pressure, but still allow the same amount of air to be moved. Essentially making the system more efficient. So you're right on the money on that one.

cliffyk

Running boost is a whole different animal with the intake flow having nearly no correlation to that on an n/a application. The intake tract between the blower/turbo becomes a reservoir of compressed air and you want as big a hole as possible through which to get that air into the engine--charge velocity is handled by the fact that you are pushing air into the engine, not sucking iot in.

That big-*** 78 mm BBK integrated unit is likely as close to optimal for f/i when using a centrifugal blower or turbo charger setup; real superchargers feed directly into the intake manifold so the upper plenum goes in the trash anyway.

For the ease of resale scenario presented above I can think of no reason to hobble n/a performance because "someday" you may want to go f/i--unless perhaps someday is next week...