Port Whipple Manifold?

[WhoMadeWho]

I noticed while installing my Whipple that the intake ports on the Whipple manifold are 2-3mm smaller than the head port. Would there be any benefit to porting it to match the head intake port size?

[stanwilliams]

I port matched mine just because. Who knows if it made any difference or not but it bugged me to have such pretty intake ports get choked off. Didn't take that long to do.

[WhoMadeWho]

Originally Posted by stanwilliams

I port matched mine just because. Who knows if it made any difference or not but it bugged me to have such pretty intake ports get choked off. Didn't take that long to do.

That was my thinking too. Any tips for doing the porting? Any thing to watch out for?

[GMRULZ]

Originally Posted by WhoMadeWho

That was my thinking too. Any tips for doing the porting? Any thing to watch out for?

Just don`t make them larger than the head ports...

I`m sure you`ll do fine.

[Inferno LSX]

Interesting, I wish I knew about this before we got the new Whipple on my car.

[stanwilliams]

I coated the manifold flange with layout fluid (or just spray paint it), let it dry of coarse, then I bolted it to the heads and centered the bolt holes. Then I heated the end of a pick with a torche and bent it into a U shape to easily allow me to scribe the intake port size onto the flange. Just take your time with the grinding, it cuts pretty fast. Radius the opening just a little when your done.

[GMRULZ]

Originally Posted by Inferno LS3

Interesting, I wish I knew about this before we got the new Whipple on my car.

Its actually not a big deal on a forced induction car IMO. NA cars benefit more from port matching for velocity reasons, however, the blower forces air in instead of the engine sucking in air like it does NA so the blower in a sense creates its own velocity and port match is not as critical, however the last thing you want is the intake ports larger than the head ports that will create a lot of turbulence. In saying that you still might pick up some power on a blown car by port matching like Stan said, I just don`t think it will be that much. If you are going all out on your build there is no reason not to port match, it sure can`t hurt if done correctly.

[stanwilliams]

Set the intercooler in the manifold and look how close it comes to the bottom of the manifold. Is amazing any air gets to the ports at all. Not really though it has a wide area to fill the manifold, the air is just not going to make a straight shot into the port like you would like. How much difference does it make to have the intake ports opened up on a blown car??? I see a lot of builds with ported or bigger heads. Just wonder if anyone has before and after data on its gain???

[GMRULZ]

Originally Posted by stanwilliams

Set the intercooler in the manifold and look how close it comes to the bottom of the manifold. Is amazing any air gets to the ports at all. Not really though it has a wide area to fill the manifold, the air is just not going to make a straight shot into the port like you would like. How much difference does it make to have the intake ports opened up on a blown car??? I see a lot of builds with ported or bigger heads. Just wonder if anyone has before and after data on its gain???

Good question Stan. I would love to know the answer too. The manifold is pressurized by the blower so the air is going to take the pass of least resistance, ie... when the intake valve opens its being forced in the cylinder as long as the valve remains open. The manifold is constantly being pressurized by the blower once the bypass is closed. The Intake side of the head may not be as critical on a blown car as a na car, but I bet the exhaust side being ported on the heads makes a big difference. you have to get as much of the burnt gasses out of the cylinder as you can. Still one would think w/ port matched manifold to the head it should pick up something. I wonder if Ted has ever tested this out??

[stanwilliams]

Think of it this way though, NA your under apx 15 psi of pressure pushing the air thru the port. With a blower at 10 lbs your really at 25 psi. I would think the same rules apply to both engines. However with a given blower size and pulley you probably get the same air flow thru the engine with good flowing ports or not so good. You just do it with less boost on the good heads, less heat, and therefore a little more power.

It didn't cost me anything to clean up the manifold on my personal car. If I was doing it for a customer and charging by the hour I'm not sure I would waste my time. Before and after test anyone????

[old motorhead]

With the big Whip's excellent boost cooling system, this seems to be something useful on only a very high end build. An extra dab of boost due to a little intake mani restriction seems inconsequential