Port Matching???? gains????

[g4ebguyGTX]

Ok i was reading in this book about matching a gasket perfectly with the head??? the intake manifold gasket.... i was wondering what are the gains and procedures on a accent 1.5L if anyone has a idea and the cost.... i would have my mechanic help me do this so feel free to tell me any information.

[skierd]

A mechanic can't really help you with this, you need a machine shop if you can't do it yourself (and you probably can't if you're asking this question).

Port matching is the process of making the intake manifold and intake ports on the cylinder head blend smoothly into each other (i.e. matching the ports in terms of size, shape, etc). You have to remove and strip the head, grind out the offending material, and reassemble it. The actual porting isn't too expensive, but there's obviously a lot of work and down time for the vehicle to get to that point unless you are using a spare head and swapping them out. HP gain depends entirely on how good the head was to begin with, but at most I'm going to guestimate 1-5hp maximum. You'd gain more performance by removing the sound system lol weight.

[g4ebguyGTX]

i figured i would do this myself i was told it might take a couple hours? like 3-5 i dont really know what to do i heard all u have to do is grind the head down to wear the head and gasket match evenly cuz the gasket is always made bigger then head

[skierd]

Ok, but how much bigger? What you're trying to match is the size of the intake port on the intake manifold and the the size of the port on the head, the gasket (so long as its bigger than either of those as it typically is) is irrelevant. If you match to the gasket there's a good chance you'll end up with what amounts to a bubble in the intake track at the gasket, costing you power.

Not to mention, again, that you have to *completely* strip down the head you're grinding, after taking it off the car, and then clean it thoroughly to make sure none of the material ground off makes it into the engine before reassembling it and reinstalling it. Just because the actual machining work being done is simple doesn't mean its easy.

[MechaniX_034]

Originally Posted by skierd

Ok, but how much bigger? What you're trying to match is the size of the intake port on the intake manifold and the the size of the port on the head, the gasket (so long as its bigger than either of those as it typically is) is irrelevant. If you match to the gasket there's a good chance you'll end up with what amounts to a bubble in the intake track at the gasket, costing you power.

Not to mention, again, that you have to *completely* strip down the head you're grinding, after taking it off the car, and then clean it thoroughly to make sure none of the material ground off makes it into the engine before reassembling it and reinstalling it. Just because the actual machining work being done is simple doesn't mean its easy.

+1.

Port matching is pretty negligable unless you are dealing with a turbocharged setup, where the pressure source can be inverse from an NA motor; the "step" turns into a upsweep of flow and reduces the effective port area. On an NA motor, the air streaming into the port with vacuum being determined and driven by the inlet stroke will simply see the smaller diameter as the effective charge path.

In both scenarios, there is power to be gained. However, for street use the amount of power gained is negligible. This is a modification more common to those who are looking for every last ounce of power on the dyno; gains tend to be at the high end unless the shape of the ports themselves has been changed(ironically, port matching is usually billed as a seperate job)