A quick search turned up nothing on this forum, heading over to the Cobalt one next.

Has anyone played with doing a basic stage 1 port on their head? A little gasket matching, raising the roof a bit, smoothing the entire port and churching up the slop left from casting. I'm thinking it's not going to provide any more ponies, but just a feel good thing that amounts to just a waste of time. Waaaaaay down on the to do list is fab some custom exhaust headers for a dual set up exhaust, that might capitalize on this a bit more but that is to far down the line to talk about right now.

Anyone have any words of wisdom? I figure it couldn't hurt to spend a few hours with a grinder on the new head since I'm already changing it, but with so much to do is it really worth the effort? Think anyone would benifit from doing a photo tutorial or even a video? Am I just really board at work and wasting my time even thinking about porting a 2.2 ecotec?

 

"Raising the roof" gives more cubic inches so it should add some HP and run faster.

Back in the day we used to "split" the exhaust manifold on Stove Bolt six cylinder Chevys and the sound was awesome. Getting on it as you were going by a house would rattle the windows and you could get a ticket in town. Split manifold exhaust sounds as good (or better) when in gear and slowing down - if you can imagine that.

I'd be curious to hear the 4 cyl with split manifold.

Boydie

 

port and polish is never a waste of time, just not very much gain on these 2.2's but when I have to replace the engine in mine, I will be doing just that, kind of a tradition in my garage, if its apart then you have to at lease port match to the gaskets, and a split manifold exhaust would be very cool, I wish I still have my fab shop, a lot more equipment to make up parts.

 

The main reason I'm looking at fabing a split manifold is I'm not a huge fan of the I4 wimpy sounds. If I wanted a rice rocket I would have bought a Honda. Doing 1 and 2, split with 3 and 4, gives it a more a v8 sound, or like a v4 Motorcycle because of the firing order. Some guys say the intake manifold should be modified too, but that's a little extreme even for me. I'm not a big fan of the plastic, but 20 or 30 hours worth of welding to make a intake manifold for 3 percent sound improvement is a little much, even to me.

 

I am thinking of doing this to mine too. I have to replace the valve cover gasket soon and figured it wouldn't be much to take the head off and do some porting. Maybe a nice weekend project. What is this split header?

 

A split header takes the exhaust from cylinders 1 & 2, and the exhaust from cylinders 3 & 4, and separates them into two distinct exhausts. These are commonly called "Y" type headers.

If those two exhausts are kept as a "true dual" system, the firing order of a 4 cylinder engine(1-3-4-2), would give the vehicle a sound at idle not unlike a V-8 engine running a flat plane crankshaft. If done properly they can sound fantastic, if done wrong, they sound like a Subaru flat 4 in need of a tune up.

Here's an example of a split header setup on an inline 4, please note that this engine is an example of early hot rodding. Your looking at a Ford Model B engine converted to overhead valves, dual carbs, and other ancient black magic goodies enabling it to pound out a whopping 104hp.

 

I fab'd a split exhaust manifold for an Olds Quad four in 1992 for a friend building a 4 banger hot rod, I ran 1 and 3 together and 2 and 4 together in sounded ok but not like a V8. he eventually sold the project and that guy scraped the quad 4 and went with a SBC.

 

hmm, sounds easy enough to build in the garage! ill have to give it a shot when I put it away for a full build.