What does this process involve?

How much does it usually cost?

How does it improve performance?

Where can I get it done?

Thanks,
Victor

 

Here's a good article about porting and polishing:

http://www.sa-motorsports.com/diyport.htm

A proper port job can net you anywhere from 15-30 hp extra. The process can be costly: I was quoted about $2500 for a port job.

And most machine shops that specialize in engine buildup can do a port job for ya. Be wary of anyone that says they can do it for "cheap". If they do, then expect your work to be cheap.

 

Hey mike, usually a good port work will run around $2,000. Porting out the head will allow the maximum amount of airflow to flow through the chambers. There is a lot involved with this. Usually the porting place will have different stages depending on how much HP you are looking for (Stage 1 – Stage 5.) Most of the time the process involves porting out the runners and polishing them. In the higher stages the will do a 3 angle valve job, which basically means they will port out the valve seats and the valve runners. Some places will also do a swirl job on the valves. A lot of times with these port works they will mill down the head too. Also with these port jobs it can also be common for them to weld material to the head to improve on the airflow. The improvement that this does on the car is pretty major, and you usually can’t pass smog afterwards. It is also important to know what you ultimate goal will be since a NA port job will be different from a FI port job. FI port jobs require larger porting where NA might require some material to be welded onto the head…it all depends. This is a major mod and it is best to go with someone that has done your vehicle before. Make sure they use a flow bench this is very important. Hopefully this will help you out a little.

 

Thanks! I'm going NA.

 

A few years ago I had a long discussion witha porting pro. What stuck in my mind was...
1. Anyone without a flow bench just guesses
2. Flow the system ( heads and manifolds together ) with the valves in and at a range of lifts - thats the actual conditions that the engine works under.
Could be BS but there seems to be logic underneath it.

 

I agree, a good flowbench is the key to fully porting the heads. Some of the more basic things like gasket matching and cleaning up the casting can be done yourself for the cost of a die grinder and some carbide cutters. Another thing to consider is the extrudehone process.

 

What's extrude honing?

 

xtrude hone is a process when they push this putty/sludge mixture through whatever you want smoothed out, and this mixture has these tiny particles which polish the surface super smooth....

 

Get the VQ35DE swap that has a compression ratio of 14.5:1. If I remember correctly it produces around 450hp

 

I plan on going all NA also keep me up to date with your mod choices ill do the same! This winter the NA work will begin... Look for updates

 

That is not readily availble, and is uber expensive. Plus it's not "STREETABLE"

 

The extrude hone medium can actually remove a lot of material, depending on how abrasive it is and the process used -- it is not primarily a polishing process. But, whereas air compresses when it meets resistance, like a bend in a port, or a rough or high-spot, the honing medium, being liquid, resists being compressed, allowing the abrasives to act against the head surface material, and incrementally remove material. It is useful for removing casting imperfections and relieving areas that are particularly restrictive, but, is no substitute for professional porting. The best scenario would be a combination of the two approaches.

Regarding what ForceInduction said:

1) Polishing is over-rated and, in fact, can be detrimental.
2) Valve-seat and valve-pocket work is 'Stage I' in most cases.
3) Headwork will not necessarily cause you to fail smog-testing. There are too many variables, to be able to predict that (although radical cam-timing will just about guarantee failure).

My head-guy:

Progressive Automotive
3036 68th Avenue West,
University Pl, WA 98466
(253) 565-3633

 

How much you gain depends a lot on how good the stock ports are.

On most older GM smallblock V8s the ports were not very smooth, and did not line up with the manifolds very well. There was a lot of power "left on the table".

Some other engines are better from the factory and would be harder to get a big increase from. There is always SOME gain to be had since I don't think any mass produced cars have hand shaped and polished heads. But the gain may or may not be large.

The cost is high for several reasons. It is very labor intensive and it is a bit of an art. A cheap port job is probably worth what you paid for it.

If the insides of the ports are very rough a talented do it yourselfer can polish the surfaces and gain a boost. It is best to leave re-shaping the ports to a pro.

The intake manifold on my old camaro were very rough (raw casting). Smoothing them out helped some. In hind sight it might not have been worth the zillion hours it took me to do it.

 

Oh, and regarding cost... The amount of headwork you have done should be driven by whatever other engine mods you do.

At one extreme -- all-out 'race' -- cylinder head work will not only be fairly expensive, but probably be developmental, and therefore, recurring.

At a modest level -- mild cams and some bolt-ons -- the work can be pretty inexpensive. E.g., head-to-manifold port matching, simple clean-up of casting seams, and valve-seat work is probably doable for $500-600. Even today's cylinder heads tend to show a minimum 5% increase in flow from this level of work.

 

I had spoken to Doug at Crawford Z regarding this issue.....it was one of the reasons for his plenum. He says that when they flow benched the 350Z heads they flowed GREAT!! But as soon as you put the intake manifold on the head it absolutley killed airflow through the head. He saw a 30% airflow decrease to the front 4 cylinders compared to the rear 2 cylinders. This was/is the reason for the plenum and it's success with the power increases after it's installation.

 

awesome, i prob won't touch any heads then.

 

What I might do with the heads is maybe just have the exhaust ports polished smooth......but not a lot of material removed. A good port match to the intake manifold and exhaust manifolds would be a really good idea as well to help her exhale.

 

Listen to THIS guy he has a clue.