Ported and Polished Heads

[hoff944]

I know a Porsche shop thats close to me (200 miles) that will port and polish my heads for $250. I've done business with these guys before and they are great. I don't know that much about pricing on this kind of work, but it seems fair enough though. Has anyone had this done? I know the pros, but what are the cons of having this done?

[Obin Robinson]

your fuel consumption will go up a tiny bit. but other than that, just make sure that your fuel injection and ignition systems are running good. there is no real "downside" to a good port and polish if it is done correctly.

if it is done incorrectly, then the head will be too thin and it may be more susceptible to stress. just make sure your coolant system is running nice and cool also because your engine will create a tad bit more heat.

enjoy! tell us how it goes!

obin

[hoff944]

How about emissions?

[Obin Robinson]

hmm,

i'm in a part of the country that doesn't really do emissions on cars built before 1993, so i've never had to worry. from what i understand, it doesn't blow the emissions thing out fo the water. if you're concerned, check with the shop first.

obin

[tri]

I just did a valve job on my car and thought about a Pollish and port. Every porsche mech. I talked to said that I would not feel any great differnce. They told me to save my mony and buy some headers instead.

[951EATS5.0]

If done correctly, p/p jobs can be great for power, but it will expose the next weakest link in the chain like fuel injection, weak rings, etc. just have it proffesionally done. it's not a bad time to change the cam either, I hear on a 951 that alone is good for like 20 horse. I did it on my Trans am drag race car and it took almost 1 full second off the 1/4 mile time ( Pontiac heads are not quite as expensive a porsche heads, especially in Detroit)

[Pilot_951S]

On a 951 a good port/polish will also help the turbo spool up faster (not as fast as a test pipe but every little bit helps.)

BTW if it is a REALLY good PnP it could be worth as much as 30-40hp on a turbo.

[Obin Robinson]

i rode in a friend's 924 that had a port and polish and that car had more power than our old 931! the car just had a whole new life in it that i never felt in a N/A 924!

since then, i have been looking for places to port and polish the heads in my car. i have FELT the difference and it was NOT slight!

obin

[hoff944]

What do you mean "next weekest link"?

[951EATS5.0]

A ported head is great as long as the rest of the engine is in good shape also, an engine tends to wear very evenly, so by re doing a head and making it like new again, you can potentially, not always, find something else that has worn. the most common thing that happens with a new head (or ported and polished, I assume you will have the valves done and the head cleaned and all that) is that the ring wear begins to show in the form of some smoking, not very severe. I have noticed this more on high compression NA cars like V-8 and some 4 cyl. but it still happens on a turbo.

The biggest thing to make sure of is that your engine is in good over all shape and that the work is done correctly by someone who will back it up if a problem arises. I have been told that a high flowing head can be greatly improved by the addition of a good cam. it's a good time to do it when you have the head off anyway.

[RealRideRacing]

Porting an Polishing the head can indeed increase the power a bit. I have done so in my na944. However, the biggest hindrance that I run into is still the factory DME which doesn't allow for anything other than a pure stock setup.
Without switching over to a full tuneable aftermarket system (such as Motec, Zytec, Electramotive or Haltech) the P&P won't be optimized. I'm looking into a Haltech system for my car as it's the most affordable with good recommendations. Chips could help but by the time I spend hours on a dyno to tune & burn chips, I might as well have bought a complete system. Besides the chips don't allow for any tuneability.

David www.RealRide.com/racing
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