ALFAGTV6.COM

GarthW · Post by **GarthW** » Mon Oct 29, 2007 12:34 am

Is it worth while porting the heads if engine is going to be boosted?
I though head porting is better suited to N/A engines, but wondered if
there would be any more power to be had if i ported mine for a turbo application?

Mats · Post by **Mats** » Mon Oct 29, 2007 1:04 am

A good N/A engine should be the base of any boosted engine IMO.

x-rad · Post by **x-rad** » Mon Oct 29, 2007 3:47 am

especially the exhaust side....

Greg Gordon · Post by **Greg Gordon** » Mon Oct 29, 2007 7:23 am

I am going to disagree a bit on this one. Normally I would agree that porting will help. However things are a bit different with the GTV6/Milano cars.

Here is my argument: The transaxle is the main limiting factor on these cars. I think about 300rwhp is all you can run before you start to run into trouble, and even then you have to be careful. Barry has said on at least one occasion he has found an absolute limit of around 350rwhp. At that point the transaxle will fail regardless of how careful you are.

We can easily reach 300rwhp without any head work. It makes a lot more economic sense to sink that cash and effort into the intercooler setup, aftermarket injection and other areas directly related to the forced induction system. These items will give you relatively large and predictable results.

Now, if you are going with a front mounted gearbox and 400rwhp, I would agree that special headwork is a good idea.

Nikoror · Post by **Nikoror** » Mon Oct 29, 2007 12:37 pm

Ported engine has less restriction, so same power with less boost=less heat=less stress. Worth it? Depends on the price. If you're doing it yourself = definitely.

Barry · Post by **Barry** » Mon Oct 29, 2007 8:40 pm

Nikoror wrote:Ported engine has less restriction, so same power with less boost=less heat=less stress. Worth it? Depends on the price. If you're doing it yourself = definitely.

+1..

Greg Gordon · Post by **Greg Gordon** » Tue Oct 30, 2007 12:32 pm

Hmm, do you guys really expect me to believe you do porting work so you can dial back the boost and keep horsepower the same?

Nikoror · Post by **Nikoror** » Tue Oct 30, 2007 2:55 pm

Not really until I see the pinion as a round rod

Post by **Zamani** » Tue Oct 30, 2007 3:38 pm

Greg, you've known us for a long time. We don't tell lies.

GarthW · Post by **GarthW** » Fri Nov 02, 2007 4:17 am

Well i'm not going for huge power with this engine, around 300rwhp is fine.
If i dont have to port heads thats great, like greg said there's other things that can do with improving. The engine is so efficient anyway, with more air its going to be amazing.

Greg Gordon · Post by **Greg Gordon** » Fri Nov 02, 2007 6:26 am

I think you could get 300rwhp out of a 3.0 with: 10pounds of boost, a good intercooler, a 12.5:1 afr, forged pistons, and a low redline of around 6200rpm. Of course I have not done it, but I probably will.

Keep in mind 300rwhp is a lot. Don't get brainwashed by the tuner magazines and internet b.s. With that much power you rarely run into a quicker car at a stoplight. I suggest reading this: http://www.sdsefi.com/tech400.htm . This article tells the truth about the 400whp Hondas we keep hearing about.

Barry · Post by **Barry** » Fri Nov 02, 2007 8:58 am

Greg,The Alfa v6 has serious shortcomings when it comes to the ports and how they are shaped from the factory..

Your BIGGEST obstacle to good flow firstly is the shape of the exhaust port as it leaves the seat..The roof is squashed and the port diverges from there outwards..Simply opening this massive restriction will give you noticeable differences to power delivery in the engine..especially boosted.
The second flow restriction is the anemic intake port shape where the shape changes and starts biasing flow to the valve..By helping the flow bias and opening this area up works brilliantly!
Now all this with the std. cams and n/a will not give huge improvements..Simply fit a more performance orientated
cam here and this engine will come alive!!You will feel the difference immediately..Next up after the ports and cams come the valve sizes on the intake...Thats another story though.

Compare a stock std.head configuration with turbo and note the "lag" low down..
Do the same with a well ported head and slightly wilder cam-still turbo ed-day and night difference..Way better than scenario 1..

Greg Gordon · Post by **Greg Gordon** » Fri Nov 02, 2007 10:35 am

Thanks Barry, as soon as Jim's book is out, I will port a set of these heads.

Greg

Barry · Post by **Barry** » Fri Nov 02, 2007 11:53 am

Greg Gordon wrote:Thanks Barry, as soon as Jim's book is out, I will port a set of these heads.

Greg

Yea,that was only my opinion....

Greg Gordon · Post by **Greg Gordon** » Fri Nov 02, 2007 1:32 pm

I have some extra heads sitting around, however I want to wait until that book is out. In the meantime, it's a whole lot easier and cheaper to shove in another 2.5 psi.

Greg

Porting heads?