Head porting for supercharged engine - worth doing?

blueoval · 14-07-2009, 04:59 PM

Hey fellas,

My old man has a fully reconditioned head he just gave to me as he just bought a BF2 tray top ute in lieu of his trusty AU1 futura.

He said it costed him $350 to get it reconditioned/change over, he had it on his previous engine idling for about 1/2hour as he thought his head was stuffed but found out that the bottom end carked it. So took it off.

Anyway, long story short, he said it hasnt done any work what so ever and wanted to know if I wanted the head BBM and stock cam for spares, free. So I said yeah I'll take it.

Now a few things went thru my mind as I saw this basically new head sitting in the boot of my car.

Since I have forced induction on my beast, would some of you proven guru's recommend giving this head say, a mild port job and clean up of casting dags and match its flow with a mild cam to suit my application? or would porting be a waste of money?

T3man · 14-07-2009, 05:08 PM

Regardless of what type of induction your engine has, a "port and polish" will always yield improvements. It is probably fair to say that, all other things being equal, then port matching a blown engine will yield even better results dollar for dollar than doing it to a N/A motor. This is because friction causes heat and any reduction or lessening of heat in a forced engine is a very good thing. Excessive heat will quickly erode the benefits of forced induction.

blueoval · 14-07-2009, 05:20 PM

Quote:

Originally Posted by T3man

Regardless of what type of induction your engine has, a "port and polish" will always yield improvements. It is probably fair to say that, all other things being equal, then port matching a blown engine will yield even better results dollar for dollar than doing it to a N/A motor. This is because friction causes heat and any reduction or lessening of heat in a forced engine is a very good thing. Excessive heat will quickly erode the benefits of forced induction.

Thanks mate, the heat issue you mention is basically what my tuner says too. But I can also see your point with friction too. Im just wondering if I bother doing this work spending say, $500-800 on port work, fitting better valve springs, a decent cam, if say I may only gain barely noticeable power difference. i.e. 10-15rwkw.

GK · 14-07-2009, 05:26 PM

Quote:

Originally Posted by blueoval

Thanks mate, the heat issue you mention is basically what my tuner says too. But I can also see your point with friction too. Im just wondering if I bother doing this work spending say, $500-800 on port work, fitting better valve springs, a decent cam, if say I may only gain barely noticeable power difference. i.e. 10-15rwkw.

How many rwkw does it have at the moment?

GK

blueoval · 14-07-2009, 05:30 PM

194rwkw

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;)

GK · 14-07-2009, 05:54 PM

Quote:

Originally Posted by blueoval

194rwkw

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V

;)

Okay, should have had a look there! LOL!

So porting the head would give you 10-20 more? 20 more would be over 10% and if you've already got 194, that's a fair increase for the money.

You might not even notice the extra ponies that much, but if the drive-ability of the car improved, and you've got the cash to spend, why not?

GK

blueoval · 14-07-2009, 06:03 PM

Quote:

Originally Posted by GK

Okay, should have had a look there! LOL!

So porting the head would give you 10-20 more? 20 more would be over 10% and if you've already got 194, that's a fair increase for the money.

You might not even notice the extra ponies that much, but if the drive-ability of the car improved, and you've got the cash to spend, why not?

GK

Thats a positive way of looking at it George. I guess Im just weighing up the pro's and con's of doing this kind of mod. Ive been doing some searching on the forums with regards to head porting AU's but there hasnt been any hard and fast sort of results that claim that this is a worthwhile mod to undergo. Especially for a blown 6 setup.

Would cleaning up the port dags and opening up the restrictive areas increase torque too? Essentially, thats the improvement I really want. A rwkw number is good and all but I need to 'feel' the improvement of this sort of mod.

I know porting also is excellent for NA high lift cam applications, but for me, IF I chose to do a cam with this head as a combo, I know a bigger cam duration rather than higher lift would be better for boost. How would the head be ported to assist that?

What about the valves? Is there any more work that needs to be done there?

I guess Im after opinion's/advice on IF this is a worthy avenue to pursue. i.e. bang for buck