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Hi,

I am doing a round of modifications to my r34 gtt rb25 neo that is basically copying a setup that should make ~330 RWKW on 98

Is there much to be had at this level from getting the head ported?

The engine has 100,000 km on it so could be due for a freshen up top, I was planning on doing stem seals since I am replacing cams and springs anyway but was going to leave the head on, but this would be a good time to pull the head off and get it ported if the gains made it worthwhile and install some arp head studs.

I read on the 'Lewis engines' website and it seems like a worthwhile upgrade, is there any machining shops that would come recommended by SAU members?

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What he said.

At 330rwkW there is absolutely no need to port the head. It is very possible to get to that sort of power just by using boost. If you do port the head, you will need a turbo that can make the target air flow level at lower boost. This might ultimately mean the difference between using a GT3076 or a GTX3076 (just to pull an arbitrary turbo size out of the air. The GTX are optimised to make power at higher pressure ratios.

If you do port it, and it is done well (sensibly, not just hogging shit out of it) then gas flow will increase even before the turbo is up on boost, so you should improve response.

But.....How else would you spend $2k?

Anyone can hack up a port.

Seen it too many times to mention. :/

The more boost you run the less runner size you want imo, so a little bowl work is fine, and I agree with port matching, but I would like to actually add material to the port to increase the gas speed before the valve.

Just think how long the valve is open for at 8000 revs, and what speed the air needs to be going to fill the cylinder in that time...

Apparently stored correctly in a 44 drum it would be good for 3 months max, not sure I would go through it that fast especially considering the car only comes out to leave town and It wouldn't make it to the next servo selling e85

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