Rightio guys.
I'm after some information about the pro's and con's of retaining/removing the squish pads in RB26 heads. I've had a bit of a sniff around both SAU and the UK forum and the opinions are very inconsistant. Some guys almost puke at the thought of removing them, others swear by it.
On my current engine, the head was ported by HKS Japan and combustion chamber CNC work was done by NAPREC Japan. I had the option of A) leaving both in, B) Removing the inlet, C) removing both. I chose B and I can't say it had a negative affect. The car definitely drove better from idle to redline than the previous head which had both pads in, throttle response was like a lightswitch.
It seem's that the pads are there for emissions and fuel economy, two things I couldn't give a toss about. What i'm after is the best performing combination. The extra space in the chamber is easily sorted by a piston to suit so the disadvantage of the compression ratio dropping becomes a mute point.
When I was going through the build of the last head, it was advised that above 800 HP to take both out. I have noticed that JUN also do this too. I also believe the Porka 996 911 turbo doesn't have squish pads.
The rough spec of the engine will be
- Engine capacity of 3.15 - 3.4 L
- EFR 9180 (more than likely. I believe the 8374 is going to be too small for such a large donk)
- Comp ratio of something between 9.0-9.5:1
- Cams undecided yet. Possibility of V cam.
- Max RPM of 8000.