petert 588 Posted August 23, 2006 (edited) Here's something I stumbled upon whilst gathering data for the GTi6 manifold thread, http://forum.205gtidrivers.com/index.php?showtopic=63496. I know you only need "X" amount of exhaust flow, but have a look at these figures! The S16 head was absolutely standard, while the 1.9L Mi16 head has standard valves, 3 angle seats and is fully ported/polished (not by me). The value of the good seat work shows in the low lift figures on the 1.9L head but then look at the rest. At first glance the ports look identical, but I'm going to investigate further. Edited August 23, 2006 by petert Share this post Link to post Share on other sites
camgti 56 Posted August 23, 2006 Here's something I stumbled upon whilst gathering data for the GTi6 manifold thread, http://forum.205gtidrivers.com/index.php?showtopic=63496. I know you only need "X" amount of exhaust flow, but have a look at these figures! The S16 head was absolutely standard, while the 1.9L Mi16 head has standard valves, 3 angle seats and is fully ported/polished (not by me). The value of the good seat work shows in the low lift figures on the 1.9L head but then look at the rest. At first glance the ports look identical, but I'm going to investigate further. What are you trying to get a Peter. That the porting job on the 1.9 was poor?? Or that the s16 is better. I thought they were the same but with different exhaust and inlet manifolds?? Cam (kinda confused) Share this post Link to post Share on other sites
petert 588 Posted August 23, 2006 The porting job is superb. The S16 head just flows better. Share this post Link to post Share on other sites
PumaRacing 2 Posted August 23, 2006 The porting job is superb. The S16 head just flows better. I might take that the other way round. It's actually very easy to get exhaust ports to flow well compared to how hard it is to get inlet ones to do so. We could also conclude that the Mi16 head has been ported badly to lose so much mid range flow to the standard S16 one. In any case it's fairly irrelevant as exhaust flow has a minimal effect on engine power. Share this post Link to post Share on other sites
petert 588 Posted August 23, 2006 I've had a closer look. The S16 port has a very nice, continuous as cast long radius, from the seat to the guide. Whereas the Mi16 port has a deep machining divot from the factory that makes a ridge in the long radius, which hasn't been completely removed. Irrelevant but interesting. Share this post Link to post Share on other sites
James_R 3 Posted August 23, 2006 Looking at the scales, I'm guessing the lit is in inches, but is the flow in CFM or some imperial measure? Share this post Link to post Share on other sites
Anthony 1,003 Posted August 23, 2006 Looking at the scales, I'm guessing the lit is in inches, but is the flow in CFM or some imperial measure? Looks like it, as the figures are similar looking to those that I got from Matt's flowbench and that's lift in inches and flow in CFM. Share this post Link to post Share on other sites
petert 588 Posted August 23, 2006 inches vrs. CFM @ 28in. Share this post Link to post Share on other sites
Sandy 191 Posted August 24, 2006 (edited) No mention of cam timing then? If you're looking to increase scavenge, the low lift performance of the Mi16 will likely mean the gases keep flowing well beyond the pushing phase and into scavenge. With the right cam timing and pipe lengths, it could well work better. Or not, if it happens at the wrong rpm. Flow is more about marketing than engine performance IMO! Edited August 24, 2006 by sandy309 Share this post Link to post Share on other sites
