kvansic162 Posted April 12, 2008 Share Posted April 12, 2008 Which head is the best to use on a 77 L series block. I am using the 10:1 comp pistons from nissan motorsports. I plan on adding a turbo later on. I have a megasquirt system with methanol injection. Right now I have a N-47 head. I it worth changing to a p90 or p79 head? Quote Link to comment Share on other sites More sharing options...
Xnke Posted April 12, 2008 Share Posted April 12, 2008 Search!!!!!!!!!!!!!!!!!!!!!1 Quote Link to comment Share on other sites More sharing options...
JSM Posted April 12, 2008 Share Posted April 12, 2008 You can use your current setup, you just can't run very much boost w/ the high CR. Quote Link to comment Share on other sites More sharing options...
kvansic162 Posted April 12, 2008 Author Share Posted April 12, 2008 You can use your current setup, you just can't run very much boost w/ the high CR. I figured on running 5 or 6 pounds of boost. Quote Link to comment Share on other sites More sharing options...
kvansic162 Posted April 12, 2008 Author Share Posted April 12, 2008 Search!!!!!!!!!!!!!!!!!!!!!1 I have and as always I get mixed answers!!!!!!!!!! Quote Link to comment Share on other sites More sharing options...
JSM Posted April 12, 2008 Share Posted April 12, 2008 I figured on running 5 or 6 pounds of boost. I think you would be fine, just don't get carried away. Quote Link to comment Share on other sites More sharing options...
kvansic162 Posted April 13, 2008 Author Share Posted April 13, 2008 I think you would be fine, just don't get carried away. In a Z it is hard not to! Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted April 13, 2008 Administrators Share Posted April 13, 2008 You stated 10:1 compression pistons. Could you please give us more info on these pistons i.e. deck height at TDC, dome volume, and more info on your engine, ie. is this an L-28, diesel stroker crank, over bore, etc? A couple key points on the L-6, which will give you some more “material” to search for as the answers to your questions have been discussed, argued, and even built in the past, and archived here. 1) The L-6 is very sensitive to detonation. Conservative comp ratios help reliability more than aggressive comp ratios help power! We are pretty sure it revolves around excess combustion chamber temps stemming from inefficient chamber shapes and abnormal coolant flow around the chambers etc. At any rate, many 10:1+ N/A L-6's rattle like a diesel on the best premium gas, and 15-20 lbs of boost on 7.8:1 compression turbo motors routinely pop their head gaskets, from detonation. Keep THAT in mind while building your engine. Keep the detonation in check and you will be rewarded with “reliable” performance. For a new L-6 build by someone that is somewhat new to the L-6, I strongly recommend against 10:1 compression and ANY boost with an L-series. It can be done, but ALL of your anti detonation ducks had best be lined up in a perfect row, including the use of Race gas/methanol, etc. 2) Head-piston-comp/ratio combos regarding N/A and boosted applications have been covered here Ad nauseam. I know that I’ve personally written an entire novels worth of info on this forum alone regarding all of the U.S. available L-6 heads for N/A, Turbo, Nitrous, and supercharged applications for various short block combinations, comp ratios, etc etc etc over the past 8 years. And then there is all the other info added to those and other threads from other members savvy with extreme performance Datsun L-6 engines. Below is link that is a great start for your research, please read through it completely, and if any of it is vague or not exactly what you are looking, you will find what you are looking for in reading between the lines so to speak, i.e. common L-6 nuances will stand out that that you need to build around or use to your advantage. Then after that, search for other key concepts or ideas from that reading keeping in mind those L-6 nuances in your search queries. http://forums.hybridz.org/showthread.php?t=104420 Good luck, Paul Quote Link to comment Share on other sites More sharing options...
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