1 fast z Posted January 21, 2005 Share Posted January 21, 2005 Here is the graphs of my flow bench work on a P90 head. The first line represents a stock port then from there is two different grinds. Quote Link to comment Share on other sites More sharing options...
1 fast z Posted January 21, 2005 Author Share Posted January 21, 2005 So if any one is interested in me porting a head for them, just email me. Quote Link to comment Share on other sites More sharing options...
Gollum Posted January 23, 2005 Share Posted January 23, 2005 if only i had a P90 head.... I could convert over to a turbo L28... that would be nice... too bad though. Words of encouragement: I couldn't do that stuff man... nice work. Quote Link to comment Share on other sites More sharing options...
1 fast z Posted January 24, 2005 Author Share Posted January 24, 2005 You DO NOT need a P90 head, that is just something that most think. Any head would work, espeacially if you are going to be using dished top pistons. P90 does absolutly nothing on a P90, you loose ALL of the quench. Best bet for econimy is to use a P79 with flat tops at about 10 PSI. Square ports flow EXACTLY the same as round ports stock for stock. Quote Link to comment Share on other sites More sharing options...
turbobluestreak Posted January 24, 2005 Share Posted January 24, 2005 But p79's have exhaust liners kill flow. That’s why everyone wants p90 or n42 and in reality yes p90 will lower quench but if you raise the compression you will have a more efficient motor. Efficient motors make more power and take more advantage of existing and future mods. tbs Quote Link to comment Share on other sites More sharing options...
1 fast z Posted January 24, 2005 Author Share Posted January 24, 2005 Well Turbobluestreak, you obviosly havent ever flow tested these L series heads. The linered heads flow EXACTLY the same as the square port heads. I have perfomed these test many times on all L series heads. You must have your words backwards as well because the P90/P79 Lowers compression when compared to other heads but Increases Quench. Belive me, and I can get a linered head to flow about 138 at 25 " at .55" of lift. Quote Link to comment Share on other sites More sharing options...
Drax240z Posted January 25, 2005 Share Posted January 25, 2005 If this turns into a P90 vs. N42 debate you are all being decapitated. Consider that a warning. With that aside, great info! Quote Link to comment Share on other sites More sharing options...
pallnet Posted January 25, 2005 Share Posted January 25, 2005 Can you send me some pricing on porting heads. I have done only a few and it's been mild work, nothing to great to brag about. It helps that you have a flow bench to test with.. Quote Link to comment Share on other sites More sharing options...
1 fast z Posted January 26, 2005 Author Share Posted January 26, 2005 It should be all on my website. http://www.bandmzcars.com Thanks for the replies, I really need to see how much interest is in these, to see if I should pursue the Idea of L series porting for others or not. Quote Link to comment Share on other sites More sharing options...
Guest Cronic Posted January 31, 2005 Share Posted January 31, 2005 I have a bare head I would love to get ported, but Im not all that impressed with the flow numbers. I guess Im used to Honda heads though. It's very nice that someone has a flow bench and can do their own porting. I'd love to take this spare, bare head and build it up for a 7500+rpm large turbo monster. Do you know where to get a performance upgrade for the internals, a cam, the springs, retainers, over sized valves, etc. I've heard that oversized valves, in most applications aren't the best thing to do for boost, and usually they don't help create any more power. I derno. Quote Link to comment Share on other sites More sharing options...
Guest mongrel Posted February 15, 2005 Share Posted February 15, 2005 Why the odd 25" waterpillar? 10" or 28" are more common and 25" makes for some guesswork when comparing flow! Have you tried raising the floor of the exhust port? I bet that would dramaticly improve flow! Quote Link to comment Share on other sites More sharing options...
olie05 Posted February 17, 2005 Share Posted February 17, 2005 1 fast z, when you talk about porting the linered head, do you remove the liners? I heard somewhere this was bad... I may be wrong though. -Oliver Quote Link to comment Share on other sites More sharing options...
1 fast z Posted February 17, 2005 Author Share Posted February 17, 2005 No I DO NOT remove the liners. There is no need to. I can get about 135 CFM out of a linered head with stock valves and leaving the liners in. Quote Link to comment Share on other sites More sharing options...
z-ya Posted September 12, 2005 Share Posted September 12, 2005 I'm thinking of using a P79 on a flat top turbo motor. I know that the turbo exhaust manifold ports are square, and P79s are round. From what I've read hear the P79 flows as good as the P90. Is it worth removing the liners in the P79 so that there is a smooth transisition between the head and the manifold? Or should I just leave the liners and smooth the transition as good as I can with them in there? Also, how is the P79 cam for turbo applications? Is it similar in profile to the P90? I'm building a budget turbo motor, and I have the P79 sitting on the shelf, so I would like to use it. Thanks in advance, Quote Link to comment Share on other sites More sharing options...
Midnitz Posted March 24, 2008 Share Posted March 24, 2008 I think that removing the liners is generally a bad idea....most of the work needed on these heads is at the valve bowl and the valve guide, unshrouding the valve is also a must with the newer heads as the valves are larger. Flowbench work is also a must as balanced flow is important. In some cases, I have welded the N42 exhaust ports because of the cast core shift is so bad and the ports are too large for practical header flange interfacing....Effectively raising the exhaust port floor up by up to 2 mm in some cases and adding up to 2mm to the sidewalls to make up for shifts in the cast cores.... Also I have discovered that leading up to the valve guide on the intake side, there should be a splitter that progreesively tapers air around the guide such that the guide itself doesn't produce unwanted turbulence and cause the air to tumble..... This is why being able to weld aluminum and perform clay work along with a flow bench is so necessary. To find out what works at given valve lifts. Quote Link to comment Share on other sites More sharing options...
Calgary280ZT Posted March 24, 2008 Share Posted March 24, 2008 I'm new at this, so be gentle if I post something incorrect or stupid...I just had Rebello port my P90 and the numbers are: 1) intake at 25 psi is 209; 2) exhaust at 25 psi is 150. This is the full race port, not the street port. Dave said this head flowed really really well. I'm hoping to get around 300-325 hp at 10 psi with my T3/T4. Quote Link to comment Share on other sites More sharing options...
Tony D Posted March 24, 2008 Share Posted March 24, 2008 209/150 is a good set of numbers, you will like the way that thing takes off! Dave knows his stuff. Reasonably priced as well! Quote Link to comment Share on other sites More sharing options...
Calgary280ZT Posted March 24, 2008 Share Posted March 24, 2008 Hey Tony. Yeah, I'm very excited to get this on the car. Cam is an Iskey "mild turbo grind," unfortunately I don't know the numbers. The car and JimCanuck and I will be at MSA next month, looking forward to sharing a beer or two with you and Frank. Quote Link to comment Share on other sites More sharing options...
Midnitz Posted April 3, 2008 Share Posted April 3, 2008 Calgary280zt, The numbers for airflow are decent, but what are the valve lift vs airflow at .100 inch incriments? 0.050 incriments? By knowing the dynamic flow characteristics of a cylinder head, the camshaft designer/grinder can zero in on the cam duration/lift profiles and LSA design. In most cases, a typical Turbo cam profile emphasizes the exhaust side duration and lift to help mitigate turbo lag while LSA usually won't dip under 112. In most cases a thorough flowbench analysis can yield you lots of good info to help you design the supporting components. Insufficient good data can leave you building a "detuned", powerplant. Quote Link to comment Share on other sites More sharing options...
twilsonx Posted April 8, 2008 Share Posted April 8, 2008 I have a N47 in my 280Z right now, I'm looking to either get a P90 or get some head work done to the one I already have. Do you think that with the right porting I can get similar results with my N47 or should i try to find a turbo head? I already have a header for my N47, so keeping that would be a plus. Quote Link to comment Share on other sites More sharing options...
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