slownrusty Posted March 4, 2007 Share Posted March 4, 2007 Did you guys catch this..sexy! http://cgi.ebay.com/ebaymotors/DATSUN-240Z-280Z-280ZX-REBUILT-N42-RACE-CYLINDER-HEAD_W0QQitemZ260090354136QQihZ016QQcategoryZ33617QQssPageNameZWDVWQQrdZ1QQcmdZViewItem Yasin Quote Link to comment Share on other sites More sharing options...
bubbleguinea Posted March 4, 2007 Share Posted March 4, 2007 ohh wow.... drool Quote Link to comment Share on other sites More sharing options...
Guest 280ZForce Posted March 4, 2007 Share Posted March 4, 2007 Yes, a nice piece indeed, but I believe it is only ported, NOT polished my man Yasin otherwise the intake and exhaust ports would be bling blingin Quote Link to comment Share on other sites More sharing options...
Mack Posted March 4, 2007 Share Posted March 4, 2007 and that would hurt the flow. at least on the intake side. and not to be a jerk, but 196cfm@.600" lift with 28in of vacuum on the intake?? I got 210 out of an N47 screwing around at 1 fast Zs shop, with the same numbers. merely an observation. Quote Link to comment Share on other sites More sharing options...
Guest 280ZForce Posted March 4, 2007 Share Posted March 4, 2007 and that would hurt the flow. at least on the intake side. what would hurt flow? having the ports polished or non-polished? Quote Link to comment Share on other sites More sharing options...
Mack Posted March 4, 2007 Share Posted March 4, 2007 polished on the intake side would hurt flow. If you polish it ot a mirrior finish, it hurts it. this was stolen from some site.... A course surface causes the air touching it to tumble and form a thin cushion of air. This is called a boundary layer. The boundary layer acts like a lubricant to the other air flowing in the port.A smooth surface flows well too until the drag it causes makes it tumble also but it tends to create huge waves which effectively reduces the size of the port. These waves build and collapse at an incredible rate so what you have is a "part time" port. Quote Link to comment Share on other sites More sharing options...
SHADY280 Posted March 4, 2007 Share Posted March 4, 2007 heck its not just ported, it flowbenched. you can also say there is quite the difference to that statement. i can port, no numbers to support the work i have done. it can actually hurt the flow if you do one thing and not another, or in the wrong area. Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted March 4, 2007 Share Posted March 4, 2007 Exhuast ports should be polished and smooth Intake ports should be coarse Quote Link to comment Share on other sites More sharing options...
1 fast z Posted March 5, 2007 Share Posted March 5, 2007 Stock is 176 out of the intakes. Yea thats not a big percentage increase, but he should of stated stock numbers, so we know percentage increase on the same flow bench. I get about 225 cfm, on a 176 stock port. I see why it didnt sell. Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted March 5, 2007 Share Posted March 5, 2007 That and the flow was measured at .600 lift, and at 3" water above the `standard' 25. What was the valve lift your 225 was recorded at 1fastz? Dave Quote Link to comment Share on other sites More sharing options...
slownrusty Posted March 5, 2007 Author Share Posted March 5, 2007 That and the flow was measured at .600 lift, and at 3" water above the `standard' 25. What was the valve lift your 225 was recorded at 1fastz? Dave Exactly lets compare apples with apples. Yasin Quote Link to comment Share on other sites More sharing options...
1 fast z Posted March 5, 2007 Share Posted March 5, 2007 NEW standard is 28 inches, not 25 anymore, BUT it DOESNT matter what were talking about as for PRESSURE, as one should always have a graph plotted, of before and after results on the SAME flow bench for percentage increase reasons. It should show ALL lifts, all the way to .650". Heres some of my early work. My customers recive a excell spread sheet with all of the test and pressure numbers, and percentage increase. Quote Link to comment Share on other sites More sharing options...
slownrusty Posted March 5, 2007 Author Share Posted March 5, 2007 Could you plese verify the differences between Test 1, Test 2 and Test 3. Thanks. Yasin Quote Link to comment Share on other sites More sharing options...
cpt jack Posted March 5, 2007 Share Posted March 5, 2007 Im sorry but i really do not understand what the 28" of water is and cfms things like that could someone explain what it is or a site where i can find out what it is... im intrested in port and poslish and doing some dome work for my head but i would like to understand what exactly it all is.... Quote Link to comment Share on other sites More sharing options...
sweetleaf Posted March 5, 2007 Share Posted March 5, 2007 1 fast Z is correct. Flow benches are like dynos. You need before and after comparisons on the same machine to see what kind of real gain was achived. Flow #'s is also not the endall to performance of a head, there is much more to consider. Quote Link to comment Share on other sites More sharing options...
1 fast z Posted March 6, 2007 Share Posted March 6, 2007 True there is much more to consider, I have HUNDREDS of runs down the 1/4mi track, to backup my work. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted March 6, 2007 Share Posted March 6, 2007 True there is much more to consider, I have HUNDREDS of runs down the 1/4mi track, to backup my work. Can you say that the other guy doesn't have hundreds of runs to back up his work? I think until the other guy shows up to defend himself this thread is not worth too much. I'm inclined to close it if nothing meaningful comes out of it very soon. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted March 6, 2007 Share Posted March 6, 2007 To me it seemed like alot of money for marginal returns. Personally I would spend that amount on something else to make the car faster...LSD, suspension, boost or even a bigger engine. Quote Link to comment Share on other sites More sharing options...
spork Posted March 6, 2007 Share Posted March 6, 2007 Without knowing the exact nature of the porting and talking to the guy that ported it, it would be hard to decide whether or not it's worth the money. Flow #'s are great, but a monkey can make high flow #'s. Without the trust of the shop that ported it, you don't know if you're getting a well thought out port design, or one that someone just messed around with until he saw high numbers on the bench. I'm in no way implying that this guy doesn't know what he's doing, just that ebay can be filled with junk, so it's best to research it out and talk to the shop that did the work before you commit that kind of money. Quote Link to comment Share on other sites More sharing options...
1 fast z Posted March 6, 2007 Share Posted March 6, 2007 Like I have heard from another reputable porter, Even without a flow bench, as long as your customers keep coming back for your work, and they like what their purchasing, thats all that matters. I have the same reasoning, if your customers love your work, they love how it performs, and you have proof to back up your work, what else matters? Quote Link to comment Share on other sites More sharing options...
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