FricFrac Posted December 31, 2009 Share Posted December 31, 2009 I have a few questions regarding some modifications I'm doing to my intake plenum. I've got an P79 intake that I've removed the webbing from between the runners. I've found very little info as to weather removing the webbing on this particular plenum is a good idea or not. My thinking is that if I'm running ceramic coated headers and the stock heat shield removing the webbing will help prevent hot air from getting trapped between the heat shield and webbed runners. I'm hoping in turn this will help reduce the intake temperature. My first question is would it be a good idea to use a header blanket material on the top/bottom of the heat shield to further reduce heat radiating into the intake plenum or am I just asking to have the heat shield begin rusting? Alternatively what about a heat shield made of stainless mesh and a piece of header blanket sandwiched in between? Secondly is wrapping a ceramic coated header a bad idea? The limited info I could find on that would seem to indicate its a bad idea as the ceramic coating would likely get too hot and begin to fail but the info is vauge.... I am also porting the intake for a 60mm TB (I basically got it for free and I know the gains are minimal but I'll be doing the same for my turbo build and appreciate the exercise). My question is (after reading for hours on manifolds, etc) is it a good idea to port match the runner to the head? I can get down into the runner about three inches but beyond that around the bends there is little I can do. That being said the runner will cone out as it approaches the port of the runner. Will this cause a problem from it being narrow to wide in that the air velocity will be reduced going into the head or is this negligible. There seems to be a significant difference in the size of the head ports compared to the size of the runner ports. Is this normal? The stock setup would have a significant lip which would cause a fair amount of swirling going over the sharp lip of the intake runner. Is this benificial for air/fuel mixture or detrimental because the flow is restricted or negligible again? At the very least I'll be taking the flashing off the inside of the runners. Oh and lastly is it OK to powder coat the intake plenum? I'm assuming the heat from the head transfered to the intake isn't enough to cause problems with the powder coating.... Quote Link to comment Share on other sites More sharing options...
kolonelklink87 Posted December 31, 2009 Share Posted December 31, 2009 I think almost all of your questions have been answered in other threads, you might need to do a bit more searching. Best of luck, Pete Quote Link to comment Share on other sites More sharing options...
FricFrac Posted December 31, 2009 Author Share Posted December 31, 2009 I've spent literally hours and hours searching... its funny how people will take the time to post totaly useless info like "use the search you idiot" which is just a much of a waste of space in the forum as asking how to do a turbo swap, etc. If you type in "manifold porting" you get 20 pages of threads. There are literally years and years of info chaotically posted here on the forum and finding anything can sometimes be a major challenge. The wording and search engine make finding stuff on here half art / half science. I've spent well over a hundred hours researching on this forum on various topic and I always post questions as a last resort because of the typical response. There are a lot very intelligent people and I apperciate their knowledge and willingness to share it. I understand that there are countless dumb questions posted and it becomes tiring. HybridZ is a goldmine of info - there is just a lot of slag to go through to get some of that info. I stated that I searched for this info (three times actually) and was unable to find it so how is telling me to search for it in any way helpful? There has to be some sort of balance here where we aren't slagging people who are eager to learn and have put in an effort into finding the info. You obviously are aware that this info is here. I stated I couldn't find it. It seems reasonable to me if you are in any way interested in helping out a simple link to the info would be appropriate. Or am I missing something here? Quote Link to comment Share on other sites More sharing options...
ozconnection Posted December 31, 2009 Share Posted December 31, 2009 I thought that Nissan cast the webbing on their efi manifolds to help to keep radiant heat off the injectors.....hell didn't they even use a blower arrangement with the 280's just for that reason? At the manifold/head interface many people port out the intake manifold as much as they can to match the diameter of the head port. This, as you know, is port matching. The idea in removing the step is to streamline the airflow into the head, promoting cylinder filling and ultimately power because, more often than not, the manifold and head ports are bigger than stock. Big ports potentially flow more air than small ones. My understanding of the manifold/head junction is this. Injecting fuel this close to the back of the intake valve gives little time for the fuel to mix with the rushing air going into the engine. The 'step' or size difference causes turbulence and encourages air/fuel homogenisation. The other reason there is a step here is because it acts as an anti-reversion barrier. Strong pulses in both directions occur in a running engine and to help stabilize manifold vacuum and allow the air flow meter to 'meter' correctly, the step was intentionally built in. And finally, you touched on the idea of air speed. A stock engine has to provide good throttle response at low engine speeds. A small runner diameter will keep velocity high and meet the criteria it was originally intended for. Modify the engine and you will inevitably move away from what was originally designed. Just remember this. Match porting for example, will make more top end power. You will loose some low speed torque as a result though. Also, cut out the webbing between the runners of the manifold and you now find yourself having to worry about heat soak. Just a friendly suggestion...consider why the Nissan engineers did what they did. Not all of our decisions to modify something will bring about the results we want or expected. Quote Link to comment Share on other sites More sharing options...
FricFrac Posted December 31, 2009 Author Share Posted December 31, 2009 I hear what you're saying about the webbing/blower. As far as I know this was to keep the fuel from boiling out of the injectors/vapor lock in the fuel rail. Yes the webbing will give you a larger surface area to disapate the heat when the car is stopped but it also gives you more mass to cool. My concern is that the heat trapped between the two will cause more heat soak than the benefits of the larger surface area for cooling when the engine is stopped. Its all purely conjecture and I suspect the effects either way are not really worth worrying about since we don't seem to have any real data either way. I think a non-radiating heat barrier like the header blanket/stainless mesh would be benificial but again I'm just guessing based on what little I know. I guess with the sensitivity to knocking I'm looking for little ways to keep the charge temp down for my future turbo build. I do agree with you 100% that the Nissan engineers are no slouches when it comes to designing the car. They do also have to come to a middle road based on comfort, efficiency, etc. It the tweeks that give us the performance and we give up comfort, efficency, etc without too much fuss. I guess I'm still don't get it though - is it worth porting for the flow or is the turbulence/anti-reversion more important? Thanks for the response! Quote Link to comment Share on other sites More sharing options...
ozconnection Posted December 31, 2009 Share Posted December 31, 2009 Thanks for the response! No worries mate, you're welcome. Post a few pics of your progess...I might be tempted to pinch a few of your ideas. I'm right into thermal management at the moment! Cheers. Quote Link to comment Share on other sites More sharing options...
kolonelklink87 Posted December 31, 2009 Share Posted December 31, 2009 It wasn't my intention to be rude to short... Essentially in my own readings on these topics as you probably noticed there are many conflicting opinions on these issues. Unfortunately there is no manual that says "this way is best 100% of the time". I guess it really depends on application... some people get positive results from portmatching due to a higher RPM focus, some do not and feel it detracts from low-end power. Likewise with the temperature control steps- I read an anecdote about a fellow who was crazy about thermal resistance and ceramic coated every port and surface - the result was an engine barely able to hold idle at 2000rpm due to fuel vapourisation issues. MY personal take at the moment is deciding on the big goals first - screamer/turbo/stump-puller then move to details from there rather then getting a bunch of good parts and slapping them together to make a mismatched engine. FYI my personal experiences with port matching have been positive, I went from 32mm to ~36mm manifold ports and honestly feel i gained low end torque afterwards, however I have no dyno sheets to back this up so I was tentative to post my experience. In my example I think having multi-port EFI really assisted with acheiving this and thus negated the need for a rough sand-cast surface and higher intake temp to achieve fuel vapourisation. I'm sorry if I came around course, admittedly I was having a bit of a rotten day. I guess my main point that im trying to communicate is experiences vary and sometimes you just gotta do a little thinking on how each mod fits into your goals and then go for it! Where do you want to make power? how much? Are you happy waiting for start-warmup? what kind of EFI/camming etc will fit with these goals? Best Regards, Pete Quote Link to comment Share on other sites More sharing options...
280zNHChris Posted December 31, 2009 Share Posted December 31, 2009 You can powdercoat the manifold no problem, I have done many. http://forums.hybridz.org/showthread.php?t=156897 You can also wrap ceramic coated headers in a wrap. The purpose of the ceramic is to do the inside so the heat flows out vs. being absorbed by the non-protected metal. The headers will still get hot just not as hot, so a wrap will still perform it's main function. The black ceramic is good to 2000 degrees, if you get that high you will probably have other problems soon. Good luck Quote Link to comment Share on other sites More sharing options...
FricFrac Posted December 31, 2009 Author Share Posted December 31, 2009 It wasn't my intention to be rude to short...Essentially in my own readings on these topics as you probably noticed there are many conflicting opinions on these issues. Unfortunately there is no manual that says "this way is best 100% of the time". I guess it really depends on application... some people get positive results from portmatching due to a higher RPM focus, some do not and feel it detracts from low-end power. Likewise with the temperature control steps- I read an anecdote about a fellow who was crazy about thermal resistance and ceramic coated every port and surface - the result was an engine barely able to hold idle at 2000rpm due to fuel vapourisation issues. MY personal take at the moment is deciding on the big goals first - screamer/turbo/stump-puller then move to details from there rather then getting a bunch of good parts and slapping them together to make a mismatched engine. FYI my personal experiences with port matching have been positive, I went from 32mm to ~36mm manifold ports and honestly feel i gained low end torque afterwards, however I have no dyno sheets to back this up so I was tentative to post my experience. In my example I think having multi-port EFI really assisted with acheiving this and thus negated the need for a rough sand-cast surface and higher intake temp to achieve fuel vapourisation. I'm sorry if I came around course, admittedly I was having a bit of a rotten day. I guess my main point that im trying to communicate is experiences vary and sometimes you just gotta do a little thinking on how each mod fits into your goals and then go for it! Where do you want to make power? how much? Are you happy waiting for start-warmup? what kind of EFI/camming etc will fit with these goals? Best Regards, Pete No worries. I think the intent of the forum is to help preserve these cars and to support those who want to modify them. I think that a modified Z creates more interest from people outside the community and hopefully will help to preserve these cars by expanding the community. We get a ton of dumb questions here and I understand the frustration but we also should be fostering those who are truely interested in modifying the Z cars. My goal is to learn about how all this works. I'm no mechanic but I am an avid learner and a passionate Z car fanatic. I've got an '09 370Z that is probably close to 300WHP weighing in at 3200 lbs so it would be a lot of modding to get my 280ZX to perform close to that not to mention 26 years of technology improvments. I don't need a screamer. That being said I bought the 280ZX because I want a car I can play around with. My 240Z is a bit of a time capsule in its mods and I would feel bad doing any real mods to it. The plan for the 280ZX is first to change the suspension - it feels like I'm driving on marshmallows. I have a set of Tokico springs/struts on their way. I also have to fix the leak in the exhaust gasket so I've already got a case of "while that's off". I have an extra F54/P90 so I took the manifold off that and I've bead blasted it, cleaned up the flashing, etc. I have a ceramic coated header from MSA (not sure what coating they use) and a 2.5" exhaust. I've replaced the stock air cleaner with a K&N cone. I'm using the stock EFI so doing a cam is not adviseable. I would like to play around with a MS2 setup (I'm an Electronics Eng so that's up my ally) but I have an L28ET which I bought to do a swap probably next year. Once I do the swap then I'll look at adding a MS2 after the conversion is done and up and running. I'm not planing on any other serious mods for the L28E - I'll save that for the L28ET. As for longer warm ups, etc not too worried about that. The manifold is a "spare" so if this ends up being a complete failure I'll just swap the original back in. Quote Link to comment Share on other sites More sharing options...
FricFrac Posted December 31, 2009 Author Share Posted December 31, 2009 You can powdercoat the manifold no problem, I have done many.http://forums.hybridz.org/showthread.php?t=156897 You can also wrap ceramic coated headers in a wrap. The purpose of the ceramic is to do the inside so the heat flows out vs. being absorbed by the non-protected metal. The headers will still get hot just not as hot, so a wrap will still perform it's main function. The black ceramic is good to 2000 degrees, if you get that high you will probably have other problems soon. Good luck Thanks - I only had three hits when I was searching on powder coating and didn't see your thread there. I was sure I had seen powder coated intakes before but I just wanted to be sure before I went ahead... Quote Link to comment Share on other sites More sharing options...
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