DIY plenum porting
11-28-2009, 07:11 PM
#481
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I know most of you on hear like trying to make cheaper do it yourself modifications like the good old days but in all reality the lower and upper plenum design of the 350z is terrible at best. it gets pools of oil and heat soaks unbelievibly bad. it gets extreamly high amounts of fuel reversion with just a simple intake and cat back exhaust.
the best thing you could do at this point is go to work and put in extra hours and save up for a better plenum. (one that is nothing like the stock 350z one.) even the cosworth plenum internaly is compleatly diffrent and has hardly any resemblance to the stock plenum besides that it has 3 runners on each side.
the best thing you could do at this point is go to work and put in extra hours and save up for a better plenum. (one that is nothing like the stock 350z one.) even the cosworth plenum internaly is compleatly diffrent and has hardly any resemblance to the stock plenum besides that it has 3 runners on each side.
11-28-2009, 08:21 PM
#482
I know most of you on hear like trying to make cheaper do it yourself modifications like the good old days but in all reality the lower and upper plenum design of the 350z is terrible at best. it gets pools of oil and heat soaks unbelievibly bad. it gets extreamly high amounts of fuel reversion with just a simple intake and cat back exhaust.
the best thing you could do at this point is go to work and put in extra hours and save up for a better plenum. (one that is nothing like the stock 350z one.) even the cosworth plenum internaly is compleatly diffrent and has hardly any resemblance to the stock plenum besides that it has 3 runners on each side.
the best thing you could do at this point is go to work and put in extra hours and save up for a better plenum. (one that is nothing like the stock 350z one.) even the cosworth plenum internaly is compleatly diffrent and has hardly any resemblance to the stock plenum besides that it has 3 runners on each side.
if you did your research you would know that the Cosworth doesn't do NA builds any good. Heat soak would be just as big of a problem on the Cosworth as it "is" in the stock setup.
However, I do realize the benefits of keeping the air as cool as you can all the way to the heads and thats why I not only have the Motordyne ISO thermal gasket on the lower plenum, but I purchased some special gaskets for the runners to heads so I have additional protection against heat to the plenum assembly. I also removed the throttle body heater line. With just the motordyne iso thermal and the heater line removed the plenum is very cool to the touch after driving for any amount of time, It is literally as cool as the body of the car.
11-29-2009, 09:39 AM
#483
if you did your research you would know that the Cosworth doesn't do NA builds any good. Heat soak would be just as big of a problem on the Cosworth as it "is" in the stock setup.
However, I do realize the benefits of keeping the air as cool as you can all the way to the heads and thats why I not only have the Motordyne ISO thermal gasket on the lower plenum, but I purchased some special gaskets for the runners to heads so I have additional protection against heat to the plenum assembly. I also removed the throttle body heater line. With just the motordyne iso thermal and the heater line removed the plenum is very cool to the touch after driving for any amount of time, It is literally as cool as the body of the car.
However, I do realize the benefits of keeping the air as cool as you can all the way to the heads and thats why I not only have the Motordyne ISO thermal gasket on the lower plenum, but I purchased some special gaskets for the runners to heads so I have additional protection against heat to the plenum assembly. I also removed the throttle body heater line. With just the motordyne iso thermal and the heater line removed the plenum is very cool to the touch after driving for any amount of time, It is literally as cool as the body of the car.
And the pools of oil are due to blow-by, from what i understand have nothing to do w the intake manifold itself.
As far as heat soak, unless someone makes an Entire intake manifold out of plastic, or some sort of plastic composite [something with low heat transfer/heat soak properties], ones best alternative is the phenolic gaskets to help minimize the heat transfer from the heads to the lower intake manifold.
IMHO the best way to go, to rid of all the said issues is to:
*smooth out all the castings and flaws of the interior of the entire intake manifold
*Gasket match everything for smooth transitions
*get rid of the upper plenum's center bolt "legs" or whatever you want to call them
*Lower the tops of the front 2 runners
*Get a plenum spacer
*get rid of the OEM coolant fed heater at the mouth of the upper plenum
*phenolic based gaskets to minimize heat transfer
*Ceramic coat the entire intake manifold and plenum spacer, inside and out, to really minimize heat soak.
And seeing how one will be sending the intake manifold to get ceramic coated, one mine as well get the intake tube done as well
11-30-2009, 08:26 PM
#484
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if you did your research you would know that the Cosworth doesn't do NA builds any good. Heat soak would be just as big of a problem on the Cosworth as it "is" in the stock setup.
However, I do realize the benefits of keeping the air as cool as you can all the way to the heads and thats why I not only have the Motordyne ISO thermal gasket on the lower plenum, but I purchased some special gaskets for the runners to heads so I have additional protection against heat to the plenum assembly. I also removed the throttle body heater line. With just the motordyne iso thermal and the heater line removed the plenum is very cool to the touch after driving for any amount of time, It is literally as cool as the body of the car.
However, I do realize the benefits of keeping the air as cool as you can all the way to the heads and thats why I not only have the Motordyne ISO thermal gasket on the lower plenum, but I purchased some special gaskets for the runners to heads so I have additional protection against heat to the plenum assembly. I also removed the throttle body heater line. With just the motordyne iso thermal and the heater line removed the plenum is very cool to the touch after driving for any amount of time, It is literally as cool as the body of the car.
and if you are really going say the stock plenum is good i just want you to know i installed a new plenum and removed my stock plenum at a mans house who just so happens to be a Canadian engineer and thermodynamicist who founded CET racing and has started boosting engines effeciancy from 15% to 85%
(most effecincy of a motor is lost do to heat) and he happend to take one look at the manifold and all he said was "wow. this is one of the biggist peice of ***** i have ever seen. i can't even beleive they would put that on there."
and then he looked at it more and was wondering why nissan would spend time and money developing something so terrible.
this guy makes a fortune building and designing software for motors.
i am pretty sure he knows what he is talking about.
11-30-2009, 08:55 PM
#485
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IMHO the best way to go, to rid of all the said issues is to:
*smooth out all the castings and flaws of the interior of the entire intake manifold
*Gasket match everything for smooth transitions
*get rid of the upper plenum's center bolt "legs" or whatever you want to call them
*Lower the tops of the front 2 runners
*Get a plenum spacer
*get rid of the OEM coolant fed heater at the mouth of the upper plenum
*phenolic based gaskets to minimize heat transfer
*Ceramic coat the entire intake manifold and plenum spacer, inside and out, to really minimize heat soak.
And seeing how one will be sending the intake manifold to get ceramic coated, one mine as well get the intake tube done as well[/QUOTE]
why not just save up 700 dollers and not worry with all that BS and get the new kenetix manifold?
comes stock with a boost guage hole already tapped in and you can keep the stock strut brace.(these last 2 are apenions i know) looks wayyyyyy sweeter and sounds amazing at all Wot positions)
my spelling and grammer sucks. don't care.
*smooth out all the castings and flaws of the interior of the entire intake manifold
*Gasket match everything for smooth transitions
*get rid of the upper plenum's center bolt "legs" or whatever you want to call them
*Lower the tops of the front 2 runners
*Get a plenum spacer
*get rid of the OEM coolant fed heater at the mouth of the upper plenum
*phenolic based gaskets to minimize heat transfer
*Ceramic coat the entire intake manifold and plenum spacer, inside and out, to really minimize heat soak.
And seeing how one will be sending the intake manifold to get ceramic coated, one mine as well get the intake tube done as well[/QUOTE]
why not just save up 700 dollers and not worry with all that BS and get the new kenetix manifold?
comes stock with a boost guage hole already tapped in and you can keep the stock strut brace.(these last 2 are apenions i know) looks wayyyyyy sweeter and sounds amazing at all Wot positions)
my spelling and grammer sucks. don't care.
Last edited by SLIdEwAyZ25; 11-30-2009 at 09:00 PM. Reason: adding more details
12-03-2009, 11:33 AM
#486
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IMHO the best way to go, to rid of all the said issues is to:
*smooth out all the castings and flaws of the interior of the entire intake manifold
*Gasket match everything for smooth transitions
*get rid of the upper plenum's center bolt "legs" or whatever you want to call them
*Lower the tops of the front 2 runners
*Get a plenum spacer
*get rid of the OEM coolant fed heater at the mouth of the upper plenum
*phenolic based gaskets to minimize heat transfer
*Ceramic coat the entire intake manifold and plenum spacer, inside and out, to really minimize heat soak.
And seeing how one will be sending the intake manifold to get ceramic coated, one mine as well get the intake tube done as well
*smooth out all the castings and flaws of the interior of the entire intake manifold
*Gasket match everything for smooth transitions
*get rid of the upper plenum's center bolt "legs" or whatever you want to call them
*Lower the tops of the front 2 runners
*Get a plenum spacer
*get rid of the OEM coolant fed heater at the mouth of the upper plenum
*phenolic based gaskets to minimize heat transfer
*Ceramic coat the entire intake manifold and plenum spacer, inside and out, to really minimize heat soak.
And seeing how one will be sending the intake manifold to get ceramic coated, one mine as well get the intake tube done as well
comes stock with a boost guage hole already tapped in and you can keep the stock strut brace.(these last 2 are apenions i know) looks wayyyyyy sweeter and sounds amazing at all Wot positions)
my spelling and grammer sucks. don't care.[/QUOTE]
Obviously you didnt care for reading the last 25 pages either. So why care and post anything at all.
12-03-2009, 08:37 PM
#487
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why not just save up 700 dollers and not worry with all that BS and get the new kenetix manifold?
comes stock with a boost guage hole already tapped in and you can keep the stock strut brace.(these last 2 are apenions i know) looks wayyyyyy sweeter and sounds amazing at all Wot positions)
my spelling and grammer sucks. don't care.
comes stock with a boost guage hole already tapped in and you can keep the stock strut brace.(these last 2 are apenions i know) looks wayyyyyy sweeter and sounds amazing at all Wot positions)
my spelling and grammer sucks. don't care.
[/QUOTE]i understand your 25 page post but i don't see why people like the ones who i quoted think they can make the stock manifold better then everything else.
i have actually thought about porting my own stock intake manifold just for fun. because yes things like that are fun to me i ported the carb intake manifold on my xr50 knowing the stock intake valve couldnt flow much then it already was, just for fun.
i respect what your doing here i enjoi hearing everyones ideas on airflow i just wish you wernt doing work on a junk part.
now if it was DIY intake manifold porting (i don't even know if the stock valves/cam can flow any better) but if they could i would be all over that.
i would have done it they day you started the post just so i can say and know i actually did something to my car that is going to help the performance besides bolt on a couple parts
12-05-2009, 12:30 PM
#488
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man this thread has gotten jacked since the last time i was on lol. the point of the thread isn't have my friend who is a thermodynamics expert blah blah blah prove its a bad design and it seems obvious that is not a thread about "you know you can just spend $700 on a plenum" its about people sharing what they have done to improve their intakes on their own hence DIY. most people are doing it for fun just to see what happens and others don't feel like dropping $700 on an over priced intake or $1100 on one that won't do anything for NA people. so unless you have something to contribute as far as self modifying one yourself then why waste your time posting here and bashing other people that want to get their hands dirty.
12-06-2009, 01:07 PM
#490
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man this thread has gotten jacked since the last time i was on lol. the point of the thread isn't have my friend who is a thermodynamics expert blah blah blah prove its a bad design and it seems obvious that is not a thread about "you know you can just spend $700 on a plenum" its about people sharing what they have done to improve their intakes on their own hence DIY. most people are doing it for fun just to see what happens and others don't feel like dropping $700 on an over priced intake or $1100 on one that won't do anything for NA people. so unless you have something to contribute as far as self modifying one yourself then why waste your time posting here and bashing other people that want to get their hands dirty.
12-06-2009, 08:03 PM
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12-08-2009, 03:50 PM
#494
man this thread has gotten jacked since the last time i was on lol. the point of the thread isn't have my friend who is a thermodynamics expert blah blah blah prove its a bad design and it seems obvious that is not a thread about "you know you can just spend $700 on a plenum" its about people sharing what they have done to improve their intakes on their own hence DIY. most people are doing it for fun just to see what happens and others don't feel like dropping $700 on an over priced intake or $1100 on one that won't do anything for NA people. so unless you have something to contribute as far as self modifying one yourself then why waste your time posting here and bashing other people that want to get their hands dirty.
As for your engineer friend....Im sure he is a very smart guy. But for you to try to smash on our experimintation w/another man's opinion, and trying to state that his opinion is fact, puts you in the wrong. Unless you are stating proven facts, i suggest you keep your comments to yourself. Or at least reword your future comments so that they are no longer a "put down" towards what we are doing. This is a DIY thread, not a debate thread. Im all for helpful critizism, but when you are putting down an entire thread based on someones opinion that was purely based on a visual inspection, it makes me wonder why you even bother wasting yours and our time
Not trying to put you down, but im just saying...
12-08-2009, 04:00 PM
#495
i understand your 25 page post but i don't see why people like the ones who i quoted think they can make the stock manifold better then everything else.
All we ever talked about is "trying" to make what we already have better.
But if you will like to stand behind your accusation, I will certainly like to see some solid proof that an aftermarket IM is better than what we are doing.
Again im not saying that aftermarket IMs arent better, but if someone is going to say Aftermarket IMs are better, id like to see proof
12-09-2009, 03:24 PM
#497
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Tried it. One of our employees tried it on his G35. The car had a plenum spacer on it before. You have to make sure the plenum is bolted down correctly. Here is what we got out of it. This is with in a 1hr time span.
This morning I asked how it felt and he said that it feel like a tuned car. Tuned meaning that the power delivery felt smoother to him.
No one paid us or gave us a deal to test this product (wish we could get a freebie). So since nobody else would do it we did.
This morning I asked how it felt and he said that it feel like a tuned car. Tuned meaning that the power delivery felt smoother to him.
No one paid us or gave us a deal to test this product (wish we could get a freebie). So since nobody else would do it we did.
and red is the kenetix velocity plenum
12-09-2009, 07:21 PM
#499
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it looks pretty much the exact same as the old one but it gradually narrows the plenum chamber so the air must speed up to satisfy the equation of continuity which improvs flow to all cylinders. every cylinders has perfect equal leangth runners that shorter for more high rpm power.
its really a work of art to me. there are a countless number of people who have asked if i had a swapped motor because it changes the way everything looks in a good way.
its really a work of art to me. there are a countless number of people who have asked if i had a swapped motor because it changes the way everything looks in a good way.
