Plenum vs Spacer
Originally Posted by SteveZ
Intense Motorsports Jorge Lozano's Turbo 350Z
yeap thanks! , its in my zig, i went with md spacer cause it was all available at the time.
That mod list is old, and a lot has been replaced...my stage 1 project
, some time in the next few weeks ill be posting a thread about my new build 
Once that happens the link will be updated with new pics and mod list.
Originally Posted by SpoilsofWar
...but probably not the fixed length models, due to the change in geometry.
Originally Posted by SteveZ
Price is always a good reason all things equal, one of my turnoffs to the MD spacer is to me they charge quite a lot for their product.
As for comparison:
Bling Vs Stealth.
If you want people or inspectors to see your plenum spacer, depending on which look you want (bling or stealth) what is best is subjective and depends on your objectives.
For everything else, design, thermal, size, safety and shape... Motordyne is best.
Shape:
MD conforms to the plenum contures much more tightly. No customer complaints of the spacer hanging 1/4" over the edge of the plenum with the MD spacers.
Thermal:
Thermal design is far superior with the MD Iso Thermal kits.
Simply using a barbed fitting as a coolant bypass doesn't make much of a difference in overall plenum assembly temperature.
There are two main heat input sources to the plenum assembly.
1) Hot coolant flow.
2) Conductive heat transfer from the heads (@~250'F) into the heavy guage aluminum lower manifold and into the lower plenum.
Both heat input sources must be cut off to make a significant difference in overall assembly temperature. Without cutting off both, it doesn't make a significant difference.
The two heat input sources are analogous to having two blow torches blasting on the intake assembly with cool air flowing into it. If one torch is removed, the majority of the aluminum plenum will still run very hot.
Both heat input sources must be adressed. The Aramid insulating gasket cuts the heat transfer through the lower plenum. The CCV or Copper throttle body heater cut the hot coolant flow. (These parts arent found in any other kit.)
To allow the upper and lower plenum assembly to run substantially cooler, while not risking the throttle body getting frozen up in cold weather. Heat must be applied directly to the throttle body. And this is what is done in all the MD spacers.
Even though all the other spacers on the market throw in a coolant bypass to claim reduced plenum temperatures, no other spacer kit reduces plenum assembly temperature as effectively. Not even close.
No Safety Compromise:
All the other spacer kits on the market offer a simple coolant bypass as an excuse to claim the lower plenum temperatures. But with just a simple bypass used, there is a large thermal gradient (of decreasing temperature) at the entrance of the plenum. The lower plenum and much of the upper plenum will still be hot, but the throttle body can still have ice formation if the weather is cold enough.
A simple coolant bypass gives you the worst compromise of thermal control and safety.
Note: No matter what the climate is, none of the MD spacers will impose the potential of freezing your throttle body while driving. Basic, Iso Thermal or Copper Iso Thermal. There are no safety compromises in any of the MD designs.
Size:
Motordyne used to offer a 3/8" spacer a few years back, but with extensive dyno testing, a better optimum was found with the 5/16". 5/16" yeilds the highest overall gain.
Aluminum Material:
The same.
Thread lock:
Not necessary but supplied in every MD kit as an additional measure of reliability. Not found in any other kit.
Internal supports:
Not just billet plastic machined to size like all the others spacers on the market. Each MD internal support is a custom molded part (of carefully researched plastic material properties) and with safety design features not found in the other spacer kits.
The internal supports snap on like a zip tie and once installed they will stay in place even if its respective bolt is removed.
Once installed, you could remove all 6 of the bolts in the center of the plenum and none of the MD internal supports will come lose. With their cupped design, they are captured in place and cannot move until the upper plenum is removed.
Do not try this with any other spacer kit!
This safety design feature is only one more detail of many, but the design of the entire kit is all about engineering details. Some are elements are obvious while most are not, but they are all there.
Originally Posted by Hydrazine
Aluminum Material:
The same.
The same.
Thanks! I needed a good laugh before going bed!
You are being totally misleading and disingenuous if you're claiming that your "aluminum material" is the same (either in quality or manufacturing expense) as the CNC machined billet used in the PowerLab spacer.
Originally Posted by RudeG_v2.0
Thanks! I needed a good laugh before going bed! You are being totally misleading and disingenuous if you're claiming that your "aluminum material" is the same (either in quality or manufacturing expense) as the CNC machined billet used in the PowerLab spacer.
Do you know the word "material"?
Please elaborate in very specific detail.
Edit: No need for a vage generalizations or a hostile reply. A civilized technical discussion would be nice.
Last edited by Hydrazine; Jul 11, 2008 at 05:19 AM.
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Joined: Dec 2007
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From: Arizona
It seems to me that someone can't accept that there is competition in the market.
I personally don't like the fact that certain companies brain wash people in to thinking that certain accessories are needed, which are only included in there product, when they are not.
If you feel you most promote your product by "trash talking" other products then so be it. I personally find that distasteful and sad. Also, make sure you know your facts about your competitor’s products before you take time out of your day to make a lengthy inaccurate post, and I’m not talking about just one brand.
And no, I will not elaborate with a lengthy technical response….. Remember, you’re the engineer here. I’m just a car guy that refuses to be brain washed.
I personally don't like the fact that certain companies brain wash people in to thinking that certain accessories are needed, which are only included in there product, when they are not.
If you feel you most promote your product by "trash talking" other products then so be it. I personally find that distasteful and sad. Also, make sure you know your facts about your competitor’s products before you take time out of your day to make a lengthy inaccurate post, and I’m not talking about just one brand.
And no, I will not elaborate with a lengthy technical response….. Remember, you’re the engineer here. I’m just a car guy that refuses to be brain washed.
what ever, I think your attitude with the press release thread of the PL spacers shows your true colors...
Originally Posted by Hydrazine
Price? We just had a really good 4th of July sale on them. Have you visited the classified section recently? They are on sale now. Depending on the dealer and the sales they are running, in some cases the MD spacers are priced even lower.
...To allow the upper and lower plenum assembly to run substantially cooler, while not risking the throttle body getting frozen up in cold weather. Heat must be applied directly to the throttle body. And this is what is done in all the MD spacers.
Even though all the other spacers on the market throw in a coolant bypass to claim reduced plenum temperatures, no other spacer kit reduces plenum assembly temperature as effectively. Not even close.
No Safety Compromise:
All the other spacer kits on the market offer a simple coolant bypass as an excuse to claim the lower plenum temperatures. But with just a simple bypass used, there is a large thermal gradient (of decreasing temperature) at the entrance of the plenum. The lower plenum and much of the upper plenum will still be hot, but the throttle body can still have ice formation if the weather is cold enough.
Even though all the other spacers on the market throw in a coolant bypass to claim reduced plenum temperatures, no other spacer kit reduces plenum assembly temperature as effectively. Not even close.
No Safety Compromise:
All the other spacer kits on the market offer a simple coolant bypass as an excuse to claim the lower plenum temperatures. But with just a simple bypass used, there is a large thermal gradient (of decreasing temperature) at the entrance of the plenum. The lower plenum and much of the upper plenum will still be hot, but the throttle body can still have ice formation if the weather is cold enough.
I live in a sometimes very cold climate, so I am of course curious how I could ever have ice in the throttle body, given its proximity to a large heat source (with or w/o a coolant bypass)?
Is this something that you have observed? I am confused as to how this would happen - the air is extremely dry in severely cold conditions here, e.g. the sub-zero Fahrenheit conditions I drive though in the Winter (I use my car year-around despite a fair amount of snow, ice, etc.
Also, how do MD spacers "apply heat directly to throttle body"? Assuming I want this when it's cold, isn't this not such a good thing when it's hot? I'm not splitting hairs between direct or indirect, just curious how this works.
Please take these questions in the spirit it's intended, I don't even pretend to know much about the thermodynamics of the interaction of the VQ's plenum and throttle body, so if you could elaborate I'd appreciate that very much.
Thanks in advance.
Originally Posted by SteveZ
Please take these questions in the spirit it's intended, I don't even pretend to know much about the thermodynamics of the interaction of the VQ's plenum and throttle body, so if you could elaborate I'd appreciate that very much.
...(in for a lengthy post of theorethical crap)
Hmmm...$210 for a basic spacer, which isn't recommended by MD for my use,
The only time I would say the basic is not recommended is if you put it on a REVUP engine without the MREV2 also in place. Otherwise I can't think of a reason "not" to use it.
I've see that sometimes people can confuse the application of the different spacers to the environment they will be drivng in. IE the Copper can be used in any weather hot or cold, but sometimes people will get the impression that it can't be used in hot weather, or, that it can't be used in cold weather.
I probably need to clairify this better in the descriptions.
I was following you (except for the "not even close" part unless you've done very extensive scientific testing under controlled conditions),
Yes, I actually did do a lot of that. I had an array of thermocouples all over the plenum assembly and tested a lot of different different configurations to figure out what the heat sources were, steady state temperatures, heat flux rates, soak back temperatures, shut down temperature signatures and much more.
Testing was performed on the same car, same day, same stretch of freeway, same speed, same acceleration rates, same ambient temperatures and so forth. With and without the Aramid gasket. With and without the CCV in the open&closed position.
Independant testing was also performed by other forum members here too. And they all correlated.
I live in a sometimes very cold climate, so I am of course curious how I could ever have ice in the throttle body, given its proximity to a large heat source (with or w/o a coolant bypass)?
Is this something that you have observed? I am confused as to how this would happen - the air is extremely dry in severely cold conditions here, e.g. the sub-zero Fahrenheit conditions I drive though in the Winter (I use my car year-around despite a fair amount of snow, ice, etc.
If it gets cold enough, it is certaintly possible. The throttle body is the first metal object to be exposed the the cold incomming air.
The only heat input source (if a simple bypass is used) is conduction at the interface between the lower manifold and the lower plenum. The heat has no problem going through the lower plenum because the aluminum is so thick. Much of the upper plenum will be heated too, but the upper plenums aluminum gets thinner the higher up it goes. The curved gooseneck area of the plenum also gets a lot thinner all the up to the point where Nissan put in the channel for hot coolant to flow through it. The flange surface for the throttle body is also thick too.
But all the way up to that area, there is a large thermal gradient or decrease in heat flux (temperature).
Note: Nissan flows hot coolant through that area of the plenum exactly for this reason. To prevent throttle body freezing. Nissan put it in there for safety reasons. To assure it won't freeze up no matter what the conditions are. And they have to design their cars to work safely in all environments from Siberia to the Sahara desert.
Also, how do MD spacers "apply heat directly to throttle body"?
In the case of the Basic spacer, the throttle body is heated exactly like stock. All the time.
In the case of the Iso Thermal spacer, the throttle body is heated exactly like stock when the CCV is in the open position. Hot coolant flows to the the goose neck of the plenum like stock to keep it heated.
In the case of the Copper Iso Thermal, hot coolant flow is re-routed to the copper throttle body heater. This heater is made of a thick copper plate that conducts heat very well. The plate is insulated on the side that bolts to the plenum. The other side of the copper plate is bare copper metal that uses a thin steel gasket to bolt to the aluminum throttle body.
This plate conducts enough heat into the throttlebody to insure it won't freeze, but it doesn't heat the plenum in the process.
Assuming I want this when it's cold, isn't this not such a good thing when it's hot?
In the case of the Basic, yes.
In the case of the CCV, just turn the valve on or off based on the conditions.
In the case of the Copper, its all automatic. Only the throttle body is heated and the rest of the plenum stays isolated.
I'm not splitting hairs between direct or indirect, just curious how this works.
Please take these questions in the spirit it's intended, I don't even pretend to know much about the thermodynamics of the interaction of the VQ's plenum and throttle body, so if you could elaborate I'd appreciate that very much.
Thanks in advance.[/quote]
These are actually very good questions SteveZ. Thanks for asking.
I would like to put this kind of information into the FAQ section of my website, but if I did, it would probably be way too much information in most cases. The website already has a little too much in it.
Then again, this is perfect for forum reading material.
Over the years, I've done so much testing, research and development on these cars I could make an archive of technical reports on it. A lot of it would be very interesting reading to Z&G enthusiasts. Test reports on what works and even what didn't work.
The problem is what to do with it all? I should probably link a blog for it.
The only time I would say the basic is not recommended is if you put it on a REVUP engine without the MREV2 also in place. Otherwise I can't think of a reason "not" to use it.
I've see that sometimes people can confuse the application of the different spacers to the environment they will be drivng in. IE the Copper can be used in any weather hot or cold, but sometimes people will get the impression that it can't be used in hot weather, or, that it can't be used in cold weather.
I probably need to clairify this better in the descriptions.
I was following you (except for the "not even close" part unless you've done very extensive scientific testing under controlled conditions),
Yes, I actually did do a lot of that. I had an array of thermocouples all over the plenum assembly and tested a lot of different different configurations to figure out what the heat sources were, steady state temperatures, heat flux rates, soak back temperatures, shut down temperature signatures and much more.
Testing was performed on the same car, same day, same stretch of freeway, same speed, same acceleration rates, same ambient temperatures and so forth. With and without the Aramid gasket. With and without the CCV in the open&closed position.
Independant testing was also performed by other forum members here too. And they all correlated.
I live in a sometimes very cold climate, so I am of course curious how I could ever have ice in the throttle body, given its proximity to a large heat source (with or w/o a coolant bypass)?
Is this something that you have observed? I am confused as to how this would happen - the air is extremely dry in severely cold conditions here, e.g. the sub-zero Fahrenheit conditions I drive though in the Winter (I use my car year-around despite a fair amount of snow, ice, etc.
If it gets cold enough, it is certaintly possible. The throttle body is the first metal object to be exposed the the cold incomming air.
The only heat input source (if a simple bypass is used) is conduction at the interface between the lower manifold and the lower plenum. The heat has no problem going through the lower plenum because the aluminum is so thick. Much of the upper plenum will be heated too, but the upper plenums aluminum gets thinner the higher up it goes. The curved gooseneck area of the plenum also gets a lot thinner all the up to the point where Nissan put in the channel for hot coolant to flow through it. The flange surface for the throttle body is also thick too.
But all the way up to that area, there is a large thermal gradient or decrease in heat flux (temperature).
Note: Nissan flows hot coolant through that area of the plenum exactly for this reason. To prevent throttle body freezing. Nissan put it in there for safety reasons. To assure it won't freeze up no matter what the conditions are. And they have to design their cars to work safely in all environments from Siberia to the Sahara desert.
Also, how do MD spacers "apply heat directly to throttle body"?
In the case of the Basic spacer, the throttle body is heated exactly like stock. All the time.
In the case of the Iso Thermal spacer, the throttle body is heated exactly like stock when the CCV is in the open position. Hot coolant flows to the the goose neck of the plenum like stock to keep it heated.
In the case of the Copper Iso Thermal, hot coolant flow is re-routed to the copper throttle body heater. This heater is made of a thick copper plate that conducts heat very well. The plate is insulated on the side that bolts to the plenum. The other side of the copper plate is bare copper metal that uses a thin steel gasket to bolt to the aluminum throttle body.
This plate conducts enough heat into the throttlebody to insure it won't freeze, but it doesn't heat the plenum in the process.
Assuming I want this when it's cold, isn't this not such a good thing when it's hot?
In the case of the Basic, yes.
In the case of the CCV, just turn the valve on or off based on the conditions.
In the case of the Copper, its all automatic. Only the throttle body is heated and the rest of the plenum stays isolated.
I'm not splitting hairs between direct or indirect, just curious how this works.
Please take these questions in the spirit it's intended, I don't even pretend to know much about the thermodynamics of the interaction of the VQ's plenum and throttle body, so if you could elaborate I'd appreciate that very much.
Thanks in advance.[/quote]
These are actually very good questions SteveZ. Thanks for asking.
I would like to put this kind of information into the FAQ section of my website, but if I did, it would probably be way too much information in most cases. The website already has a little too much in it.
Then again, this is perfect for forum reading material.
Over the years, I've done so much testing, research and development on these cars I could make an archive of technical reports on it. A lot of it would be very interesting reading to Z&G enthusiasts. Test reports on what works and even what didn't work.
The problem is what to do with it all? I should probably link a blog for it.
Last edited by Hydrazine; Jul 11, 2008 at 08:45 AM.
I've see that sometimes people can confuse the application of the different spacers to the environment they will be drivng in. IE the Copper can be used in any weather hot or cold, but sometimes people will get the impression that it can't be used in hot weather, or, that it can't be used in cold weather.
I probably need to clairify this better in the descriptions.
I agree, that was confusing. It sounds like if you live where it gets cold, don't use the basic spacer, but since that leaves the CCV intact, that's not really what is meant. As I understand it, MD recommends the Copper if you're going to use a bypass, and live in a sometimes cold climate, so you can easily turn it back on.
The only heat input source (if a simple bypass is used) is conduction at the interface between the lower manifold and the lower plenum. The heat has no problem going through the lower plenum because the aluminum is so thick. Much of the upper plenum will be heated too, but the upper plenums aluminum gets thinner the higher up it goes. The curved gooseneck area of the plenum also gets a lot thinner all the up to the point where Nissan put in the channel for hot coolant to flow through it. The flange surface for the throttle body is also thick too.
These are actually very good questions SteveZ. Thanks for asking.
Thanks for the info. I am just guessing but probably for most forum members, really cold weather isn't an issue. I get both extremes, hot and humid to sub-zero. I don't see many Z33/V35's out and about here in Winter, I have to admit. I don't really know much about the coolant bypass and I am guessing for a large number of people just eliminating it is a good thing for cooler intake temps. I can see where ideally when you live in a place where it ranges -10F to 100F over the year, you'd probably want to be able to control that, or just choose not to bypass it.
I do notice how much my car likes "cool" air, but really cold air isn't exactly a performance plus, I'd probably just not bypass the CCV unless I stopped driving in Winter.
The problem is what to do with it all? I should probably link a blog for it.
Well, the tech section here is a pretty good spot, and I haven't checked the Top 100 Questions, but if there isn't a basic explanation of "What is Coolant Bypass?" or similar, I'd suggest adding one with some explanation of pros/cons to how it's done. If you go off-site, it's unsearchable through the forum.
Honestly, I think when you get right down to it a spacer by itself you can argue a case for the various technical merits of different approaches and let people figure out what fits their need. I am sure like everything else, there's someone making total garbage out there, just like intakes, headers and everything else. Still, if it's well made, quality materials, quality fit and fittings, it is still a spacer we're talking about here, and until you add the thermodynamic issues, quality of fit, materials, cost, etc. are mostly the key issues.
As I said before, when I looked awhile ago, I felt the $300 tag for the MD was getting a little high, I won't retract that. A good product with a lot of the the sunk engineering cost up front, all things considered, I'd expect the price to drop a bit over time with volume and competition, usually 10-20%, unless they're the only game in town, or the product is significantly improved.
I do however appreciate the concept of things falling down the intake after seeing a guy working on his built FI SR20 try to fish a small spacer/washer out of the motor, I think it was a valve retainer that fell in somehow through the top end. He was not a happy camper, just finishing up a really nice high output turbo.
-
I probably need to clairify this better in the descriptions.
I agree, that was confusing. It sounds like if you live where it gets cold, don't use the basic spacer, but since that leaves the CCV intact, that's not really what is meant. As I understand it, MD recommends the Copper if you're going to use a bypass, and live in a sometimes cold climate, so you can easily turn it back on.
The only heat input source (if a simple bypass is used) is conduction at the interface between the lower manifold and the lower plenum. The heat has no problem going through the lower plenum because the aluminum is so thick. Much of the upper plenum will be heated too, but the upper plenums aluminum gets thinner the higher up it goes. The curved gooseneck area of the plenum also gets a lot thinner all the up to the point where Nissan put in the channel for hot coolant to flow through it. The flange surface for the throttle body is also thick too.
These are actually very good questions SteveZ. Thanks for asking.
Thanks for the info. I am just guessing but probably for most forum members, really cold weather isn't an issue. I get both extremes, hot and humid to sub-zero. I don't see many Z33/V35's out and about here in Winter, I have to admit. I don't really know much about the coolant bypass and I am guessing for a large number of people just eliminating it is a good thing for cooler intake temps. I can see where ideally when you live in a place where it ranges -10F to 100F over the year, you'd probably want to be able to control that, or just choose not to bypass it.
I do notice how much my car likes "cool" air, but really cold air isn't exactly a performance plus, I'd probably just not bypass the CCV unless I stopped driving in Winter.
The problem is what to do with it all? I should probably link a blog for it.
Well, the tech section here is a pretty good spot, and I haven't checked the Top 100 Questions, but if there isn't a basic explanation of "What is Coolant Bypass?" or similar, I'd suggest adding one with some explanation of pros/cons to how it's done. If you go off-site, it's unsearchable through the forum.
Honestly, I think when you get right down to it a spacer by itself you can argue a case for the various technical merits of different approaches and let people figure out what fits their need. I am sure like everything else, there's someone making total garbage out there, just like intakes, headers and everything else. Still, if it's well made, quality materials, quality fit and fittings, it is still a spacer we're talking about here, and until you add the thermodynamic issues, quality of fit, materials, cost, etc. are mostly the key issues.
As I said before, when I looked awhile ago, I felt the $300 tag for the MD was getting a little high, I won't retract that. A good product with a lot of the the sunk engineering cost up front, all things considered, I'd expect the price to drop a bit over time with volume and competition, usually 10-20%, unless they're the only game in town, or the product is significantly improved.
I do however appreciate the concept of things falling down the intake after seeing a guy working on his built FI SR20 try to fish a small spacer/washer out of the motor, I think it was a valve retainer that fell in somehow through the top end. He was not a happy camper, just finishing up a really nice high output turbo.
-
