Professional Producs or Stack Racing
TECH SAVANT
Joined: Dec 2006
Posts: 10,937
From: Saint Augustine, FL
When running n/a opening up the intake tract allows the engine to more freely draw in air, and as long as you don't make it so free-flowing as to impact charge velocity¹ there will be a power gain.
However when running forced induction the limiting factor, once in boost, is no longer in the intake, TB, or upper plenum's flow capacity--all of which when pressurised are far greater than the flow of the head's ports and valves could ever be. You're pushing air into the engine from a pressurised intake tract², it's the head/valve flow that becomes the bottleneck.
The 78mm TB/plenum will likely hurt 2V WOT performance when running n/a, and add very little if anything to a 2V f/i setup.
Read Heywood if you want to know more...
----------------------------------
¹ - The intake air flow (n/a) is not a homogeneous steady stream, it's a series of pulses just like the exhaust. The difference is that the intake pulse has a low pressure head, a near ambient pressure mid-section and a higher pressure tail--the opposite of the exhaust because the intake air is being sucked, and the exhaust gases are being blown.
Since air has mass, once you get it moving it wants to keep moving, and the faster you get it moving the more it wants to stay moving. When running n/a this moving mass of air helps to both clear the combustion chamber during valve overlap, and ram a bit more fuel charge in once both valves are closed.
This is the RAM effect JLT says is accomplished by their redesigned intake plenum (yes Virginia, the part of the intake on the upstream side of the TB is a plenum too). By tuning the size and shape of the intake tube, at certain intake air charge frequencies the "outer plenum" is actually slightly pressurized further improving charge velocity.
JLTs RAM has nothing to do with the silly notion that a forward facing funnel can add boost...
² - On a boosted engine the intake tract becomes a pressure vessel holding a compressed gas (air). At WOT that pressurised vessel extends right down into the lower plenum (intake manifold)--when the intake valve(s) open that pressurised air (and fuel at this point) is squirted into the cylinder through that little tiny hole that the intake valve exposes. As long as the path between the blower and the intake manifold can maintain sufficient flow to keep the pressure vessel pressurised it's "big enough".
Last edited by cliffyk; Jul 22, 2010 at 04:25 PM.
6th Gear Member
Joined: Oct 2006
Posts: 10,551
From: Texas
Nope.
When running n/a opening up the intake tract allows the engine to more freely draw in air, and as long as you don't make it so free-flowing as to impact charge velocity¹ there will be a power gain.
However when running forced induction the limiting factor, once in boost, is no longer in the intake, TB, or upper plenum's flow capacity--all of which when pressurised are far greater than the flow of the head's ports and valves could ever be. You're pushing air into the engine from a pressurised intake tract², it's the head/valve flow that becomes the bottleneck.
The 78mm TB/plenum will like hurt 2V WOT performance when running n/a, and add very little if anything to a 2V f/i setup.
Read Heywood if you want to know more...
----------------------------------
¹ - The intake air flow (n/a) is not a homogeneous steady stream, it's a series of pulses just like the exhaust. The difference is that the intake pulse has a low pressure head, a near ambient pressure mid-section and a higher pressure tail--the opposite of the exhaust because the intake air is being sucked, and the exhaust gases are being blown.
Since air has mass, once you get it moving it wants to keep moving, and the faster you get it moving the more it wants to stay moving. When running n/a this moving mass of air helps to both clear the combustion chamber during valve overlap, and ram a bit more fuel charge in once both valves are closed.
This is the RAM effect JLT says is accomplished by their redesigned intake plenum (yes Virginia, the part of the intake on the upstream side of the TB is a plenum too). By tuning the size and shape of the intake tube, at certain intake air charge frequencies the "outer plenum" is actually slightly pressurized further improving charge velocity.
JLTs RAM has nothing to do with the silly notion that a forward facing funnel can add boost...
² - On a boosted engine the intake tract becomes a pressure vessel holding a compressed gas (air). At WOT that pressurised vessel extends right down into the lower plenum (intake manifold)--when the intake valve(s) open that pressurised air (and fuel at this point) is squirted into the cylinder through that little tiny hole that the intake valve exposes. As long as the path between the blower and the intake manifold can maintain sufficient flow to keep the pressure vessel pressurised it's "big enough".
When running n/a opening up the intake tract allows the engine to more freely draw in air, and as long as you don't make it so free-flowing as to impact charge velocity¹ there will be a power gain.
However when running forced induction the limiting factor, once in boost, is no longer in the intake, TB, or upper plenum's flow capacity--all of which when pressurised are far greater than the flow of the head's ports and valves could ever be. You're pushing air into the engine from a pressurised intake tract², it's the head/valve flow that becomes the bottleneck.
The 78mm TB/plenum will like hurt 2V WOT performance when running n/a, and add very little if anything to a 2V f/i setup.
Read Heywood if you want to know more...
----------------------------------
¹ - The intake air flow (n/a) is not a homogeneous steady stream, it's a series of pulses just like the exhaust. The difference is that the intake pulse has a low pressure head, a near ambient pressure mid-section and a higher pressure tail--the opposite of the exhaust because the intake air is being sucked, and the exhaust gases are being blown.
Since air has mass, once you get it moving it wants to keep moving, and the faster you get it moving the more it wants to stay moving. When running n/a this moving mass of air helps to both clear the combustion chamber during valve overlap, and ram a bit more fuel charge in once both valves are closed.
This is the RAM effect JLT says is accomplished by their redesigned intake plenum (yes Virginia, the part of the intake on the upstream side of the TB is a plenum too). By tuning the size and shape of the intake tube, at certain intake air charge frequencies the "outer plenum" is actually slightly pressurized further improving charge velocity.
JLTs RAM has nothing to do with the silly notion that a forward facing funnel can add boost...
² - On a boosted engine the intake tract becomes a pressure vessel holding a compressed gas (air). At WOT that pressurised vessel extends right down into the lower plenum (intake manifold)--when the intake valve(s) open that pressurised air (and fuel at this point) is squirted into the cylinder through that little tiny hole that the intake valve exposes. As long as the path between the blower and the intake manifold can maintain sufficient flow to keep the pressure vessel pressurised it's "big enough".
Maybe now ppl will get off this things nuts.
TECH SAVANT
Joined: Dec 2006
Posts: 10,937
From: Saint Augustine, FL
Great example of this mentality: I recently bought a Sony A330 digital SLR camera, in large part because it can use the collection of Minolta AF lenses that have been collecting dust in my closet (and in part because WallyWorld had it for $350).
After I bought it I took time to read some online reviews and found that the most common critique was that it didn't weigh enough and "felt cheap". Not one reviewer put forth that perhaps "Sony applied state-of-the-art material selection and engineering to set a new standard in DSLR weight!"
I wonder if their review of a titanium Rolex would conclude that "...it was very lightweight and felt cheap".
5th Gear Member
Joined: Sep 2009
Posts: 2,797
From: KY, was MA
America is based on a "bigger is better" philosophy, and marketing people are more than aware of that. What often surprises me most is that I'm old and supposed to be one of those who stamps their cane and says "they don't make 'em like that anymore!"--in between disparaging comments regarding women and minorities of course...
Great example of this mentality: I recently bought a Sony A330 digital SLR camera, in large part because it can use the collection of Minolta AF lenses that have been collecting dust in my closet (and in part because WallyWorld had it for $350).
After I bought it I took time to read some online reviews and found that the most common critique was that it didn't weigh enough and "felt cheap". Not one reviewer put forth that perhaps "Sony applied state-of-the-art material selection and engineering to set a new standard in DSLR weight!"
I wonder if their review of a titanium Rolex would conclude that "...it was very lightweight and felt cheap".
Great example of this mentality: I recently bought a Sony A330 digital SLR camera, in large part because it can use the collection of Minolta AF lenses that have been collecting dust in my closet (and in part because WallyWorld had it for $350).
After I bought it I took time to read some online reviews and found that the most common critique was that it didn't weigh enough and "felt cheap". Not one reviewer put forth that perhaps "Sony applied state-of-the-art material selection and engineering to set a new standard in DSLR weight!"
I wonder if their review of a titanium Rolex would conclude that "...it was very lightweight and felt cheap".
Without a doubt....just how heavy a$$ 24" rims are a good idea with stock brakes. (I know jackasses came out with bigger rims but you get the point.)
In some situations bigger may actually be better...with a s/c is a 75mm better than a 65mm or even 70mm? Sure...but don't get carried away and extrapolate that into "Well if I put an 80mm or 90mm I'll be making crazy power mannnn!" lol
But back on topic...It comes down to you should go with a 75mm setup and then it's up to you to try and justify the price difference b/w an Accufab pretty looking doo-hicky on your motor, or something cheaper that will flow relatively just as well (I'm not splitting hairs here with cfm) and get the job done for you? If this was a high HP car and you NEED every amount of hp you can get and dissecting EVERYTHING...then sure go with the tb that flows THE MOST/BEST. But for us average Joe's I can't see the justification in the price difference. BUT your car, your money.
Last edited by smitty2919; Jul 22, 2010 at 05:29 PM.
TECH SAVANT
Joined: Dec 2006
Posts: 10,937
From: Saint Augustine, FL
A friend of mine and I were in Roxbury many years ago, his young daughter was with us. After viewing a number of "ghetto sleds" with flash wheels and primered, rusting, and otherwise multi-color bodies Lucy asked why it was that all these cars had flashy wheels but otherwise looked like crap (my words, not hers).
I told her it was because you can't steal a paint job...
I told her it was because you can't steal a paint job...
Last edited by cliffyk; Jul 23, 2010 at 07:20 AM.
4th Gear Member
Joined: Apr 2009
Posts: 1,501
From: oregon
edit: my only reason for saying accufab, would be it may flow the same as cheaper stuff, but im looking at my car being DD i want something that built with better parts and put together with the intent of being a factory replacement so that you know you can get years of service out of it. Im not saying that bbk does not make nice stuff, or that some of the other companys are all crap. Just getting the pp and upr stuff, for me hasnt been impressive stuff. And if there is one thing ive figured out in my years of production welding. Its this. If the people around you dont care about the stuff they put out, and the company lets parts roll out the door that dont meet quality standards....then its likely all the parts are that way.
I say this because im very picky when it comes to quality, even though most people will never ever know i welded something, If its going to have my name on it i want it as good as i can make it. And so many places ive been to trade speed for quality because it makes more money. Inevitibly if speed is more important quality will suffer. Price is often a great indicator of this. If something is built well and with high quality parts, they dont stay cheep for long because the company builds a name of having nice high quality parts and shortly after starts charging for the better stuff, because often it costs more to make. (this is not a blanket statement though)
Last edited by Bman2000; Jul 22, 2010 at 07:10 PM.
5th Gear Member
Joined: Mar 2008
Posts: 2,994
From: Ohio
Nope.
When running n/a opening up the intake tract allows the engine to more freely draw in air, and as long as you don't make it so free-flowing as to impact charge velocity¹ there will be a power gain.
However when running forced induction the limiting factor, once in boost, is no longer in the intake, TB, or upper plenum's flow capacity--all of which when pressurised are far greater than the flow of the head's ports and valves could ever be. You're pushing air into the engine from a pressurised intake tract², it's the head/valve flow that becomes the bottleneck.
The 78mm TB/plenum will likely hurt 2V WOT performance when running n/a, and add very little if anything to a 2V f/i setup.
Read Heywood if you want to know more...
----------------------------------
¹ - The intake air flow (n/a) is not a homogeneous steady stream, it's a series of pulses just like the exhaust. The difference is that the intake pulse has a low pressure head, a near ambient pressure mid-section and a higher pressure tail--the opposite of the exhaust because the intake air is being sucked, and the exhaust gases are being blown.
Since air has mass, once you get it moving it wants to keep moving, and the faster you get it moving the more it wants to stay moving. When running n/a this moving mass of air helps to both clear the combustion chamber during valve overlap, and ram a bit more fuel charge in once both valves are closed.
This is the RAM effect JLT says is accomplished by their redesigned intake plenum (yes Virginia, the part of the intake on the upstream side of the TB is a plenum too). By tuning the size and shape of the intake tube, at certain intake air charge frequencies the "outer plenum" is actually slightly pressurized further improving charge velocity.
JLTs RAM has nothing to do with the silly notion that a forward facing funnel can add boost...
² - On a boosted engine the intake tract becomes a pressure vessel holding a compressed gas (air). At WOT that pressurised vessel extends right down into the lower plenum (intake manifold)--when the intake valve(s) open that pressurised air (and fuel at this point) is squirted into the cylinder through that little tiny hole that the intake valve exposes. As long as the path between the blower and the intake manifold can maintain sufficient flow to keep the pressure vessel pressurised it's "big enough".
When running n/a opening up the intake tract allows the engine to more freely draw in air, and as long as you don't make it so free-flowing as to impact charge velocity¹ there will be a power gain.
However when running forced induction the limiting factor, once in boost, is no longer in the intake, TB, or upper plenum's flow capacity--all of which when pressurised are far greater than the flow of the head's ports and valves could ever be. You're pushing air into the engine from a pressurised intake tract², it's the head/valve flow that becomes the bottleneck.
The 78mm TB/plenum will likely hurt 2V WOT performance when running n/a, and add very little if anything to a 2V f/i setup.
Read Heywood if you want to know more...
----------------------------------
¹ - The intake air flow (n/a) is not a homogeneous steady stream, it's a series of pulses just like the exhaust. The difference is that the intake pulse has a low pressure head, a near ambient pressure mid-section and a higher pressure tail--the opposite of the exhaust because the intake air is being sucked, and the exhaust gases are being blown.
Since air has mass, once you get it moving it wants to keep moving, and the faster you get it moving the more it wants to stay moving. When running n/a this moving mass of air helps to both clear the combustion chamber during valve overlap, and ram a bit more fuel charge in once both valves are closed.
This is the RAM effect JLT says is accomplished by their redesigned intake plenum (yes Virginia, the part of the intake on the upstream side of the TB is a plenum too). By tuning the size and shape of the intake tube, at certain intake air charge frequencies the "outer plenum" is actually slightly pressurized further improving charge velocity.
JLTs RAM has nothing to do with the silly notion that a forward facing funnel can add boost...
² - On a boosted engine the intake tract becomes a pressure vessel holding a compressed gas (air). At WOT that pressurised vessel extends right down into the lower plenum (intake manifold)--when the intake valve(s) open that pressurised air (and fuel at this point) is squirted into the cylinder through that little tiny hole that the intake valve exposes. As long as the path between the blower and the intake manifold can maintain sufficient flow to keep the pressure vessel pressurised it's "big enough".
This is true^
America is based on a "bigger is better" philosophy, and marketing people are more than aware of that. What often surprises me most is that I'm old and supposed to be one of those who stamps their cane and says "they don't make 'em like that anymore!"--in between disparaging comments regarding women and minorities of course...
Great example of this mentality: I recently bought a Sony A330 digital SLR camera, in large part because it can use the collection of Minolta AF lenses that have been collecting dust in my closet (and in part because WallyWorld had it for $350).
After I bought it I took time to read some online reviews and found that the most common critique was that it didn't weigh enough and "felt cheap". Not one reviewer put forth that perhaps "Sony applied state-of-the-art material selection and engineering to set a new standard in DSLR weight!"
I wonder if their review of a titanium Rolex would conclude that "...it was very lightweight and felt cheap".
Great example of this mentality: I recently bought a Sony A330 digital SLR camera, in large part because it can use the collection of Minolta AF lenses that have been collecting dust in my closet (and in part because WallyWorld had it for $350).
After I bought it I took time to read some online reviews and found that the most common critique was that it didn't weigh enough and "felt cheap". Not one reviewer put forth that perhaps "Sony applied state-of-the-art material selection and engineering to set a new standard in DSLR weight!"
I wonder if their review of a titanium Rolex would conclude that "...it was very lightweight and felt cheap".
Also true^^^
Without a doubt....just how heavy a$$ 24" rims are a good idea with stock brakes. (I know jackasses came out with bigger rims but you get the point.)
In some situations bigger may actually be better...with a s/c is a 75mm better than a 65mm or even 70mm? Sure...but don't get carried away and extrapolate that into "Well if I put an 80mm or 90mm I'll be making crazy power mannnn!" lol
But back on topic...It comes down to you should go with a 75mm setup and then it's up to you to try and justify the price difference b/w an Accufab pretty looking doo-hicky on your motor, or something cheaper that will flow relatively just as well (I'm not splitting hairs here with cfm) and get the job done for you? If this was a high HP car and you NEED every amount of hp you can get and dissecting EVERYTHING...then sure go with the tb that flows THE MOST/BEST. But for us average Joe's I can't see the justification in the price difference. BUT your car, your money.
In some situations bigger may actually be better...with a s/c is a 75mm better than a 65mm or even 70mm? Sure...but don't get carried away and extrapolate that into "Well if I put an 80mm or 90mm I'll be making crazy power mannnn!" lol
But back on topic...It comes down to you should go with a 75mm setup and then it's up to you to try and justify the price difference b/w an Accufab pretty looking doo-hicky on your motor, or something cheaper that will flow relatively just as well (I'm not splitting hairs here with cfm) and get the job done for you? If this was a high HP car and you NEED every amount of hp you can get and dissecting EVERYTHING...then sure go with the tb that flows THE MOST/BEST. But for us average Joe's I can't see the justification in the price difference. BUT your car, your money.
Again, I can agree with this....^^
A friend of mine were in Roxbury many years ago, his young daughter was with us. After viewing a number of "ghetto sleds" with flash wheels and primered, rusting, and otherwise multi-color bodies Lucy asked why it was that all these cars had flashy wheels but otherwise looked like crap (my words, not hers).
I told her it was because you can't steal a paint job...
I told her it was because you can't steal a paint job...
^^^Takes the flipping cake as being the truest statement on this page.
Period.
The one and ONLY reason I ever actually promoted the 78mm Throttle Body Plenum unit from BBK was because it was all one piece, and it would save some money...if I had all kinds of money, I would gladly go do back to back testing with each and every one of the manufactured aftermarket setups...but alas, I'm a broke sum bich and that's never gonna happen...