need power plate education
- Thread starter Ross L
- Start date
It's one of those useless "novelty" gadgets in which a lot of guys believe until they go to the track and notice that none of the real, "serious" racers use...like the old school 7th. injectors, smaller diameter crank pulleys, plenum spacers, water-cooled up-pipes, "TPS-tec's"...that's what they are : GADGETS...
No one can argue the numbers your car runs, but calling the powerplate a "useless novelty gadget" seems extreme. This gent is a pretty serious racer, no? http://www.turbobuick.com/forums/590140-post6.html
BTW, there was a full-weight, stock block, iron head GN here that ran a 9.99 in 1999. It ran a 7th.
Upper Intake Tests and Stock PP
I bought two stock lower intake manifolds and (2) 62mm throttle bodies, RJC PP for stock dog house. Dog houses were Race Hemco, Mease, and Stock upper. I used a Heavy duty 1/4 horse Sears shop vac and set it on blower side. This is what i noticed right off the bat, with the stock plenum. Intake runners 6,5 and 3 had a noticeably more air flowing through them as compared to Intake runners 1,2,and 4. Installed the PP and checked the runners again and the air flow felt more evenly distributed. Next i tested the Mease Intake Dog House that has more volume then the Stock Upper and PP. I used a thin rubber coupling to attach the vacuum to throttle body like a rubber glove sleeve. Stock plenum with PP actually ballooned up some indicating the vacuum having to work harder. Didnt see this with the Mease or the Hemco. The Mease and Hemco uppers all had more even distribution to the intake runners vs the stock upper. But i did notice the PP does block air to the rear intake runners to balance the flow. I am running the Hemco on my car now and i did notice quicker smoother throttle response with the Hemco. I will be installing the Mease Upper next as i just purchased longer IC hose to attach to throttle body. I wanna see how my TR will respond to added intake volume. These were my tests in the garage but i had no flow bench to record numbers. I do have alot of money invested in these parts and am only trying to see what works best with what i have. I hope some of this information can be of help our members.
I bought two stock lower intake manifolds and (2) 62mm throttle bodies, RJC PP for stock dog house. Dog houses were Race Hemco, Mease, and Stock upper. I used a Heavy duty 1/4 horse Sears shop vac and set it on blower side. This is what i noticed right off the bat, with the stock plenum. Intake runners 6,5 and 3 had a noticeably more air flowing through them as compared to Intake runners 1,2,and 4. Installed the PP and checked the runners again and the air flow felt more evenly distributed. Next i tested the Mease Intake Dog House that has more volume then the Stock Upper and PP. I used a thin rubber coupling to attach the vacuum to throttle body like a rubber glove sleeve. Stock plenum with PP actually ballooned up some indicating the vacuum having to work harder. Didnt see this with the Mease or the Hemco. The Mease and Hemco uppers all had more even distribution to the intake runners vs the stock upper. But i did notice the PP does block air to the rear intake runners to balance the flow. I am running the Hemco on my car now and i did notice quicker smoother throttle response with the Hemco. I will be installing the Mease Upper next as i just purchased longer IC hose to attach to throttle body. I wanna see how my TR will respond to added intake volume. These were my tests in the garage but i had no flow bench to record numbers. I do have alot of money invested in these parts and am only trying to see what works best with what i have. I hope some of this information can be of help our members.
there has been numerous threads about this over the past few years.. MAYBE do a search ???
We run Jason's PP on all of our cars here. Melissa's GN went 9.94 @ 138+ in STREET trim (just the way she drives it everyday!) . Plugs always look great and have never blown a plug . BUT I have never tried it without the plate.. Car runs wayyyy to good to make changes
We run Jason's PP on all of our cars here. Melissa's GN went 9.94 @ 138+ in STREET trim (just the way she drives it everyday!) . Plugs always look great and have never blown a plug . BUT I have never tried it without the plate.. Car runs wayyyy to good to make changes
I still picture this large chamber of pressurized air(or water). If the pressure is constant i just don't understand how "more" air will follow the roof of the plenum and into the rear cylinders. If thats the case wouldn't that mean there's more psi on the rear 2 cylinders? Trying to learn(it rainy here, can't get the buick or bike out)
Ross
You're thinking one dimensionally. You're looking only at pressure, and not at flow/volume. They are two different things.
Good info! It's a given that:
1) lots of people run fast with it.
2) lots of info on power plate if I search.
3) I may never understand:wink:
I guess some may be missing my thought(easy to do).... If the system is pressurized from the turbo compressor all the way to the lower manifold with 24 psi...... how does the power plate make the rear cylinders see less air flow(when the *entire* lower manifold is at 24 psi)? Its a pressurized system. The valves open/close the same letting in the same amount of air(its at 24 psi). I can understand how runner shape could affect the airflow once the valve opens but not how a plate located above the lower manifold(thats still at 24psi)could. So do the rear cylinders see "a little less" boost than the others when using a power plate?
Ross ( ready to agree to never understand:biggrin: )
1) lots of people run fast with it.
2) lots of info on power plate if I search.
3) I may never understand:wink:
I guess some may be missing my thought(easy to do).... If the system is pressurized from the turbo compressor all the way to the lower manifold with 24 psi...... how does the power plate make the rear cylinders see less air flow(when the *entire* lower manifold is at 24 psi)? Its a pressurized system. The valves open/close the same letting in the same amount of air(its at 24 psi). I can understand how runner shape could affect the airflow once the valve opens but not how a plate located above the lower manifold(thats still at 24psi)could.
So do the rear cylinders see "a little less" boost than the others when using a power plate? Ross ( ready to agree to never understand:biggrin: )
- Joined
- Feb 18, 2006
Lots of opinions on this but I'm with you Ross. Your thinking right IMO.
Most people here are going off what they read and been told.
Once you go from vacuum to boost, it's a whole different ball game.
UNGN knows what he's talking about.
Most people here are going off what they read and been told.
Once you go from vacuum to boost, it's a whole different ball game.
UNGN knows what he's talking about.
I admit to not knowing ANYTHING about the powerplate specifically (I have a hotair, so it doesn't apply to me). But I DO know a LOT about fluid mechanics. I have a Masters of Science in Mechanical Engineering (not bragging, just stating) and am working towards a doctorate. Besides the several semesters of coursework in fluid mechanics, I have done a fair bit of research in the area, and messed around with CFD (computational flow dynamics) a little bit.
As far as Ross' specific question, "why does the plate matter, isn't the entire plenum at the same pressure?" the answer is yes and no. There are two components of pressure you must consider: static pressure and dynamic pressure. You can think of this as stationary pressure and moving pressure. If your plenum had no flow through it, if it were essentially a tank filled with still air pressurized to 24 psig, and you opened the intake valves, then you'd be correct,they would all flow the same volume of air (well, not exactly, there would be slight differences even then due to differing geometries in the intake, etc). The problem with this simplification is it does not account for the 'flow' (movement) of air through the intake. This is where dynamic pressure comes into play. Dynamic pressure is the result of moving fluid. Think of it like this: If you're driving down the road on a 'standard day' at sea level, the air pressure around you is about 14.7 psia. Now if you stick your hand out the window into the airstream, you will feel a large amount of pressure on your hand. The air inside and outside your car are at the same static pressure (14.7 psia) but the motion of the air relative to your hand creates a dynamic pressure which is added to the static pressure to find the total pressure. A simple device called a pitot tube uses these principles to determine flow characteristics, for example flow velocity. It consists of two small tubes with their openings 90* to each other. One tube is oriented so its opening faces into the flow, and the other is therefore perpendicular to flow (and therefore sees only static pressure). The difference in pressure seen by the two tubes can be used to determine flow velocity (many aircraft use these to determine airspeed). The greater the velocity of a fluid, the greater the dynamic pressure (specific gravity of the fluid also obviously plays a role, but since we're not comparing different fluids here, thats kind of a moot point).
How this comes into play in your intake is this: for reasons that would be difficult to explain easily and concisely (hell, its tricky for me to understand this stuff and I do it for a living) the air moving along the back wall of the intake moves at a higher velocity. This increased velocity means the dynamic pressure (in the direction of flow) is also increased. This means the total pressure in that area will be higher. Since fluid flow is driven by pressure differential, intake runners/valves in that area will flow more air when opened. As an illustration, consider this example: (disclaimer, I'm picking these numbers right outta my a$$, I can guarantee you they are waaaaay off, i'm just using them to illustrate a point) Lets say the static pressure is at the 24 psig you mentioned. Lets further say that the air at the back of the intake is moving so fast that it has a dynamic pressure of 10 psig, while the air at the front of the intake was so slow it only had 2 psig dynamic pressure. The net effect would be that while the whole plenum was pressurized to "24 psig" as indicated on your boost gauge (which measures static pressure), when the intake valves opened onto cylinders (that are at 0 psig), the pressure differential at the rear would be 34 psig, while only 26 at the front. This difference in the pressure differential across the intake valves will cause the the flow difference (more air and fuel to some cylinders than others).
As to whether or not the powerplate will "restrict flow" or not, its not a simple answer in any way. As stated previously, if you have 2 'restrictions' in a system, one with a cross sectional area of 10 sq. in. and one of 20, changing the second one to 15 sq. in. will still likely hinder flow, even though its still larger than the first restriction. In a system as complex as our intake, it would be virtually impossible to arrive at an analytical solution. You could model the system and make some approximations, or use a finite elements/CFD approach, and that might shed some light on it. Or the simplest way would be to test an intake setup on a flow bench with and without the plate and get some empirical data. The fact is though that as I understand it, it's a moot point whether or not it reduces flow or not. I don't think any of us compare whose intakes flow more CFM at a certain pressure differential, do we? We generally compare power and torque numbers, or 1/4 mile trap speeds and ET's. If the plate allows for more boost and more power on a given setup (which I think the consensus and the limited testing i've come across says it does) then does it matter if in the process of doing that it reduces flow through the intake?
Think of it this way, we all know that better exhaust flow means more power in an internal combustion engine (thats why headers and 3" exhaust systems are made). By bolting a turbo into that exhaust stream, you are adding one hell of a restriction to exhaust flow. Do any of us care? No, because the net result is more power and more speed. The powerplate seems to make people's cars run faster. If in the process it reduces intake volumetric flow slightly (which it very well could, and certainly seems like it would) does anyone care?
If I sounded like I was talking down to anyone on technical issues by over-simplifying, my apologies, it certainly wasn't my intent. If I sounded like I was talking over anyones heads, same thing goes. It's hard for me to put this stuff into words when I barely understand it myself, much less make sure other people can make sense of those words Fluid mechanics is tricky stuff, very little of it is intuitive. I was just trying to shed some light on a subject that for once I actually know something about
As far as Ross' specific question, "why does the plate matter, isn't the entire plenum at the same pressure?" the answer is yes and no. There are two components of pressure you must consider: static pressure and dynamic pressure. You can think of this as stationary pressure and moving pressure. If your plenum had no flow through it, if it were essentially a tank filled with still air pressurized to 24 psig, and you opened the intake valves, then you'd be correct,they would all flow the same volume of air (well, not exactly, there would be slight differences even then due to differing geometries in the intake, etc). The problem with this simplification is it does not account for the 'flow' (movement) of air through the intake. This is where dynamic pressure comes into play. Dynamic pressure is the result of moving fluid. Think of it like this: If you're driving down the road on a 'standard day' at sea level, the air pressure around you is about 14.7 psia. Now if you stick your hand out the window into the airstream, you will feel a large amount of pressure on your hand. The air inside and outside your car are at the same static pressure (14.7 psia) but the motion of the air relative to your hand creates a dynamic pressure which is added to the static pressure to find the total pressure. A simple device called a pitot tube uses these principles to determine flow characteristics, for example flow velocity. It consists of two small tubes with their openings 90* to each other. One tube is oriented so its opening faces into the flow, and the other is therefore perpendicular to flow (and therefore sees only static pressure). The difference in pressure seen by the two tubes can be used to determine flow velocity (many aircraft use these to determine airspeed). The greater the velocity of a fluid, the greater the dynamic pressure (specific gravity of the fluid also obviously plays a role, but since we're not comparing different fluids here, thats kind of a moot point).
How this comes into play in your intake is this: for reasons that would be difficult to explain easily and concisely (hell, its tricky for me to understand this stuff and I do it for a living) the air moving along the back wall of the intake moves at a higher velocity. This increased velocity means the dynamic pressure (in the direction of flow) is also increased. This means the total pressure in that area will be higher. Since fluid flow is driven by pressure differential, intake runners/valves in that area will flow more air when opened. As an illustration, consider this example: (disclaimer, I'm picking these numbers right outta my a$$, I can guarantee you they are waaaaay off, i'm just using them to illustrate a point) Lets say the static pressure is at the 24 psig you mentioned. Lets further say that the air at the back of the intake is moving so fast that it has a dynamic pressure of 10 psig, while the air at the front of the intake was so slow it only had 2 psig dynamic pressure. The net effect would be that while the whole plenum was pressurized to "24 psig" as indicated on your boost gauge (which measures static pressure), when the intake valves opened onto cylinders (that are at 0 psig), the pressure differential at the rear would be 34 psig, while only 26 at the front. This difference in the pressure differential across the intake valves will cause the the flow difference (more air and fuel to some cylinders than others).
As to whether or not the powerplate will "restrict flow" or not, its not a simple answer in any way. As stated previously, if you have 2 'restrictions' in a system, one with a cross sectional area of 10 sq. in. and one of 20, changing the second one to 15 sq. in. will still likely hinder flow, even though its still larger than the first restriction. In a system as complex as our intake, it would be virtually impossible to arrive at an analytical solution. You could model the system and make some approximations, or use a finite elements/CFD approach, and that might shed some light on it. Or the simplest way would be to test an intake setup on a flow bench with and without the plate and get some empirical data. The fact is though that as I understand it, it's a moot point whether or not it reduces flow or not. I don't think any of us compare whose intakes flow more CFM at a certain pressure differential, do we? We generally compare power and torque numbers, or 1/4 mile trap speeds and ET's. If the plate allows for more boost and more power on a given setup (which I think the consensus and the limited testing i've come across says it does) then does it matter if in the process of doing that it reduces flow through the intake?
Think of it this way, we all know that better exhaust flow means more power in an internal combustion engine (thats why headers and 3" exhaust systems are made). By bolting a turbo into that exhaust stream, you are adding one hell of a restriction to exhaust flow. Do any of us care? No, because the net result is more power and more speed. The powerplate seems to make people's cars run faster. If in the process it reduces intake volumetric flow slightly (which it very well could, and certainly seems like it would) does anyone care?
If I sounded like I was talking down to anyone on technical issues by over-simplifying, my apologies, it certainly wasn't my intent. If I sounded like I was talking over anyones heads, same thing goes. It's hard for me to put this stuff into words when I barely understand it myself, much less make sure other people can make sense of those words
Fluid mechanics is tricky stuff, very little of it is intuitive. I was just trying to shed some light on a subject that for once I actually know something about ThatDamGoldCar
not a Buick nutt hugger
- Joined
- Oct 8, 2006
Bottom line throw it in the trash...
turbo nasty
Turbo Dojo / MNTR
- Joined
- Jul 19, 2001
Sorry but if its not a measureable amount then it doesnt mean much and no one has yet to produce an actual loss of power. Back to back data logged runs where the duty cycle dropped would be good indicator. The cfm is dictated by the engine speed. 1000psi or 5 inches of vacuum at WOT its still the same cfm for any given rpm. I went nearly 134mph on a tired stock bottom ended engine and had the plate installed. Pressure above the plate was 28.5psi at 5750rpm in 3rd.. I wish i data logged under the plate. Id buy it if it was more than .1psi difference but figured id be disappointed after removing it. Until someone produces an accurate datalogged number what has been posted is of little use as a before and after comparison. Im sure you agree that any increase in plenum volume is the way to minimize the air distribution problems.
Corey, I have read a lot of these PP threads over the years. Your contribution makes more sense to me than any I have read in a long time. It affirms a couple of views on this subject I have been just keeping to myself due to lack of expertise. Thanks for your input!
BlackBandit
God loves Buicks!
- Joined
- Mar 29, 2003
http://www.turbobuick.com/forums/general-turbo-buick-tech/282362-rjc-plate.html
Look at the pictures.
Look at the pictures.
Turbo6Smackdown
Well-Known Member
- Joined
- Dec 31, 2005
I'm with him. My engines going to get rebuilt (to stock specs) this winter. After this takes place, I will make those runs. Some with the plate, and some without. And I will have it all logged. We shall see..
Though, I can't help to think, that the throttle response will be increased by a bit, without it there...
