George Bryce
Enthusiast
Re: Vacuum pump tech; free up that hidden horsepower
OK, it won't work.......go back to sleep. Jack, I think you could be right.
GB3
OK, it won't work.......go back to sleep. Jack, I think you could be right.
GB3
Vacuum pump tech; free up that hidden horsepower
- Thread starter FE 065
- Start date
Re: Vacuum pump tech; free up that hidden horsepower
Also, to reiterate a comment made above (and one that probably won't show until you find out the hard way) is the effect on oil pressure. If you are able to draw a 20 in vacuum (approx 10 psi) the oil pump will be sucking against a pretty hard pull. Not sure what the area of the oil pick-up is but I would guess it is several inches in cross-sectional area. I believe that would have a significant effect on the delivered oil pressure.
Also, to reiterate a comment made above (and one that probably won't show until you find out the hard way) is the effect on oil pressure. If you are able to draw a 20 in vacuum (approx 10 psi) the oil pump will be sucking against a pretty hard pull. Not sure what the area of the oil pick-up is but I would guess it is several inches in cross-sectional area. I believe that would have a significant effect on the delivered oil pressure.
ChicagoGTS
Enthusiast
I am one of those that are on the fence on something like this. I just bought a puke can to catch any oil that may get blown out, but if a vaccume system would be better(still looking for a link, I seached for one too) convince me with some dyno numbers.
Edit: Pictures please
Sorry for the ignorant question, but who makes the puke can you're using. I've been wanting to do something along these lines but I've never been able to find anything.
~Matt~
Re: Vacuum pump tech; free up that hidden horsepower
The magazine articles do mention a drop in oil pressure is typical, though with my pump
I haven't noticed any drop in pressure at 10in/Hg . No big deal if you know what to expect was the Hot Rod comment on it if I remember corectly
The magazine articles do mention a drop in oil pressure is typical, though with my pump
I haven't noticed any drop in pressure at 10in/Hg . No big deal if you know what to expect was the Hot Rod comment on it if I remember corectly
Re: Vacuum pump tech; free up that hidden horsepower
25 inches, wow! George is there anything done to the engine's oil system to accomodate that kind of vacuum? Or don't you feel in this case the engine's oiling system is affected at all by the high vacuum?
Failing to achieve more than 7-8in at WOT I added a second electric pump and in a short test didn't gain anymore vacuum at all! (I sent the second pump back for a full refund) I also tried adding an accumulator tank using large diameter PVC (airtight) as a quick experiment, also with no increase in vacuum-not even for a second!
I'm open as to where such a leak might be if there's something unique about the Viper engine that should be looked at. I am thinking the lifter valley PCV hose is a potential leak source where is just slips into the valley grommet. I haven't had the intake off yet to examine it.
The electric pump will pull 24in vacuum with a short length of hose and a gauge on it. The pump will hold that vacuum on the gauge when I shut it off too, so there's no bleeding off or backflow loss through the pump. The pump also pulled 24in within a few seconds when connected to the accumulator tank I made.
The inability for the little pump that could to pull higher vacuum on the engine is probably seepage past rings, ring end gaps, and open intake/exhaust valves.
Though I would have thought adding a second pump would have given another inch or two of vacuum. I even tried an electric boost-a-pump on the single vacuum pump before adding the second electric pump. The pump would speed up from the extra voltage, but there was no more vacuum prodcued at all.
From plugging the end of the hose with my finger, getting 24in of vacuum, and then moving my finger just a hair to produce a small crack, I can see it doesn't take much of a leak to drop the vacuum in half.
I've sealed off the forward facing valve cover PCV spigots, removed and capped the rest of the PCV ports, and tested everything for leaks, but the leak is probably so small it'd be almost impossible to find without a smoke machine leak detector.
I'm kind of betting on a main seal being the problem. Something is sealing well enough to allow 10in of vacuum which is quite a bit, but apparently gets pulled open just a tad by any higher vacuum, and won't allow any more.
The electric pump will vent even when it's off, but makes an odd noise while doing so, but more adequate system should probably be used if the pump's not on continuously.
JackB I remember a post where someone had installed 2 Krankvents on their Viper engine and complained of an odd noise. They didn't measure any actual levels of vacuum; as a wild guess I don't see the one way valve Krankvent(s) achieving high levels of vacuum.
25 inches, wow! George is there anything done to the engine's oil system to accomodate that kind of vacuum? Or don't you feel in this case the engine's oiling system is affected at all by the high vacuum?
Failing to achieve more than 7-8in at WOT I added a second electric pump and in a short test didn't gain anymore vacuum at all! (I sent the second pump back for a full refund) I also tried adding an accumulator tank using large diameter PVC (airtight) as a quick experiment, also with no increase in vacuum-not even for a second!
I'm open as to where such a leak might be if there's something unique about the Viper engine that should be looked at. I am thinking the lifter valley PCV hose is a potential leak source where is just slips into the valley grommet. I haven't had the intake off yet to examine it.
The electric pump will pull 24in vacuum with a short length of hose and a gauge on it. The pump will hold that vacuum on the gauge when I shut it off too, so there's no bleeding off or backflow loss through the pump. The pump also pulled 24in within a few seconds when connected to the accumulator tank I made.
The inability for the little pump that could to pull higher vacuum on the engine is probably seepage past rings, ring end gaps, and open intake/exhaust valves.
Though I would have thought adding a second pump would have given another inch or two of vacuum. I even tried an electric boost-a-pump on the single vacuum pump before adding the second electric pump. The pump would speed up from the extra voltage, but there was no more vacuum prodcued at all.
From plugging the end of the hose with my finger, getting 24in of vacuum, and then moving my finger just a hair to produce a small crack, I can see it doesn't take much of a leak to drop the vacuum in half.
I've sealed off the forward facing valve cover PCV spigots, removed and capped the rest of the PCV ports, and tested everything for leaks, but the leak is probably so small it'd be almost impossible to find without a smoke machine leak detector.
I'm kind of betting on a main seal being the problem. Something is sealing well enough to allow 10in of vacuum which is quite a bit, but apparently gets pulled open just a tad by any higher vacuum, and won't allow any more.
The electric pump will vent even when it's off, but makes an odd noise while doing so, but more adequate system should probably be used if the pump's not on continuously.
JackB I remember a post where someone had installed 2 Krankvents on their Viper engine and complained of an odd noise. They didn't measure any actual levels of vacuum; as a wild guess I don't see the one way valve Krankvent(s) achieving high levels of vacuum.
joe117
Enthusiast
Re: Vacuum pump tech; free up that hidden horsepower
Why would the engine oil pressure change?
If the stock engine makes 40psi at some rpm, what we really are seeing is a 40lb delta between outside air pressure and the oil in a gallery tube under pressure from the oil pump.
When there is a vacuum in the crankcase,
What will cause the volume of oil delivered to the engine to change?
The oil pump is a positive displacement gear pump.
It pumps a volume not a pressure delta.
Is the quantity of pumped oil less because of the vacuum in the crankcase?
If the quantity of oil is not changed then why would the measured oil pressure change?
The oil isn't compressable is it?
Why would the engine oil pressure change?
If the stock engine makes 40psi at some rpm, what we really are seeing is a 40lb delta between outside air pressure and the oil in a gallery tube under pressure from the oil pump.
When there is a vacuum in the crankcase,
What will cause the volume of oil delivered to the engine to change?
The oil pump is a positive displacement gear pump.
It pumps a volume not a pressure delta.
Is the quantity of pumped oil less because of the vacuum in the crankcase?
If the quantity of oil is not changed then why would the measured oil pressure change?
The oil isn't compressable is it?
Tom F&L GoR
Enthusiast
Re: Vacuum pump tech; free up that hidden horsepower
The 40 psi the pump puts out is psi "gauge" relative to the crankcase, since the back of the relief valve has to see the crankcase when the valve opens and releases oil. The 40 psig the oil pressure measurement shows is relative to the atmospheric pressure. When the crankcase is under vacuum, you are shifting the reference for one, but not the other. If you had 7 in Hg vacuum, you would see about 3.4 psi drop.
I guess you could think of the vacuum working against (to open) the relief valve spring.
The pump is positive displacement, so the volume (relief valve closed) through the pump won't change. Other factors besides the crankcase pressure affect pressure differential further downstream through the engine (fluid friction through the oil gallery, centrifugal forces in the crank) and so I want to say that oil delivery to the end points might be less.
The 40 psi the pump puts out is psi "gauge" relative to the crankcase, since the back of the relief valve has to see the crankcase when the valve opens and releases oil. The 40 psig the oil pressure measurement shows is relative to the atmospheric pressure. When the crankcase is under vacuum, you are shifting the reference for one, but not the other. If you had 7 in Hg vacuum, you would see about 3.4 psi drop.
I guess you could think of the vacuum working against (to open) the relief valve spring.
The pump is positive displacement, so the volume (relief valve closed) through the pump won't change. Other factors besides the crankcase pressure affect pressure differential further downstream through the engine (fluid friction through the oil gallery, centrifugal forces in the crank) and so I want to say that oil delivery to the end points might be less.
George Bryce
Enthusiast
Re: Vacuum pump tech; free up that hidden horsepower
Hi everyone, I did a test 10 years ago that HotRod mag. has not done yet. My NHRA engine runs at 10 oil psi....I watched the gauge drop to zero as my vacuum pump went to 25 inches. It startled me so I put clear hose on the oil psi to the head, so I could watch what was going on. I fired the engine, watched the hose fill, then I turned on the electric pump...the hose stayed full of oil and the oil psi went to zero again. Then I shut off the engine and turned on the vacuum pump, I let it build to 25 inches, then I fired the engine again, the oil jumped through the clear hose even as the gauge showed zero. 10 years ago I could not call anyone to ask about this. The late great John Myers and I won lots of races ...keeping this as a secret for a couple of years. We covered it in a black aluminum box. We would switch it on after the burnout. The internals in the engine were always great looking....so I have used as much vacuum as I could since 1994. A few years ago we realized that the zero oil psi was, as Tom and Joe said, was referenced to the outside atmosphere. We always had our 10 pounds above pan atmosphere in the engine. Later on as we kept increasing rpm we would need more vacuum. Angelle and I won 28 NHRA races with 3 vacuum pumps on the bike. NHRA tech. department just about had enough at this point. So all the motorcycle teams had a meeting and voted on how many pumps you could have. Everyone voted, out loud ONE!!!! Angelle said FIVE!!! Then I almost peed in my pants, she said in front of all of the Tech crew and racers....If I can have only one pump, then I vote that the riders can only have one BALL!!! Peace out, GB3
Hi everyone, I did a test 10 years ago that HotRod mag. has not done yet. My NHRA engine runs at 10 oil psi....I watched the gauge drop to zero as my vacuum pump went to 25 inches. It startled me so I put clear hose on the oil psi to the head, so I could watch what was going on. I fired the engine, watched the hose fill, then I turned on the electric pump...the hose stayed full of oil and the oil psi went to zero again. Then I shut off the engine and turned on the vacuum pump, I let it build to 25 inches, then I fired the engine again, the oil jumped through the clear hose even as the gauge showed zero. 10 years ago I could not call anyone to ask about this. The late great John Myers and I won lots of races ...keeping this as a secret for a couple of years. We covered it in a black aluminum box. We would switch it on after the burnout. The internals in the engine were always great looking....so I have used as much vacuum as I could since 1994. A few years ago we realized that the zero oil psi was, as Tom and Joe said, was referenced to the outside atmosphere. We always had our 10 pounds above pan atmosphere in the engine. Later on as we kept increasing rpm we would need more vacuum. Angelle and I won 28 NHRA races with 3 vacuum pumps on the bike. NHRA tech. department just about had enough at this point. So all the motorcycle teams had a meeting and voted on how many pumps you could have. Everyone voted, out loud ONE!!!! Angelle said FIVE!!! Then I almost peed in my pants, she said in front of all of the Tech crew and racers....If I can have only one pump, then I vote that the riders can only have one BALL!!! Peace out, GB3
joe117
Enthusiast
Re: Vacuum pump tech; free up that hidden horsepower
So,
If you mount the oil pressure gauge inside a rigid box with a clear window,
and you run a vent line from the box to the crankcase to keep the outside of the gauge at crankcase pressure,
Then run a pressurized oil line to the gauge,
you will see the actual oil pressure in the engine with no effect from the positive or negative pressure in the crankcase.
So,
If you mount the oil pressure gauge inside a rigid box with a clear window,
and you run a vent line from the box to the crankcase to keep the outside of the gauge at crankcase pressure,
Then run a pressurized oil line to the gauge,
you will see the actual oil pressure in the engine with no effect from the positive or negative pressure in the crankcase.
Tom F&L GoR
Enthusiast
Re: Vacuum pump tech; free up that hidden horsepower
Joe,
You will be measuring the pressure change (an increase in this case) between the inlet and the outlet of the pump (assuming the pressure gauge tap is near the outlet of the pump.) Same as if you put the gauge inside the crankcase.
To both explain and confuse things, if you put the vacuum gauge inside the crankcase, it would always read zero! When it's outside the crankcase, it's measuring the pressure change (negative relative to atmospheric) between the crankcase and the barometric pressure.
Lastly, if you didn't have a rigid box to measure "actual" pressure, you could add the vacuum level (15 in Hg is about 7.5 psi) and the apparent gauge pressure (example : 30 psi) and then the pressure change from the inlet to outlet of the oil pump would be 37.5 psi.
Joe,
You will be measuring the pressure change (an increase in this case) between the inlet and the outlet of the pump (assuming the pressure gauge tap is near the outlet of the pump.) Same as if you put the gauge inside the crankcase.
To both explain and confuse things, if you put the vacuum gauge inside the crankcase, it would always read zero! When it's outside the crankcase, it's measuring the pressure change (negative relative to atmospheric) between the crankcase and the barometric pressure.
Lastly, if you didn't have a rigid box to measure "actual" pressure, you could add the vacuum level (15 in Hg is about 7.5 psi) and the apparent gauge pressure (example : 30 psi) and then the pressure change from the inlet to outlet of the oil pump would be 37.5 psi.
joe117
Enthusiast
Re: Vacuum pump tech; free up that hidden horsepower
Well, here's what I'm saying.
In a normal car the crankcase is at about atmospheric pressure, so the dash mounted gauge connected by a tube to the oil gallery shows psig oil pressure and that is close to the real pressure in the oil gallery. if the crankcase is at atmospheric, then psig is the real oil pressure.
If there is a negative pressure in the crankcase, the psig will not be the pressure in the oil gallery since the crankcase pressure is negative and the gauge is showing pressure above atmospheric since the gauge is mounted on the dash.
I think we are both saying that.
So,
measuring the delta between the inlet and outlet is what we want to measure and a way to do that is to put the gauge in the box I talked about.
Of course a gauge in the crankcase or a gauge in your toolbox will read zero since both sides of the gauge are at the same pressure, negative or positive.
I think we are saying the same thing.
If you want to monitor the actual oil pressure with a gauge in a system that picks up oil from the crankcase, and pumps it under pressure to the bearings, then you must normalize the measurement system so that you are measuring the delta between the inside of the bearings and the outside of the bearings. If the outside of the bearings are in the crankcase, then the outside of the gauge must be at the pressure of the outside of the bearings. Thus the box.
If you do that, you will see the pressure to the bearings if the engine is somehow running deep under the sea or in outer space.
And the pressure to the bearings is what we are monitoring.
Again, I think we are saying the same thing.
Well, here's what I'm saying.
In a normal car the crankcase is at about atmospheric pressure, so the dash mounted gauge connected by a tube to the oil gallery shows psig oil pressure and that is close to the real pressure in the oil gallery. if the crankcase is at atmospheric, then psig is the real oil pressure.
If there is a negative pressure in the crankcase, the psig will not be the pressure in the oil gallery since the crankcase pressure is negative and the gauge is showing pressure above atmospheric since the gauge is mounted on the dash.
I think we are both saying that.
So,
measuring the delta between the inlet and outlet is what we want to measure and a way to do that is to put the gauge in the box I talked about.
Of course a gauge in the crankcase or a gauge in your toolbox will read zero since both sides of the gauge are at the same pressure, negative or positive.
I think we are saying the same thing.
If you want to monitor the actual oil pressure with a gauge in a system that picks up oil from the crankcase, and pumps it under pressure to the bearings, then you must normalize the measurement system so that you are measuring the delta between the inside of the bearings and the outside of the bearings. If the outside of the bearings are in the crankcase, then the outside of the gauge must be at the pressure of the outside of the bearings. Thus the box.
If you do that, you will see the pressure to the bearings if the engine is somehow running deep under the sea or in outer space.
And the pressure to the bearings is what we are monitoring.
Again, I think we are saying the same thing.
George Bryce
Enthusiast
Re: Vacuum pump tech; free up that hidden horsepower
I think that is the same thing I was saying too. It made sense to me 10 years ago. And it worked...but it still was scary to me with my trusty gauge showing zero! GB3
I think that is the same thing I was saying too. It made sense to me 10 years ago. And it worked...but it still was scary to me with my trusty gauge showing zero! GB3
George Bryce
Enthusiast
Re: Vacuum pump tech; free up that hidden horsepower
Oh yeah, the 3 pumps Angelle and I used were about 150.00 each. One pulled 14 inches, adding one more gave us 17. When we ran all three with three batteries we pulled 20 or 21 inches. This was on a lil ol 92 cu. in. engine. I think they were rated at 5 cfm each.....so three was barely enough. The one pump the racers forced us into is rated at 24 cfm! This pump is run with 24 volts too. Oh I forgot, it cost 2000.00. So like I said earlier....if it don't cost much....it might be worth about that much. GB3
Oh yeah, the 3 pumps Angelle and I used were about 150.00 each. One pulled 14 inches, adding one more gave us 17. When we ran all three with three batteries we pulled 20 or 21 inches. This was on a lil ol 92 cu. in. engine. I think they were rated at 5 cfm each.....so three was barely enough. The one pump the racers forced us into is rated at 24 cfm! This pump is run with 24 volts too. Oh I forgot, it cost 2000.00. So like I said earlier....if it don't cost much....it might be worth about that much. GB3
James Bell
Enthusiast
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Re: Vacuum pump tech; free up that hidden horsepower
I used a Stainless Steel Brakes vacuum pump to make vacuum for the power booster and the crankcase. I needed to run a separate pump because my Hogans Racing intake manifold did not have any vacuum bungs, also the cam profiles are very aggressive in the 540ci+.
Gen-1. I replaced the emissions charcoal canister with the electric pump inside the front bumper. It fit in perfectly, the canister is almost the same size as the pump. It runs very quite inside the bumper. I am controlling the vacuum pressure with a billet (adjustable)Moroso valve cover breather, which has a filter. The plumbing is run on the opposite (drivers) valve cover. Then the stainless hoses from the booster, valve cover and accessories are sent into a catch can. The pump pulls the vacuum in the catch can that I attached a gauge to. Stainless Steel Brakes sells the pump for a little less than Summit, but that was over a year ago. (hope this helps)
I used a Stainless Steel Brakes vacuum pump to make vacuum for the power booster and the crankcase. I needed to run a separate pump because my Hogans Racing intake manifold did not have any vacuum bungs, also the cam profiles are very aggressive in the 540ci+.
Gen-1. I replaced the emissions charcoal canister with the electric pump inside the front bumper. It fit in perfectly, the canister is almost the same size as the pump. It runs very quite inside the bumper. I am controlling the vacuum pressure with a billet (adjustable)Moroso valve cover breather, which has a filter. The plumbing is run on the opposite (drivers) valve cover. Then the stainless hoses from the booster, valve cover and accessories are sent into a catch can. The pump pulls the vacuum in the catch can that I attached a gauge to. Stainless Steel Brakes sells the pump for a little less than Summit, but that was over a year ago. (hope this helps)
Bugeater
Enthusiast
Re: Vacuum pump tech; free up that hidden horsepower
All this been going on for decades and nobody has graphical proof ie: before/after dyno?
Alot of people would like to see hard data.
All this been going on for decades and nobody has graphical proof ie: before/after dyno?
Alot of people would like to see hard data.
George Bryce
Enthusiast
Re: Vacuum pump tech; free up that hidden horsepower
I got some hard data:
No Pro race cars, trucks, or bikes run down the track without plenty of crankcase vacuum.
In 1994 when we started to use our vacuum pump, this is so long ago, that I don't think Al Gore had invented the Internet yet.
GB3
I got some hard data:
No Pro race cars, trucks, or bikes run down the track without plenty of crankcase vacuum.
In 1994 when we started to use our vacuum pump, this is so long ago, that I don't think Al Gore had invented the Internet yet.
GB3
David Jenkins
Enthusiast
Re: Vacuum pump tech; free up that hidden horsepower
The hard data is all the trophies on the shelves in GB3's barn. You and Chip comin' to Pamona ? dj
The hard data is all the trophies on the shelves in GB3's barn. You and Chip comin' to Pamona ? dj
George Bryce
Enthusiast
Re: Vacuum pump tech; free up that hidden horsepower
YES! And if you don't stop by and flag me down....you won't see me. GB3
YES! And if you don't stop by and flag me down....you won't see me.
GB3Re: Vacuum pump tech; free up that hidden horsepower
Racers don't like to give up their secrets!
I brought the subject up to a number of people in the last year. They usually dismissed it like I'd seen a UFO or something...
How much work does it take to move around 1700cfm of oil mist and blow-by laden air at 6000rpm?How much faster can an airplane fly in 25-50% less atmosphere?
How come no Viper shops are (apparently) using crank scrapers? (they've been around decades as well) I mentioned scrapers to one Viper tuner whose shop produces 9sec Vipers recently and he didn't know what they were; no idea. - Which only means that there's more from the racing world to be applied to Vipers.
Dogpile, Yahoo, Google etc searches with enough key words to separate industrial pumps from racing pumps will provide info.
Racers don't like to give up their secrets!
I brought the subject up to a number of people in the last year. They usually dismissed it like I'd seen a UFO or something...
How much work does it take to move around 1700cfm of oil mist and blow-by laden air at 6000rpm?How much faster can an airplane fly in 25-50% less atmosphere?
How come no Viper shops are (apparently) using crank scrapers? (they've been around decades as well) I mentioned scrapers to one Viper tuner whose shop produces 9sec Vipers recently and he didn't know what they were; no idea. - Which only means that there's more from the racing world to be applied to Vipers.
Dogpile, Yahoo, Google etc searches with enough key words to separate industrial pumps from racing pumps will provide info.
joe117
Enthusiast
Re: Vacuum pump tech; free up that hidden horsepower
I asked if the power gain could be coming from aerodynamic drag against the crank/rods.
Now remember, I'm not talking about crank contact with liquid oil or dense foam, that's a dry sump question, not vacuum in the crankcase.
The crank and rods are really not moving that fast. I just can't see aerodynamic drag inside the crankcase being a big deal.
Perhaps the gain is coming from the vacuum in the crankcase sucking more fuel/air into the cylinders on intake stroke.
there seems to be a general agreement that the lower pressure in the crankcase produces more power, I can't argue with the guys that have been doing it for a decade.
But,
I still haven't gotten a good answer as to exactly where the power is coming from.
I asked if the power gain could be coming from aerodynamic drag against the crank/rods.
Now remember, I'm not talking about crank contact with liquid oil or dense foam, that's a dry sump question, not vacuum in the crankcase.
The crank and rods are really not moving that fast. I just can't see aerodynamic drag inside the crankcase being a big deal.
Perhaps the gain is coming from the vacuum in the crankcase sucking more fuel/air into the cylinders on intake stroke.
there seems to be a general agreement that the lower pressure in the crankcase produces more power, I can't argue with the guys that have been doing it for a decade.
But,
I still haven't gotten a good answer as to exactly where the power is coming from.
Torquemonster
Enthusiast
Re: Vacuum pump tech; free up that hidden horsepower
Joe - racers do not typically bother themselves with the science behind why some things work. After satisfying themselves there is some logic to why they should try it - the only 2 things that interest them are:
1 - will it hurt anything?
2 - will it help them go faster?
If the answers are "no" and "yes" to the above - they'll be into it like a fly to road kill.
It is the same with cyrogenics and many other things that are proven to work in racing - but there is not a lot of public forum info around to create a scientific case outside the hype and data from those that offer the services.
Back to vacuum pumps - they are universally accepted in the racing industry to aid power in a racing engine. Why?
Does vacuum really help flatten the rings and reduce flutter and blow by? Does the power come instead from reduced pumping losses, or reduce windage?
Your thoughts about why are as good as anyones - maybe if it was better understood some laws and models could be developed around the data that would enable engine builders to predict exactly what engines would benefit and how much vacuum they needed. This would take out the trial and error of racing.
In the meantime - oil control is worthy of attention in a serious engine.
FE - crank scrapers indeed work, the problem with them is if the engine develops a problem and that leads to something hitting the scraper which can (and many times has) lead to it getting caught up and thrown all over the engine doing all sorts of nasty things that would make a grown man cry.
For this reason some will not use them, while others use them and say "oh well - if anything hits, we'll have to rebuild something anyway". Sounds like someone with a really big budget might say that.... lol the rest would rather minimize collatoral damage
There is a better way to control oil via sump and baffle design, internal oiling mods, and a cam undercarriage fabricated to stop oil from dripping onto the crank that directs the oil away. Also, in a high rpm'g engine, oil often accumulates up in the valve cover area which creates drag in the valvetrain and can starve the bottom end unless oil capacity is not increased. The most common fix is to create oil drain back lines from the back of each bank to the sump to assist in getting the oil back quickly and without hitting the crank on the way down.
Oiling can be massively improved and capacity needs can be further reduced via clever machining tricks - but if I revealed those here the person who taught them to me might kill me
and i hate to die
Joe - racers do not typically bother themselves with the science behind why some things work. After satisfying themselves there is some logic to why they should try it - the only 2 things that interest them are:
1 - will it hurt anything?
2 - will it help them go faster?
If the answers are "no" and "yes" to the above - they'll be into it like a fly to road kill.
It is the same with cyrogenics and many other things that are proven to work in racing - but there is not a lot of public forum info around to create a scientific case outside the hype and data from those that offer the services.
Back to vacuum pumps - they are universally accepted in the racing industry to aid power in a racing engine. Why?
Does vacuum really help flatten the rings and reduce flutter and blow by? Does the power come instead from reduced pumping losses, or reduce windage?
Your thoughts about why are as good as anyones - maybe if it was better understood some laws and models could be developed around the data that would enable engine builders to predict exactly what engines would benefit and how much vacuum they needed. This would take out the trial and error of racing.
In the meantime - oil control is worthy of attention in a serious engine.
FE - crank scrapers indeed work, the problem with them is if the engine develops a problem and that leads to something hitting the scraper which can (and many times has) lead to it getting caught up and thrown all over the engine doing all sorts of nasty things that would make a grown man cry.
For this reason some will not use them, while others use them and say "oh well - if anything hits, we'll have to rebuild something anyway". Sounds like someone with a really big budget might say that.... lol the rest would rather minimize collatoral damage
There is a better way to control oil via sump and baffle design, internal oiling mods, and a cam undercarriage fabricated to stop oil from dripping onto the crank that directs the oil away. Also, in a high rpm'g engine, oil often accumulates up in the valve cover area which creates drag in the valvetrain and can starve the bottom end unless oil capacity is not increased. The most common fix is to create oil drain back lines from the back of each bank to the sump to assist in getting the oil back quickly and without hitting the crank on the way down.
Oiling can be massively improved and capacity needs can be further reduced via clever machining tricks - but if I revealed those here the person who taught them to me might kill me
and i hate to die
joe117
Enthusiast
Re: Vacuum pump tech; free up that hidden horsepower
Barry, all that talk about oil control is true, but it doesn't have anything to do with vacuum in the crankcase.
Racers who see someone going fast with a trick part will copy it and go faster.
These copy cats are not the ones who really know what's going on.
In fact, I knew stock car racers that would put a bag of dog crap in the trunk if they thought the leaders had them.
So, just because they decide the answers to the two questions are "no" and "yes", and that's all they care about,
doesn't mean that the real science isn't worth understanding.
Again,
I'm not questioning the reality of the power gains. It's just that I can't seem to get anyone to pin down the cause and effect.
Folks keep talking about oil control and aero drag. The first isn't vacuum related. The second can't be worth much.
It works, OK. Why?
Barry, all that talk about oil control is true, but it doesn't have anything to do with vacuum in the crankcase.
Racers who see someone going fast with a trick part will copy it and go faster.
These copy cats are not the ones who really know what's going on.
In fact, I knew stock car racers that would put a bag of dog crap in the trunk if they thought the leaders had them.
So, just because they decide the answers to the two questions are "no" and "yes", and that's all they care about,
doesn't mean that the real science isn't worth understanding.
Again,
I'm not questioning the reality of the power gains. It's just that I can't seem to get anyone to pin down the cause and effect.
Folks keep talking about oil control and aero drag. The first isn't vacuum related. The second can't be worth much.
It works, OK. Why?
Torquemonster
Enthusiast
Re: Vacuum pump tech; free up that hidden horsepower
I don't know Joe - I accepted the usual answers about reducing ring blow by... your questions are good but I don't have the answers.
It's like we used to pick up 6% at the wheels on muscle cars and hi perf carby engines by fitting large activated carbon fuel cannisters we made up using PVC piping and pantyhose and a few fittings (wife never missed the hose...lol).... I have no idea why it made power, we had theories, but the results worked everytime so we kept doing it and sold a few to customers who wanted the same results.... a few years later we discovered many EFI cars were having them fitted as an "emissions" device. Our experience is that if they are big enough to not hurt flow, and proper activated carbon is used - they do something to the fuel and it increases power - but why? No idea. Actually - it also reduces octane requirement - we got a car that previously needed avgas to run even quicker on 91 using carbon (without knock) - but with no real understanding that i could hold a debate over it.
Like vacuum pumps - it worked so we did it, but unlike vacuum pumps - we did not know anybody else who did what we did so had no other data to go off other than some theory me and my employee came up with, tried it for fun, then found it worked.
Measuring the gains is easy - explaining why - that is not easy.
I don't know Joe - I accepted the usual answers about reducing ring blow by... your questions are good but I don't have the answers.
It's like we used to pick up 6% at the wheels on muscle cars and hi perf carby engines by fitting large activated carbon fuel cannisters we made up using PVC piping and pantyhose and a few fittings (wife never missed the hose...lol).... I have no idea why it made power, we had theories, but the results worked everytime so we kept doing it and sold a few to customers who wanted the same results.... a few years later we discovered many EFI cars were having them fitted as an "emissions" device. Our experience is that if they are big enough to not hurt flow, and proper activated carbon is used - they do something to the fuel and it increases power - but why? No idea. Actually - it also reduces octane requirement - we got a car that previously needed avgas to run even quicker on 91 using carbon (without knock) - but with no real understanding that i could hold a debate over it.
Like vacuum pumps - it worked so we did it, but unlike vacuum pumps - we did not know anybody else who did what we did so had no other data to go off other than some theory me and my employee came up with, tried it for fun, then found it worked.
Measuring the gains is easy - explaining why - that is not easy.
Re: Vacuum pump tech; free up that hidden horsepower
The thought did occur to me last year that maybe high vacuum was pulling extra intake charge into the cylinders. If it was, wouldn't it also be pulling on exhaust gases?
Exhaust gases are under tremenduous pressure and are going to head for the path of least resistance; the exhaust valve, for the most part. There should still be enough dilution that it'd upset overall power if the pump vacuum is present above the piston.
Pick up the new Popular Hotrodding and read their carefully done comparisons of crank throws before and after aero mods if you want recent evidence of the gains to be had in the crankcase. Aero crank mods aren't new either.
There's still that 1700cfm of crankcase air that has to be pumped back and forth at 6000rpm; and that confined air just gets denser as RPMs increase.
A 10 cylinder's crankcase pumping losses would be even greater than an 8 cylinder's...
The thought did occur to me last year that maybe high vacuum was pulling extra intake charge into the cylinders. If it was, wouldn't it also be pulling on exhaust gases?
Exhaust gases are under tremenduous pressure and are going to head for the path of least resistance; the exhaust valve, for the most part. There should still be enough dilution that it'd upset overall power if the pump vacuum is present above the piston.
Pick up the new Popular Hotrodding and read their carefully done comparisons of crank throws before and after aero mods if you want recent evidence of the gains to be had in the crankcase. Aero crank mods aren't new either.
There's still that 1700cfm of crankcase air that has to be pumped back and forth at 6000rpm; and that confined air just gets denser as RPMs increase.
A 10 cylinder's crankcase pumping losses would be even greater than an 8 cylinder's...
joe117
Enthusiast
Re: Vacuum pump tech; free up that hidden horsepower
I don't have a copy of Popular Hotrodding. I'll take a look.
Are they claiming reduced loss from oil contact or just aero drag?
I don't see the crank going fast enough for reduced aero to be a big gainer,
and remember, the air in the crankcase will probably start turning with the crank.
This will reduce the V delta.
I'll bet we are on to something with the crankcase vacuum pulling more charge into the cylinder during intake.
Remember, the intake stroke is the only time when the rings are not driven against the lower side of the ring groove.
I'll bet that there is leakage past the rings on intake and the vacuum in the crankcase leaks into the cylinder causing a larger pressure delta between the outside air and the cylinder.
That seems like the only way substantial power gains could be produced by a crankcase vacuum.
I don't have a copy of Popular Hotrodding. I'll take a look.
Are they claiming reduced loss from oil contact or just aero drag?
I don't see the crank going fast enough for reduced aero to be a big gainer,
and remember, the air in the crankcase will probably start turning with the crank.
This will reduce the V delta.
I'll bet we are on to something with the crankcase vacuum pulling more charge into the cylinder during intake.
Remember, the intake stroke is the only time when the rings are not driven against the lower side of the ring groove.
I'll bet that there is leakage past the rings on intake and the vacuum in the crankcase leaks into the cylinder causing a larger pressure delta between the outside air and the cylinder.
That seems like the only way substantial power gains could be produced by a crankcase vacuum.
