Vacuum pumps
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Joined: Oct 2002
Posts: 6,518
You guys have some cool ideas with this. I never thought about doing all of this.
Some things you should look into though.
There have been some interesting Spintron tests on engines just to test vaccum pumps. Holding the engine steady, say at 6,000rpm and then changing the speed of the vaccum pump and look at the power it takes to spin the engine (basically the frictional HP) the results are pretty interesting. Bill Hancock of Arrow Racing Engines is the guy to talk to about this. He might not tell you the answer to this. But his tests have lead him not to like Vaccum Pumps, belt or electric.
I do think that a crankcase evac system is helpfull. As long as you can vent the crankcase to lower the pressure it's a good deal.
The other side of this is piston rings. The only need for a low vaccum crankcase is that you are running really low tension rings, say oil rings with a tension in the 2-5lbs range. Standard tension 15-20lbs rings really don't need them and the middle tension (or low tensions as most companies call them) in the 8-10lbs range can be run easy with nothing helping them out other than a filter IF you have the right ring pack and cylinder wall finish. The best way to do that is to keep the pressure that gets into the compression rings up there and not get down into the oil ring. Going with the right gapless set is the way to go. The standard theory of having a big second ring gap to let the pressure by just causes oil ring problems. Fix the sealing issue and you can run low tension oils on a non vaccum pump engine.
Bret
Some things you should look into though.
There have been some interesting Spintron tests on engines just to test vaccum pumps. Holding the engine steady, say at 6,000rpm and then changing the speed of the vaccum pump and look at the power it takes to spin the engine (basically the frictional HP) the results are pretty interesting. Bill Hancock of Arrow Racing Engines is the guy to talk to about this. He might not tell you the answer to this. But his tests have lead him not to like Vaccum Pumps, belt or electric.
I do think that a crankcase evac system is helpfull. As long as you can vent the crankcase to lower the pressure it's a good deal.
The other side of this is piston rings. The only need for a low vaccum crankcase is that you are running really low tension rings, say oil rings with a tension in the 2-5lbs range. Standard tension 15-20lbs rings really don't need them and the middle tension (or low tensions as most companies call them) in the 8-10lbs range can be run easy with nothing helping them out other than a filter IF you have the right ring pack and cylinder wall finish. The best way to do that is to keep the pressure that gets into the compression rings up there and not get down into the oil ring. Going with the right gapless set is the way to go. The standard theory of having a big second ring gap to let the pressure by just causes oil ring problems. Fix the sealing issue and you can run low tension oils on a non vaccum pump engine.
Bret
Registered User
Joined: Feb 2000
Posts: 35
From: Chickasha, OK
Brett,
I have to disagree with you a little here. First, venture on to the NMCA or PRO board and see what their experiences are with gapless rings. An overwhelming majority of these heads-up racers detest gapless rings. Also, a large majority of these racers use vacuum pumps. A good friend of mine is the winner of the PRO Pro Stock category in 2002, Chris Uratchko. He has dyno tested his engine with different levels of vacuum, and the dyno showed HP improvements up to 18-20" Hg. And, yes he has very low tension oil rings. I agree that one of the major benefits of vacuum pumps is the ability to run lower oil ring tensions. For this reason, the spintron test is not totally accurate. Sure, a vacuum pump takes power, and the higher the vacuum, the higher the power consumption. Noone argues with that. The advantage is that while the engine is running, the benefits of vacuum in the crankcase can outweigh, and even overcome the losses due to the pump. A Spintron just turns the engine at a specified RPM, and cannot take all parameters of a running engine into consideration.
Also, almost all serious Comp engines I've seen use vacuum pumps. And, everyone I have spoken to has seen improvements in e.t. and on the dyno with them. For me, the benefits of less oil leaks and combustion contamination make the vacuum pump worthwhile, even if there is no power increase.
Now, back to the original question. First, it is incorrect to say that ANY vacuum pump can pull 28" Hg. Also, the electric smog pump used on 88-92 LT-1's will NOT pull 28" Hg. I have tested them, others I know have also tested them. The results vary, I guess depending on the condition of the pump. Vacuum levels vary between 3-5" Hg. Not really enough to claim any HP improvements, but definitely enough to eliminate oil leaks and minimize combustion contamination. If you don't believe me, go to www.gofastzone.com and do a search. A couple of guys on that board are using the pumps and have measured their vacuum levels up to 5" Hg, but not over.
The reason these pumps don't pull high vacuum levels is because they were designed to MOVE air, not pull a vacuum. They were designed to take outside air and inject it into the exhaust. The internal tolerances of this pump are not good, and do not allow the pump to pull vacuum efficiently. The distance between the pump vane and body of the pump I tore apart was over 1/8". Also, they are NOT a positive displacment pump, like most aftermarket pumps are. They are like a small fan, they move a lot of air, but operate on very low static pressures.
The vacuum pumps used for brakes are just the opposite. They were desinged to pull high vacuums, but do not move much air. And, moving quite a bit of air is a requirement for a vacuum pump on an engine that will blowby about 2-3 percent of it's volume.
I am very anxious to see the new pump from Mr. Gasket. My friends and I have tried the electric pumps on our drag cars without much luck, and mounting a smog or aftermarket vacuum pump can be dificult. It is about time someone makes an electric pump that can pull around 12-15" Hg. My only question is what kind of amperage a pump like this would pull. We might have to put a small generator in the trunk to keep up!!!
lol
Shane
I have to disagree with you a little here. First, venture on to the NMCA or PRO board and see what their experiences are with gapless rings. An overwhelming majority of these heads-up racers detest gapless rings. Also, a large majority of these racers use vacuum pumps. A good friend of mine is the winner of the PRO Pro Stock category in 2002, Chris Uratchko. He has dyno tested his engine with different levels of vacuum, and the dyno showed HP improvements up to 18-20" Hg. And, yes he has very low tension oil rings. I agree that one of the major benefits of vacuum pumps is the ability to run lower oil ring tensions. For this reason, the spintron test is not totally accurate. Sure, a vacuum pump takes power, and the higher the vacuum, the higher the power consumption. Noone argues with that. The advantage is that while the engine is running, the benefits of vacuum in the crankcase can outweigh, and even overcome the losses due to the pump. A Spintron just turns the engine at a specified RPM, and cannot take all parameters of a running engine into consideration.
Also, almost all serious Comp engines I've seen use vacuum pumps. And, everyone I have spoken to has seen improvements in e.t. and on the dyno with them. For me, the benefits of less oil leaks and combustion contamination make the vacuum pump worthwhile, even if there is no power increase.
Now, back to the original question. First, it is incorrect to say that ANY vacuum pump can pull 28" Hg. Also, the electric smog pump used on 88-92 LT-1's will NOT pull 28" Hg. I have tested them, others I know have also tested them. The results vary, I guess depending on the condition of the pump. Vacuum levels vary between 3-5" Hg. Not really enough to claim any HP improvements, but definitely enough to eliminate oil leaks and minimize combustion contamination. If you don't believe me, go to www.gofastzone.com and do a search. A couple of guys on that board are using the pumps and have measured their vacuum levels up to 5" Hg, but not over.
The reason these pumps don't pull high vacuum levels is because they were designed to MOVE air, not pull a vacuum. They were designed to take outside air and inject it into the exhaust. The internal tolerances of this pump are not good, and do not allow the pump to pull vacuum efficiently. The distance between the pump vane and body of the pump I tore apart was over 1/8". Also, they are NOT a positive displacment pump, like most aftermarket pumps are. They are like a small fan, they move a lot of air, but operate on very low static pressures.
The vacuum pumps used for brakes are just the opposite. They were desinged to pull high vacuums, but do not move much air. And, moving quite a bit of air is a requirement for a vacuum pump on an engine that will blowby about 2-3 percent of it's volume.
I am very anxious to see the new pump from Mr. Gasket. My friends and I have tried the electric pumps on our drag cars without much luck, and mounting a smog or aftermarket vacuum pump can be dificult. It is about time someone makes an electric pump that can pull around 12-15" Hg. My only question is what kind of amperage a pump like this would pull. We might have to put a small generator in the trunk to keep up!!!
lolShane
Banned
Joined: Oct 2002
Posts: 6,518
Originally posted by 81ZMouse
Bret,
I have to disagree with you a little here. First, venture on to the NMCA or PRO board and see what their experiences are with gapless rings. An overwhelming majority of these heads-up racers detest gapless rings. Also, a large majority of these racers use vacuum pumps. A good friend of mine is the winner of the PRO Pro Stock category in 2002, Chris Uratchko. He has dyno tested his engine with different levels of vacuum, and the dyno showed HP improvements up to 18-20" Hg. And, yes he has very low tension oil rings. I agree that one of the major benefits of vacuum pumps is the ability to run lower oil ring tensions. For this reason, the spintron test is not totally accurate. Sure, a vacuum pump takes power, and the higher the vacuum, the higher the power consumption. Noone argues with that. The advantage is that while the engine is running, the benefits of vacuum in the crankcase can outweigh, and even overcome the losses due to the pump. A Spintron just turns the engine at a specified RPM, and cannot take all parameters of a running engine into consideration.
Also, almost all serious Comp engines I've seen use vacuum pumps. And, everyone I have spoken to has seen improvements in e.t. and on the dyno with them. For me, the benefits of less oil leaks and combustion contamination make the vacuum pump worthwhile, even if there is no power increase.
Shane
Bret,
I have to disagree with you a little here. First, venture on to the NMCA or PRO board and see what their experiences are with gapless rings. An overwhelming majority of these heads-up racers detest gapless rings. Also, a large majority of these racers use vacuum pumps. A good friend of mine is the winner of the PRO Pro Stock category in 2002, Chris Uratchko. He has dyno tested his engine with different levels of vacuum, and the dyno showed HP improvements up to 18-20" Hg. And, yes he has very low tension oil rings. I agree that one of the major benefits of vacuum pumps is the ability to run lower oil ring tensions. For this reason, the spintron test is not totally accurate. Sure, a vacuum pump takes power, and the higher the vacuum, the higher the power consumption. Noone argues with that. The advantage is that while the engine is running, the benefits of vacuum in the crankcase can outweigh, and even overcome the losses due to the pump. A Spintron just turns the engine at a specified RPM, and cannot take all parameters of a running engine into consideration.
Also, almost all serious Comp engines I've seen use vacuum pumps. And, everyone I have spoken to has seen improvements in e.t. and on the dyno with them. For me, the benefits of less oil leaks and combustion contamination make the vacuum pump worthwhile, even if there is no power increase.
Shane
Shane,
This is what I do here, put out things that are completely different than anybody else. Alot of my ideas are different from anybody else.
As for the gapless rings, I hear it all the time. "We can't get them to work, they are junk!" I'm not talking about gapless 2nds' and I get them to work perfectly. First key to oil control is to stop blow by, running a traditional setup with a gapped top and a large gap in the second just causes the oil ring to do less work. Running the right cylinder finish and the gapless tops virtually elminates this problem. The top rings are supposed to stop the pressure not oil ring. So even in a gapless setup where people feel they are getting "flutter" you open up the top gap more. The cylinder wall finish is a big part of all of this. Most people never pay any attention to the surface finish numbers on the wall, that's half of the equation with gapless rings. My number one rule to engine is "Just because everyone is doing it, doesn't mean it's right" Gapless rings fall into that rule for me. Nobody has to agree with me, but there is another side to the coin.
A vaccum pump that is not run by a belt drive off the engine is a good idea no matter what. It is bound to gain power that way. The jury is still out for me if there is enough gained power to out weight the parasidic losses. Most high end engines that use them also run a dry sump so they go hand in hand.
Still this is a good topic
Bret
Registered User
Joined: Feb 2000
Posts: 35
From: Chickasha, OK
Brett,
Almost NONE of the comp engines and heads-up engines I'm talking about use dry sump pumps. All use a wet sump pump, and most of them are mounted externally, like mine is. In fact, a lot of dry sump users don't use additional vacuum pumps because they pull enough vacuum on their own.
Your statement on eliminating blowby is interesting. I don't have test data, but Grumpy Jenkins believes blowby IS necessary, and without it oil control is impossible. And I must say, I trust what this man says. According to him, some amount of blowby is necessary to "clean" the rings and keep the oil from building up between them. Yes, in a perfect world, where no oil bypasses the oil ring, this is not necessary, but I think we all know it is not a perfect world, and no matter what you do, a small amount of oil will get by the oil ring. In fact, Grumpy even states that the main job of the second ring is an oil scraper, not a compression ring.
I have too many dyno charts from too many different people that show HP improvements from using a vacuum pump with vacuum levels around 15-20" Hg. Chris's engine was dyno tested by Tony at Bischoff Racing Engines, the same guys who build Gary Rohe's engines, and help out with Billy Glidden's engines. Again, people I trust because I always see thier engines in the winners circle at the track.
I agree that different opinions are required, but I would have to see a lot of different dyno tests from a lot of different people to disprove all the data I have showing vacuum pumps are worth power. When the winners circle is full of people using gapless rings with only breathers or header e-vacs, I might change my mind. But until then, I will continue to use my vacuum pumps. And I guess we'll just have to agree to disagree.
Shane
Almost NONE of the comp engines and heads-up engines I'm talking about use dry sump pumps. All use a wet sump pump, and most of them are mounted externally, like mine is. In fact, a lot of dry sump users don't use additional vacuum pumps because they pull enough vacuum on their own.
Your statement on eliminating blowby is interesting. I don't have test data, but Grumpy Jenkins believes blowby IS necessary, and without it oil control is impossible. And I must say, I trust what this man says. According to him, some amount of blowby is necessary to "clean" the rings and keep the oil from building up between them. Yes, in a perfect world, where no oil bypasses the oil ring, this is not necessary, but I think we all know it is not a perfect world, and no matter what you do, a small amount of oil will get by the oil ring. In fact, Grumpy even states that the main job of the second ring is an oil scraper, not a compression ring.
I have too many dyno charts from too many different people that show HP improvements from using a vacuum pump with vacuum levels around 15-20" Hg. Chris's engine was dyno tested by Tony at Bischoff Racing Engines, the same guys who build Gary Rohe's engines, and help out with Billy Glidden's engines. Again, people I trust because I always see thier engines in the winners circle at the track.
I agree that different opinions are required, but I would have to see a lot of different dyno tests from a lot of different people to disprove all the data I have showing vacuum pumps are worth power. When the winners circle is full of people using gapless rings with only breathers or header e-vacs, I might change my mind. But until then, I will continue to use my vacuum pumps. And I guess we'll just have to agree to disagree.
Shane
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Joined: Mar 1999
Posts: 659
From: Chicago, IL
I think Madman was the first one to really talk about it.
It's off those 4/6/8 Caddys.
I don't have a part number, I think it's like $120.
Supposedly pulls enuff vacuum to work.
It's electric.
Some of those aftermarket setups are huge and are belt driven so where are you gonna put it.
It's off those 4/6/8 Caddys.
I don't have a part number, I think it's like $120.
Supposedly pulls enuff vacuum to work.
It's electric.
Some of those aftermarket setups are huge and are belt driven so where are you gonna put it.
Registered User
Joined: Nov 2001
Posts: 1,751
From: Surrey, BC, Can
This is a great thread. I asked the VERY same question about 10 days ago. Thanks everyone.
http://web.camaross.com/forums/showt...+case+pressure
I have to read this thread over again but what I need is to try and get the crankcase pressure down on my daily driven SC'ed engine.
A guy at a GM dealership recommneded I use the air pump. He said that the LT1 air pumps were quite robust. I'm not really interested in any extra HP potential just keeping the blow-by down, preventing oil leaks (which HAVE been a problem for me) and keeping the engine bay clean.
He also talked about using the special valve that is attached at the header for the air pump as your vacuum check valve.
Basically running the air pump with the header valve in REVERSE with a puke tank. Does that idea have merit?
http://web.camaross.com/forums/showt...+case+pressure
I have to read this thread over again but what I need is to try and get the crankcase pressure down on my daily driven SC'ed engine.
A guy at a GM dealership recommneded I use the air pump. He said that the LT1 air pumps were quite robust. I'm not really interested in any extra HP potential just keeping the blow-by down, preventing oil leaks (which HAVE been a problem for me) and keeping the engine bay clean.
He also talked about using the special valve that is attached at the header for the air pump as your vacuum check valve.
Basically running the air pump with the header valve in REVERSE with a puke tank. Does that idea have merit?
Registered User
Joined: Nov 2001
Posts: 2,985
From: In a house by the bay
Bret,
Have you personally talked with Bill Hancock about this? I remember reading something right along the lines of what you said in a magazine here a while back.
I have to say that having been a dragger for the past 24 years, some of those competetive, that I agree with Shane on this one. I have seen countless dyno test that show very nice gains with vacuum pumps pullling 16-20" and low tension ring sets. As for the Grump Jenkins statement on blow-bye being a necessary evil to oil control, I agree also. Although I think quite a few people hold this to be true and have said so for a long time now.
wrt Gapless being "junk"... well that sums it up pretty good for me. It seems that everyone is changing their tune now.... see, before guys were praising the gapless second rings but then we found out that they caused more problems than they fixed... now everyone's jumping on the gapless 1st ring bandwagon. I'm sorry but I'll be taking the A-train this time around. My Speed Pro plasma moly ringsets work just fine for me and they work fine for everyone else I talk to. If it aint broke.....
Shane, interesting 377 you have there. What class are you building this engine for or is this just something you bracket race with? Interesting choice in the 11X heads, would you be interested in a set of sb2.2s?
-Mindgame
Have you personally talked with Bill Hancock about this? I remember reading something right along the lines of what you said in a magazine here a while back.
I have to say that having been a dragger for the past 24 years, some of those competetive, that I agree with Shane on this one. I have seen countless dyno test that show very nice gains with vacuum pumps pullling 16-20" and low tension ring sets. As for the Grump Jenkins statement on blow-bye being a necessary evil to oil control, I agree also. Although I think quite a few people hold this to be true and have said so for a long time now.
wrt Gapless being "junk"... well that sums it up pretty good for me. It seems that everyone is changing their tune now.... see, before guys were praising the gapless second rings but then we found out that they caused more problems than they fixed... now everyone's jumping on the gapless 1st ring bandwagon. I'm sorry but I'll be taking the A-train this time around. My Speed Pro plasma moly ringsets work just fine for me and they work fine for everyone else I talk to. If it aint broke.....
Shane, interesting 377 you have there. What class are you building this engine for or is this just something you bracket race with? Interesting choice in the 11X heads, would you be interested in a set of sb2.2s?
-Mindgame
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Joined: Oct 2002
Posts: 6,518
What I saw from Bill Hancokc is from the AETC which was covered in some mags. Just a different look at it, not saying it's anything serious. It's just some things I have listened to, I'd like to see some back to bak testing with and without it in the right setups to make up my mind completely. Not saying it's the bible, but then again thinking outside the box is where the real advancements are in engine development.
As far as the top gapless rings go, I'll just say I like them. There's a point where I'm preaching to the choir about this and it's something you gotta see on a dyno to see that it works.
I remeber reading a interesting thread around here buy Chuck about laser etching the bore. That is along the right way to get oil control (it's a really good way but too much for most of us to get into), rather than working with blow by to control the oil.
It's odd, drag racers ALWAYS look to Grumpy for their engine stuff, while circle track guys look to Smokey for theirs. I'm with Smokey, I'd rather have the rings way up there sealing the piston off as much as possible and have the cylinder walls and the oil rings do the oil control for me. Then again Smokey and Grumpy disagreed on the rod length issue too.
Bret
As far as the top gapless rings go, I'll just say I like them. There's a point where I'm preaching to the choir about this and it's something you gotta see on a dyno to see that it works.
I remeber reading a interesting thread around here buy Chuck about laser etching the bore. That is along the right way to get oil control (it's a really good way but too much for most of us to get into), rather than working with blow by to control the oil.
It's odd, drag racers ALWAYS look to Grumpy for their engine stuff, while circle track guys look to Smokey for theirs. I'm with Smokey, I'd rather have the rings way up there sealing the piston off as much as possible and have the cylinder walls and the oil rings do the oil control for me. Then again Smokey and Grumpy disagreed on the rod length issue too.
Bret
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Joined: Nov 2001
Posts: 2,985
From: In a house by the bay
No biggie Bret... I'm not about to discount anything. Been proven wrong many times before.
Me, I'll have to wait to see the proof though and then I might still not wanna change what I've been doing..... "mule headed" is a good word to describe myself but you already knew that.
As for Grump vs Smoke.... hell, we all learned a little from each of those guys. I side with Grump on some things and Smoke on a few others but that's where its at.... everyone has to make their own decisions as to what they want to accept. The important thing is getting past the, "Whatever he says I take as the cardinal truth" mentality. I think that once a racer can get past that, he can start trying his own thing... experimenting around etc., cause that's the only way you ever really know if something works for you.
-Mindgame
Me, I'll have to wait to see the proof though and then I might still not wanna change what I've been doing..... "mule headed" is a good word to describe myself but you already knew that.
As for Grump vs Smoke.... hell, we all learned a little from each of those guys. I side with Grump on some things and Smoke on a few others but that's where its at.... everyone has to make their own decisions as to what they want to accept. The important thing is getting past the, "Whatever he says I take as the cardinal truth" mentality. I think that once a racer can get past that, he can start trying his own thing... experimenting around etc., cause that's the only way you ever really know if something works for you.
-Mindgame
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Joined: Oct 2002
Posts: 6,518
Mindgame,
Outside the box man, outside the box.
We are both a little pig headed. Nothing is going to change that here. Grumpy has some good things, gotta respect him, Smokey has always amazed me though. That whole thing he did with cutting donw the Pontiac mains to make them turn some R's was a great idea back in the day. He even confused Pontiac with that one.
Bret
Outside the box man, outside the box.
We are both a little pig headed. Nothing is going to change that here. Grumpy has some good things, gotta respect him, Smokey has always amazed me though. That whole thing he did with cutting donw the Pontiac mains to make them turn some R's was a great idea back in the day. He even confused Pontiac with that one.
Bret
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Joined: Mar 2000
Posts: 2,037
From: 51°N 114°W, 3500' elevation
Originally posted by 81ZMouse
Now, back to the original question. First, it is incorrect to say that ANY vacuum pump can pull 28" Hg. Also, the electric smog pump used on 88-92 LT-1's will NOT pull 28" Hg. I have tested them, others I know have also tested them. The results vary, I guess depending on the condition of the pump. Vacuum levels vary between 3-5" Hg.
Now, back to the original question. First, it is incorrect to say that ANY vacuum pump can pull 28" Hg. Also, the electric smog pump used on 88-92 LT-1's will NOT pull 28" Hg. I have tested them, others I know have also tested them. The results vary, I guess depending on the condition of the pump. Vacuum levels vary between 3-5" Hg.