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jstrboy183
06-29-2004, 12:13 PM
I had recently read a thread about how by using a a smog pump to to put the cracnk case in zero air molecule condition can give u 30-40 horsepower or something like that. Can anyone tell me more about this? 30-40 ponies i think is quite a lot of power.

TriFlow
06-29-2004, 12:30 PM
Sounds like :roll: BULL SHIAT

jstrboy183
06-29-2004, 12:36 PM
The thread was on this site or on bmwe30.net and was being seriously discussed. I wish i could find the damn thing.

jstrboy183
06-29-2004, 12:40 PM
here we go. http://www.e30tech.com/index.php?name=PNphpBB2&file=viewtopic&t=1201&highlight=smog+pump

about half way down bimmerjim talks about a vacuum pump giving you 20-30 hp on N/A engine and 40-50 on a blown. Giving a call out to bimmerjim. How well would a vacuum pump work with a our engines (M20)?

bimmerjim®
06-29-2004, 12:59 PM
here, ill repost what i said. i was wonding if somone was going to pay attention to that....

i did NOT say that we could get 40 hp off our motors, i said that the domestic v8 guys (with 3X the displacement) can get that kind of power. and i also did NOT say that vacume pump would make 0 air molocules present in the crankcase. i said there would be fewer air molocules present.

dont put words in my mouth.


iv been doing some research lately about this sort of thing. and i have an idea... its not a new idea by any means. muscle car guys have been doing it for years. but im thinking about doing this;

we all know that a stock motor has the crankcase breather that goes to the intake manifold so it has a constant source of vacume. when the crankcase vacume is replaced with a filter or catch can its exposed to atmospheric pressure. there is no longer a vacume in the crankcase. the only problem with that -- (and its not realy a problem just a drawback) is when the crankcase is at atmospheric pressure, there are more air mollocules present in the crankcase that the internal components bump into. this causes more drag, and consiquently causes a power loss.

However, when the crankcase is under a state of vacume it promotes ring seal. also there are less air molocules present for the internal components to run into because of the vacume. thus, the engine is more efficent and makes more power than if it were open to atmosphere. the pistion moves so fast that its almost trying to share the same space with the air in the crank case.

At WOT on a NA car, the crankcase is no longer in a vacume, its atmospheric. its not pulling vacume from the intake manifold anymore becaseu the throttle body is wide open. only when the throttle body is closed or nearly closed will it make vacume in the intake manifold. but a smog pump, or a vacume pump will make a vacume in the crankcase no mater what the rpm.

i have talked to several domestic V-8 guys here at work and they have said that a good constant source of vacume (throuought the rpm range) in the crankcase on a NA V8 motor will make about 20-30 hp. on a blown motor it will make about 40-50 hp.

so... im thinking about trying to fit a GM smog pump in the location my AC compressor was and run it off a belt to use as a vacume pump for the crankcase. im thinking im going to seal the crankcase except for the line to the vacume pump. Doing that i will loose a ponie or two fromt he belt and spinning mass that is driving the pump, but i will make that power back by having a constant souce of vacume to the crankcase no mater what the throttle position or rpm. i will get those few ponies back plus some.

plus, the beter ring seal will increase compression and its supsed to extend the longevity of the motor.

when refering to less air molocules being in the crankcase, i did some numbers just to put things in persepctive. think about how much wind resistance there is on your arm at 60 mph. now multiply that by 33 times. its hard to imagine, but at 6000 rpm, the m20b25's pistion speed is 2,950 feet per second, thats 2,012 miles per hour. Or 3,238 KPH for you metric boys and girls.

now imagine having half that resistance in the motor. how much power would that make?

comments?

jstrboy183
06-29-2004, 01:08 PM
I didn't mean to put words inot your mouth man. Sry. At the time when i was writing i couldn't really remember the exacts. Now i understand a little better now that i reread what you said. Sry about that. What kind gains do u think we could get out a vacuum pump?

bimmerjim®
06-29-2004, 01:30 PM
its not so much the gains that intrest me, its the "better for the motor" factor that im interested in. idk, if gains are possible i wouldnt expect much, maybe 5 hp.

Chris
06-29-2004, 01:32 PM
IMO, anything that puts less stress on the internal components of an engine, while freeing up some power is a wise investment.

Josh Q
06-29-2004, 01:57 PM
here, ill repost what i said. i was wonding if somone was going to pay attention to that....

i did NOT say that we could get 40 hp off our motors, i said that the domestic v8 guys (with 3X the displacement) can get that kind of power. and i also did NOT say that vacume pump would make 0 air molocules present in the crankcase. i said there would be fewer air molocules present.

dont put words in my mouth.


iv been doing some research lately about this sort of thing. and i have an idea... its not a new idea by any means. muscle car guys have been doing it for years. but im thinking about doing this;

we all know that a stock motor has the crankcase breather that goes to the intake manifold so it has a constant source of vacume. when the crankcase vacume is replaced with a filter or catch can its exposed to atmospheric pressure. there is no longer a vacume in the crankcase. the only problem with that -- (and its not realy a problem just a drawback) is when the crankcase is at atmospheric pressure, there are more air mollocules present in the crankcase that the internal components bump into. this causes more drag, and consiquently causes a power loss.

However, when the crankcase is under a state of vacume it promotes ring seal. also there are less air molocules present for the internal components to run into because of the vacume. thus, the engine is more efficent and makes more power than if it were open to atmosphere. the pistion moves so fast that its almost trying to share the same space with the air in the crank case.

At WOT on a NA car, the crankcase is no longer in a vacume, its atmospheric. its not pulling vacume from the intake manifold anymore becaseu the throttle body is wide open. only when the throttle body is closed or nearly closed will it make vacume in the intake manifold. but a smog pump, or a vacume pump will make a vacume in the crankcase no mater what the rpm.

i have talked to several domestic V-8 guys here at work and they have said that a good constant source of vacume (throuought the rpm range) in the crankcase on a NA V8 motor will make about 20-30 hp. on a blown motor it will make about 40-50 hp.

so... im thinking about trying to fit a GM smog pump in the location my AC compressor was and run it off a belt to use as a vacume pump for the crankcase. im thinking im going to seal the crankcase except for the line to the vacume pump. Doing that i will loose a ponie or two fromt he belt and spinning mass that is driving the pump, but i will make that power back by having a constant souce of vacume to the crankcase no mater what the throttle position or rpm. i will get those few ponies back plus some.

plus, the beter ring seal will increase compression and its supsed to extend the longevity of the motor.

when refering to less air molocules being in the crankcase, i did some numbers just to put things in persepctive. think about how much wind resistance there is on your arm at 60 mph. now multiply that by 33 times. its hard to imagine, but at 6000 rpm, the m20b25's pistion speed is 2,950 feet per second, thats 2,012 miles per hour. Or 3,238 KPH for you metric boys and girls.

now imagine having half that resistance in the motor. how much power would that make?

comments?

Hmmm...looks like someone is cranky. :wink:

bimmerjim®
06-29-2004, 03:11 PM
not cranky, i just dont like it when people skew what i say. i dont think you do either?

x628x
06-29-2004, 04:19 PM
i dont think anyone does.

kyle325
07-05-2004, 02:28 PM
they do something simliar to that on F1 engines don't they? But at 18000 rpms air resistance is much more of an issue. I wan tot try that along with a dry sump on my m50 swap