C3 crankcase ventilation vacuum pump smog pump
Le Mans Master
Joined: Oct 2007
Posts: 9,702
Likes: 3,472
From: Akron Ohio
2025 Corvette of the Year Finalist - Modified
2024 C5 of the Year Winner - Modified
2023 C5 of the Year Finalist - Modified
2022 C5 of the Year Finalist - Modified
St. Jude Donor '09-'10-'11
I'm the original poster (OP) and thjs thread contains good info. Based on the info, I've decided that I'm going to pursue crankcase ventilation.
A few more questions:
@Kubs: yes, i have an electric fuel pump. When you say attach hose to mechanical fuel pump inlet, your assumtption (sorry to be dense on this) is that the mechanical fuel pump is still installed, correct?
To those that run crankcase vac pumps: the parts list includes: pump, some sort of regulater to set vac (example: 'not to exceed 15 inches), a catch can, and a valve cover for driver side bank, correct? Am i missing anything?
Can vacuum for crankcase, hvac, headlights, and brakes all be run off one pump, or are two separate systems required or recommended?
A few more questions:
@Kubs: yes, i have an electric fuel pump. When you say attach hose to mechanical fuel pump inlet, your assumtption (sorry to be dense on this) is that the mechanical fuel pump is still installed, correct?
To those that run crankcase vac pumps: the parts list includes: pump, some sort of regulater to set vac (example: 'not to exceed 15 inches), a catch can, and a valve cover for driver side bank, correct? Am i missing anything?
Can vacuum for crankcase, hvac, headlights, and brakes all be run off one pump, or are two separate systems required or recommended?
Safety Car
Joined: Jan 2009
Posts: 4,000
Likes: 299
From: New York
I admit I am not an expert on race engines, I understand physics, and don't claim to know everything.
but looking at it in a different way, using the 25hp figure, are we saying it takes 25hp to move the air in the engine? if it was a single cylinder, instead of a v8, would it take 3 hp just to move the air? does that mean a lawnmower engine making 3.5 hp could make 6.5hp by adding a vacuum pump?
it just does not seem logical to me that the engine uses that much HP just to move the air in the crank case. and even if it did, the difference between 400hp and 425hp would be difficult to notice in the everyday world, especially considering the relationship to power and speed is not linear.
I stand by the opinion that yes, there may be some gains, but in the bigger picture any gains are negligible and wouldn't be noticeable on the average street/mild build engine.
I have yet to see any definitive proof otherwise but always willing to learn...
but looking at it in a different way, using the 25hp figure, are we saying it takes 25hp to move the air in the engine? if it was a single cylinder, instead of a v8, would it take 3 hp just to move the air? does that mean a lawnmower engine making 3.5 hp could make 6.5hp by adding a vacuum pump?
it just does not seem logical to me that the engine uses that much HP just to move the air in the crank case. and even if it did, the difference between 400hp and 425hp would be difficult to notice in the everyday world, especially considering the relationship to power and speed is not linear.
I stand by the opinion that yes, there may be some gains, but in the bigger picture any gains are negligible and wouldn't be noticeable on the average street/mild build engine.
I have yet to see any definitive proof otherwise but always willing to learn...
You are not willing to learn you are way past that.
And the lawn mower comment proves my point ..
Go read about it elsewhere , learn and com back and share results. Otherwise all your doing is wasting time.
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,171
From: Hermosa
but looking at it in a different way, using the 25hp figure, are we saying it takes 25hp to move the air in the engine? if it was a single cylinder, instead of a v8, would it take 3 hp just to move the air? does that mean a lawnmower engine making 3.5 hp could make 6.5hp by adding a vacuum pump?
Go back to the video and the post quoted from Joe Sherman. In both those examples the gain was on the order of 4.5%. 4.3 and 4.8 to be exact.
Second these HP numbers were at 7500 and 8500 Rpm. No lawn mower engine can spin that fast.
25HP on a 400 HP engine is not likely. Maybe if you are spinning an engine to 8000-9000 RPM to achieve that 400 HP, but not in our 5500 to 6000 RPM engines.
The losses due to friction and windage are not linear. If you move something twice as fast through the air the friction goes up more on the order of a factor of four, not two. There are boring equations that can be used, but this is a general rule of thumb.
Referred to as aerodynamic drag. In addition, as the density of the fluid (air) increases do does the drag.
So as the pressure in the crank case rises, so does the density creating even more aerodynamic drag.
Another factor is the throw of the crank. A longer throw, ie a stroker motor is going to experience greater resistance than a 302 short stroke motor. Just imagine it as sticking your hand out the window of a moving car 3" or sticking your hand out 4". Which is going to push harder on your hand?
Most don't look at air as a factor, but it is. It is a fluid as surely as your oil is, just less viscosity.
Steps like crank scraper are often used to keep the oil in the bottom of the oil pan so as to not get tangled up in the crank in a order to save HP. Dry sumps do precisely this.
Your lawn mower engine that spins at 2500-3000 RPM or so it may gain on the order of 1% to 0% power with vacuum added to the crank case due to it's low RPM. Even if you were able to gain 4.5% of power from it that would only be .158 HP. Not even measurable.
Everything adds up. 4% here, 2% there, 3% somewhere else, pretty soon that all starts to make a difference.
Last edited by REELAV8R; Jun 27, 2016 at 09:33 AM.
Burning Brakes
Joined: Apr 2008
Posts: 1,222
Likes: 93
From: shelbyville West Michigan
if you want to discuss whether I am willing to learn, I'd be happy to put my degree's and certifications against yours any day but that's not the point of this thread. the OP asked, several of us answered, and nobody has proven anything except a doctored up video clip of a completely different application than the OP's stated build.
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,171
From: Hermosa
DYNO TESTING
Testing of the ’65 GTO was performed at Real Performance
Motorsports in Lewisville, Texas. RPM has a Dynojet Model-248C dyno.
The car was running on drag slicks, which pulls down the rear-wheel
horsepower on a chassis dyno compared to street tires. Due to electrical
interference present in the ignition system, rpm was not recorded con-
sistently across all pulls. In addition, torque is not noted as the torque
maximums were always dependent on when the engine was floored and
the converter was flashed.
Key Engine Parameters: air-inlet temperature (AIT). Vacuum was
measured on a sealed system at a valve-cover bung at idle and at 6,000
rpm in Third gear. Maximum horsepower was achieved at 5,400 rpm.
The GTO’s big-cube mill put out 340.7 hp in its baseline configura-
tion. Although the firewall and valve covers were clean before the
run, the pressure that built up in the engine pushed oil out of the dip-
stick tube, and it dripped onto the passenger-side header. In addition,
the back of the driver-side valve cover was wet, and both breathers
had oil residue where they mounted to the valve covers.
After cleaning the mess and finishing the installation of the stan-
dard Butler Evac Pump Kit, a vacuum gauge was connected to the pas-
senger-side valve-cover fitting. At idle, the car registered 0 inches of
vacuum being pulled from the engine—not unexpected since the
pump was rotating so slowly. Once the GTO was unleashed, it was
evident that the Evac Pump Kit was performing its job. At a maximum
rpm of 6,000 in Third gear on the Turbo 400 transmission, the pump
pulled 5 inches of vacuum, and the decreased pressure and more
effective ring seal allowed horsepower to
jump by almost 6. As significant was the fact
that the pump completely eliminated the oil
leaks that had previously plagued the car on
the dyno.
Following a cool down, the Moroso Evac
Pump Kit was installed, and the car was back
on the dyno for testing. At idle, the three-vane
Moroso pump pulled
1
⁄
2
inch of vacuum. Recorded at the same 6,000
rpm in Third gear, the pump generated 9
1
⁄
2
inches of vacuum and
achieved an outstanding gain of 14.5 hp over the baseline.
As compared to the standard kit, the Moroso kit was able to pull
out almost double the volume of pressurized crankshaft gases, allow-
ing even better ring seal and elevated horsepower numbers. Once
again, the reduction of crankcase pressure kept any oil from escaping
Testing of the ’65 GTO was performed at Real Performance
Motorsports in Lewisville, Texas. RPM has a Dynojet Model-248C dyno.
The car was running on drag slicks, which pulls down the rear-wheel
horsepower on a chassis dyno compared to street tires. Due to electrical
interference present in the ignition system, rpm was not recorded con-
sistently across all pulls. In addition, torque is not noted as the torque
maximums were always dependent on when the engine was floored and
the converter was flashed.
Key Engine Parameters: air-inlet temperature (AIT). Vacuum was
measured on a sealed system at a valve-cover bung at idle and at 6,000
rpm in Third gear. Maximum horsepower was achieved at 5,400 rpm.
The GTO’s big-cube mill put out 340.7 hp in its baseline configura-
tion. Although the firewall and valve covers were clean before the
run, the pressure that built up in the engine pushed oil out of the dip-
stick tube, and it dripped onto the passenger-side header. In addition,
the back of the driver-side valve cover was wet, and both breathers
had oil residue where they mounted to the valve covers.
After cleaning the mess and finishing the installation of the stan-
dard Butler Evac Pump Kit, a vacuum gauge was connected to the pas-
senger-side valve-cover fitting. At idle, the car registered 0 inches of
vacuum being pulled from the engine—not unexpected since the
pump was rotating so slowly. Once the GTO was unleashed, it was
evident that the Evac Pump Kit was performing its job. At a maximum
rpm of 6,000 in Third gear on the Turbo 400 transmission, the pump
pulled 5 inches of vacuum, and the decreased pressure and more
effective ring seal allowed horsepower to
jump by almost 6. As significant was the fact
that the pump completely eliminated the oil
leaks that had previously plagued the car on
the dyno.
Following a cool down, the Moroso Evac
Pump Kit was installed, and the car was back
on the dyno for testing. At idle, the three-vane
Moroso pump pulled
1
⁄
2
inch of vacuum. Recorded at the same 6,000
rpm in Third gear, the pump generated 9
1
⁄
2
inches of vacuum and
achieved an outstanding gain of 14.5 hp over the baseline.
As compared to the standard kit, the Moroso kit was able to pull
out almost double the volume of pressurized crankshaft gases, allow-
ing even better ring seal and elevated horsepower numbers. Once
again, the reduction of crankcase pressure kept any oil from escaping
http://www.jbp-pontiac.com/images/EvacPumpKit/evac.pdf
This engine showed a 4.25% increase in HP at the wheels over the base HP without a vacuum pump.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
For those that don't understand how the video was "doctored", here's what you need to do:
Start the video; you can either watch it till it gets to 2 min, 30 sec or you can click/drag the 'time' marker over to that time. Just before 2:30, Pause the video. At this point, the "honest" display screen should be showing. Now, without starting the video again, use the click/drag process to barely move the timing mark to 2:31 and keep it stopped on that time. If you read the HP output at 7000 rpm, you will note that it reads "449.xx" HP. Now, click/drag the timing mark to 2:32. Amazing!! the display screen gets much brighter and the [fixed] HP readout at 7000 rpm now reads "481.xx" HP.
This guy inserted a phony screen of "better" data just to 'prove' that this hardware actually works. Well, from the 'real' data screen (just prior to the bogus insertion), that device actually absorbs 20 HP from the engine.
If you can't check this for yourself, you either don't want to do so, or you can't work a YouTube player.
FLASH:
Just went to view that video again and, guess what! The doctored video has been REMOVED so that readers can't see for themselves what was done. How convenient!!
Start the video; you can either watch it till it gets to 2 min, 30 sec or you can click/drag the 'time' marker over to that time. Just before 2:30, Pause the video. At this point, the "honest" display screen should be showing. Now, without starting the video again, use the click/drag process to barely move the timing mark to 2:31 and keep it stopped on that time. If you read the HP output at 7000 rpm, you will note that it reads "449.xx" HP. Now, click/drag the timing mark to 2:32. Amazing!! the display screen gets much brighter and the [fixed] HP readout at 7000 rpm now reads "481.xx" HP.
This guy inserted a phony screen of "better" data just to 'prove' that this hardware actually works. Well, from the 'real' data screen (just prior to the bogus insertion), that device actually absorbs 20 HP from the engine.
If you can't check this for yourself, you either don't want to do so, or you can't work a YouTube player.
FLASH:
Just went to view that video again and, guess what! The doctored video has been REMOVED so that readers can't see for themselves what was done. How convenient!!
Last edited by 7T1vette; Jun 27, 2016 at 06:28 PM.
