Is the Catch Can really needed?
#14
06-29-2013, 12:47 PM
Quality is hit and miss from BT lately. Years ago, it was superb. Now, I've received a bunch of items, specifically black anodized, that had little spots chipped off. Of course, you can send it back for a refund, but after waiting weeks, it takes the fun out of modding.
With that said, I'll say it again. The stock composite manifold has a catch can like feature molded into the PCV area so a can isn't really necessary.
Are any of you retaining the stock engine cover with the can? If so, please post pictures of your hose routing. Seems to be a common question on the forums.
With that said, I'll say it again. The stock composite manifold has a catch can like feature molded into the PCV area so a can isn't really necessary.
Are any of you retaining the stock engine cover with the can? If so, please post pictures of your hose routing. Seems to be a common question on the forums.
#16
06-29-2013, 07:45 PM
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I apologize if this is an obvious answer, I am just not very mechanically inclined.
#17
06-29-2013, 10:20 PM
Thanks for the photo. I was hoping the Zbracket would work as I don't particularly care for that location.
As for the integral "catch can", here's a post from another forum (I've noted important points via *)
It is common knowledge that enough oil present in the combustion process will reduce the octane rating of fuel during oxidation (the burn process/combustion), thereby increasing flame-front rate-of-travel and possibly resulting in knock (shock waves created by improper/uneven combustion, or worse piston skirts slapping the cylinder walls).
The proponents of catchcans state the above is occurring often enough it can be addressed by simply installing a catchcan.
There are variables;
- Actual amount of oil consumption
- The amount of engine oil required to alter the combustion process enough to generate knock
- Type of oil (different base stock - different oxidation rates)
- Knock detecting devices (electronic components secured to the block)
- Range of frequencies and their amplitudes associated with knock, and what the PCM is programmed to respond to
- Operating rpm
Oil consumption varies from engine to engine, even HEMI to HEMI. In fact all internal combustion engines on the planet create the same conditions. It's a given the 6.1 engine which utilize oil squirters to spray the bottom of the piston domes (which help reduce temperature) will generate more aerosoled oil (suspended particulate in the air occupying the crankcase cavity). This in combination with no real oil separating mechanism to speak of, more oil will be present in the intake tract.
***** The 5.7 and smaller engines have an oil separator (catchcan) molded into the intake manifold. These engines consume considerably less oil when compared to the 6.1. What’s ironic is the oil being collected by any aftermarket catchcan would simply be accomplished further downstream by a similar unit the engineers designed into the OEM composite manifold. The oil removed by the built-in oil separator (integral to the PCV system), simply returns to the crankcase. *****
The key here is how much oil is being consumed; another member some time ago did some simple math in an effort to point out the number of times each cylinder in an engine experiences the combustion stroke between oil changes. The number was astronomical!
It easily drove the point home that in order for any given cylinder to experience knock from ingesting engine oil at intervals frequent enough to validate the premise timing is regularly being pulled…it would empty the crankcase of engine oil long before the next oil change.
Most folks on here like their vehicles enough to check their oil periodically; it's pretty clear even on modified engines the majority (by far) of drivers show either little or no consumption, all the way up to maybe a quart. This is normal.
Those engines that have forced induction are likely to consume even more as blow-by around the piston rings is inevitable resulting in a pressurized crankcase.
The bottom line is the amount of oil required to speed up the flame front sufficiently to induce knock is significant. If it occurred on anywhere approaching a regular basis...the dipstick would show it.
Different oil configurations (base stock, the additives, etc) oxidize and therefore alter the combustion process at different rates and temperatures. Nobody has (yet) put this on the radar.
What few wish to acknowledge are the knock sensors, their manufacturing tolerances, and most importantly their sensitivity as a direct result of the torque required to secure them to the engine block. The torque value is critical to ensure the devices output raw information (in the form of voltage) that is indicative of the frequencies and amplitude recognized (by the PCM) as actual engine cylinder “knock”. If they are not, the devices can respond to other harmonics, O/P a voltage, and the PCM responds.
Altering, or re-torquing knock sensors to proper values alters the O/P every time. This has been learned through personal experiences on local platforms/dyno runs and input from others at the tuning level, and finally after speaking with those who designed the system when it became evident catchcans were being marketed as a panacea for knock reduction on every engine within all platforms.
Of note is this forum is by no-means the only one to flog catchcans, every single forum out there is doing the same thing. Because of the manner in which they are marketed…it generates significant volumes and returns for those who sell them.
The amount of aerosoled engine oil generation changes with rpm. The higher the engine rpm, the more aerosoled oil generated in any combustion engine on the planet. Those with engines that spend most of their time at or near redline under hi-loading are always going to consume more oil. Normally that’s race engine territory, and why folks employ oil separators at that level.
***** There is “no harm” in installing a catchcan, as was recently pointed out by SRT engineers at online chat. They were and still are steadfast on a number of key points though;
- None of the engines have enough airflow or air turbulence within the intake plenum to “lift” significant amounts of oil off the plenum floor
- Offline they shake their heads at the continued zeal folks place on catchcans. Lots of reasons for this they surmise not the least of which is the quote “touchy-feely thing about protecting their investments from unwarranted danger”.
- Even on the SRT’s they will not relent that there is excessive oil consumption. Now this could be (publically) towing the company line, but even offline they are frustrated and perplexed by the continued mis-direction and banter. *****
***** Regarding the contents one may observe when emptying their catchcan;
- Every internal combustion engine generates significant moisture within the crankcase volume during warm-up. Gathered water in combination with blow-by (partially burned hydrocarbons) and oil can make the contents in a catchcan look like multi-colored sludge. This is absolutely normal, and has no effect on the internal operation of any engine which experiences regular oil changes (one of the functions of additives and detergents in the oil to begin with). Once the internals reach operating temperature, within a few minutes all that moisture has evaporated. The whole process is repeated every time the engine is started from a complete cool-down. Ironically, if one checked the contents of a catchcan after the engine (and the catchcan) has been at operating temperature for a while, one would never observe that water/oil mixture.
- The amount of moisture varies directly with humidity and temperature; the colder and/or higher the humidity, the greater the presence of water. One can imagine just how much might be present by observing the amount of water exiting the exhaust system alone shortly after start-up, either directly out the tail pipes or flowing out the bottom drain holes in every muffler and resonator (this moisture is generated simply by the hot exhaust gasses interacting with the inner chamber walls of the exhaust system until it heats up sufficiently). This is normal
There are too many variables to call a catchcan the panacea for engine knock. Yet in every thread posted regarding this device it's eventually stated that it is a mandatory addition to every single engine. It is not mandatory on any modern production engine.
If your goal is to install a catchcan to keep your intake tract somewhat free of oil (a catchcan distills only a portion of the aerosoled oil present in the crankcase air), install a catchcan. The best unit I have seen/used is Billet Technology’s version. They have a great (and efficient) design. *****
p.s. Not all OEM’s let alone race engines/race teams employ catchcans; by simply restricting(!) the PCV systems rate-of-flow one can easily control the amount of ingestion and still(!) meet EPA and/or target HP/TQ figures…without a catchcan.
As for the integral "catch can", here's a post from another forum (I've noted important points via *)
It is common knowledge that enough oil present in the combustion process will reduce the octane rating of fuel during oxidation (the burn process/combustion), thereby increasing flame-front rate-of-travel and possibly resulting in knock (shock waves created by improper/uneven combustion, or worse piston skirts slapping the cylinder walls).
The proponents of catchcans state the above is occurring often enough it can be addressed by simply installing a catchcan.
There are variables;
- Actual amount of oil consumption
- The amount of engine oil required to alter the combustion process enough to generate knock
- Type of oil (different base stock - different oxidation rates)
- Knock detecting devices (electronic components secured to the block)
- Range of frequencies and their amplitudes associated with knock, and what the PCM is programmed to respond to
- Operating rpm
Oil consumption varies from engine to engine, even HEMI to HEMI. In fact all internal combustion engines on the planet create the same conditions. It's a given the 6.1 engine which utilize oil squirters to spray the bottom of the piston domes (which help reduce temperature) will generate more aerosoled oil (suspended particulate in the air occupying the crankcase cavity). This in combination with no real oil separating mechanism to speak of, more oil will be present in the intake tract.
***** The 5.7 and smaller engines have an oil separator (catchcan) molded into the intake manifold. These engines consume considerably less oil when compared to the 6.1. What’s ironic is the oil being collected by any aftermarket catchcan would simply be accomplished further downstream by a similar unit the engineers designed into the OEM composite manifold. The oil removed by the built-in oil separator (integral to the PCV system), simply returns to the crankcase. *****
The key here is how much oil is being consumed; another member some time ago did some simple math in an effort to point out the number of times each cylinder in an engine experiences the combustion stroke between oil changes. The number was astronomical!
It easily drove the point home that in order for any given cylinder to experience knock from ingesting engine oil at intervals frequent enough to validate the premise timing is regularly being pulled…it would empty the crankcase of engine oil long before the next oil change.
Most folks on here like their vehicles enough to check their oil periodically; it's pretty clear even on modified engines the majority (by far) of drivers show either little or no consumption, all the way up to maybe a quart. This is normal.
Those engines that have forced induction are likely to consume even more as blow-by around the piston rings is inevitable resulting in a pressurized crankcase.
The bottom line is the amount of oil required to speed up the flame front sufficiently to induce knock is significant. If it occurred on anywhere approaching a regular basis...the dipstick would show it.
Different oil configurations (base stock, the additives, etc) oxidize and therefore alter the combustion process at different rates and temperatures. Nobody has (yet) put this on the radar.
What few wish to acknowledge are the knock sensors, their manufacturing tolerances, and most importantly their sensitivity as a direct result of the torque required to secure them to the engine block. The torque value is critical to ensure the devices output raw information (in the form of voltage) that is indicative of the frequencies and amplitude recognized (by the PCM) as actual engine cylinder “knock”. If they are not, the devices can respond to other harmonics, O/P a voltage, and the PCM responds.
Altering, or re-torquing knock sensors to proper values alters the O/P every time. This has been learned through personal experiences on local platforms/dyno runs and input from others at the tuning level, and finally after speaking with those who designed the system when it became evident catchcans were being marketed as a panacea for knock reduction on every engine within all platforms.
Of note is this forum is by no-means the only one to flog catchcans, every single forum out there is doing the same thing. Because of the manner in which they are marketed…it generates significant volumes and returns for those who sell them.
The amount of aerosoled engine oil generation changes with rpm. The higher the engine rpm, the more aerosoled oil generated in any combustion engine on the planet. Those with engines that spend most of their time at or near redline under hi-loading are always going to consume more oil. Normally that’s race engine territory, and why folks employ oil separators at that level.
***** There is “no harm” in installing a catchcan, as was recently pointed out by SRT engineers at online chat. They were and still are steadfast on a number of key points though;
- None of the engines have enough airflow or air turbulence within the intake plenum to “lift” significant amounts of oil off the plenum floor
- Offline they shake their heads at the continued zeal folks place on catchcans. Lots of reasons for this they surmise not the least of which is the quote “touchy-feely thing about protecting their investments from unwarranted danger”.
- Even on the SRT’s they will not relent that there is excessive oil consumption. Now this could be (publically) towing the company line, but even offline they are frustrated and perplexed by the continued mis-direction and banter. *****
***** Regarding the contents one may observe when emptying their catchcan;
- Every internal combustion engine generates significant moisture within the crankcase volume during warm-up. Gathered water in combination with blow-by (partially burned hydrocarbons) and oil can make the contents in a catchcan look like multi-colored sludge. This is absolutely normal, and has no effect on the internal operation of any engine which experiences regular oil changes (one of the functions of additives and detergents in the oil to begin with). Once the internals reach operating temperature, within a few minutes all that moisture has evaporated. The whole process is repeated every time the engine is started from a complete cool-down. Ironically, if one checked the contents of a catchcan after the engine (and the catchcan) has been at operating temperature for a while, one would never observe that water/oil mixture.
- The amount of moisture varies directly with humidity and temperature; the colder and/or higher the humidity, the greater the presence of water. One can imagine just how much might be present by observing the amount of water exiting the exhaust system alone shortly after start-up, either directly out the tail pipes or flowing out the bottom drain holes in every muffler and resonator (this moisture is generated simply by the hot exhaust gasses interacting with the inner chamber walls of the exhaust system until it heats up sufficiently). This is normal
There are too many variables to call a catchcan the panacea for engine knock. Yet in every thread posted regarding this device it's eventually stated that it is a mandatory addition to every single engine. It is not mandatory on any modern production engine.
If your goal is to install a catchcan to keep your intake tract somewhat free of oil (a catchcan distills only a portion of the aerosoled oil present in the crankcase air), install a catchcan. The best unit I have seen/used is Billet Technology’s version. They have a great (and efficient) design. *****
p.s. Not all OEM’s let alone race engines/race teams employ catchcans; by simply restricting(!) the PCV systems rate-of-flow one can easily control the amount of ingestion and still(!) meet EPA and/or target HP/TQ figures…without a catchcan.
#19
06-29-2013, 10:42 PM
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#20
06-30-2013, 03:00 AM
All Star
