itb's and positive "crankcase" ventilation
12-10-14, 02:20 PM
#26
Rotary Freak
Really interesting read. I run the socks and knew they were restrictive, but not that bad. I guess I need to build the airbox. I already have a model for it, just need to glass it up to make it strong enough and seal.
Very very interesting, especially the part about oil making them even more restrictive. every time I check mine, spit back through the ITB's has the socks all damp inside. Can anyone say, winter project!
Eric
Very very interesting, especially the part about oil making them even more restrictive. every time I check mine, spit back through the ITB's has the socks all damp inside. Can anyone say, winter project!
Eric
12-10-14, 04:00 PM
#27
Isaiah 53.7
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Looking at your air filter setup reminded me of this thread: stack filtration ? Speed Talk
And this thread linked inside that one: Foam Sock filters cost me 55bhp - PistonHeads
And this thread linked inside that one: Foam Sock filters cost me 55bhp - PistonHeads
I've been planning on ditching my current intake setup, but now I really want to try it open before I go with something else. If it's enough of a difference to make me smile, we might be on to something!
12-10-14, 06:47 PM
#28
Old [Sch|F]ool
I'd never run a filter designed to be oiled without the oil. At that point it is little more than a screen to keep bugs out.
The theory behind individual filters being restrictive is sound, though. The airflow through the filter becomes more of a pulse flow with higher peak flows, and high peak flow through a restriction means a higher pressure drop, excactly when you want it to happen the least, since peak flow is going to be when you want to be moving air the fastest.
Just to throw some numbers out there, when I had my peripheral port on independent throttle EFI, I ran two of those Spectre cone air filters, one on each throttle plate. Manifold pressure at WOT was ~81kpa. Took the filters off as an experiment and manifold pressure rose to ~89kpa.
Current bridge port is running just one of those filters stuck on a blower hat on a Holley carb (hey, made filtration simple), and manifold pressure stays rock solid at 94kpa (local atmospheric) until over 10k at which point it starts dropping to 92kpa or so. Given that I really should not be winging the engine that high because the injectors go static at 8500-9000 or so, I feel this is acceptable
Changing the airbox setup to something with a little mor volume, and length in the pipe between the air filter and "carb", is something on my wish list, but I need to address a few other things first.
These same injectors never saw over 55% duty cycle or so on the peripheral port. Can you say restricted heavily?
The theory behind individual filters being restrictive is sound, though. The airflow through the filter becomes more of a pulse flow with higher peak flows, and high peak flow through a restriction means a higher pressure drop, excactly when you want it to happen the least, since peak flow is going to be when you want to be moving air the fastest.
Just to throw some numbers out there, when I had my peripheral port on independent throttle EFI, I ran two of those Spectre cone air filters, one on each throttle plate. Manifold pressure at WOT was ~81kpa. Took the filters off as an experiment and manifold pressure rose to ~89kpa.
Current bridge port is running just one of those filters stuck on a blower hat on a Holley carb (hey, made filtration simple), and manifold pressure stays rock solid at 94kpa (local atmospheric) until over 10k at which point it starts dropping to 92kpa or so. Given that I really should not be winging the engine that high because the injectors go static at 8500-9000 or so, I feel this is acceptable
Changing the airbox setup to something with a little mor volume, and length in the pipe between the air filter and "carb", is something on my wish list, but I need to address a few other things first.These same injectors never saw over 55% duty cycle or so on the peripheral port. Can you say restricted heavily?
12-10-14, 07:30 PM
#29
Isaiah 53.7
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This really makes me jittery. I never thought to look at the map at wot. I'll keep that in mind, too, and post results later... after I fix the rear end, which might be a while, like months.
This really encourages me further to ditch my intake, and go for a setup more like yours; four barrel manifold, aluminum carb plenum, and better filter location for <140* summer intake temps. I was even thinking about using two secondary injectors on top of the aluminum plenum for the secondary throats on the throttle body (probably all the throats to some degree) at higher rpm. My center iron is bridged deep, so I could also drive on those as primaries instead of all six ports fighting my drivetrain.
This really encourages me further to ditch my intake, and go for a setup more like yours; four barrel manifold, aluminum carb plenum, and better filter location for <140* summer intake temps. I was even thinking about using two secondary injectors on top of the aluminum plenum for the secondary throats on the throttle body (probably all the throats to some degree) at higher rpm. My center iron is bridged deep, so I could also drive on those as primaries instead of all six ports fighting my drivetrain.
12-11-14, 07:34 AM
#30
Rotary Freak
Wow, wow, wow, wow, wow......
There is so much interesting stuff here that really explains a number of issues I had while tuning my car as well as future plans. It also reminds me of my time before Dorito motors when we ran huge air filters to not restrict airflow.
Just on the tuning. Back when I was having all kinds of issues in trying to get the pig to run right without detonation, I pulled the socks off the bodies and ran it in a couple of sessions. Had to really bump up the fueling to cover for it and the car flatout screamed. We thought we had it licked, so I put the socks back on and went out for the race and the thing ran like crap and was sooo rich. Ended up pulling about 20% of the fueling out of the upper bins to get the car running right again. Still pulling fuel out and improving the driveability each time I look at it.
Now I am concerned that the one cone style filter I am planning on using may not be enough. I wonder if I should look at using some kind of huge filter element. Anyone have an idea on cfm minimums required for a 13b PP at 10,000 rpm? I am heading to PRI and will try to find something that can work.
Eric
There is so much interesting stuff here that really explains a number of issues I had while tuning my car as well as future plans. It also reminds me of my time before Dorito motors when we ran huge air filters to not restrict airflow.
Just on the tuning. Back when I was having all kinds of issues in trying to get the pig to run right without detonation, I pulled the socks off the bodies and ran it in a couple of sessions. Had to really bump up the fueling to cover for it and the car flatout screamed. We thought we had it licked, so I put the socks back on and went out for the race and the thing ran like crap and was sooo rich. Ended up pulling about 20% of the fueling out of the upper bins to get the car running right again. Still pulling fuel out and improving the driveability each time I look at it.
Now I am concerned that the one cone style filter I am planning on using may not be enough. I wonder if I should look at using some kind of huge filter element. Anyone have an idea on cfm minimums required for a 13b PP at 10,000 rpm? I am heading to PRI and will try to find something that can work.
Eric
12-11-14, 09:51 AM
#31
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the speed source cars just used the Rx8 air filter, its quite big.
12-12-14, 06:36 PM
#32
Old [Sch|F]ool
The wilder the port, the more important having a minimal pressure drop will be, because the longer the port remains open past TDC, the more the port depends on intake velocity, you need to allow the air to really get moving when at peak chamber expansion (happens at I-forget-where on rotaries, roughly 80atdc intake stroke on pistons) so that there is still lots of inertia when past BDC so the port continues to cram air into the chamber before it shuts. Later closing means you need more inertia...
This is why even though i'm seeing atmospheric, I want to try to do better, because I'm only seeing an AVERAGE of atmospheric across both rotors, I don't know if there are any momentary pressure drops when I'd really rather the air be moving faster. But without more injector, there'd be no point. Yet.
This is why even though i'm seeing atmospheric, I want to try to do better, because I'm only seeing an AVERAGE of atmospheric across both rotors, I don't know if there are any momentary pressure drops when I'd really rather the air be moving faster. But without more injector, there'd be no point. Yet.
12-30-14, 10:14 PM
#33
Hah. I just now saw these last two posts. Sorry.
I can't really tell from your picture, but the gassy smelling line is probably going to the charcoal canister, right? From what I gathered from Peejay, the nipple on the filler neck went to a PCV valve then to the intake - this creates vacuum throughout the sump to suck in all the fumes/emissions into the intake to burn off... I think.
Just cap the center iron nipple, and route your filler nipple to whatever catchcan you have. Cap the nipple on your charcoal canister where the metal line goes, and discard your metal line. By the way, your charcoal canister isn't a catch can.
Again, sorry I didn't see this sooner.
Turbocharging is a completely different animal. Upon boost, your engine sees a much higher compression ratio than our gutless na's. From what I understand, this creates pressure in your sump due to natural blowby, which can push some oil along with vapors right out of the sump.
This is where we see a can of worms. Some say just getting a catch can is sufficient, so whenever your catch can fills up with oil and gunk, dump it. Some say recirculated oil blowby gunk through a quality catch can is the ticket; just hook it up to your intake tract, drain periodically, and enjoy.
This is coming from a non turbo guy, so the turbo forum would probably be the best place to torment yourself over this. I'll confess, though. I was eyeing a Holset HX40, but then reality kicked in. Have fun!
I can't really tell from your picture, but the gassy smelling line is probably going to the charcoal canister, right? From what I gathered from Peejay, the nipple on the filler neck went to a PCV valve then to the intake - this creates vacuum throughout the sump to suck in all the fumes/emissions into the intake to burn off... I think.
Just cap the center iron nipple, and route your filler nipple to whatever catchcan you have. Cap the nipple on your charcoal canister where the metal line goes, and discard your metal line. By the way, your charcoal canister isn't a catch can.
Again, sorry I didn't see this sooner.
Turbocharging is a completely different animal. Upon boost, your engine sees a much higher compression ratio than our gutless na's. From what I understand, this creates pressure in your sump due to natural blowby, which can push some oil along with vapors right out of the sump.
This is where we see a can of worms. Some say just getting a catch can is sufficient, so whenever your catch can fills up with oil and gunk, dump it. Some say recirculated oil blowby gunk through a quality catch can is the ticket; just hook it up to your intake tract, drain periodically, and enjoy.
This is coming from a non turbo guy, so the turbo forum would probably be the best place to torment yourself over this. I'll confess, though. I was eyeing a Holset HX40, but then reality kicked in. Have fun!
This intake information is fascinating as I was planning on running socks on my itb's. Now I need to rethink my whole game plan.
05-10-15, 03:49 PM
#34
So I deleted my catch can and ran some lines. My only question is if this setup will work correctly.
I capped off the center nipple and I ran a line from the fuel evap hardline to a T. Then I ran one side of that T to the oil filler neck. The last side I ran to a vacuum port on the backside of the intake manifold. Will this setup be sufficient? I will have to re-route some lines once I put my ITBS on but if this method will work than it can easily be adapted.
I capped off the center nipple and I ran a line from the fuel evap hardline to a T. Then I ran one side of that T to the oil filler neck. The last side I ran to a vacuum port on the backside of the intake manifold. Will this setup be sufficient? I will have to re-route some lines once I put my ITBS on but if this method will work than it can easily be adapted.
05-10-15, 04:55 PM
#35
Old [Sch|F]ool
It'd be nice if the hoses were larger. I use 3/8" hose and it's probably still too small.
BTW - I removed the boosters from my non-carburetor. Engine picked up a LOT of power. Powerband went from completely flat to picking up and going ballistic over 6,000. So even though I was seeing atmospheric at the (averaged) MAP sensor, there was still a significant restriction just from having those little pieces of metal in the airstream.
BTW - I removed the boosters from my non-carburetor. Engine picked up a LOT of power. Powerband went from completely flat to picking up and going ballistic over 6,000. So even though I was seeing atmospheric at the (averaged) MAP sensor, there was still a significant restriction just from having those little pieces of metal in the airstream.
05-10-15, 05:34 PM
#37
Old [Sch|F]ool
I assume you mean the MAP sensor. It needs to see something appropriate to load.
Although playing with some of the things in my new MS2, it looks like I can have it only read the sensor at certain crank angles, which would be awesome if I had a crank angle sensor
Although playing with some of the things in my new MS2, it looks like I can have it only read the sensor at certain crank angles, which would be awesome if I had a crank angle sensor
05-10-15, 05:45 PM
#38
Sorry, I wasn't clear. I meant the t fitting port. Does that need to see significant vacuum? When I put the hose on to the nipple with strong vacuum the car idled rough. When I switched to a different one the car ran normal. Btw. Stock ecu still until I install my haltech.
Main concern is that I have this plumbed right.
Main concern is that I have this plumbed right.
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