Crankcase vent again - anyone try venting to exhaust?
02-22-2006, 01:41 PM
#16
Rennlist Junkie Forever
Weston Dillard
The venturi in the exhaust trick was tried by Neal Wright and was setup by John Anderson. While it looked to be correctly designed, the car had to have the dip stick tie-wrapped down as the pressure would blow it up, get oil all over the hood, and did infact start an oil fire at the track.
It was ripped out, put back stock, and the dip stick no longer had to be tied down, no oil pushed out, no oil on the hood, and no oil fires.
TonyG
The venturi in the exhaust trick was tried by Neal Wright and was setup by John Anderson. While it looked to be correctly designed, the car had to have the dip stick tie-wrapped down as the pressure would blow it up, get oil all over the hood, and did infact start an oil fire at the track.
It was ripped out, put back stock, and the dip stick no longer had to be tied down, no oil pushed out, no oil on the hood, and no oil fires.
TonyG
02-22-2006, 02:32 PM
#17
Racer
Thread Starter
TonyG - thanks, that's the sort of info I needed.
Brian - I did mention I have 10% leakdown on one cylinder, which is higher than I'd like. Do you ever do PCA events at TWS?
West
Brian - I did mention I have 10% leakdown on one cylinder, which is higher than I'd like. Do you ever do PCA events at TWS?
West
02-22-2006, 03:35 PM
#18
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Originally Posted by Weston Dillard
Brian - I did mention I have 10% leakdown on one cylinder, which is higher than I'd like. Do you ever do PCA events at TWS?
I usually go to spectate for the annual club race. Somehow that's usually on a weekend off. That would change the instant I bought a track car, of course.
02-22-2006, 05:17 PM
#20
Three Wheelin'
Mr. Edge, the evacuator gets plumbed into the downpipe (post-turbo)...
The guy that took that shot:
Remember, this setup definitely wouldn't pass a smog visual check, and would likely give you a fail on the sniff test. Of course you could just vent the crank to ATM for the sniff test and be fine.
Tony, while I give real-world experince 10x the consideration of interweb bench racing, I have to think the example you've written about wasn't designed properly. The exhaust tie-in has to be at 45* (angled toward the turbo) and the tube must protrude into the main exhaust pipe to a small degree, I've read 1/16th of an inch. If either of those aren't followed, then yes I can believe there wouldn't be enough vacuum. Each of the accounts I've read from others who've tried it has been much the opposite of your experience. Often the complaint is too much vacuum at the first attempt. Its become clear the system has to be designed carefully both in how its mounted in the exhaust and where it draws from the crankcase. I'm not familiar enough with the 951's engine to know if the stock breather hole is sufficiently baffled and far enough from the sump to prevent liquid oil from finding its way into the exhaust.
Also, there's no reason this setup couldn't be used in parallel with a catch can and even a breather to ATM. Just plumb a PCV valve in line with the breather filter so that if the evacuator is pulling sufficient vacuum, the crankcase can drop below ATM. That would be a simple/cheap safeguard to use while testing/calibrating the evacuator system. Costs on everything but the catch can are minimal.
The guy that took that shot:
If your getting your parts from a salvage yard the check valves in Ford's are bigger and better sealing than the smaller GM truck ones. The one pictured above is a Ford unit, the GM ones are black and more hex shaped than the Ford round one.
Tony, while I give real-world experince 10x the consideration of interweb bench racing, I have to think the example you've written about wasn't designed properly. The exhaust tie-in has to be at 45* (angled toward the turbo) and the tube must protrude into the main exhaust pipe to a small degree, I've read 1/16th of an inch. If either of those aren't followed, then yes I can believe there wouldn't be enough vacuum. Each of the accounts I've read from others who've tried it has been much the opposite of your experience. Often the complaint is too much vacuum at the first attempt. Its become clear the system has to be designed carefully both in how its mounted in the exhaust and where it draws from the crankcase. I'm not familiar enough with the 951's engine to know if the stock breather hole is sufficiently baffled and far enough from the sump to prevent liquid oil from finding its way into the exhaust.
Also, there's no reason this setup couldn't be used in parallel with a catch can and even a breather to ATM. Just plumb a PCV valve in line with the breather filter so that if the evacuator is pulling sufficient vacuum, the crankcase can drop below ATM. That would be a simple/cheap safeguard to use while testing/calibrating the evacuator system. Costs on everything but the catch can are minimal.
02-22-2006, 05:32 PM
#21
Rennlist Junkie Forever
DanG
That's good info. The cusory glance I made of John Anderson's install appeared to be setup properly. It's quite obvious it was not due to serious problems outlined above.
My only one concern, even if designed properly, would be the potentional of the system to draw out oil, and expel it onto a race track through the exhaust, or even the vapor with enough emulsified oil could coat a windshield of a car behind you... the results of which would be disasterous.
I would think that a system like this, even if designed properly, should be used with an aftermarket seperator to prevent this (paragraph above) from happening. And if this is the case, what's the point when could simply use an aftermarket seperator in series with the stock seperator?
TonyG
That's good info. The cusory glance I made of John Anderson's install appeared to be setup properly. It's quite obvious it was not due to serious problems outlined above.
My only one concern, even if designed properly, would be the potentional of the system to draw out oil, and expel it onto a race track through the exhaust, or even the vapor with enough emulsified oil could coat a windshield of a car behind you... the results of which would be disasterous.
I would think that a system like this, even if designed properly, should be used with an aftermarket seperator to prevent this (paragraph above) from happening. And if this is the case, what's the point when could simply use an aftermarket seperator in series with the stock seperator?
TonyG
02-22-2006, 05:46 PM
#22
Three Wheelin'
Originally Posted by TonyG
DanG
That's good info. The cusory glance I made of John Anderson's install appeared to be setup properly. It's quite obvious it was not due to serious problems outlined above.
My only one concern, even if designed properly, would be the potentional of the system to draw out oil, and expel it onto a race track through the exhaust, or even the vapor with enough emulsified oil could coat a windshield of a car behind you... the results of which would be disasterous.
I would think that a system like this, even if designed properly, should be used with an aftermarket seperator to prevent this (paragraph above) from happening. And if this is the case, what's the point when could simply use an aftermarket seperator in series with the stock seperator?
TonyG
That's good info. The cusory glance I made of John Anderson's install appeared to be setup properly. It's quite obvious it was not due to serious problems outlined above.
My only one concern, even if designed properly, would be the potentional of the system to draw out oil, and expel it onto a race track through the exhaust, or even the vapor with enough emulsified oil could coat a windshield of a car behind you... the results of which would be disasterous.
I would think that a system like this, even if designed properly, should be used with an aftermarket seperator to prevent this (paragraph above) from happening. And if this is the case, what's the point when could simply use an aftermarket seperator in series with the stock seperator?
TonyG
The reason I'm geeked about the evacuator are the positive benefits of keeping the crankcase under vacuum:
- Removes blowby vapors and some of the contaminants
- Decreases windage and oil foaming
- Partially improves sealing, although not the same as reducing leakage (air just leaks in now)
- Trivial HP gain
02-22-2006, 05:55 PM
#23
Rennlist Junkie Forever
DanG
You should measure to see what sort of vacuum is created by the turbo compressor. Specifically where the crank case blowby hose connects in front of the compressor inlet. It is at a 90 degree angle. I would bet it's comparible to that of the exhaust.
TonyG
T
You should measure to see what sort of vacuum is created by the turbo compressor. Specifically where the crank case blowby hose connects in front of the compressor inlet. It is at a 90 degree angle. I would bet it's comparible to that of the exhaust.
TonyG
T
02-22-2006, 06:18 PM
#24
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Rennlist Member
Originally Posted by Weston Dillard
Drop by during the club race and say Hi, I'll be in garage 1 car 281.
02-23-2006, 01:57 AM
#25
Three Wheelin'
Originally Posted by TonyG
DanG
You should measure to see what sort of vacuum is created by the turbo compressor. Specifically where the crank case blowby hose connects in front of the compressor inlet. It is at a 90 degree angle. I would bet it's comparible to that of the exhaust.
TonyG
You should measure to see what sort of vacuum is created by the turbo compressor. Specifically where the crank case blowby hose connects in front of the compressor inlet. It is at a 90 degree angle. I would bet it's comparible to that of the exhaust.
TonyG
Once the car is running I will most certainly do some experiments. I'll likely start with a plain catch can vented to atmos because I'll have a bunch of other things to be worrying about. But a few months down the line, I'll give the exhaust evacuator a shot and see how it works.
02-23-2006, 02:21 AM
#26
Rennlist Junkie Forever
>>>True, thats definitely another option for a vacuum source. But the big benefit going with the exhaust plumbed route is that oil fumes/vapors no longer enter the intake track to slime things up or contaminate the mixture. Enough fumes/vapor can lower the effective octane rating and cause detonation.<<<
The benefits of not having crankcase blowby recirculated into the engine are obvious and well documented. We don't need to know why. But the real issue is how best to deal with it. And I'm not sure that, at least on a forced induction application, pumping it into the exhaust pipe is a good idea. Additionally, I'm sure there are rules somewhere that would address this exact issue in sanctioned racing.
The origination of this type of crank case evacutation was on normally aspirated cars which don't have the benefit of a compressor sucking in air at near supersonic speeds. Likewise, they also don't have anywhere near the amount of blowby a forced induction car will have. Thus pulling from the exhaust probably isn't a real problem.
On a forced induction car, where there's a LOT more blowby (no matter the condition of the engine).
I can guarantee that if you did this on a turbo car and had any sort of oil mist exiting out the exhaust pipe on a track, even if it was enough to slightly "mist" a windshield or two (which wouldn't be difficult) you'd be black flagged big time. For good reason.
By using the factory seperator with the orrifice drilled out, and another aftermarket seperator (with steel wool inside) plumbed in series, proved in my testing to reduce the oil consumption to near zero. And if the oil consumption is near zero, there's not much oil nor oil vapor being burned... which pretty much puts the issue to rest.
However, I'm sure that this would not be a good solution by itself on a normally aspirated car due to the lack of a compressor. In that case, the venturi in the exhaust would be the way to go for sure.
TonyG
The benefits of not having crankcase blowby recirculated into the engine are obvious and well documented. We don't need to know why. But the real issue is how best to deal with it. And I'm not sure that, at least on a forced induction application, pumping it into the exhaust pipe is a good idea. Additionally, I'm sure there are rules somewhere that would address this exact issue in sanctioned racing.
The origination of this type of crank case evacutation was on normally aspirated cars which don't have the benefit of a compressor sucking in air at near supersonic speeds. Likewise, they also don't have anywhere near the amount of blowby a forced induction car will have. Thus pulling from the exhaust probably isn't a real problem.
On a forced induction car, where there's a LOT more blowby (no matter the condition of the engine).
I can guarantee that if you did this on a turbo car and had any sort of oil mist exiting out the exhaust pipe on a track, even if it was enough to slightly "mist" a windshield or two (which wouldn't be difficult) you'd be black flagged big time. For good reason.
By using the factory seperator with the orrifice drilled out, and another aftermarket seperator (with steel wool inside) plumbed in series, proved in my testing to reduce the oil consumption to near zero. And if the oil consumption is near zero, there's not much oil nor oil vapor being burned... which pretty much puts the issue to rest.
However, I'm sure that this would not be a good solution by itself on a normally aspirated car due to the lack of a compressor. In that case, the venturi in the exhaust would be the way to go for sure.
TonyG
02-23-2006, 03:20 AM
#28
Three Wheelin'
Tony, again very good points. Hows this for a compromise? Catch can and atmospheric breather for the track, catch can and exhaust evacuator for the street. 
That way I can pump out smoke screens and mist up the cop's windshields for a clean get away!
Seriously though, the concerns about oil on the track or misting the air are very well grounded and I also wouldn't be suprised if exhaust evacuators were forbidden with some groups.
That way I can pump out smoke screens and mist up the cop's windshields for a clean get away!
Seriously though, the concerns about oil on the track or misting the air are very well grounded and I also wouldn't be suprised if exhaust evacuators were forbidden with some groups.
02-23-2006, 04:57 AM
#29
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Originally Posted by TonyG
...
By using the factory seperator with the orrifice drilled out, and another aftermarket seperator (with steel wool inside) plumbed in series, proved in my testing to reduce the oil consumption to near zero. And if the oil consumption is near zero, there's not much oil nor oil vapor being burned... which pretty much puts the issue to rest.
...
TonyG
By using the factory seperator with the orrifice drilled out, and another aftermarket seperator (with steel wool inside) plumbed in series, proved in my testing to reduce the oil consumption to near zero. And if the oil consumption is near zero, there's not much oil nor oil vapor being burned... which pretty much puts the issue to rest.
...
TonyG
02-23-2006, 05:55 AM
#30
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Regarding blowing the oil pan with an atmo can, if the crank case is at barometric, not under vacuum, it takes far less blowby to pressurize the crank case. If its pressurizing faster then it can dispell from the catch can vent, it will bulge the gasket. I've heard many times (agian, HEARD) that a vacuum in the crank case is worth HP, dunno the facts on that one.
on a side note, my dipstick keeps comming up. I'm not sure if its wrong size o-ring, excessive vibration, or excessive blowby (doubt it, compression was 150, 155, 150 150 last I checked)
any ideas?
Eyal
on a side note, my dipstick keeps comming up. I'm not sure if its wrong size o-ring, excessive vibration, or excessive blowby (doubt it, compression was 150, 155, 150 150 last I checked)
any ideas?
Eyal