It's not a "regular journal bearing" if it depends on pressure to prevent wobbling. In fact, I've never heard of such a bearing.
If you're talking about cooling, that is flow dependent, not pressure dependent.
5w20 in High Performance Turbo Engine
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If the turbo center section isn't water cooled then it's only cooled by the oil. The heat could shear an inferior oil.
To me it shounds like you don't know too much about turbos?
The "journal" and thrust bearings in most turbos aren't like wheel bearings. They allow oil thru them and this oil pressurizes the shaft and centers it. This oil pressure/film is what keeps the wheels from wobbling. The shaft should never come into contact with anything but oil...
Read up on journal and ball bearing turbos, turbo lubrication, etc...
http://www.hpamotorsports.com/product_turbo_menu.htm#ball
http://www.innovativeturbo.com/pages/turbo_damage.asp?ml=team&sl=tech
http://www.forcedperformance.net/faq.aspx
http://www.turbomustangs.com/turbotech/main.htm#bearingsystem
http://www.holset.co.uk/files/2_3_1-how a turbocharger works.php
To me it shounds like you don't know too much about turbos?
The "journal" and thrust bearings in most turbos aren't like wheel bearings. They allow oil thru them and this oil pressurizes the shaft and centers it. This oil pressure/film is what keeps the wheels from wobbling. The shaft should never come into contact with anything but oil...
Read up on journal and ball bearing turbos, turbo lubrication, etc...
http://www.hpamotorsports.com/product_turbo_menu.htm#ball
http://www.innovativeturbo.com/pages/turbo_damage.asp?ml=team&sl=tech
http://www.forcedperformance.net/faq.aspx
http://www.turbomustangs.com/turbotech/main.htm#bearingsystem
http://www.holset.co.uk/files/2_3_1-how a turbocharger works.php
The way to determine the answer to your question is to have an oil temperature guage in the car. Water temp does not do it, nor does oil pressure guage do it.
Once you have an oil temp guage, then if the oil in hard useage does not exceede 250dF then 5W-20 oil will be fine, up to 265dF 5W-30 will be fine. Above this I recommend an oil cooler or a bigger oil cooler or better ducting of air to the cooler already in place.
Once you have an oil temp guage, then if the oil in hard useage does not exceede 250dF then 5W-20 oil will be fine, up to 265dF 5W-30 will be fine. Above this I recommend an oil cooler or a bigger oil cooler or better ducting of air to the cooler already in place.
I am a firm believer in 5W-20 for engines designed for it. However, I'd be curious to see what manufacturers that normally use 5W-20 recommend for their turbos. The two that come to mind are the Acura RDX and Mazda CX-7. Since Accura/Honda use 5W-30 in the high output non-turbo 2.4L in the TSX, I'd be surprised to see it in the turbo RDX. Does anyone know about these two?
Fernando R: Acura requires an oil that meets a new Honda spec (HTO-06) for their new turbocharged RDX. As of today, the only oil that meets this spec is Mobil 1.
Here's a recent thread discussing this:
New Honda HTO-06 Oil Spec
Shown in that thread is an illustration of the RDX's oil fill cap which is embossed with "5W-30".
Here's a recent thread discussing this:
New Honda HTO-06 Oil Spec
Shown in that thread is an illustration of the RDX's oil fill cap which is embossed with "5W-30".
oil temp and pressure gauges should be mandatory on an engine like this.
vacuum/boost, WBO2 AFR, water temp, fuel pressure, and EGT would also be good to have.
www.pocketlogger.com/index.php?pid=pldsm reads the factory sensors
http://www.forbes.com/businesswire/feeds/businesswire/2006/08/30/businesswire20060830005525r1.html
http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=1;t=016009
I guess it'd be okay if the engine could handle a 20wt b/c that's what it'd be by the time it was drained.
Do Mazda dealers stock anything other than 5W20? I think they're stuck in the Ford/CAFE rut?
vacuum/boost, WBO2 AFR, water temp, fuel pressure, and EGT would also be good to have.
www.pocketlogger.com/index.php?pid=pldsm reads the factory sensors
http://www.forbes.com/businesswire/feeds/businesswire/2006/08/30/businesswire20060830005525r1.html
http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=1;t=016009
M1 5W30 is A1/B1 and 11.3cSt @ 100C. Not thick enough IMHO. But OCI isn't listed.
I guess it'd be okay if the engine could handle a 20wt b/c that's what it'd be by the time it was drained.
Do Mazda dealers stock anything other than 5W20? I think they're stuck in the Ford/CAFE rut?
Nope...your misinterpreting what is being said in those links. You need to look at a good mechanical engineering book that describes how journal bearings work.quote:
Originally posted by gtx510:
If the turbo center section isn't water cooled then it's only cooled by the oil. The heat could shear an inferior oil.
To me it shounds like you don't know too much about turbos?
The "journal" and thrust bearings in most turbos aren't like wheel bearings. They allow oil thru them and this oil pressurizes the shaft and centers it. This oil pressure/film is what keeps the wheels from wobbling. The shaft should never come into contact with anything but oil...
Read up on journal and ball bearing turbos, turbo lubrication, etc...
http://www.hpamotorsports.com/product_turbo_menu.htm#ball
http://www.innovativeturbo.com/pages/turbo_damage.asp?ml=team&sl=tech
http://www.forcedperformance.net/faq.aspx
http://www.turbomustangs.com/turbotech/main.htm#bearingsystem
http://www.holset.co.uk/files/2_3_1-how a turbocharger works.php
Further, just like in an engine, it's the flow of oil meeting the resistance of the engine's passages and bearings that create pressure.
Then they would simply be out of spec and would require shorter OCI.
Then you'd be doing 1,000 mile OCIs.
Quote:
Nope...your misinterpreting what is being said in those links. You need to look at a good mechanical engineering book that describes how journal bearings work.quote:
Originally posted by gtx510:
If the turbo center section isn't water cooled then it's only cooled by the oil. The heat could shear an inferior oil.
To me it shounds like you don't know too much about turbos?
The "journal" and thrust bearings in most turbos aren't like wheel bearings. They allow oil thru them and this oil pressurizes the shaft and centers it. This oil pressure/film is what keeps the wheels from wobbling. The shaft should never come into contact with anything but oil...
Read up on journal and ball bearing turbos, turbo lubrication, etc...
http://www.hpamotorsports.com/product_turbo_menu.htm#ball
http://www.innovativeturbo.com/pages/turbo_damage.asp?ml=team&sl=tech
http://www.forcedperformance.net/faq.aspx
http://www.turbomustangs.com/turbotech/main.htm#bearingsystem
http://www.holset.co.uk/files/2_3_1-how a turbocharger works.php
Further, just like in an engine, it's the flow of oil meeting the resistance of the engine's passages and bearings that create pressure.
To me it sounds like you need a physics book or class so you can better understand how flow, pressure, and cross-sectional restrictions are interrelated.
How many times does it have to say that the oil pressure centers the shaft and wheels before you beleive it?
Dude, since the books I acquired while earning BOTH my physics and engineering degrees, tell me differently, I prefer those over what some yahoo, who doesn't understand what their talking about, spews on a website.
So you're saying the gryoscopic effect centers the wheels?
And it's ok to start-up a turbo car and rev the crap out of the engine before the oil pressure comes up?
On a journal bearing turbo the wheel is gonna hit the housing. It needs pressure to keep from wobbling.
Ever grab a turbo wheel and try to move it around? It's got a fair amount of play to it.
A little radial play is normal, axial (in/out) is BAD.
And if turbo's don't need oil pressure, just lube, why send pressure to them?
They lower the pressure for a ball bearing turbo but not for a journal bearing one...
And all newer turbos are water-cooled so don't try pulling oil-cooling...
I'd suggest the both of you have another look at Bernoulli's equations. As I understand it the smaller passages in the turbo (bearings) create higher oil pressures as the oil flows thru them. It's this pressure that holds the wheels. I don't believe it's a thin film like in rod or main bearings. But that might be true for ball bearing turbos.
And it's ok to start-up a turbo car and rev the crap out of the engine before the oil pressure comes up?
On a journal bearing turbo the wheel is gonna hit the housing. It needs pressure to keep from wobbling.
Ever grab a turbo wheel and try to move it around? It's got a fair amount of play to it.
A little radial play is normal, axial (in/out) is BAD.
And if turbo's don't need oil pressure, just lube, why send pressure to them?
They lower the pressure for a ball bearing turbo but not for a journal bearing one...
And all newer turbos are water-cooled so don't try pulling oil-cooling...
I'd suggest the both of you have another look at Bernoulli's equations. As I understand it the smaller passages in the turbo (bearings) create higher oil pressures as the oil flows thru them. It's this pressure that holds the wheels. I don't believe it's a thin film like in rod or main bearings. But that might be true for ball bearing turbos.
Sorry gtx510, you're wrong. This is basic mechanical engineering knowledge.
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What stops an oil wedge from forming
At this present moment, I'm responsible for 300 tonnes of steel spinning at 3000rpm (the other 100 tonnes of steel are in pieces for maintenance) sitting on ISO32 turbine oil.
Oil is introduced in the unloadded part of the bearing.
Guess I better run in and tell them that they are wrong.
I can tell you the worst thing is when the oil can't exit the turbo bearings because of a coked oil outlet....well it doesn't take long after that. You don't need flow to "lift" the cartridge, but you do need flow to keep the oil from killing itself and then the turbo. I think a really advantage of a XW-20 or 0W-XX is the most rapid flow on starts.
I lean toward TS's recommendation, but I think you should try a 5W-20 for a short OCI or two and run a UOA.
I lean toward TS's recommendation, but I think you should try a 5W-20 for a short OCI or two and run a UOA.
I am using these:
5W-20 Red Line in my twin turbo Maybach 57 with over 600 BHP
5W-20 Red Line in my wife's Lamborghini with over 600 BHP
aehaas
5W-20 Red Line in my twin turbo Maybach 57 with over 600 BHP
5W-20 Red Line in my wife's Lamborghini with over 600 BHP
aehaas
Unlike the Lambo and Maybach this engine should be producing at least twice it's original design horsepower. Would 5w20 be approiate if the Maybach had oversize turbos that produced 1100+ horsepower? I don't think an overboosted turbo motor will live as long with 5w20 vs an equal quality thicker oil.
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