Going over motor oil labels and I see that oils in the 10w-30 and 5w-30 range often list benefits in reduced turbo lag. Do you think there really is much of a difference in turbo lag between 30 weights as compared to 40 weight oils ?.
Do 30 Weight Oils Really Result in Less Turbo Lag over 40 Weights. ....
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Actually this is completely untrue.
Any load placed on the engine (especially when the turbo is not spooled) will promote additional exhaust gases to spin the turbine.
The engine in a sense works harder because of the additional friction (this is purely hypothetical, you probably won't feel any difference) caused by moving a heavier oil around. Because of this, more exhaust gas = spooled turbo quicker.
This is why lightweight flywheels are not recommended in turboed vehicles. Same principle.
Any load placed on the engine (especially when the turbo is not spooled) will promote additional exhaust gases to spin the turbine.
The engine in a sense works harder because of the additional friction (this is purely hypothetical, you probably won't feel any difference) caused by moving a heavier oil around. Because of this, more exhaust gas = spooled turbo quicker.
This is why lightweight flywheels are not recommended in turboed vehicles. Same principle.
I could tell a difference in my 93 Talon between thick and thin oil, not so much in transient boost respone, but off idle from a start.
Hey, another fellow Springser.
Turbo lag is a function of thermodynamic or better yet it's management. The heat from your exhaust is what spool up a turbocharger. The larger the turbocharger the more volume of air it can compress adn send to the intake. THe larger the turbocharger the greater the volume and heat in the exhaust is needed to spool it up! This is were lag comes in. SOme ways around this were twin seq. turbos were you had one small turbo and one larg turbo bolter together, variable inlet venturi's,new inpeeler designs, better bearings, more advanced throtle and waste gate strategies, if running rich enough shooting NO2 into the exhaust to combust unburnt fuel, useing electrical motors or super flywheels to keep turbo spooled up......
In my opion the easiest way for a novice to deal with turbo lag is to run a twin seq. set up! If that is too much work then a super charger becomes the next solution. I really do not like super chargers though as you have to feed them HP to make HP on the street they are fine though!
With a turbo charger turning 80,000+ RPM's you are not going to be able to notice the spool up times between 30Wt. and 40Wt. oils!
In my opion the easiest way for a novice to deal with turbo lag is to run a twin seq. set up! If that is too much work then a super charger becomes the next solution. I really do not like super chargers though as you have to feed them HP to make HP on the street they are fine though!
With a turbo charger turning 80,000+ RPM's you are not going to be able to notice the spool up times between 30Wt. and 40Wt. oils!
The easiest way for a novice to reduce lag is run a smaller A/R turbine housing. I see all these riceronies out there running .82 A/R 60-1 Garrets on their 1.6L Hondas, and they boast about the top end power........that doesn't come online until 6,000 rpms!
Whilst a number of factors influence so called turbo lag, the less friction (eg less viscous oil) the quicker the spool up. The engine itself will spin up quicker as well. Less friction.
The reason the most do not go to thin grades of oil is that it is difficult to make an oil that will survive the heat generated in the turbo.
Ball bearing turbos give less lag (better response) due to less friction.
The reason the most do not go to thin grades of oil is that it is difficult to make an oil that will survive the heat generated in the turbo.
Ball bearing turbos give less lag (better response) due to less friction.
I reckon (another highly technical term) that switching from a 14.8cst oil to a 12.9 improved my throttle on response of my tubodiesel.
Measureably upset my fuel economy also.
Going from a 10W-30 factory fill to a 15W-40 15.8cst oil made the engine feel sluggish.
All feel/self convincing/ etc etc.
Measureably upset my fuel economy also.
Going from a 10W-30 factory fill to a 15W-40 15.8cst oil made the engine feel sluggish.
All feel/self convincing/ etc etc.
thanks for all the great replies, I wasn't really looking to decrease lag, but I didn't want to increase it either with a 40 weight oil if it had some effect. My engine calls for Mobil1 10w-30 but I was considernig a 5w-40 weight as an alternative. I would think the Mobil1 10w-30 should hold up reasonably well with turbo heat, though the 5w-40 weight may offer more protection.
Drew99GT, Come to think of it I agree!!
After the oil crunch of the mid '70's I went to college. Everything was turbo this and that. I bought a Volvo 760 turbo and hammered it (as I do all my cars) until I sold it with 110k miles on the clock. It tested as good as new. Of course I changed the 5W-30 Pennzoil every 3 - 4,000 miles.
EVERYBODY else was running the Castrol GTX 20W-50. They all replaced their turbos in 20 - 50k miles. I think mine lasted because it was better cooled with the thinner, faster flowing oil and that was the key.
I am sticking with this thought as I use 20 wt oils in my Ferrari and Maybach with good results. The Maybach is a twin turbo V12.
aehaas
EVERYBODY else was running the Castrol GTX 20W-50. They all replaced their turbos in 20 - 50k miles. I think mine lasted because it was better cooled with the thinner, faster flowing oil and that was the key.
I am sticking with this thought as I use 20 wt oils in my Ferrari and Maybach with good results. The Maybach is a twin turbo V12.
aehaas
VERY few 30-weight oils meet VW 502.00, but a number of 40-weight synthetics, such as Mobil 1 0W-40, do. I strongly suspect the few 0W-30 and 5W-30 oils which make the spec. are on the heavy side of the 30-wt. range, well above Mobil 1 5W-30's runny 10cSt hot viscosity.
Does anyone not think that Mobil1 10w-30 oil is up to the task of keeping a turbocharged engine properly protected. I haven't seen it shear out of grade in my limited testing, but I do agree that it is slightly on the thin side viscosity wise.
Hi,
a number of things are the cause of turbo lag and but one of them is incorrect oil viscosity
In 2002 Subaru in OZ investigated varying performance with WRX vehicles. The "quick fix" result was that the spool up turbo lag in some engines was indeed caused by using too viscous lubricants
According to them the lightest recommended oil was "the" fix in that case. I believe that M1 10w-30 was an oil suggested - Subarus are easy on their engine oil
Regards
Doug
a number of things are the cause of turbo lag and but one of them is incorrect oil viscosity
In 2002 Subaru in OZ investigated varying performance with WRX vehicles. The "quick fix" result was that the spool up turbo lag in some engines was indeed caused by using too viscous lubricants
According to them the lightest recommended oil was "the" fix in that case. I believe that M1 10w-30 was an oil suggested - Subarus are easy on their engine oil
Regards
Doug
Dang, 0W-20 in a manly-man Maybach twin turbo V12 and I'm sweating bullets on 5W-20 in a NA V-6 Honda girlie-van?
one good thing about my engine is that it circulates coolant through the turbo after the engine has stopped, a bit more safety margin I guess.
Yes, oil viscosity affects turbocharger spool-up time.
No, you do not need to worry about M1 protecting a modern turbocharged engine; the turbo bearings on all relatively-recent engines are water-cooled. That means you also don't have to let them idle for cool-down for nearly as long now.
Further, turbochargers are not hard on oil except those that are not water-cooled will have a tendency to oxidize oils faster. Turbo bearings are not high shear areas at all. They are high-speed (my Abbott Racing SAAB 9-3 was seeing over 120,000 rpm), but there is almost no load and therefore no shear. Turbos are not a significant cause or direct contributor to oil shearing.
No, you do not need to worry about M1 protecting a modern turbocharged engine; the turbo bearings on all relatively-recent engines are water-cooled. That means you also don't have to let them idle for cool-down for nearly as long now.
Further, turbochargers are not hard on oil except those that are not water-cooled will have a tendency to oxidize oils faster. Turbo bearings are not high shear areas at all. They are high-speed (my Abbott Racing SAAB 9-3 was seeing over 120,000 rpm), but there is almost no load and therefore no shear. Turbos are not a significant cause or direct contributor to oil shearing.
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