What synthetic oil for turbocharged motors?

[GearHeadRD]

What good off-the-shelf brand of synthetic oil would be a wise choice for a turbocharged motor? What viscosity do you guys recommend?

I can't get Schaffers in here, and Redline and Amsoil are just too **** expensive for my blood.

Another question is, how long do you guys let your car idle (cooling down the turbo) before shutting it off?

Thanks in advance!

 

[Pablo]

quote:

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What good off-the-shelf brand of synthetic oil would be a wise choice for a turbocharged motor? What viscosity do you guys recommend?

Another question is, how long do you guys let your car idle (cooling down the turbo) before shutting it off?

Thanks in advance!

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For viscosity I recommend what the owner's manual says. Usually the car's engineering team are close to spot on for your engine and climate (see chart).

Is your turbo water cooled? With a water cooled turbo - after hard driving I idle down for about 2 minutes. Most times I just drive 5 minutes or so, gently (no boost) before my destination. So just 10-20 seconds is fine - saves fuel too!

Edit=> if your turbo isn't water cooled you may want to idle a bit longer after hard driving and sudden need to park car.....

[ December 18, 2002, 07:18 AM: Message edited by: Pablo ]

 

[Al]

This is not a slam. But if you can afford a turbo and the luxury of the more HP and resulting fuel use, you should be able to spend a couple of extra bucks to buy the best oil to preserve your investment. Mobil 1 10W-30 is the best off-the shelf synthetic oil. But Amsoil and Redline probably give some better wear numbers in "True" synthetics. Shaeffers 700 series are, from what I can gather as good as you can get. Check Bobs page: http://www.bobistheoilguy.com/

You can check the specs of the Shaeffer's stuff and order it or the Amsoil from "Site Supporters" at that page.

Al

 

[Patman]

When I used to own a turbo car, a 1988 Dodge Shadow ES, I always let the car idle for one minute before shutting down. I would also go the extra step of not driving the car hard at all in the last few minutes of operation, making sure not to invoke the turbo boost at all (the car had a boost gauge in it)

I ran 10w30 Castrol GTX in that engine, but would've run Mobil 1 10w30 if it were available up here then. Back then all we had was 5w30 Mobil 1, and it caused my Shadow to have a nasty cold start rattle (although looking back it could've been a bad Fram filter too, as I was using them back then unfortunately!)

 

[Spector]

I have a twin trubo and let it go about a minute before shut down. If you are really concerned about this get yourself a turbo timer which has the automatic shut down and saves the hassle of waiting in the car if you are in a hurry. Several are on the market. The main issue with not letting the turbos slow down is coking of the oil With synthetics this is less likely to happen. I use Amsoil 10W30 but about any one will probably do.

 

[Drew99GT]

Do not get a turbo timer, especially depending on what kind of car you drive. I have seen too many of my friends cars with turbo timers get stolen, seriously. Mostly turbo 4 banger imports. As for letting your turbo cool down, if it's water cooled and you you use synthetic oil, I honestly wouldn't worry about it that much. Modern turbochargers with 360 degree thrust bearings that accomidate larger oiling passages and the general increase in quality of motor oils these days makes it not as necessary to allow a turbo to "cool" down. I had a 92 turbo Eagle Talon with and upgraded turbo and ran helacious boost (17-19 psi daily) and pretty much never just sat there and idled after shut down. I just stayed in vacuum, not boost, for the last few minutes of driving until shut down, and that car and the turbocharger itself are still in perfect condition.

 

[G-MAN]

The more robust additive package in a HD oil like Mobil Delvac 1 or Rotella T Synthetic would be ideal in addressing the thermal stress that a hot turbo places on the oil. These two oils are relatively easy to find. You can pick up the Delvac 1 at just about any large truck stop and the Rotella T Synthetic is available at Wal-Mart.

 

[dbrowne1]

I'd recommend Mobil 1 0W-40. It will get there quick when you start the car cold, and it will work well under high temps. I have a modified turbo 4 that sees 20psi everyday (watercooled turbo) and this oil has done well in my application.

 

[Eiron]

I think the manuals for the German turbos are pretty good at recommending appropriate oil wts, but I don't know about the manuals for the Japanese or American turbos. The manual's oil recommendation for my Swedish turbo is different here in the US (due to CAFE requirements) than it is for the same car everywhere else. The US manual recommendation is also different than what the car gets shipped with from the factory.

My turbo gets Mobil 1 0W-40, since that's what the manufacturer feels is good enough to fill it with, & recommends for it everywhere else in the world.

Cool down is something you probably only need to worry about if your turbo's NOT water cooled. Unless your driveway (or job) is less than 60 seconds from the start of the exit ramp off the freeway, I'm guessing you're doing enough easy driving to cool it down to where it won't coke the oil. (Even if your work is right against the freeway, it probably takes several minutes from the point where you release the throttle to start your exit, to the point where you're actually in your parking space.)

 

[porterdog]

Another fan of M1 here- in my aftermarket turbocharged Miata I run 10w30 winter and 50/50 10w30/15w50 summer (some track time). I _am_ thinking about going to 0w40 year round, but want to see some more results first...

A guy I sometimes work with works for a company that does a lot of hi-po work with Ford. I recently asked him about the newer thinner oils, and in addition to saying that the new formulations were so good you -could- go thinner (essentially that it wasn't JUST a CAFE issue) he told me that "In my mind, Mobil 1 is the best synthetic that is readily avaiable over the counter..."

I change it out on 5k intervals.

Robert

 

[Quattro Pete]

quote:

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Originally posted by dbrowne1:
I'd recommend Mobil 1 0W-40. It will get there quick when you start the car cold, and it will work well under high temps. I have a modified turbo 4 that sees 20psi everyday (watercooled turbo) and this oil has done well in my application.

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Is this your VW 1.8T engine that you're talking about? Are you sure it is watercooled (or did you make it watercooled by yourself)? My A4 1.8T is not watercooled, only oil-cooled.

BTW, I agree on using M1 0w-40. I'll be switching to it soon myself. Right now I'm on M1 0w-30.

OK, my bad, apparently the 1.8T is both oil-cooled and water-cooled. However, my questions is: what difference does it make whether it's water-cooled or not?

[ December 18, 2002, 11:31 AM: Message edited by: Quattro Pete ]

 

[Racer X]

Mobil's website recommends the Mobil 1 15W50 specifically for turbo cars - they mention a special high-temperature formula with extra anti-wear additive. If you operate in cold temperatures I would use the M1 0W40.

I autocross a '91 MR2 Turbo and use Mobil 1 15W50. I do not drive the car much in the winter, just enough to keep the car from getting rigor mortis.

My cool-down regimen is not very extreme, I just try to keep off the boost for the last 6 blocks, drive slowly for the last 2 blocks, and then give it 10-15 seconds of standing idle. Obviously after an autocross run I let it cool for a long time, sometimes I don't even shut down between runs.

For me the big question is how long to run the oil. I use the car for competition and can run for almost two years before accumulating 3000 miles. I plan to do analysis on the oil I am running now, but it will be quite a while before I change it. I won't get TBN since the lab will be Shaeffer's so it may be hard to tell how chronological time is affecting the oil.

 

[porterdog]

quote:

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Originally posted by Quattro Pete:
However, my questions is: what difference does it make whether it's water-cooled or not?

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There are 2 factors at work in a water-cooled turbo- when the car is running, the turbo bearings stay cooler because they're bathed in a continuous flow of 'water', and the coolant temp is usually a lot lower than the oil temp. For this reason, the watercooled turbos don't generally get as hot as the oil-cooled only variety.

The second factor is in play after shutdown- the additional thermal mass of the coolant in the center section (and possibly some convective flow [=continued circulation even after shutdown]) helps to moderate the 'heat soak' that used to be so hellish on the first gen of oil-cooled-only OEM turbos. THAT'S when 'coking' would occur.

Actually- I forgot factor 2b: In my car at any rate, I can sometimes hear the coolant in the turbo boiling a bit after shutdown- this is actually a good thing in some ways in that it involves a phase change, which, as we all remember from physics (latent heat of vaporization) requires more energy input than simply changing the temp of the liquid one degree...

That's why.

Robert

[ December 18, 2002, 01:08 PM: Message edited by: porterdog ]

 

[satterfi]

I like XHVIs recommendation.

Delvac 1

If I owned a turbo engine I would also consider Redline 10w40. But, I live where I can get RL for $6.30/qt. You Canadians are getting screwed.

M1 15w50 would be my third choice.

 

[sprintman]

$6.30 a quart? You think the Canucks have it bad its A$30 a quart here (Oz)!!
I'll stick with RL gear oils and PSF etc but probably go back to Mobil for eng oil in my turbo Mazda.

 

[dbrowne1]

quote:

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Originally posted by Racer X:
Mobil's website recommends the Mobil 1 15W50 specifically for turbo cars - they mention a special high-temperature formula with extra anti-wear additive. If you operate in cold temperatures I would use the M1 0W40.

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I HIGHLY suspect that this is marketing gobble-de-gook. They also say that 10W30 is for "higher mileage" vehicles and 5W30 is for "newer vehicles", and we all know it's not that simple. I also doubt that 15W50 has any "special" additive that the others lack.

 

[darrenc]

Please tell us what kind of vehicle this is. For off the shelf, I'd probably go with M1. I use Amsoil 10W-30 for my Volvo t5. See my oil analysis results in the used oil analysis section.

 

[GearHeadRD]

Well, I just recently turbocharged my Honda, so I can't follow the original manufacturer's recommendation since it's meant for normally aspirated motors.

My aftermarket turbo is oil cooled only, so I really want a easy-to-access off-the-shelve synthetic oil that is good for my motor with a good viscosity range so I won't start cooking the oil and burning up my turbo. And yes, I'm going to get a turbo timer very soon.

I would like to use the real good stuff like Redline or Amsoil, but they are really expensive, hard to get, and they last about 3000-4000km at best from my experience. So as you can see, having a Redline/Amsoil oil change for every 3000-4000km can get expensive real quick. Plus the fact that even if the Redline/Amsoil stuff can last longer than 4000km, I just don't feel comfortable leaving that oil for that long under such extreme conditions.

Like I said before, I don't have access to the Schaffer oil, so even I would like to give it a try, I simply don't have access.

So what do you guys recommend? All I really want is a real straight answer...which brand and what viscosity range? And yes, it snows in my area, but the temperature is usually within -5C to -10C range most of the time.

By the way, these are the brands of off-the-shelf synthetic oils I have access to:

Mobil 1 SuperSyn
Castrol SynTec
Havoline full synthetic
Valvoline full synthetic
Penzoil full synthetic

Your recommendations are much appreciated!

 

[Patman]

Both Amsoil and Redline will last way longer than 3000 to 4000km! Something is seriously wrong if your engine is destroying either of those oils that quickly.

As far as having access to Schaeffer oil, you can simply do as I do and mail order it from this site.

[ December 19, 2002, 06:13 AM: Message edited by: Patman ]

 

[G-MAN]

quote:

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Originally posted by GearHeadRD:
By the way, these are the brands of off-the-shelf synthetic oils I have access to:

Mobil 1 SuperSyn
Castrol SynTec
Havoline full synthetic
Valvoline full synthetic
Penzoil full synthetic

Your recommendations are much appreciated!

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If these are your only options, then Mobil 1 gets my vote. Use the 0w40.

If you can get the Havoline or Pennzoil "European Formula" synthetic in 5w40, those would be good choices.