Power Loss With Synthetic Motor Oil?

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Hi all, this is my first post. I recently purchased a 1997 Landcruiser and also recently switched the motor oil from the Valvoline 5w30 that the original owner opted for and went with Mobil 1 15w50. I swear by synthetics and use them in my 4Runner which has over 200,000 miles now and is still running strong. One strange thing though that I observed is slightly less power with the synthetic in the motor. Can anyone explain why this would be? Would thicker oil rob some horsepower if it were synthetic as opposed to dino oil? Would a thinner synthetic oil be a better decision? Do I just need to wait for a while for the motor to adjust to the synthetic? Any advice at all is appreciated. Thank You.
 

cruiserdan

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I believe that you are imagining a difference.

In addition, but not related to any perceived power loss, 15w50 is most likely a bit heavy.

I suggest no more than 15w-40.



Disclaimer: One man's opinion, not based on Printable fact..... :flipoff2:
 
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Well, I suppose I might imagine the power loss but given my expectations of synthetic and the so called placebo effect, I thought if anything I would imagine an increase of power when none was there and not a decrease in power!!! Anyway, maybe I should put more miles on it and see if I still sense the loss of power. I should have mentioned that this cruiser is turbo charged; do not know if that is relevant with this question? Does Mobil 1 make 15w40? Thanks for the advice though, I appreciate it.
 
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Newer engine are desinged to use thinner oil. Thicker oil produce more drag and could be bad for your engine since the molecule are bigger and could not fit in the tighter tolerance on newer engine. Stick with the manufacturer recommendation.
 
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What does your owners manual suggest? On my 95 it states you should use a 5w30 weight. I have used Mobil 1 5w30 for the last 100K miles. Works for me. Why did you pick 15w50 weight? Go to www.bobtheoilguy.com to learn more about oil. Welcome to the site.
 
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Well, I switched to 15w50 for several reasons: First, I prefer synthetic but realize that Mobil1 can behave "thinner" than the weight would suggest compared to the same weight of dino oil so I did not want to get Mobil1 5w30 for example. Two, the pour temp of 15w50 is much superior to the pour temp even of the original Valvoline 5w30 so I did not think cold weather operation would suffer. Three, the thicker viscosity of the synthetic I thought would help with the performance mods on the engine such as the turbo and the turbo intercooler. Four, the ability of synthetic to withstand tremendous temps compared to dino oil, the ability to resist acids and other byproducts of combustion and the ability to resist breakdown of viscosity over time. And Fifth, perhaps most importantly, Ben at Slee Offroad, who has cared for this specific vehicle for a while suggested that 15w50 would work well for my motor. So, for all those reasons I switched. I would be willing to dump all that liquid gold out and replace with perhaps Mobil1 10w40 but I do not think I would want to put 5w30 in as Mobil is a little on the thin side from what I have heard. Sorry for the long post, any advice on this area is most appreciated. Thanks.
 
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Sounds like you have good reasons and some sound advise for what you are running. I alway ran a 15w40 in my Cummins Turbo Diesel, thats what was recommended. I know some guys in the TDR used 10w30 when the temps droped below "0". I've alway heard that you want it to flow in all the temps you experience and you want to have a good layer of protection for wear protection. I would agree that with a turbo it helps to have the synthetic to help prevent coking on the turbo when you forget to let it cool as much as it should. Like I said check out www.bobtheoilguy.com they have some real oil experts that can give you the scoop on what would work the best for your climate and driving conditions. Good luck, and welcome. :cheers:
 
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Hi, I'm in Colorado, today the temp is around 60, in a few days it could be 0 in a few more days either 80 or negative 5, you never know. This weather was something to think about with the 15w50 but the pour temp is negative 49 which we will never see here. Again, all this advice is awesome, you all rock! So should I switch to a different weight Mobil 1 or should I stick with the 15w50? Thanks.
 
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turbocruiser,
I believe your perceived drop in power is not a real drop or it's unrelated to the change in oil viscosicity. I'm not saying that a thicker oil will not effect power, I don't think it would be possible for you to "feel" the slight change. Your engine is probably pushing 300HP or more. A change of 2 or 3 HP either way would not be noticable.

You're using a heavier oil for the right reasons. The optimum weight is something the oil experts will have to advise you on. I'm not informed enough to give an opinion.

-B-
 
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does your turbo have an oil pressure actuated waste gate? the higher oil pressure at lower RPM the thicker oil gives may have slightly changed when the waste gate opens and closes, the waste gate may need adjusting (if it is adjustable)

I would stick with a thicker than recomended synthetic on a turbo, the oil will see higher operating temps than it would in a NA motor, but everybody has opinions on oil..........

you also might want to look at Mobil Delvac 1, it is their diesel oil but is also working very well in gas motors sometimes better than Mobil 1
 
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Hi, to be truthful I have no idea if in the safari turbo system there is an oil pressure actuated waste gate, anyone know? But, after reading all the posts and searching about a thousand more I think I might switch to 0w40. I think that is what Cary runs and he seems to know this stuff. BTW thanks again for all the advice, and I just want all to know that I did immediately use the search tool, it is awesome, I know the oil thing is discussed to death but with the turbo I thought there was enough difference to do a separate thread? Hope that was okay. Anyway thanks for the advice and any more votes on what weight Mobil1 I should settle on? Thanks and :beer: For All.
 
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Yes, the fuel system is good and the filters are all good, and no, my foot is not on the brake pedal! Maybe it is the fact that i forgot that I hooked my 4runner up with a tow bar and left the 4runner in park while I pulled it with the cruiser! Doh! Just joking, Keep in mind in this case it was a difference only between one type of oil and another type of oil. In other words, before the synthetic, the motor pulled super strong, scary strong actually and now it is still super strong but just somewhat softer on acceleration. I really think what it is is the crankshaft plowing through a much thicker oil resulting in some slight loss of power. I am not sure if there is a baffle system with this model's oil pan, if not the thicker oil may account for some decrease in power? I'm still leaning towards 0w40 unless someone can share some wisdom to make me think otherwise. Once again, thanks everyone for all the advice, I appreciate it. :beer: For All!
 
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IF you are in the front range you will have a winter blend gas,MTBE,or ethonal(speling?). Did the problem start when the winter grade was switched? I don't live in CO any more but when I did I some vehicles would suffer from the winter grade.
 
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Hmmm, interesting thought but, in this case, I just happened to have about 3/4 a tank of 91 grade gasoline so I do not think this is the reason. I'm still thinking that in general, whether it is the crankshaft or other parts that spin in the oil, the increased weight of the 15w50 is causing increased resistance on all those moving parts. I guess the real question is does the decrease in power, if related to the resistance of the heavier weight, harm the engine. Since I am almost absolutely sure that it does not harm the engine, the next question is if 0w40 would work well with my motor? Or possibly I should just go with Mobil 1 5w30 but for some reason I feel that this is too thin...just a hunch, no proof of this. Any thoughts from anyone on this? Again thanks for the advice, keep it coming if you wont mind. Thanks, :beer: For All!
 
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GO to the toyota dealer and get a can of Toyota Injector cleaner and dump it in and fill the tank and drive. Make sure you run the tank of gas in a couple of days as it will eat your tank/lines if you leave it in tooo long.

In Milwaukee WI they use a bad winter blend, it decreases power and mpg from what I heard.
 
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Do you know if your 80 has the TRD thermostat? The temp, from what was posted, runs cooler. That with the heavy oil could couse your problem.
I don't know how you could tell if you have one if you didn't install it.
 

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