You know, I noticed this about GC as well in my 4 banger (VW 1.8T turbo). But i don't think it's just due to thickness because I noticed the slugginess of GC even when switching from 5w-40 Synpower to the GC. I noticed it again when I switched out the GC and put in Castrol GTX (for Auto RX application).
Can German Castrol 0w30 Cause Sluggishness Over Mobil1 10w-30 ?
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I think it depends a great deal on engine design. My Northstar (99 STS) felt pretty sluggish after starting with the GC. I have been keeping it at the "ADD" mark, most oils seem to do well right there. I would need to keep adding a couple of ounces after each 300 mile trip. This is the only thing this car is used for, highway trips. This last 300 mile trip, I left it at the bottom of the dipstick, about 1/4" below ADD, and the difference is remarkable. My gas mileage is back up to 26.5 - 27 highway (after 24 - 24.5) and it feels like about 20 more HP. Used absolutely NO oil this last trip. The oil now has 5000 miles on it (55000 on motor) and it may just have sheared down. I also noticed that it was somewhat dirtier suddenly, and I do mean suddenly as I check it every trip and it has looked clean to this point. Could there be such a thing as resistance to "tearing" or "aeration" that might be noticable if the crank is running in oil that might be more noticeable in some engines?
I'd hate to think of any modern engine that has a crank low enough to "dip" into the sump. Without a windage tray you can get excessive oil on the crank but it shouldnt aerate, just slows the crank down a bit. I could be wrong but you'd have to be a pretty dumb automotive engineer to produce an engine like that. Just my guess.
Switching from GC 0W-30 to GTX 10W-30 made a huge difference in performance of my Impreza. The engine revs so much easier, runs smoother and much quieter. Noticeably better power.
UOA shows good results after 8k miles on GC. So, despite subjective deficiencies, objectively it's all good. One of these days I will post the results
UOA shows good results after 8k miles on GC. So, despite subjective deficiencies, objectively it's all good. One of these days I will post the results
This is very interesting. I hope those who have used GC will tell us what the "butt dyno" has resulted from their use. I find it interesting such an oil which tends to yield very good UOAs and is a 30wt can make a noticeable difference in power.
Maybe my butt dyno is not as finely calibrated as some, but I noticed no signifigant difference in power or "reviness" in my Mazda 6s between Motorcraft 5w-20 and GC. I ran the Motorcraft for 3 changes from new to 7500 miles, and I'm on my second run on GC. GC posted a nice UOA for me, so I'm sticking with it. I also seem to get highway mileage that is equal to or better than the EPA numbers, while many other owners report signifigantly worse mileage, so I question if GC has a higher coefficient of friction than most.
Patman
Staff member
FWIW, my car did not lose any performance in the quarter mile after switching to GC, so it's definitely not robbing me of horsepower.
Didn't someone mention that GC additive packages weren't exactly "identical" from each oil batch? I remember a post about some interesting variances depending on when and where you bought an oil.
Could this be the result of why some people notice a substaintal difference while others notice no difference?
Hey Paul,
Do you still have your pdf of the 0w-30 GC UOA? I still have the bobs oil link, but wasn't able to snag your 0w-30GC link and put it on 6tech before you took it down. Could you pm me a link so I can throw it on 6tech (hosted on 6tech) with the others?
Thanks.
Could this be the result of why some people notice a substaintal difference while others notice no difference?
Hey Paul,
Do you still have your pdf of the 0w-30 GC UOA? I still have the bobs oil link, but wasn't able to snag your 0w-30GC link and put it on 6tech before you took it down. Could you pm me a link so I can throw it on 6tech (hosted on 6tech) with the others?
Thanks.
I'm not an expert, but judging from the way our two vehicles responded (Volvo 850 turbo and Passat 1.8T), it may have more to do with the engine design than the batch. I noticed no difference in the Volvo (same batch of GC), no change in gas mileage, nothin. In the VW, there were big fluctuations in gas mileage (2-3 mpg according to the trip computer) and noticeable difference in throttle response. I can't explain it
I think it does have to do with engine design, that's why I dont want to generalize this for all vehicles. I just noticed it on my vehicle, I think the 4 cyl and balance shaft design makes it more noticeable, also my engine has no windage tray under the crank from what I've been told. Maybe my piston jet squirters cause a bit more back pressure on the oil pump as well, dunno , just a thought. If the oil works for you keep using it, as I dont think it applies to all engines.
My standard Buick 3.8 V-6 really got sluggish after switching from Syntec 10W-30 to M1 10W-30.
I can still tell after the 2nd oil change and 7,500 miles total.
I love the M1 except for this perception.
Maybe the GPIII's and slack wax give some feel (HP) advantage over full PAO's @ the same visc.??
I can still tell after the 2nd oil change and 7,500 miles total.
I love the M1 except for this perception.
Maybe the GPIII's and slack wax give some feel (HP) advantage over full PAO's @ the same visc.??
Patman
Staff member
Oh the horror! GC just rolls off the tongue so much nicer.
Their test is non-scientific. Look at the difference in oil temps-a 31* difference. Factor in the variance in most dyno's and there you go.
I noticed the same thing.
When my Prelude and my wife's Integra had both M1 10W30 TrySyn, there was a noticeable difference in power between them.
Now the Lude has GC and the Integra M1 5W30SS.
Every time I drive the Integra it surprizes me how zippy it is.Not that it caught up in power, it's just pepyer than I've known it for years compared to the Prelude.
Another good thing is that the oil consumption went down with the 5W30 Super Syn over the 10W30TrySyn.
I also noticed more engine noise with the CG.
I must have been wrong when I thought it would be quieter, since is thicker when hot.
When my Prelude and my wife's Integra had both M1 10W30 TrySyn, there was a noticeable difference in power between them.
Now the Lude has GC and the Integra M1 5W30SS.
Every time I drive the Integra it surprizes me how zippy it is.Not that it caught up in power, it's just pepyer than I've known it for years compared to the Prelude.
Another good thing is that the oil consumption went down with the 5W30 Super Syn over the 10W30TrySyn.
I also noticed more engine noise with the CG.
I must have been wrong when I thought it would be quieter, since is thicker when hot.
Patman
Staff member
But it's easier to type GC than SLX, it's one less letter for lazy people like me to type!
That Mobil 1 pictured is definitely NOT the Mobil 1 0w-40 that can be found on most auto part store shelves.
There is a specialty shop in California that sells like 15 different brands of oils, and the European and Japanese Mobil synthetic blends are designed "performance driving" and "power" (two different formulas in different bottles, same 0w-40...different than the "European Formula" in the US). I know its about $48 USD for a 4-qt metal can. Probably accounts for the increase in power over the other oils, even the SLX.
-JamesW
There is a specialty shop in California that sells like 15 different brands of oils, and the European and Japanese Mobil synthetic blends are designed "performance driving" and "power" (two different formulas in different bottles, same 0w-40...different than the "European Formula" in the US). I know its about $48 USD for a 4-qt metal can. Probably accounts for the increase in power over the other oils, even the SLX.
-JamesW
I don't care if some lab test or some dyno says otherwise, my 99 Civic was very sluggish with GC and now with M1 0w-30 it feels like a new car. I am not doubting whether GC is a good oil or not, just I have seen it in my car and by seeing this topic talked about from time to time here on this board I think it is the case that some cars run sluggish on GC. M1's 30 weights are thin, GC is thick. My gas mileage improved as well. Many of the people who are reporting this are people with 4 cylinder engines, specifically Japanese/Honda engines. My car was quieter with GC, but the sacrifice in gas mileage and overall zippyness of the car was not worth it imo.
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