Will GC cause a drop in mpg?

vad

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UOA after 3K miles? Are you planning on running GC for 3K? I'm sorry, but you're waisting your money. Under those intervals I would run a cheapo brand name dino purchased on sale. You'll get similar results to the posted UOA. Also, what do you need LC, FP for??? How do you calcualate your milage? Did you run the car under similar conditions? There are lots of variable that can significantly alter your gas mileage such as cold temperature start-ups, colder temps in general (that also affect tire air pressure), "winter" gas etc.
 
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vad - read my notes on the UOA. the oil was not changed out at 3k, only sampled. I do a lot of stop/go driving - wanted to see how the cheap ST was holding up. the ST was drained at 5k, the GC will be in there for >6k. FP is for carbon build up in the chamber. the LC is to keep the GC from thickening (as specifically advised for GC by Terry Dyson in several other posts). driving conditions are the same. tire psi checked weekly. never saw <22 mpg before switching to GC. now 2 tanks in a row <19 mpg. been running "winter" gas for at least 5 tank fulls, and gas here is oxygenated year 'round anyway. only diff here is GC... but with GC's 15% higher operating viscoisty, is this really a surprise? I'll keep an eye on it and post more data as it comes in.
 
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My sons 2.0L dohc Focus lost mpg with GC. My personal 4.0L '05 Explorer and my business 4.6L and 5.4L Ford V-8's have not dropped one bit with GC..this against Mobil 1 and others.
 
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I'll add my $.02: As crazy as I was for doing it, I used to run WM SuperTech 5w30 dino in my '00 VW GTI 1.8T. When I switched over to M1 0w40, I noticed an approx. 1 mpg drop. That remained unchanged when I used GC. I have no idea why I got better mpg's with dino. [I dont know]
 
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quote:
I have no idea why I got better mpg's with dino.
I think it's just a matter of viscosity. GC is thicker than almost every other 30wt, more like a 40wt. thicker oil = more resistance to movement of internal parts = lower MPG. this is what the EPA standards that led Honda and Ford to spec 5W20 are all about. however, i didn't expect a 4 mpg hit from a 2 cSt increase in operating viscosity.
 
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wow i'm gettin kinda scared now...GC loses that much mpg? I mean, I did hear about GC being a thicker oil and all...just didn't expect it to lose that much mpg....anybody in here with a VQ35DE lose mpg from GC? EKpolk? I especially am worried becuz my current mpg is 17...all city with aggressive driving...this is using 5w-30 Torco SR-1 synthetic
 
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Portsmouth, NH
quote:
...all city with aggressive driving...
Then you probably have very little to worry about. You'll gain more efficiency by just going a bit easier on the go pedal [Wink]
 

vad

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quote:
I especially am worried becuz my current mpg is 17...all city with aggressive driving...this is using 5w-30 Torco SR-1 synthetic
Yep, you'll lose about 5-7 mpg and on a really bad day and your gas mileage will approach the fuel economy of a Hummer. Just because it's slightly thicker than a normal 30 weight oil. Do you see any logic in this statement?
 

vad

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quote:
however, i didn't expect a 4 mpg hit from a 2 cSt increase in operating viscosity
I don't doubt you. I just want you to explain your mpg calculations. My mileage is never the same and differs dramatically from a week to week on the same route, with the same gas and oil. There are many factors that can affect your mpg. Sometimes I hit a disproportional number of red lights - my mileage goes down, on a windy day - my mileage goes down on a very cold morning - my mileage goes down I get stuck in a traffic jam - my mileage goes down I decide to open my engine up to blow out all that carbon - my mileage goes down I have a passenger in my car - my mileage goes down I decide to take an alternate route on the city streets - my mileage goes down. I'm saying all this just to show you guys that your reports are not accurate unless you accumulate a huge amount of data over a long period of time (months) in order to zero out the enormous amount of variables in our everyday driving. And even then it won't be too accurate when you'll have to consider other long term factors like the wear on your tires (the tire radius gets smaller with time thus negatively affecting gas mileage), your spark plug wires deteriorate by increasing electrical resistance, your air filter gets dirtier and fuel injectors could change its specs. In order to get the relatively accurate numbers we need to run a car on a circle, on the same day, under the exactly the same conditions. Only then we would be able to judge the oil's effects on the gas mileage. [ December 15, 2005, 11:10 PM: Message edited by: vad ]
 

vad

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quote:
the LC is to keep the GC from thickening (as specifically advised for GC by Terry Dyson in several other posts).
I doubt Terry runs LC in his own car, but to each of his own.
 

vad

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Thanks for the link. I stand corrected. It doesn't change my opinion on LC though. [Cool]
 
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vad - your jealous defense of GC is admirable, but eventually you'll have to admit that thicker oils, like GC, will inevitably affect fuel economy -- the laws of physics dictate it. and the auto makers know this too - which is why they are specing thinner oils in response to the US CAFE fuel economy requirements. you don't think Ford and Honda spec 5W20 because it protects better do you? my only surprise is with how dramatic the difference is. you asked for info on how I track MPG. here it is... to head-off some of your comments: - yes, I assume that every time I fill up I leave the station with the same # of gallons in the tank. I know there is error here, but my data suggests it is small. - yes, driving conditions are never the same, which is why I tried to note some obvious deviations to the "norm" - sub freezing weather around here started in mid Nov, but my MPG stayed >22. - to correct on of my previous statements, there was indeed one time on thinner 5W30 when I fell below 22mpg - 21.9 on July 31.
code:
  

Date	Odom	Miles*	Gals**	MPG***	Notes
25-Jun	70,120	Oil change - ST 10W30 Syn 			
1-Jul	70,472	364	15.9	22.9	
2-Jul	70,848	376	14.4	26.1	70-80%% hwy miles
4-Jul	71,260	412	14.7	28.0	>90% hwy miles
10-Jul	71,659	399	16.6	24.0	
15-Jul	71,902	243	10.3	23.6	
17-Jul	72,253	351	14.3	24.5	
25-Jul	72,672	419	18.5	22.6	
31-Jul	72,928	256	11.7	21.9	longer traffic jams
9-Aug	73,303	375	16.9	22.2	longer traffic jams
16-Aug	73,660	357	15.9	22.5	
24-Aug	74,082	422	17.8	23.7	
26-Aug	74,166				Installed new NKG plat plugs
3-Sep	74,594	512	22.2	23.1	5 gals added at 74,475 
5-Sep	74,922	328	12.9	25.4	60-70% hwy miles
11-Sep	75,269	347	14.8	23.4	
18-Sep	75,626	357	16.2	22.0	
18-Sep	75,635	Begin ARX Clean Phase on ST 5W30 dino			
23-Sep	75,905	279	12.6	22.1	
30-Sep	76,228	323	14.3	22.6	
9-Oct	76,597	ATF Flush, pan magnets cleaned			
10-Oct	76,629	400	18.2	22.0	5 gals added at 76572
18-Oct	76,964	335	15	22.3	
26-Oct	77,230	Begin ARX Rinse Phase on Havo 5W30 dino			
26-Oct	77,245	281	12.6	22.3	
29-Oct	77,557	312	12.7	24.6	
4-Nov	77,857	300	13.3	22.6	
11-Nov	78,226	369	16.1	22.9	
21-Nov	78,638	412	18.3	22.5	3 gals added mid-fill
21-Nov	Added 20oz Techron concentrate				
27-Nov	79,012	Cooling system Flush			
28-Nov	79,039	401	17.3	23.2	
29-Nov	79,080	Oil change - Gold GC 0W30 + 5oz LC20			
6-Dec	79,333	294	15.8	18.6	3oz FP60 added to this tank
14-Dec	79,655	322	17.2	18.7	3oz FP60 added to this tank
					
AVG MPG before Gold GC		23.3	
AVG MPG w/ GC			18.7	
Diff				4.7	
					
NOTES:					
*Miles = miles driven since last fill up = (current odom) - (last odom)					
**Gals = gallons to fill tank. Tank filled until pump stops. 					
***MPG = Miles/Gals					
			

and here's a chart of the data. the red line is a 2-period moving average trend line. the error bars are the standard error of the data sample. the dataset includes 27 samples. generally, 30 samples are considered "statistically significant" for most real world interactions.  - Look at the data and decide for yourself if GC is the cause of my recent drop off in fuel economy!!
 

vad

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My jelous defence of GC... [LOL!] sky jumper, I never made a claim that thicker oils don't affect fuel economy. The do and always will. They question is how dramatic or rather negligible the effect is. Your stats are impressive. Unfortunately the data sample is too small to draw any conclusions. Plus the timing of the switch is quite telling: the end of November when the average temps take a significant dip. I see you're in Chicago. When do you guys switch to "winter" gas? Mid November? That would really explain the dramatic drop in fuel economy.
 
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appalachia
My experience is that fresh GC will cause a slight drop in MPG initially. But, after a few hundred or maybe 1k I found that mileage was as good or better than other synthetics. I drive 40k per year with GC in my job.
 
Joined
Nov 15, 2003
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Boston
Thatwouldbegreat, I saw a drop in mpg on my 2002 Subaru Impreza TS (2.5 liter normally aspirated engine, much like yours) when I used GC (the green vintage) versus M1 0W30. Me... I'm now using M1 0W30 with a quart of Redline 5W30 this winter (plus LC20, and FP60 in the gas tank)... hitting the AutoRX treatment in the spring, and then I'm going to resist any blending and use M1 5W30 EP (plus LC20, of course). Wish me luck resisting blending!
 
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Tinley park il
I have fallen into the GC triangle of "this is the greatest oil that ever was created"! I am sure that it is great oil but it will not work for all appplications. I have put GC recently into my wifes 2004 altima 3.5 and it is hurting gas mileage. I will use it and move to synpower or M1. This oil was designed for certain vehicles that needed exactly the brew it contains. Obviously it can be used in other applications and work fine. There is no "this oil works in every situation" lube on pep boys shelf. To find the perfect oil you must try things out.
 

vad

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May 1, 2003
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So Cal
quote:
This oil was designed for certain vehicles that needed exactly the brew it contains. Obviously it can be used in other applications and work fine.
Yea, and Mobil 1 is a universal oil, perfect for all vehicles, including the transgalactic ones. BTW which vehicles are "needed exactly the brew it (GC) contains"? Impatiently waiting for your response. [Big Grin]
 

vad

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So Cal
quote:
I have fallen into the GC triangle of "this is the greatest oil that ever was created"!
Common, dude. If I'm not mistaken you've just learned about GC. Used it in your car for no more than a couple of weeks. Right? Then suddenly have experienced a change of heart because GC didn't quiet down your Altima. Now GC is hurting your gas mileage. By how much? Must be by not less than 10 mpg, or at least by 4. I've seen some reports. That's all true and dandy. If I were you I would just drain this nasty Green/Gold stuff out and switch to "work in every situation" Mobil 1. GC definately hasn't met your expectations. Mobil 1 certainly will.
 

Sid

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Oct 12, 2003
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Chicago
I wanted to chime in because although I am not using German Castrol on my girlfriends car I am using Castrol 5W-30 Syntec. It seems that so far she is getting pretty nasty gas mileage. Then again I can't blame anything yet because it is winter blend gas and I haven't tested it over multiple gas tanks. I would like to think that the oil had nothing to do with it. But time and tests will tell.
 
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