Will GC cause a drop in mpg?

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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.
 
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
I'll keep an eye on it and post more data as it comes in.
 
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.
 
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.
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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.
 
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
 
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?
 
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 ]
 
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.
 
Thanks for the link.
I stand corrected.

It doesn't change my opinion on LC though.
cool.gif
 
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!!
 
My jelous defence of GC...
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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.
 
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.
 
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!
 
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.
 
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.
grin.gif
 
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.
 
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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