wow I didn't know about GTX
Anyone have spec sheets on the GTX? I can't find them on their site.
And how does GTX Compare to Pennzoil?
I know SuperTech is closer to QS specs than Pennzoil - a good last resort oil to use (it doesn't appear to flow as well as Pennzoil).
I think you have to call Castrol and ask for their data sheets. Haven't seen Castrol voluntarily post anything anywhere. The latest GTX SL info they sent me was dated 6/02.
5W20 5W30 10W30
Vis 100 C 8.8 10.7 10.7
Vis 40 C 50 63 72
Vis Index 158 160 142
HTHS 2.8 3.1 3.1
Flash C 204 204 213
Pour C -30 -33 -30
I also requested the MSDS sheet for the 5W20 oil. It's main ingedient is listed as a "highly refined petroleum basestock," followed by 15 different CAS #'s: one 64741, nine 64742, and five 72623 series numbers.
The additive package consisted of 10-30 %
a) zinc diakyl dithiophosphate,
b) calcium salts of alkylated phenolsulfides,
c) alkylated diphenylamines,
Plus 7-13% Methacrylate polymer and/or ethylene propylene copolymer with a nitrogen functional group blend.
If you're worried about them thinning out, try out the high mileage versions of those oils (Pennzoil HM, Castrol GTX HM) as they should stay in grade longer. I know the Maxlife I was using stayed in grade very well, plus these oils run on the thicker side of the 30wt (and we know how much you hate thin oils!)
As I remember it, the dino with the most ppm of moly is Citgo Supergard.
It is easier to list oils without moly, as of the last test reports: Mobil Drive Clean, Exxon Supeflo, Chevron Supreme/Havoline and Motorcraft/Conoco are 3 that are available at larger department stores...
Here's an interesting thing tho - more moly doesn't necessarily mean a better oil, right?
Redline has the most moly IIRC out of all the synthetic and dino oils (almost 600+ ppm).
I want to get Pennzoil but its $1.66/qt at walmart.
Chevron Supreme is $1.08 but no moly.
My only other choices are GTX and Super-Tech. Walmart doesn't seem to carry 5W-30 dino ST anymore, just 10W-30/40. and my dad hates GTX - he said its for small engines or something, he just doesn't like it. I dunno why exactly.
I am trying to make the same decision. Is there really any advantage to spending $0.58 / quart more money on Pennzoil?
Not that the 58 cents will break me, but I am all for getting the most for my money!
Castrol seems to be the leader in the moly department for conventional oils, their oils typically are using on the order of 60 ppm of moly. I was recently told that the over the counter Honda oil is now using good doses of moly but I can't confirm that. I've seen different results of Penzoil, some with moly and some without. In normal naturally aspirated motors Castrol GTX doesnt appear to thin out, I think in the one analysis it thinned out was in a turbo application which is known to be hard on conventional oils. In naturally aspirated applications it has held up fine, the GTX formula seems to hold up better than the Syntec and Syntec blend formulas. hth.
I really can't wait to see how GTX and Syntec hold up in my sister's car. I'll be using 5w30 and will run two intervals of each, at 10,000km. She does a lot of highway driving so the results will pile up fast, I should have all four intervals completed by this time next year.