Syntec vs. GTX???

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Both of these oils you mention have an HT/HS of 4.8 I show a VI of 122 for GTX and 180 for Syntec. Unless it's changed, the 20/50 has a boat load more zddp. My vote goes to the Syntec 10W-40. [Big Grin]
 
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I ran the GTX High Mileage 20W-50, which Castrol advertises as being more shear resistant than their regular oil, for 1,600 hard miles in my Harley and it sheared down to a 30 weight. See the UOA: http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=3;t=001382 Currently running the Syntec 20W-50 and have 1,400 brutal miles on it. Going to do a 600 mile road trip this weekend, which promises to be just as hard, and then do a UOA. Will post results as soon as they are available. Should be interesting. My bet would be that the Syntec doesn't fare much better. [ May 25, 2004, 01:25 PM: Message edited by: doyall ]
 
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doyall, is it accurate to compare a motorcycle engine to a car? Aren't you supposed to use a motorcycle oil with special addatives (eg. for dry clutches) and not just OTC automotive oil???
 
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quote:
Originally posted by Dr. T: doyall, is it accurate to compare a motorcycle engine to a car? Aren't you supposed to use a motorcycle oil with special addatives (eg. for dry clutches) and not just OTC automotive oil???
The big Harleys have three separate sumps; one for the engine, tranny and clutch. I'm not sure that there is such a thing as special motorcycle additives. The quantity of certain additives and the viscosity may be the key to calling an oil a MC specific oil. Even with the GTX HM and its horrible shearing there was not an overabundance of wear metals in the UOA. Anyway, the Motor Company recommends a HDEO if their brand is not available. The GTX had no diesel rating but the Syntec does (CF, I think). We'll see if there is a difference in the shearing. Irrespective of whether either of these oils is a MC specific oil, this should be a reasonably good comparison of the two.
 

haley10

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Castrol often designs in the apparent shear, so it's by design and not a real weakness. Syntec is friction modified and may not be appropriate for use in some bikes. I don't know that Harley or Castrol would recommend it for your use. You should consider running Mobil or Castrol Motorcycle oil, imho. Pricey. but formulated for your application better.
 
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quote:
Originally posted by haley10: Castrol often designs in the apparent shear, so it's by design and not a real weakness. Syntec is friction modified and may not be appropriate for use in some bikes. I don't know that Harley or Castrol would recommend it for your use. You should consider running Mobil or Castrol Motorcycle oil, imho. Pricey. but formulated for your application better.
Syntec was a freebie. That, combined with the I-don't-know-what's-going-to-happen-when-I-use-it situation, is why I'm only going to take it to 2,000 miles. Got some M1 V-Twin waiting.
 

pbm

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Haley, what makes you say the Syntec 10/40 is "killer stuff". Is it not Gr.3 like the other Syntecs (with the exception of 0/30 GC.)
 
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Dr. T, if I had to choose between these two oils I would go with the Syntec 5W-50. The Syntec has a TBN of about 10.5 and should keep your engine much cleaner than the Castrol GTX 20W-50 which probably has a TBN of about 7 or 8. I think both oils will eventually shear down to an SAE 40 grade. The volatility of these two oils is probaly about the same however when a group III/IV oil (Syntec) burns off it will leave fewer deposits than a group I or group II oil (GTX). [ May 25, 2004, 10:45 PM: Message edited by: Sin City ]
 
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Which of these 2 oils do you think would stand up to more punishment (especially at high temps/high rev conditions)....Castrol Syntec 5-50 or GTX 20-50 for a 5k mi. OCI?? I'm asking because I'm thinking of trying the GTX this summer. The car's never had conventional as far as I'm aware, but the thought of even trying a conventional.... [crushedcar]
 

haley10

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I'm still hoping to see some results on the Syntec 10W-40. Looks to be some killer stuff. It would be my choice hands down.
 

Patman

Staff member
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quote:
Originally posted by Sin City: Dr. T, have you decided which oil you are going to use in your BMW?
I think he should just start running GC 0w30 in there! [Smile] But then again, if he starts using GC, he'll be buying it at the same Walmart that I go to, so he'll be cutting into my supply! [Eek!] [Big Grin]
 

KW

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Motorcycle oil? I have had very good luck with the GTX 20W50 oil in my dragbike. The cams and clutch packs did very well with it. M1 5W30 was worth a couple of more horsepower and warm up time was reduced.
 
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Don't have any current experience with syntec. In a z1000 (kawasaki) the gtx 20w50 works well to about 2700-3000 oci. The z1 I had was purchased with 35k miles on it and the inside of the engine was spotless. To that point it had been run exclusivley on GTX, I was told. I'm not real gung ho about castrol but the 20w50 gtx is not bad. Now that I think of it, One of the oil field trucks ( chevy 5.7 liter engine) we used,took a gtx 20w50 oci to 12,000 miles. Not intentionally, but the truck didn't seem to suffer more than usual.
 
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quote:
Originally posted by red2rebel: . Just got back from K-Mart (New Jersey). Castrol GTX was on sale 5 qts. for $7 .
Here in Los Angeles, that's their regular price.
 
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[Roll Eyes] My brother used syntec 10/40 in his honda motorcycle for 65000 mi and he said he never had a problem.The UOI would tell if it held up as good as 20/50. I for one would not buy used because of the fact people just for the most part change their oil on time and or use the right type oil for the application.I wonder how many put COSTAL oil 10/30 in their motorcycle just because they think all oil is the same. [Eek!]
 
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