Which one RP or Mobil 1

Messages
36
Location
Chicago,IL
I have a 2001 trans am with an ls1 engine. Currently running dino oil and want to switch to synthetic when I bring it out of storage for the winter and want to either go with royal purple or mobil 1. I have no doubt that either would never cause any problems in the engine, but if you had the choice which would you use? I can get both of them easily and they are about the same price wise unless the mobil 1 is on sale then it is cheaper. My only concern with the mobil 1 it's 10w-30 viscosity is a little lower than the royal purple and on other boards some have reported oil consumption and piston slap with the mobil 1 because it is a little thiner?
 

Patman

Staff member
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21,988
Location
Oakville, Ontario
If you have consumption problems with your LS1, I'd recommend either going with Royal Purple or Amsoil or Redline over Mobil 1, simply because Mobil 1 (like you said) is thinner and tends to burn more. At the same time, a few guys have found that 2qts of 15w50 Mobil 1 to 4qts of 10w30 Mobil 1 works perfectly at reducing oil consumption and I believe it also helps to quiet down the piston slap too. When I had my 98 Formula I ran nothing but 5w30 Mobil 1 and no consumption or piston slap problems at all, but then again I only had that car from new until 27k. I have since heard that it's new owner has major consumption issues, but I don't know what oil he runs either. I wish I still had that car. [Frown]
 

ramair8

Thread starter
Messages
36
Location
Chicago,IL
Terry, no I have not had any oil analysis done yet anyway. I am currently using castrol gtx. The only reason I am still using it was because I wanted to change the oil often when I first got the car and ended up changing it at 500 miles, 1000 miles and then at 2,000, before I started to extend the drain intervals. I was going to use mobil 1 at 1000 miles but that was when everyone was saying mobil 1 was not as good as it used to be so I just stayed with the castrol. I know it was overkill, but the oil was cheap so I did not mind it. I don't think it has piston slap, although I am not real sure what it sounds like, but the car makes no obnoxious noises like some ls1 guys complain about. As far as oil consumption, not much at all. The last time it used about a 1/4 of a qt. in about 2,000 miles, but that was all in one trip and drove the car hard during the trip as I was going through the mountains and and spent a lot of time in low gears at higher rpm's, so I expected to use some. I should have done an oil analysis on the oil before I changed it for the winter since it only had the miles from the trip on it, but didn't. Also, what are EP characterisitcs? [ January 10, 2003, 01:59 PM: Message edited by: ramair8 ]
 

ramair8

Thread starter
Messages
36
Location
Chicago,IL
One more question, while looking over the specs of the royal purple oil, I noticed the 5w-30 has a higher viscosity. The 10w-30 has a viscosity of 10.7cst @100C while 5w-30 has a viscosity of [email protected] Shouldn't the 10w-30 be higher? [Confused]
 

Patman

Staff member
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21,988
Location
Oakville, Ontario
quote:
Originally posted by ramair8: One more question, while looking over the specs of the royal purple oil, I noticed the 5w-30 has a higher viscosity. The 10w-30 has a viscosity of 10.7cst @100C while 5w-30 has a viscosity of [email protected] Shouldn't the 10w-30 be higher? [Confused]
Not always. It all depends on how the oil was created. Some companies like to create their 5w30 and 10w30 so that they have equal viscosity at 100c, while others like to have their 5w30 run a bit thicker. They do this because the natural tendancy is for a 5w30 oil to thin out under hard use. So if it starts out a bit thicker it's got more wiggle room.
 
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3,845
Extreme pressure additives, adds that react with the wear points or coat it so that when the oil,film or wedge is distorted or broken the two components don't try to self lubricate with metal to metal wear. 0.3 cSt is not much difference. Sae 30w is judged as 9.3 to < 12.5 cSt at 100 C.
 
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3,845
ramair, are you one of my customers ? If so I can help you make a decison based on your analysis results and consulting with you. PM or email me I can't keep everybodies handle here straight with you real name ! If not, my customers using both oils are very happy with either one in the 5w-30 and 10w-30 weights. The RP will have a an advantage in EP characteristics.
 
Messages
666
Location
Triad, NC
Mobil 1 is every bit as good as it used to be........actually with the new SS formula, it contains some Moly and is even better than in the past.....I have M1 in my 96 vette, my wife's 01 Trans Am and my 02 Suburban...only the T/A has a little bit of piston slap on the first few seconds of start up and also uses about half a quart every 2,000 miles...the other cars don't use any at all......
quote:
Originally posted by ramair8: Terry, no I have not had any oil analysis done yet anyway. I am currently using castrol gtx. The only reason I am still using it was because I wanted to change the oil often when I first got the car and ended up changing it at 500 miles, 1000 miles and then at 2,000, before I started to extend the drain intervals. I was going to use mobil 1 at 1000 miles but that was when everyone was saying mobil 1 was not as good as it used to be so I just stayed with the castrol. I know it was overkill, but the oil was cheap so I did not mind it. I don't think it has piston slap, although I am not real sure what it sounds like, but the car makes no obnoxious noises like some ls1 guys complain about. As far as oil consumption, not much at all. The last time it used about a 1/4 of a qt. in about 2,000 miles, but that was all in one trip and drove the car hard during the trip as I was going through the mountains and and spent a lot of time in low gears at higher rpm's, so I expected to use some. I should have done an oil analysis on the oil before I changed it for the winter since it only had the miles from the trip on it, but didn't. Also, what are EP characterisitcs?
 
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