Why should i not use a motorcycle oil in a car?

FCD

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Over on the other side of the pond, we don't have Mobil 1 15W-50, however i would be able to get Mobil 1 15W-50 Racing 4T motorcycle oil for a reasonable price, there's a small parts store in my town that is closing and all the motor oils are 50% off or more, so i could get it for relatively cheap.
No cats or anything on the car in question, and it has a flat tappet cam... owners manual specs API SE 15W-40 or 20W-50 for my climate.
 
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Not sure there would be the correct friction modifiers in motorcycle oil. Most motorcycle oils have additives for the wet clutches in the transmission. I’m sure there will be more specific answers. Why not Castrol Classic oil for flat tappet car engines?
 
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Not sure there would be the correct friction modifiers in motorcycle oil. Most motorcycle oils have additives for the wet clutches in the transmission. I’m sure there will be more specific answers. Why not Castrol Classic oil for flat tappet car engines?
Friction modifiers are to give microscopic improvements in mpgs . The M/C oil will work.
 
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I would be suspicious of the additive package in a racing motorcycle oil for street use. But I'm one of those that won't use a Diesel oil in a gas engine.
 
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My latest motorcycle which is a 2016, say's to use a Jaso oil rated ma2, and Api oil rated SL. That tells me that if you have an oil rated at least api sl, you can use it in your car, and your motorcycle. Can't say what every other motorcycle in the world recommends.,,
 
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Racing oil.... most use the term loosely and just for marketing. Gotta hit the drivthru for some Racing Coffee for the commute.
Actually, some racing oils don't contain the "usual additives" that regular oil has. These can include additives to keep the engine interior clean, prevent oxidation and others.
 
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Some? Specifically which ones? I haven't found any at the local autoparts stores.

This is a motorcycle oil.... it'll do all it needs to do for any engine. Because people sometimes want to 'race' their motorcycles and annoy us drones during the commute. So, racing is a marketing term.

Don't confusing real racing oils with 'marketing' for consumer rice rockets, vtwins, or coolness factor.
 
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Motorcycle oils typically don't have the detergent levels found in automotive oils, something to keep in mind. Otherwise you should be good.
I would not worry about motorcycle oils having friction modifiers for wet clutches --- motorcycle oils are also designed to lubricate the engine as well as the transmission gears, which means these oils are plenty slippery and plenty tough.
 

FCD

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Not sure there would be the correct friction modifiers in motorcycle oil. Most motorcycle oils have additives for the wet clutches in the transmission. I’m sure there will be more specific answers. Why not Castrol Classic oil for flat tappet car engines?
Friction Modifiers are nice to have but not essential by any means, Valvoline VR1 for example i think has little or no moly either...
 

FCD

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Motorcycle oils typically don't have the detergent levels found in automotive oils, something to keep in mind. Otherwise you should be good.
I would not worry about motorcycle oils having friction modifiers for wet clutches --- motorcycle oils are also designed to lubricate the engine as well as the transmission gears, which means these oils are plenty slippery and plenty tough.
I definitely don't plan on running extended intervals, 4500 miles tops.
 
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Info on the Mobil1 15w50 4t is on the web. We get the 20w50 vtwin equivalent here. Mobil brags about detergencydispersancy and how well it keeps an engine clean and its oxidative stability and deposit formation prevention and blah blah blah. With many motorcycles with equivalent intervals to cars now, I doubt that the detergent level is less or even something to worry about.

I don't need friction modifiers for MPG when I have more z/p for protection, and the motorcycle oils have a good amount. The OP could always mix it with whatever oil he uses.

Should have no problem with that 5000 mile run.
 
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