Some oils are labelled "synthetic blend", some "synthetically enhanced" & others "semi synthetic".
To me & my dictionary "semi" means 50%, but Penrite says (& credit to them for making the info available) their semi-synthetics have a minimum of 20% synthetic.

I couldn't find any info on the Valvoline internet site.

Anyone seen other figures? Worth knowing if you're paying a fair bit more than for a straight mineral oil & perhaps not much less than for a full synthetic that's on special.

Update - I've been told by Valvoline that Engine Armour is 7 to 20% synthetic (depending on grade - my guess is that 10W-40 would be the highest). Durablend is a genuine "semi" (ie 50%).

Semi synthetic is generally about 30% synthetic. It's all a words game really. Different words for the same thing. They do change a bit but I wouldn't imagine any reputable brand (such as valvoline or castrol) going under 20%. Hope this helps

It is word spin a lot of the time, like Turkish Delight advertising we have 99% less fat, less fat than what?????

Penrite do advertise and for the record, as the old HPR series gets sold off, the new HPR range is all fully synthetic. Not sure about other brands as I dont use them so am not really interested in them

I agree with Mal. The only way to know that you are getting the best oil it to use only fully synthetic. For all you know, semi-synthetic "may contain traces of synthetic", but is otherwise just mineral

Full synth isn't even that costly.. I use penrite everyday full syn, $50 a bottle. Best oil I've ever used too

Full synth isn't even that costly.. I use penrite everyday full syn, $50 a bottle. Best oil I've ever used too

Last oil change a couple of months ago I chucked in some Penrite Everyday full synthetic, 10W-40. Cost $49.95 at Ripco IIRC.

After years of using the more expensive Mobil 1 or Penrite Sin5 (usually around the $75 per 5 litre bottle mark).

On Mal's recommendation I also added a 500ml bottle of Wynn's Gold Premium oil treatment. Not cheap, $29.95 from SCA.

But this combo really works, engine runs the best it ever has, dare I say better than new. Now at 113,xxxk.

Semi synthetic is generally about 30% synthetic. It's all a words game really. Different words for the same thing. They do change a bit but I wouldn't imagine any reputable brand (such as valvoline or castrol) going under 20%. Hope this helps

I've rung Valvoline & been told that Engine Armour is 7 - 20% synthetic, depending on grade. No wonder it can be so heavily discounted.
Durablend is 50% synthetic but last visit to SCA I saw new packs of 100% synthetic Penrite HPR at a similar or lower price. At $44 SCA seem to be charging the same price for new HPR as they did for the "semi" synthetic HPR - so far, anyway.

Wow, 7%. I can't believe that they can advertise it as semi synthetic when it is almost all mineral. Just goes to show that you should only get 'fully' synthetic oils or face the consequences.

Wow, 7%. I can't believe that they can advertise it as semi synthetic when it is almost all mineral. Just goes to show that you should only get 'fully' synthetic oils or face the consequences.

In fairness, the wording on the Engine Armour packs is "synthetic blend".

The wording on Shell Helix HX7 packs is a worry though: "synthetic technology motor oil". I hope no-one has bought it thinking it was full synthetic.

Penrite HPR10-50. Easy as that. No synthetic blend/semi-synthetic for me

All that being said, synthetic oils are simply more highly refined mineral oils. They are not man made as the word synthetic may imply.
Cheers,
Wilyum.

Fully synthetic, even though the name might be misleading in itself, is a much better oil than your standard mineral crap. I am more worried about the various companies making representations that make customers believe that their oil is a higher quality than it actually is.