Whats the best oil to use?

[Godden87]

Hi guys,
 
I\'m new to the rotary world and was just wondering what would be the best oil to use for a highly modded single turbo rx7?
 
Thanks

[lee mills]

most people use castrol 10w/40 mineral oil from halfords

[Jim_rx7]

Everyone seems to use something different, but most use mineral oil. I myself use 10/40 Halfords mineral oil.

[trotter]

Not this old chestnut again!!! lol

You\'ll find opinions vary according to individuals, some use semi-sythetic, some use mineral. Although Mazda do recommend that only mineral is used and several tuners will tell you the damage they\'ve seen caused by synthetic/semi-sythetic , although loads of people do it and are fine!!

Personally I use Castrol GTX 10/40. Cheap, decent mineral, it shouldnt be in your engine for longer than a few thousand miles anyway!!

[turbo boy]

Whats the best gearbox oil to use?

[johnm]

I have read lots of stuff on oil, but most seems to be opinion, with little or no back-up facts to support the choice.  There\'s a tuner Aus who says Mobil1 is the only choice, and mineral is rubbish and many other who say the oposite.  Opie oils seems to say use synthetic.  

Quoted things for synthetic,
1. Does not burn, or does not burn at a low enough temperature (not sure if this applies to all oils)
2. Damages rotor seals (although the Aus tuner says Mobil1 does not)
3. Expensive, but good life and good for turbos

Mineral stated facts
1.  Mazda says use it, burns well and good for seals
2.  Cheap, but short installed life, not that good for turbos
3.  Loads of people use it

Does anyone have a real evidence of what is best?  Looking for engines that have done 50-60k miles and then been stripped.  Was carbon/slime build-up ok, worse than expected, was the carbon buildup caused by oil or over fueling?

John

[trotter]

I was talking to Pip before xmas when she was in for an MOT, he didnt have the bits in the shop anymore but explained that they had recently taken apart a not-long rebuilt engine (if memory serves 5-8k) for an unrelated reason, and found a huge amount of fouling on the inside of the housings that was the result of non-mineral oil not burning cleanly, breaking down and carbonising on the walls.

Again, not documented fact but at least \'straight from the horses mouth\'

HTH

[Jim_rx7]

Pineapple racing say the same. Synthetic oils can supposedly cause issues.