In Reply to: Re: Who uses synthetic oil? Info needed posted by A.Sharma on February 28, 2001 at 09:50:00:
The only problem people have with switching to synthetics is that gaskets absorb mineral-based oils and expand, whereas they do not absorb the synthetic oil. This can cause gaskets to leak as they dry out and contract back. This is only a problem with switching. If you use synthetic oil from early on, you will not have this problem. Replacing the affected gaskets will permanently fix this as well.
The only other possible problem would be when you actually need some friction as with a limited-slip diff or the synchros in your gearbox. This is fine as long as you use the proper oils with the proper friction-modifying components.
If you do find a correlation between synthetic motor oil and chain tension, please let me know. I have never heard of this and cannot imagine what the problem would be.
As always, correct me if I'm wrong.
I believe Semi Synthetic is better because Synthetic is too thin. it is okay for newer performance cars but not so for the E30 M3.
Its something to do with the tension of the chains. I'll mail you 2morrow exactly why cos I have forgotten but have it noted down at home.