I found this comparison between synthetic oils on the
rec.autos.tech newsgroup.
I use synthetic in my 505 turbo and I thought in might be of interest
to other list members too.
>---------- Forwarded message ----------
>Date: Thu, 13 FEB 1997 13:38:18 -0500
>From: Patrick Gattafoni <gatts@pathcom.com>
>Newgroups: rec.autos.tech
>Subject: Re: synthetic oils
>
[...]
> Recent data I obtained from Mobil 1 shows
>that their new SJ rated oils have the following flash points:
>0w30-460degF
>5w30-455degF
>10w30-470degF
>
>All of their pour points remain at -65F
>
[...]
>Recent data that I obtained on the Amsoil suggested [...] the following
>flash points and pour points for Amsoil (if anyone can confirm these
>numbers or give new numbers, I'd be appreciative)
>
>Amsoil 0w30-460degF flash point, -76F pour point
>5w30-478F flash, -60F pour
>10w30-464F flash, -54 pour
>
>(the reason I'm not so sure on these data points is because the info I
>have on the SG rated Amsoil shows better data on the 5w30 and 10w30
>numbers, so if anyone has the real numbers let me know)
>
>
>I also emailed Redline to get their technical data and got the following
>numbers for their SJ rated 10w30 viscosity only:
>
>Flash point-475degF
>Pour point of -40F
>Noack volatility-6%
>
>
> So you can see that based on the following data, I feel that all three
>are worthy for use in high performance engines (or for those that just
>feel better using synthetics). A typical conventional motor oil of 10w30
>viscosity has a flash point of between 400 and 420 degrees, and a pour
>point of around -25 to -35F. You can see that synthetics are clearly
>better, but which one you use is totally up to you. I just don't like
>the numbers I've seen on the 5w50 viscosity synthetics though, and would
>steer people away from using them-stick to the 5w30 and 10w30s instead.
>For instance, the data I've seen on Castrol Syntec 5w50 shows a 437 deg
>F flash point, and a -45F pour point. If you're going to spend an equal
>amount of money on Castrol that you will on the other synthetics, you
>aren't getting your money's worth with that large viscosity spread. I
>haven't seen the data on their 5w30 or 10w30 viscosity oils, so I can't
>comment on them yet.
>
[...]
>Patrick Gattafoni
>95 Trans Am
>87 Mustang GT
>http://www.geocities.com/MotorCity/Downs/1320/