[Subscribe to Daily Digest] |
xylene has higher octane
both occur in pump gas now
both are aromatics
some fuels in Europe are 40% aromatics
aromatics are lower concenration in the US and CDN markets
Some vehicles respond very well to high levels of T&X. Those vehicles are obviously very hampered by premium pump gas. In some cases, these vehicles are highly modified and can't run well on pump gas. And when the fuel is spiked, the increase in power is really a testiment to how much the modfied system was not right for pump gas.
I think that most Saab vehicles will run very well on 93-94 octane. I feel that my Saab finds 92 octane to be borderline marginal. I find that 1/2 gallon of 50:50 T&X seems to solve the problems with my 9-5 Aero. That mixture should be around 93 octane. I tried 1 gallon, then 1.3 gallon in a tank with no precieved improvement. If I had a stage 3 system, (currently stock), then perhaps I would note an improvement at higher concentrations. At these levels, there is no need to any added lubrication. The 9-5 has a big tank. I have had 18.3 gallon fills. So the concentration of added T&X is very low.
For engines that are modified so that they really have octane requirements way past premium pump gas, the higher levels of T&X might benefit from added lubricant.
So one has to experiment to see how their particular vehilce responds to added T&X. Adding T&X to the tank is a pain and expensive. Once you demonstrate that you need and want higher octane, then I think you have a case for adding water injection. That will be cheaper to operate over a few years.
Basically we have a vehicle designed to run at sea level with 93-94 octane. It is marketed at 92 octane for marketing reasons. When you are at higher altitudes, the T7 still tries to move the same amount of air, but the added turbo compression makes the air hotter as a result and the lower octane fuels are marginal at best. So all turbocharged engine owners have this problem with lower octane. And then Califonia is all lower octane, 91 it seems. And I don't know why.
Some of the Saabs with lower performance may be perfectly happy with 92 or 91 octane. The Viggen's and 9-5 Aeros are probably all suffering from marginal octane when 93-94 is not available.
So I see adding T&X as an experiment to see if your engine is not up to its potential with locally availalbe pump gas. If you see that it helps, water injection might be the logical solution. If added T&X seems to provide no improvements at all, then you don't need higher octane!
For some, the added cost of T&X might be totally appropriate for a day at the track killing cones etc.
When I notice problems that I attribute to lower octane I feel a power surge comming off of WOT on boost, and sometimes a hesitation to get on power. Meanwhile I have the factory plugs out and am tried Dr. Boost's recommended 7ES-11's at .041. I can't feel any benefit, maybe the other plugs at .035" were more responsive or willing. Its hard to tell. I will try the 7ES's at a smaller gap as well. I suspect that Dr. Boosts experiences with that plug and gap at 300HP on an engine dyno, might not translate to an optimal solution with low volitility RFG-II fuels.
03 Aero S/W 5spd, 30K, TurboXS SMBC, TurboXS BPV (corked), J&R filter, yet to be installed.
posted by 207.43.195...
No Site Registration is Required to Post - Site Membership is optional (Member Features List), but helps to keep the site online
for all Saabers. If the site helps you, please consider helping the site by becoming a member.
 |
 |
 |
 |
 |
