Tuesday, April 11, 2006 - 10:11 am, by: Dave Hart(Davyboy)
Every spec I've seen for the Soarer only mentions 'use premium unleaded'. No where does it say use '98'. Just about everyone on this forum says use 98 if at all possible but where/when did that come about. I don't think the latest Lexus V8's need to use 98 so what's the guts? Has anyone proven that using 98 pays for itself with extra mileage.
David Vaughan Goo Roo ACT UZZ31 V8 manual and Lexus IS300
Tuesday, April 11, 2006 - 11:12 am, by: David Vaughan(Davidv)
I think we have covered that one pretty well in other threads Dave.
I found it interesting when buying the IS300 that the Lexus salesman said that standard fuel for those cars was 91, and that was all that was required. At home I opened the manual to find that it recommended 95 although lower octanes could be used where 95 was unavailable. I use 98 of course. Both cars are dyno-tuned for 98 so I will not be using anything else aside from emergencies.
I have never seen evidence that 98 fully pays for itself in fuel economy, although I do get better fuel economy. I'm paying for performance, not economy.
Wednesday, April 12, 2006 - 08:06 pm, by: Dan McColl(Hoon)
I started running 95 ( because where I am doesn't have 98) and I think it has a little more midrange than 98, and I have the trc light flashing a lot more than I did on 98.
I don't think the factory tune is agressive enough for 98 to be necessary, but with aftermarket tuning it will gain more power through the use of more advanced timing.
Wednesday, April 12, 2006 - 08:21 pm, by: Emanuel Spinola(Manny)
Morgan I agree completely with TTs but the V8s appear different. Our 32 has no perceivable performance or mileage gain on 98 RON compared to 95 RON. On the one occasion when someone accidentally filled with 91 RON, it ran like crap and pinged it's nuts off under anything more than 50% throttle until it copped a dose of octane booster.
Wednesday, April 12, 2006 - 11:26 pm, by: Mark Paddick(Sparks)
I think Actives run a bit more initial advance. The ECUs are internally identical to normal V8 ones but have a different part number so may run different PROM in them. An Active ECU in my car does seem to give a bit more instant grunt but seems to lack midrange compared to a normal V8 ECU. This is probably not actually the case; the midrange just feels worse because it's better down low. I'll hope to eventually set up a test rig that will tell me for sure what the difference is.
Thursday, April 13, 2006 - 01:29 pm, by: Dave Hart(Davyboy)
As I said earlier, all the specs I've seen have said use premium unleaded and that to me means 95 and not 100 or 98. I have yet to see anything than other on this forum which says use 100. All I'm asking for is to see something officially from Toyota to use 100 or 98 octane. The SC430 has a higher compression but uses a lower octane fuel, not sure about the LS400/430/GS430 or the Celsior. I've been happily filling up on 98 but now the price is getting too much especially as I don't have a heavy right foot. I was lead to believe that the extra cost of 98 paid for itself with extra mileage as well as power but I don't think I really need any more power for normal every day driving. So if there's nothing to be gained with extra mileage I might as well go back to premium 95.
David Vaughan Goo Roo ACT UZZ31 V8 manual and Lexus IS300
Thursday, April 13, 2006 - 04:19 pm, by: David Vaughan(Davidv)
So far as I have seen, Toyota recommend 95 for all their Lexus-style cars (of which the Soarer is one) and allow that you may use 92 without harming the engine, but it is not preferred. I know of no recommendations for 98+ from Toyota but have already given my rationale for using it. I would need to pay for a retune to switch back to 95 which would mean two to three years of driving to pay off the economy measure!
Thursday, April 13, 2006 - 04:23 pm, by: Ken Packer(Kpack)
I've been using Freedom Fuel's 95e (10% ethanol), I can't feel any drop in performance , the economy is improved ( an extra 100 km's per tank) & it's 2cents a litre cheaper that regular unleaded. Anyone else had the experience with ethanol blend?
Thursday, April 13, 2006 - 05:06 pm, by: Anish Varsani(Yomama)
There's a definate change in the seat of the pants and wheel chirp dyno with 98 vs 91 octane. Can even feel the extra acceleration with 98 compared to 95RON.
Saturday, July 11, 2009 - 12:16 am, by: Robert Pressnell(Bob_pressnell)
I would'nt run my Soarer on fuel with ethonol in it i've used it in x3 other cars.And i've always gotton less k's from ethonol based fuel.Anyway acouple of weeks after i got my Soarer it started pinging and running like i started running it on Premium unleaded and it runs like a dream on it and i get about 100k's or abit more extra to a tank.I went to SYDNEY at XMAS time i filled the tank up as much as i could i left WALLAN and i stopped in Goulburn as i has a 20litre jerry can of fuel in the boot.But i could'nt be botherd putting it in so i just put $20 of cash in and with the 4cent off it was only 96cents alitre or something.Anyway after putting $20 in i proceeded back on the hwy and drove straite to my motel in Liverpool and i had about a 1/4 of a tank left when i got to the motel in LIVERPOOL.Thats one thing that supprized me was the milage i was getting out of atank of juice when i first got my SOARER i thought v8 eat juice but i get top mileage out ofmy SOARER
Saturday, July 11, 2009 - 10:32 am, by: Matthew Sharpe(Madmatt)
Indeed, I drove from central Auckland to Mirimar Wellington on a shade more than 3/4 of a tank in my UZZ30 once - thats just over 650km on just over 60 litres of fuel. Not too bad and I wasn't taking it easy either. Even my JZZ31 isn't much better than that on the open road.
Disagree about E10 though, the 98 Octane that Gull (local brand) sell here is very, very good stuff, so it is possible to have a good quality ethanol mix.
Adam Peterson Goo Roo Western Australia Supercharged & Intercooled V8
Sunday, July 12, 2009 - 06:36 am, by: Lawrence Ostle(Lawrence)
There's a thread on Clublexus about this. 98 is apparently UNHEARD of in the USA based on observations of the comments, most of the SC400's run on lower octane it would appear.