Which Petrol?

transglobal · Post by **transglobal** » Tue Oct 02, 2007 3:09 pm

Saw a thread a day or two ago re fuel type and thought it was on here but can't see it.

Anyway. Up until yesterday I've only ever used standard unleaded in the Elise R as I'm a bit tight. Read the thread and thought I'd stick a tankfull of Shell V-Power unleaded in. Was out last night and today had to run over to Edinburgh from Hamilton and I have to say that the difference is night and day. Some were saying that they didn't see much if any difference but with me the difference was really marked. Much cleaner and sharper pick away on the 1st cam and seems to be a bit more urgent on the 2nd cam. Was only using Jet standard unleaded before so maybe it was just that the Jet stuff was not the best.

Any thoughts?

Dominic · Post by **Dominic** » Tue Oct 02, 2007 3:19 pm

I have been using Vpower in the golf. There is a noticeable difference in performance and economy (worth paying extra for), but it is a turbo and therfore more sensitive to better RON. Tesco fuel (99 ron) is even better, though I'm not sure how kind it is to the engine compared to Vpower.

I know some have said Vpower or BP Ultimate is much cleaner for the engine too.

Others have said it make little difference, and just put the good stuff in occasionally.

Rich H · Post by **Rich H** » Tue Oct 02, 2007 3:33 pm

On the Yota lumps (and Golfs I assume!) you have a knock sensor, so it will advance the ignition until it knocks a bit, then back off a little. That way you take advantage of the higher octane of the fuel.

Cars without knock sensing are set conservatively to avoid knock and allow for the worst quality of fuel (2-star-eastern-european-brewed-from-spuds-and-socks spec or just the tescos own

) Therefore they do not get the best performance possible from the fuel.

One solution is to tune the ECU (where possible) to a "standard" fuel such as Optimax, problem with that is you run the risk of knock if you have to use normal unleaded car juice.

Most aftermarket ECUs (Even my Pikey Megasquirt) can be configured to accept a knock sensor input and automatically compensate, but aftermarket knock senders appear to be a bit of a black art as it;s sensitivity and location are critical.

Agressive knock sensing will get the best possible fomr the fuel but a could lead to damage if anything goes wrong with home brew senders.

From what I have read, anyway.

HTH
Rich

PS I'm bored...

transglobal · Post by **transglobal** » Tue Oct 02, 2007 3:41 pm

Rich, my boy,

You're a wealth of information. You really need to get some pals and get out a bit more.

Thanks for the assurance that's its not just my imagination.

Stuart.

Rich H · Post by **Rich H** » Tue Oct 02, 2007 3:46 pm

I have a call center full of vegetbles, does that count?

Staring at the sunshine outside while trying to look busy....

j2 lot · Post by **j2 lot** » Tue Oct 02, 2007 4:36 pm

I use v-power every other fill up and 'feel' there is a benefit in pick up (yota lump) also cars seems to pop and bang a bit more on the over run which is goood.

Fifth gear did a test last night on fuel additives on a k series engine and ALL the tested brands resulted in a 2 % drop in power ?!! WTF ?? - how can they get away with claimed power increases when they have opposite effect

Rich H · Post by **Rich H** » Tue Oct 02, 2007 4:38 pm

Snake Juice, cures all ill's...

BiggestNizzy · Post by **BiggestNizzy** » Tue Oct 02, 2007 4:44 pm

j2 lot wrote: how can they get away with claimed power increases when they have opposite effect

they probably start with an engine in a bad state of tune get a dyno figure add their "magic jesus juice" then tune the engine to suit the "advanged hydro electric bawbag effect" that their particular addative is supposed to enduce and voila +20hp just like the guys ebay who supercharge your car by adding a kids fan infront of your air intake

SteveBanks · Post by **SteveBanks** » Tue Oct 02, 2007 5:55 pm

"advanged hydro electric bawbag effect"

bawbag is such a colourful word and should be used more often!

tut · Post by **tut** » Tue Oct 02, 2007 6:12 pm

Very often it just comes down to the fuel that the engine and ECU were designed to give maximum power at.

With the Honda Type R engine, the JDM version that I have in both cars is mapped for Japanese 100RON fuel, which is rarely available elsewhere and gives 217hp. Run it on 97 and you will lose 5hp. However it runs perfectly on 95 which I use on the road, but I use V-Power on the track as why waste the hp.

As far as I know, Scoobys and Evo's actually need 97 or more, which is why when we did the TDE they carried Octane booster for when they could only get 95.

If V-Power actually does have cleansing properties, then it is probably worth putting a tank full through now and again on any car.

tut

Jamie84 · Post by **Jamie84** » Tue Oct 02, 2007 6:25 pm

I tend to stick to the better stuff but on occasion use the lower ron , only when the other stuffs not available . Also found out my dads been sticking in normal stuff when ever he has filled it , which isnt very often !

Jacobite · Post by **Jacobite** » Tue Oct 02, 2007 10:18 pm

I've been useing Shell's optimax then V power in the old 405 then the Merc 300TE for years with no problems although you quickly get used to the extra horses ~until you get caught short and have to fill with some other go~go juice and its just not the same

I did read somewhere that BP Built a car which had 2 seperate fuel systems tanks, pumps seperate fuel lines the lot, to a V8 to demonstrate the differance their fuel made with Ulitimax fueling one bank of cylinders and some regular unleaded supplying the other bank it was like night and day