Is 91 Octane petrol ruining the car...

[mkefalia]

Hey everybody,

Before I post my question just to let everyone know I'm a nooby to these forums and I have tried to do a search as well as look at various FAQ / Usefull threads - READ FIRST! links in different threads in the forums but I can't seem to find the exact answer I'm looking for.

I recently bought a brand new Honda Civic Sport 08 Last Monday 5th and the car came a little under half a tank of petrol. When I picked up the car I asked the dealer what fuel to use and he said 91 Premium. Since that Monday I have filled up the car twice with 91 Octane petrol from Shell.

My question is will this petrol harm the car? Reading the forums, many have said that 91 Octane fuel has made their vehicle run worse and or make funny noises, and since reading these posts, I am now worried that i may have caused harm to the engine. The car had done 75km when i bought it and now has done approx 450km.

Since the car is factory tuned what petrol do you recommend I use and from which fuel brand, i.e BP, Shell, Mobile.

I apologise if this is in the wrong forum section.

Thanks

Michael

[EuroAccord13]

*MOVED*

The Civic Sports is tuned from factory to run minimum 91 RON. You can continue running 91 RON. There is no such thing as 91 Premium, 91 is 91 RON.

As for your question on which company offers the best petrol, each to their own as there are supporters of Shell, BP, Caltex and Mobil.

I have tested two brands, Shell Optimax and BP Ultimate, tested on my old car, There were more carbon build up using Optimax (at 20000kms thereabouts), switched to BP Ultimate, Carbon build up was reduced after. The tests involved taking apart my engine on both occasions. Ultimate is cleaner but delivers less power.

I'm pretty sure this has been covered somewhere in the forums before.. Unless it's been cleaned up and archived.

[krogoth]

first of all, let me say, welcome to ozhonda!

congrats on ur new car

91 is fine, but personally id run 95octane or 98octane

there are some major and minor benefits, though it depends on who u ask..

personally i think its worth spending the extra few $$$ per tank to get better fuel

give 95octane from shell a go

but 91 octane is definitely safe, but make sure u get it from a relatively new petrol station with new tanks, less chance of contaminated fuel

[mkefalia]

Hey guys thanks for the reply's. I was thinking of getting 95 RON earlier today. Is it worth paying for 98 do you think? Are the extra $$$ worth it? If it helps in longevity of the engine or better running of the engine then I personally think its worth it, but will putting 98 RON do this?

P.S thanks for the welcome!! :D And can I say that the CIVIC sport was an awesome buy in my eyes, I have yet to have any regrets (knock on wood) and look forward to applying light mods to the car. In fact as a side note, I have spent a better part of the night learning about the K20 as all my car knowledge pertains to EVO's. What a jump!!

[krogoth]

yeh look, again its very subjective

i use only 98octane, shell v-power

gives u piece of mind, and i def get a power increase, though small

but gearbox shifts better, throttle response is vastly improved

less carbon build up as 98octant burns more slowly, more completley, less left overs....

and if fuel does get a little dirty, the extra octane acts as a buffer to protect ur engine...

but 95 is fine man, if ur comfortable paying for 98, go ahead, its worth it

[dahon]

bp ultimate is a fuel id recommend. cleans the engine aswell i hear (has cleansing agents) and my civic runs awesome + uses less fuel on it.
what im wondering is alot of Unleaded E10 fuels are popping up. would this harm the newer cars? how bout the older ones?
i can see it being a little ok on newer cars as the timing can be modified by the ecu apparently easily while us old cars with distys it wuldnt be so well with the extra ethanol. is this assumption right?

[mkefalia]

Yeah thanks mate thats exactl what I wanted to hear. I filled her to 3/4 today and i'm going to run her to empty then start to put 98 octane Shell. For one reason or another I have always found that I getter better milleage and response from Shell over BP. When I put BP in my old Magna I wouldn't get many km's out of the tank as opposed to Shell.

Thanks for your help though mate

P.S. the reason I ask if the car needs to be tuned to run on 95 or 98 is that the EVO's need to be tuned to run 100 and by default they took 98 RON. So i'm just wondering that if the civic was tuned for 91, would putting in 98 RON mean that the car needed to be tuned

[NSPYRE]

you should find that running 98 RON consistently will give more km per litre. there is a person i kno who ran a test personally with using a 98 RON and 91 RON fuel. i'll copy and paste results:

during my experiments i filled up the tank to overflowing point (~45L) with each type of petrol and drove the car until it was bone dry (i have always got a small jerry can in the boot)

basicly after running through a few tanks of each i came to this conclusion:
i always get about 520km from a tank of optimax and around 420km from caltex regular.

now because im a tight ahhs i want to get every last bit of value for my money so i sat down and thought about it.
optimax costs ~$1.50
regular costs ~$1.30

obviously optimax is more expensive so its straight away the least atractive of the two.
but is the extra milage i get from it worth the money spent?

on average (current costs) it costs me $67.50 to fill up with optimax and $58.50 to fill up with regular
seeing as i get 520km from optimax and 420km from regular
i pay $1.298 per km for optimax
and i pay $1.393 per km on regular

so despite the fact that it initialy costs more its actualy cheaper to get optimax

[EuroAccord13]

If you have the extra cash to spend an extra $6-7 dollars per tank on refuelling with a higher octane fuel, by all means go ahead.

I agree that BP Ultimate has cleaning agents in their fuel as I've seen first hand of it "cleaning" my engine.

I am currently testing Caltex Vortex against Shell....

[mkefalia]

I'm SOLD 98 RON IT IS!!! I'm going to bleed (aka drive my car a lot) of this petrol. Thanks everybody.

[trism]

i did a test as well, in my old rolla with the 100kw 4AGE motor.

started with 91 ron, then went to bp ultimate, shell optmax, caltex vortex.

all teh higher octane fuels i got more kilometres, the engine was more responsive, and felt nicer to drive.

out of the different 98 ron fuels, i felt ultimate was the best for my car.

but try them all and see what you think

[trism]

oh also, i keep a bottle of octane booster in the car for those emergencies when i can only put 95ron in the car

[mkefalia]

oh also, i keep a bottle of octane booster in the car for those emergencies when i can only put 95ron in the car

hahaha thats funny. I might follow that path LOL

[trism]

ive been in situations where the only server in teh town only had 91ron

suckzorz

[diffuzn]

98 defs. my 3/4 tank on 98 lasts probably nearly a week more than 91. (i only drive to uni and back)

[yfin]

My question is will this petrol harm the car? Reading the forums, many have said that 91 Octane fuel has made their vehicle run worse and or make funny noises, and since reading these posts, I am now worried that i may have caused harm to the engine. The car had done 75km when i bought it and now has done approx 450km.

I think you are being waaay over cautious. The car is designed to run on 91 Octane fuel - you are not harming the car by using 91 Octane.

[mkefalia]

yeah a couple of rsponders told me it won't "harm" my car but tht the 91 RON isn't good for it. I have decided to strt to put 98 RON petrol in my car.

[SPEEDCORE]

*shakes head*
People need to look into how different grades of fuel actually burn.
Higher octane than needed IMO = waste of money.
Anyone who claims otherwise is a victim of hearsay or placebo.

[krogoth]

*shakes head*
People need to look into how different grades of fuel actually burn.
Higher octane than needed IMO = waste of money.
Anyone who claims otherwise is a victim of hearsay or placebo.

u definetley have a point

but my butt dyno tells me 98 gets me a bit more power

i can definetley say throttle response is much improved

fuel economy about 30-40kms extra per tank

and ive seen first hand the difference between 91 and 98 in an engine reco shop, 98 octane engines had hardly any carbon build up on them, took 2 seconds to get rid of

91 octane engines, although we are talking about 300k kmz+ had a very thick and large coating of carbon, esp around the valves

since i drive a civic, i only ever fill up about 34L or so, so since 98 is only 10c or so more expensive than 91, it only costs an extra $4 or so to get all those benefits...

[SPEEDCORE]

Yer...I did not dismiss the benefits of cleaners that fuels like BP Ultimate have. I am simply focussing on the RON requirements as per this thread.

[dahon]

i regularly take on say 12 bux of BP ultimate to 'cleanse' the car, and then the rest with normal unleaded. but ive seen alot of people starting to queue up for the cheaper unleaded E10. has anyone tried that?

[aaronng]

I'm SOLD 98 RON IT IS!!! I'm going to bleed (aka drive my car a lot) of this petrol. Thanks everybody.
No, don't bleed. Just top it up with 98 RON. Mixing is better than running your car low on fuel.

[krogoth]

no1 is saying we know more than honda man, relax

my primary concern is for the lack of trust in retarded fuel station owners that dont do proper maintenence on their tank, corrosion, water seapage, soil seapage, contamination, who knows

95/98 protects againts that, acting as a buffer right?

and again, for my car, i get 35-40kmz extra per tank, and it only costs an extra $3.5

not to mention the butt dyno results and throttle response that YES can differ from car to car

and as i mentioned before, the higher the octane the slower and more completley it burns, so less left over carbon, less carbon build up, less power loss as the kms pile on

claymore and i have discussed this numerous times before, lol

[Red_EG4]

i ran a few tanks on 95 premium from BP and I was getting better km's with harder (high rev) driving, I have just put 98 in and it has been very dissapointing.

[mkefalia]

No, don't bleed. Just top it up with 98 RON. Mixing is better than running your car low on fuel.

why is it better? I don't understand, i would have thought mixing it would be worse? but you would know better than me

[aaronng]

why is it better? I don't understand, i would have thought mixing it would be worse? but you would know better than me

If you have any crap at the bottom of the tank, they will be drawn towards the fuel pump pickup. Also, if you are running low on fuel and use full throttle full RPM, there is a chance of the fuel sloshing and moving away from the fuel pickup, resulting in the engine not getting enough fuel and running lean.

Nothing wrong with mixing. Do it.

[mkefalia]

ah ok thanks, I will still probably run it in to near empty. Maybe 3 or 4 bars left on the meter?

[dahon]

i run mine till its 1/4 or 1/8 full. plenty of fuel still left, and if i need to top up i use BP ultimate. usually i use 95. definately nothing wrong with mixing.

[aaronng]

ah ok thanks, I will still probably run it in to near empty. Maybe 3 or 4 bars left on the meter?

Yup, 3-4 bars are fine. When you're at zero bar and the fuel light comes on, then try not to use full throttle full RPM hard driving.

[mkefalia]

Yup, 3-4 bars are fine. When you're at zero bar and the fuel light comes on, then try not to use full throttle full RPM hard driving.

ah dude i have never run a car that low before. I have never run it to that point in any of my cars LOL

Another forum member that likes BP ultimate. Maybe I should switch from Shell to BP :o

[dahon]

ah dude i have never run a car that low before. I have never run it to that point in any of my cars LOL

Another forum member that likes BP ultimate. Maybe I should switch from Shell to BP :o

u can always try BP ultimate and just see how your car responds to it. in the end its your choice. ive had friends who hate BP, and love caltex, while for me, my car feels way less responsive with caltex in comparisson to shell & BP. etc etc.

[vasquaz]

u can always try BP ultimate and just see how your car responds to it. in the end its your choice. ive had friends who hate BP, and love caltex, while for me, my car feels way less responsive with caltex in comparisson to shell & BP. etc etc.

Heh, that's the opposite to me. I absolutely LOVE Caltex Vortex.. I swear by it. I can't stand Shell Optimax.. I find that it (I don't know the correct term, but) lags my engine and doesn't really give me as much power as the Vortex does. I haven't tried BP or Mobil 2000, so I can't give a good comparison, but I'm very happy with Caltex =)

(slightly OT) The new Petrol consumer watchdog has also shown that Shell is consistently more expensive than other brands, even with the discount fuel vouchers, but if you like Shell, I don't think you should compromise due to cost, unless you have a really tight budget.

IMO, you should just test different fuels for yourself and see what works for your engine and your driving style :p

[aaronng]

ah dude i have never run a car that low before. I have never run it to that point in any of my cars LOL

Another forum member that likes BP ultimate. Maybe I should switch from Shell to BP :o

Try all of them. They are about the same price. I've tried all the 98RON except for the ethanol blended ones. I usually use Mobil 8000 or Caltex Vortex98.

[BiLL|z0r]

I find my car runs better on 95RON than 98RON. I get more km's and smoother drive with 95. I know other Euro drivers will dissagree but Honda made it for 95RON so that's what I put in it. I actually got 100-50km's less per tank with 98RON.

In my old car that was designed for 91RON I put 95 in it. 98 was useless but did find I got more km's out of 95RON compared to 91/92.

[mkefalia]

Yeah I found the same. My previous car was a 93 Magna and I used to put 98 RON in it from BP. I found that it was just a waste of money cause the car was so old so I started putting in 95 from BP. I then one day had to put shell as there where no stations around and i found it better for my car and haven't changed since. But I am going to test the 98 RON from various stations such as Shell, Caltex and Mobiloe and BP.