How Much Power Loss Using 91 Fuel

[ascenion24]

What are 33 gtst designed to run on? 95 ron?

If so and 91 is put it, does it automatically pull timing to make the 91 run safe? if so how much power is loss?

Is it safe to run 91 all day or should something be done to make it safe?

Now I dont want people reaplying bout I should use high octane because i know all this, so dont reply with that, I have my reasons for these questions, so if you dont have answers to these please dont reply. Thank you.

[paulr33]

They are designed around 98 ron. Running lower octane or "penis fuel" will make the car detonate and then the stock ecu will drop to the low octane maps (retard timing).

I am unsure how much timing exactly is backed out but it will be sucky and extra laggy. if you dont have access to high octane you can look at water / meth injection as an alternative or make your own (tolulene)

[ascenion24]

So they do have a knock sensor?

If 91 is run constantly will it just keep the timing back and the car will run fine?

I know it will suck but at the moment im just worried about any detonation or other concerns.

Also roughly how much power would you lose? 20 kw?

[paulr33]

yes the r33 has a factory knock sensor.

once detonation occurs and it reaches a certain level the stock ecu will activate the low octane map which retards the timing (and problaby richens up).

it will certainly detonate on low octane or "penis fuel" if you run it all the time. not sure on exact power loss, but youll loose a fair whack of midrange and torque too

[GTshortie]

Why bother running 91 octane you DON"T save that much look:

say 50L for example:

91 Octane@$1.00/Litre = $50.00

98 Octane@$1.10/Litre = $55.00

So $5 you save on 50Litres petrol, your car will run like CRAP recommend for you NOT to engage boost/turbo drive <3000rpm all day.

GOOD:

-Save $5

BAD:

-Can't Gun boost your car and drive it safely

-Risk pinging and damaging/blowing engine

-You'll travel less KM's as well compared to the 98 Octane.

BTW Paul aren't our cars (JDM spec) designed for the Jap pure 100 Octane? even running 98octane your car won't be running 100%.

Also thats based on 50L if you only fill up 30L then you save $3. ASk youself is it worth it?.

BUT if you live in area that doesn't have high octane fuel readily available i can understand.

my2c

[paulr33]

no im pretty sure they are tuned around their lowest octane rating in japlan, which would be 98ron. 98 ron to them is our 95 ron penis fuel i guess. ill see if i can find out. the pfc manual states must run 98ron

[ascenion24]

Like i said i have my reasons, and i knew someone would stick there nose in and give the whole few cents different spill.

Like i said I know this, but heres my reasoning, i can get a full tank of 91 for 20 dollars. So ill be saving like 50 bucks a full tank.

So i would rather mod the car, but when it comes to a custom tune ill tune it for 91 fuel. This way i would lose a bit of power, say 250kw instead of 290kw but since its only costing 20 dollars a full tank, who cars!

[paulr33]

it sounds like a bad idea and you will end up with a laggy and sluggish car.

a 200rwkw gtst on 98 ron will destroy your 250rwkw setup. i would advise against it and just run 98ron and tune it properly

[madbung]

Don't do it.. you'll risk your driveline and wont save any money short or long term. Your car will be less economical on 91ron..you'll drop a fair few klm's per tank and it will run like crap.

I wont run 95 ron in mine let alone 91...too much detonation, even under normal driving and forget it if it's a slightly warm day.. the engine warning light goes nuts. Tuning? I doubt it could be dumbed down enough to be acceptable.

Edited February 21, 2007 by madbung

[Strik3r]

if you want to use 91 octane fuel, go buy a daily driver for $1k or something.... seriously, do not use it in your skyline, bad things will happen.

[paulr33]

the base maps on the PFC would detonate considerably on 91 ron

i couldnt imagine backing out timing on the whole map to suit 91 ron

it will be sucky, so much less response, lag and sluggish performance

even if it made 245rwkw at 7500rpm who cares, its useless and would suck

you would have stock cars beating you all the way through the rev range

[paulr33]

ive driven my 33 with -10 deg backed out and it sucked the wang

it was terrible, like almost undriveable, i was doing it to see what happeend

and yeah it sucks.

[R31Nismoid]

This way i would lose a bit of power, say 250kw instead of 290kw but since its only costing 20 dollars a full tank, who cars!

ummm not quite

Its MORE prone to detonation as a base. Its not only going to cost you outright power dude.

Your going to loose spool time, average/torque power and peak/torque power.

You need ignition timing to bring on boost and make power/torque.

Without being able to use any decent ignition values/points, your car will feel like an N/A, no power anywhere.

I dare say you wont even be able to MAKE 250rwkw.

[Beer Baron]

no im pretty sure they are tuned around their lowest octane rating in japlan, which would be 98ron. 98 ron to them is our 95 ron penis fuel i guess. ill see if i can find out. the pfc manual states must run 98ron

since when is the lowest rating fuel in japan 98RON? it's news to me!

[paulr33]

assumption on my behalf, guess 100ron is standard then

[RellikZephyr]

really using 91RON all the time wont cause too many problems BUT ONLY IF you ACTUALLY drive it like a daily driver (always change gear at 3k,no high revving)

using 91RON, the second you get "spirited" you will run a VERY HIGH risk of destroying something in your car

my question is... if your so concerned about saving $20 on your fuel bill...why buy a turbo skyline?

so yeah

prob ok to do BUT you CANT drive your skyline like a skyline you have to drive it like a granny... and doesnt that kinda defeat the purpose of owning a skyline

EDIT: plus your quote...This way i would lose a bit of power, say 250kw instead of 290kw, wouldnt work that way you probly couldnt make ANY DECENT power on low octane fuel (too prone to detonation) just doesnt work that way

RellikZephyr

Edited February 21, 2007 by RellikZephyr

[paulr33]

well yeah you could baby it around sure but it will suck

the low comp ratio and poor mans octane along with really retard timing will make it suck. you should do engine swap to a high comp n/a instead

[paulr33]

well theres no harm in trying

with the pfc it would take about 10 seconds to do adjust it to suit 91 ron

then you could plonk it on a dyno and see how it goes.

[Kodak]

Exscuse me for been a bit slow but what is this detonation thing about?

[Devils_Advocate21]

Lol $20 saving per week on fuel, eventually would cost him $5000 plus in repairs if he stayed on there. Work it out $1040 saving per year plus Repair costs if something major goes rong, ahhh all i say is you will not save money, and if you did well you just spent it plus alot more ontop to fix anything, which assuming from the previous posts will happen alot sooner than you hope it would.

Good tip would be Drive it better, and the good old "Your fuel economy is determined BY your RIGHT FOOT"

Cheers A