I was wondering..
wot should we use for best performance and economy..
wots the recommended for Altezza? 96 or 98 octane?

I'm not concerned about the price.. only k's per ltr..
how do we improve it?

well, I hope we should start with a stock standard engine.. :D

I used to use BP Ultimate (98 octane) and that was pretty dam good ! I used to always get around 620-640kms from a full tank easy.
Ever since I had my engine flush, cleaned and service with all the filters replaced and all - I was advise to do a switch over to Shell Optimax ...

I only get around 580kms now ...
"Supposely" Shell is better ...

try and use the one brand of fuel if possible ... with the price nowadays - up to $1.20 its crazy .... !

Likewise, I only use Shell Optimax.

I also only use only Optimax, but if i get desperate I'll use BP ultimate.

Try running around with my Diff and see what sort of fuel usage you get. I wish I was getting 580km out of a tank. I proberly average about 480-500km. Over here 98 is about $1.28 at the moment

Of course, comparing GXE10s to SXE10s will be useless - so it'd help if people made clear what they have!

I'd be lucky to get 500kms from my SXE10 with intake only mods, but I'm happy enough :-p

oops.. my bad..
I think we should state that too..

as I read somewhere, recommended fuel for

• GXE-10 is Unleaded Regular

and

• SXE-10 is Unleaded Premium

I've got SXE-10 and it does about 9kms/ltr [avg urban]..
its a '99 (model) and its a stock standard as far as I know ;)
so, I think the fuel economy is pretty bad for me..

actually, I've tried both 96 and 98 octane..
98 is pretty much give you more performance for less k's.. (like high 8s a ltr)
and 96 is pretty good with more k's (low - mid 9s a ltr)..

GXE-10 have 10L larger tank capacity.

I can get 10km/L in mt RS200, but 9-9.5 is more common.

my RS200 is getting close to 11km/l...

i personally noted that using 98 and below fetches worse mileage than the 'claimed 100' octane by Caltex(it's called Platinum grade here in singapore) which i am using now for good.

we dont get 100 octane in NZ gas stations yet :P

anyway,
I think the main thing is that I've gotta reset my ECU.
Then, I've gotta start using a single type of gas..

so, at least I can get 9.5kms per ltr.. B)

100 octane? for real?
i use vortex from caltex all the time,because petrol card from work :P
cant complain :lol:

good for you man :D

wots the consumption for your IS200? is it sports model?

2000 IS200 Sport,70 litres tank,i cant remember whats the fuel consumption on it..maybe some of our expert here can tell us :P

well, it's 'claimed' and we don't have any hard facts to prove it... my apologies, it's specifically named the 'vortex platinum' here, and also the most expensive... $1.61 per litre :(

I was talking to the owner of Turbo Vehicles ( there was some evidence of detonation) some time ago he and his company are well known in high performance vehicle circles and after dynoing my car he mentioned that the only Fuel that they had tested in NZ that had any Guts was Mobil 8000 , the rest were rubbish! ( i have no shares in Mobil!).

Ron

I'm getting some relatively shockingly bad fuel economy, but then again I haven't calculated it yet, will do so from now on to see if it's just my imagination. I drive it normally, with a squirt now and then, and it seems to be chewing up petrol at an alarming rate. Could be I'm expecting it to be a super fuel efficient 2 litre. Will find out soon ....

Sport model, IS200.

I find BP Ultimate 98 is fine, also have you fitted an aftermarket air filter system- such as an HKS, K&N etc (Repco ones are no good!) I wouldnt really know about non-turbo 3SGE fuel economy as i have a 3S-GTE turbo MR2, hope this helps.

I've just put this post over on the UK forum to help up a poor Altezza owner who thinks NZ only has 91 and 96 octane fuel...

Hopefully he can find his way here for futher enlightenment. :)

Edit: Maybe edwardch is already here? The original post on the UK forum was from back in June....

At the time I bought my car a few months back the Lexus website shown that the fuel type for IS200 to be 91RON. The questions are :

1 - Does it mean that the ECU of the IS200 is set for 91RON and the continuous use of regular unlead will not cause any damage to the engine ?

2 - If that's the case, will the use of 95 or 98 octanes improve the performance or mileage ?

TIA

I am quite sure using 91 will not damage the engine.

The only difference the fuel rating makes is to the spark advance that the computer delivers.

If the fuel is low octane then the engine will detonate under load, the knock sensor will tell the ECU and the ECU will retard the timing and stop the pinking. This will reduce the power output, particularly over 3000rpm

So by upping the octane of the fuel you use you allow the engine to run more advance on the spark, and the engine revs better.

If you're not using all that power or all those revs, it doesn't matter which octane you use.

I use 96, occasionally 98 (especially trackday! :lol: ) and if petrol hits $2/litre next month then I'll mix 91 & 96!!!!!!

apparently the computer on our computers are "learning" ones, so best to stick with one grade of fuel.

apparently 95 ron is the way to go for the GXE.

in reality though, i really dont think it makes much of a differnece, i usually go with 95 ron at shell or caltex. recently i have gone bp ultimax of 98 ron and notice very marginal improvements (maybe its all in my head though)

I've tried all three RON from Caltex but did not seem to find any different for rev up to 6000rpm as that's the most I went. I made very sure that each tank was filled up without much mix of the other, ie at least 67 litres of each RON was filled at a time. The feeling of 91RON seems to be more smoother & softer on the accelerator ;) Try to tell the difference yourself by asking someone to randomly fill up one type of the RON next time, so don't try to guess it if you can not tell the difference :woot:

I've tried regular as well as Optimax / 8000 / Ultimate and haven't noticed any difference. What I did notice was fuel economy improved markedly when revs are between 3000-4000 instead of 2500-3500 during normal driving.

Drive above 3000?! Sweet, that's all the excuse I need.. 5th gear on the open road... 6th and I'll have to go 130-140 to be economic? Gunna love explaining that to the enforcers... ;)

I believe it's more to do with the throttle position, light throttle on these un-torquey engines at a slightly higher rpm would be more fuel efficient than heavier throttle at a lower rpm.

Wah, Sendog: is ur theory is true, then I m gonna try on my next tank and see if it improves fuel economy... good piece of info!! thanks.. 3000~ 4000rpm!!

Well, don't quote me on it, could just be me :)

Try it out, light on the throttle, just hold it a bit longer, so that u don't have to go heavier on the throttle at a higher gear.

Any car doesn't matter what engine running above 3000rpm will take up more petrol. The best fuel efficient is between 2000 & 3000rpm. For instant, if you can sacrafice the speed by driving between 80 & 90km/h instead of 110km/h or more on motorway, you will save at least one litre per 100km :D

I partially disagree with you there ... It also depends on how the engine is being loaded at the time. What I was talking about above, was for example you were under acceleration and wanted to get from x speed to y speed in a certain period of time. To do so close towards the car's powerband would require less throttle, but to do so at a lower rpm in a higher gear, would need more throttle. This is especially true uphills.

As I understand it, more throttle = more air, more air = more fuel. If you have an S-AFC you can check your airflow meter readings to confirm this.

If I get you right, you're talking about fuel efficient on acceleration from x speed to y speed in a certain period of time by controlling the throttle. If that's a short period in getting to, say 100km/h on high rpm will not be as fuel efficient as soft acceleration with a bit longer time to get up to 100km/h. It's easier to prove that with constant speed as I've mentioned above :D

Yeah I get what you're saying, but even to maintain a constant speed, I believe sitting at about 3000-3500rpm is better, as it requires less throttle, than more throttle at 2000rpm to maintain the same speed.

Could just be my car is weird, but I've definitely noticed better fuel economy :/

sendog i think i know where you are coming from
obviously cruising at 50 km/h in 6th gear will be inefficient and so on
i also try to keep a "light" throttle on

I use BP Unleaded and have managed to get around the 10km/L mark.
Company card so easy to obtain the data. See below


Odometer Litres 74872 Litres
75349 51.33 477 10.76
75594 26.24 245 10.71
76043 46.48 449 10.35
76541 7.36 498 1.48
76650 46.05 109 42.25
77054 42.49 404 10.52
77492 44 438 10.05
77877 42.29 385 10.98
78291 42.32 414 10.22

Overall KM 3419
Overall Ltr 348.56

10.1947938

My RS200 around akl city usually did bout 450km to the tank or 8.6km/L and 650km on straight trip (open road).

But to be honest I now get 13.5km/L around Akl city and that on 91Ron.
(figure that one out)

i've been getting about 410Km with $50 of 95

thats about 35L of fuel? that gives me 11.7km/L

I consider that not bad! Since I have an N1 type muffler and a HKS pod filter!

6 speed RS200 by the way

OMG :o how do u ppl do it?? i get approx 350km with $80 on BP 98 in my is300

Earlier discussion on similar topic - here.

I've run both 96 and 98 octane, but last time I analysed the data there was no statistically significant difference in economy between the two.

And my graphs again:

Here is my fuel economy, mine is a 1998 5AT
I have been using 91 always except for an economy test I did open road driving around the North Island. I used 98 and got 11.93 km/l (8.38 L/100km) and on 91 got 11.75 (8.51 L/100km).
95% of my other driving is in heavy traffic from North Shore to Greenlane and back, the low fuel consumption patches are from open road driving.



DATA
Date L/100km km/L
16/12/2005 10.56 9.47
22/12/2005 11.24 8.90
31/12/2005 10.54 9.49
4/01/2006 9.82 10.18
7/01/2006 8.45 11.83
8/01/2006 8.38 11.93
19/01/2006 10.42 9.60
30/01/2006 11.12 8.99
12/02/2006 10.28 9.73
23/02/2006 11.19 8.94
1/03/2006 10.06 9.94
11/03/2006 11.18 8.94
25/03/2006 11.03 9.07
6/04/2006 11.21 8.92
14/04/2006 10.59 9.44
17/04/2006 8.51 11.75
19/04/2006 8.50 11.76

Just a note for any RS200/3SGE owners who may have decided to run 91 after reading my post.
Since experiencing occasional engine knocking (pinging), I have changed to higher octanes 95+, which don't cause knocking. I suspect because the 3SGE engines are running such high compression, even the knock sensor cannot compensate for the NZ low octane 91 fuel.

(Sorry, didn't see this thread until after answering the IS300 one).
IS200 slushbox sports luxury: Best case 8.75L/100km (calculated). Worst case 11L/100km (estimate).

Difference in fuel consumption between standard unleaded and 98 is about 6%, with 10% extra cost is not economical. (Power also went down from 83rwkw to 78rwkw with different fuel but this may not be absolutely correct as other people lost power with no changes between the two runs 5 months apart). I haven't tried the 100ron stuff yet.

In normal city driving it comfortably gives me 600km per tank (IE I don't get nervous until I'm on about 650km - needle well below empty). The most that's ever gone in the tank was 69.7L. If you're really low a sharp acceleration will result in fuel starvation giving you warning (don't try it on a turbo engine under high boost smile.gif).

Fuel light, from memory, comes on with about 10L left. The only real way to tell how much fuel is left is to fill up as soon as the light comes on a see how much goes in. These tanks don't have a separate fuel light swith - the light comes off the sender itself, so it's possible the threshold will not always be the same. The cluster also smooths out the sender signal - it uses the speedo signal to work out when the car accelerates and disregards the sender reading until the vehicle speed stabilises.

Mos.