Correct Fuel

General Bellett, Gemini 75-98, Piazza 81-93, Bellel, Florian, 117 Coupe, Minx, Aska technical discussion.
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Chris
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Correct Fuel

Post by Chris » Wed Oct 21, 2009 4:46 pm

Greetings, was wondering if anyone can share some experience information regarding which fuel suits and performs best.

My daily car a 2001 V6 (3800) Commodore Berlina hates the 2000 or any other cheap fuel. It runs like crap, however i am convinced that Shells V-Power runs my engine perfect. Matter of fact, I would say I notice a 5% gain in power and smooth idling when using V-power. So I thought, I also fill up the piazza at Shell but noticed that the engine is idling rougher as well I have the feeling that Ive dropped power dramatically (8% less I would say).

I am not 100% on this but I think I filled her up with mobile fuel prior to shell... Anyone has the same experience or give advise on which fuel is optimal for the piazza?

Cheers,

Chris
LESS SHOW, MORE GO!!

2009 | 1986 White Piazza 2.2L, Man, STi Turbo (SOLD)
2006 | 1986 Black Piazza Turbo Manual (SOLD)
2005 | 1986 White Piazza Turbo Auto (Pain in the ass)
2004 | 1986 White Piazza Manual Stock
2004 | 1986 Red Piazza Manual TO3, Haltech
2001 | 1986 Silver Piazza Manual Turbo

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madmike
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Post by madmike » Fri Oct 23, 2009 9:34 pm

5% LOL Is that measured with the ass-o-meter?
Your commy should run fine on 91 octane.


I would not run anything less than 98 octane in my piazza....
If your running standard boost 96 octane will be fine..
If you up the boost or plan to fang it a bit DEF run 98 octane...

Paying a little extra for better fuel is way cheaper than a motor rebuild
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Post by devilishdesigner » Sat Oct 24, 2009 7:17 am

I'd be suggesting that the commodore needs a good tune if it prefers V power.

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Post by IZU069 » Sun Oct 25, 2009 9:36 am

madmike wrote:I would not run anything less than 98 octane in my piazza....
But the Aussie Piazzas are turbo.
The required octane/RON is determined by the compression.

These was a bit of a discussion about this recently on OzGem where someone noted WORSE performance with 98RON. (See Unleaded fuel.)

I too recently noted bad performance with high octane. Though I use 91-92RON (standard G161-OHV), I sometimes fill with 98RON for the alleged clean out, and so I can advance the timing. But last time I suffered problems - she was real gutless. I'm not sure why... although I didn't initially advance the timing, I did later, but without much change. (And yes, pinging started after continuing wit 92RON thereby confirming my timing technique.) Maybe it was a bad batch of fuel? Or the clean out fouled splugs etc?
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Post by madmike » Thu Oct 29, 2009 2:51 pm

IZU069 wrote:
madmike wrote:I would not run anything less than 98 octane in my piazza....
But the Aussie Piazzas are turbo. Yes.. So is my Japan import
The required octane/RON is determined by the compression. Compression,Boost Temperature blah blah blah...

These was a bit of a discussion about this recently on OzGem where someone noted WORSE performance with 98RON. (See Unleaded fuel.)

I too recently noted bad performance with high octane. Though I use 91-92RON (standard G161-OHV), I sometimes fill with 98RON for the alleged clean out, and so I can advance the timing. But last time I suffered problems - she was real gutless. I'm not sure why... although I didn't initially advance the timing, I did later, but without much change. (And yes, pinging started after continuing wit 92RON thereby confirming my timing technique.) Maybe it was a bad batch of fuel? Or the clean out fouled splugs etc?
.
Im picking bad batch of gas...

Correct me if i am wrong but as far as i am aware almost all turbo cars are designed to run on 95ron or higher, even the ones built in Aus.

In my opinion putting anything less than 95 in any turbocharged car is just asking for trouble...

Ask Wedgenut about his son and the results from running 91 in his g200 for the last few weeks..

In my mind your better paying a little extra for 95 or 98 than leaning out or detonating and needing a rebuild or head gasket.
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Post by IZU069 » Thu Oct 29, 2009 3:37 pm

Agreed - RON is compression related.

My hi-RON performance drop was not splug related.
And nothing to suggest it was bad fuel (supplier history, smell, contaminants).


"In my mind your better paying a little extra for 95 or 98..."
Yes - but you should still match the fuel to the engine/compression.
The money can be wasted.
If not high compression, the RON is wasted.
And it may have detrimental performance as suggested in my link above.

Is your import the 135 or 180HP engine?

If Wedgy feels like saying anything, I'm sure he will.
If you have something to say about Wedgy's experience that adds anything to what I or you have said, and my link, please do.
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Post by Rodeobob » Fri Oct 30, 2009 8:47 pm

The owners manual say to run it on 91 RON fuel or better.

Most of the carbed Isuzu motor say 89 RON or better.


My old man swears by 98. Ive tried it and i think its a crock.

I ran the pintara on E10 95 10% ethanol and it did all right. Only used it because it was cheaper by the litre.

Only got a carbed car now so i jsut stick with the 91 and it does fine on that.


Each to their own. Id probably go the E10 in a Piazza if it was driving one.


Cheers, Bob.
Too many Piazzas to little money.

Currently unemployed. Watch this space.

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Post by wedgenut » Sat Oct 31, 2009 8:57 pm

The G200 engines are either 8.8 or 9.3 compression ratio and it is true that they recommend 87 and 91 minimum respectively. However in my case all these engines have had a head skim and one has had the block decked as well to sort some corrosion issues around waterway holes. On that one the head is also below the minimum thickness. The pistons weren't topped so they protrude from the block at TDC so it has a head shim. Even then it is still running about 9.4 as near as I can calculate. When it comes down to it I find it good insurance to use the higher octane. At the end of the day the difference on a full tank is only $3 - $4 so why piss about. The turbo cars are lower compression but I have the same issues with heads being skimmed so I don't waste energy worrying about which car does or doesn't need which fuel. I use 95 or 98 in all of them and have used Gull force 10 as well at times. There are far more important things to worry about.
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Post by Rodeobob » Sat Oct 31, 2009 9:26 pm

Over the past few days ive put new ball joints in the Piazza as well as refitting a front bumper. (what a Kent of a job)

I swapped in an air box and AFM from one of the other cars. This one had a pod filter on it and i sent the adapter out with a motor i sold for a Rodeo conversion.

Still wont run worth a bag of shit.
Im gathering by the smell it makes that its way too rich and the fuel is too old and off. It was last on the road in 2004. It has a bit of a varnish smell to it, sorta like a plastic motorbike fuel tank thats been sitting on the shelf in the shed for ten years.

So the next thing will be too drain the tank and put a new fuel filter in it and flush out the fuel system as best i can.

Where is the fuel filter, up beside the gearbox on the drivers side isnt it???

Its funny because the little Pulsar (i think thats a Sunny in NZ speak) never complained about its fuel being the same vintage. Drove it back and forwards to he RWC place then down to get Rego then filled it with fresh fuel on the way home. its done nearly 8000kms since it was serived in 04 and the oil looks as cleans as the day it went in.


Maybe the Piazza was runnning the E10 and the Ethanol content of the fuel is now water.
Its not a job im looking forward too.


Cheers, Bob.
Too many Piazzas to little money.

Currently unemployed. Watch this space.

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Post by IZU069 » Sat Oct 31, 2009 9:42 pm

Stale fuel was one of those great money spinners. People actually used to drain their carbies BEFORE storing the car. LOL!

But apparently lead was a preserver.

The newer fuels do deteriorate, and yes, they small like varnish. A knowledgeable mate reckoned that varnish is stale fuel. (I don't use ethanols.)
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Post by Rodeobob » Sat Oct 31, 2009 9:52 pm

Hes probably not far off.

Its more that as the fuel evapourates, the good stuff gets less in quantity and the crap thats added stays the same. The varnish is just condensed fuel colouring dye.


I have a few bike carbs here that are full of soild red/brown looking crap.


Bob.
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Currently unemployed. Watch this space.

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Post by Rodeobob » Sat Oct 31, 2009 11:01 pm

Problem half solved, only got about hlaf a cup of yellow stinky stuff out of it.

Now to find the fuel filter and get a new one.



Bob.
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Currently unemployed. Watch this space.

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Post by Chris » Thu Nov 05, 2009 12:50 pm

I am beginning to see that Fuel is not my issue here. I've done some testing. Filled up over the past weeks at all kinds of petrol stations, always using 98 or the high fuel grade and I didnt get the results I wanted to however I did noticed:


Caltex, BP, MOBILE = Engine runs smooth and Idle fines but consumption seems greater
Independent stations = Engine runs noticeably rougher
Strangely enough I give Shells V-Power thumbs up, engine runs smooth and its seems I get alot more out of my tank than others.

Though it makes me wonder now why I am having this power decreased. Honestly 15- 20% less.

Tracing back what could have gone wrong, well my mate drove her very hard for 10 min and fuckwit stalled her. I cant hear or see any signs that this might damaged the sTi Turbo. How can you tell without taking it out?

Also the next day the car went to a mechanic, "Mike Nolas Racing, good NZ bloke". He was ment to inspect the car for RWC and also replaced front brake pads, discs and few other little things. After picking it up I noticed the power was dropping when she went of 3000+ revs. Was strange, but a quick look under the bonnet I found that one of the terminals to the dizzy cap was unplugged. Not actually visibly unplugged but enough to not give contact anymore, firing only 3 cylinders.

Why would it be unplugged, coincidence or has the mechanic done this? So she went straight away to padders to get the front bushes done and he turned the wheel bearings to get more space between my "Too wide" calibra tires who where scrapping against the suspension when the car was lifted.

Driving it home, was now the first time I noticed the power drop. I used to get pulled back into my seat and even 3 gear she would go side wides if I wanted to.. Engine sounds fine, no smoke, no leaks apart from the diff but I found that she feels a lot rougher around the gearbox or diff.

Any speculation what could cause this huge power decrease?

Chris
LESS SHOW, MORE GO!!

2009 | 1986 White Piazza 2.2L, Man, STi Turbo (SOLD)
2006 | 1986 Black Piazza Turbo Manual (SOLD)
2005 | 1986 White Piazza Turbo Auto (Pain in the ass)
2004 | 1986 White Piazza Manual Stock
2004 | 1986 Red Piazza Manual TO3, Haltech
2001 | 1986 Silver Piazza Manual Turbo

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Post by Rodeobob » Thu Nov 05, 2009 1:20 pm

Have you actually paid for someone to service and tune it???


Could be any number of things.
The descrition you just typed out tells me youve got an eye for detail, perhaps you should get under the bonnet yourself.



Because the Piazza has a fuel only ECU changing from one fuel to another could well be noticeable. The ignition can not be compensated on the fly to get the best out of a better fuel. You reall need to run a few tanks of the same fuel through it then go and get it tuned on that fuel.


When you first got it it might have had a tank full of dirty old 91 RON fuel and be lovin it.


Bob.
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Currently unemployed. Watch this space.

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Post by Chris » Thu Nov 05, 2009 2:31 pm

yeah i am mechanically minded, and also taken 2 piazzas apart and remember me and my gearbox adventures lol.

I doubt it is the fuel though. I refilled her since i bought her atleast 4 times before I noticed the power drop.

So I am really confused on why this is happening. How do you tell if the turbo is faulty without actually looking at it. It winds up nicley, it boosts fine as far as I can tell and I can't hear any strange noises coming from it. What are the symptoms of a blown or half blown turbo?

I know that I would need to take the turbo out and check if there is play in the the turbine shaft yeah?
LESS SHOW, MORE GO!!

2009 | 1986 White Piazza 2.2L, Man, STi Turbo (SOLD)
2006 | 1986 Black Piazza Turbo Manual (SOLD)
2005 | 1986 White Piazza Turbo Auto (Pain in the ass)
2004 | 1986 White Piazza Manual Stock
2004 | 1986 Red Piazza Manual TO3, Haltech
2001 | 1986 Silver Piazza Manual Turbo

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