Japanese Starion - Fuel Advice

SpidersWeb · Post by **SpidersWeb** » Fri Apr 09, 2004 1:22 am

DO NOT USE 96 OCTANE IN A JAPANESE 8 VALVE STARION

I put 91 in there and she's back to normal.

Using 96 is what caused my car to die. The NZ/AUS models are designed for higher octane fuels. In Japan they run a much lower octane, and the fuel maps on the ECU are adjusted to suit, so running 91 makes the car run slightly rich. Running 96 octane kills it.

I hear so much of people running 96, so this clearly shows a difference in ECU. Resetting the ECU had no effect either. Car was unplugged for three days.

I blamed an air leak, turned out the noise was from a slightly loose boost guage line, fixed it made no difference but noise was gone. Put the 91 in there and it made an enourmous imporvment over the 96.

I'm so wrapped to have her running properly again, but thought I'd mention this for the benefit of any other Jap owner.

Although I'm sure there are Jap Starions that will run 96, I just know now that mine definatley does not like it one bit.

Paradoxx · Post by **Paradoxx** » Fri Apr 09, 2004 3:57 pm

*strokes haltech computer*

can't say i'm too fond of stock computers. can u lean it up a bit with the ecu or is it fixed? i assumed there was a mixture screw or something on the computer that allows you to change the factory setting.

Project2501 · Post by **Project2501** » Fri Apr 09, 2004 4:10 pm

This must be the first case I've heard of where higher octane had a detrimental effect on a car?? I thought the rule of thumb was run as high octane as you could find..

cheers

tom.

RiceThief · Post by **RiceThief** » Fri Apr 09, 2004 4:31 pm

I dont know about the 80's but from the 90's onwards japan has always had higher octane than australia their premium is in the region of 100+ ron.

Using a higher octane fuel by itself doesnt make more power and in some cases makes less power, having a higher octane fuel will reduce preignition and detonation, so having a higher octane fuel than necessary could mean the combustion wont burn as strong which means less power. The benefits of premium is it has solvents which will clean the lines, engines, injectors etc, if your starion only requires 91 ron, you could increase the boost and timing to take advantage of the higher octane. I believe this is the case, so please correct me if I am wrong.

Mai

SpidersWeb · Post by **SpidersWeb** » Fri Apr 09, 2004 4:41 pm

Also my 4G63 NA Galant shows a significant decrease in power on 96.

Both 4G63 Mitsi's I have run best on 91. I will have a look on the ECU since the plastic panel is not screwed in anyway, and if I find that magic screw I will be very very happy.

This is quite common, friend of mine had his car tuned for 98 octane, but ran ~110 octane Avgas, on Avgas the car was dead and would misfire and backfire heavily, had to have the fuel maps redone to support the higher octane. If they run too rich the petrol just doesn't burn properly.

Definately Aftermarket ECU = one of the early upgrades on a Starion I'd say.

Well this is what I have found, any large increase of fuel octane on a car that runs rich, will cause it to overdose, if I'm wrong correct me, but have had this happen on three different cars now.

jrod82 · Post by **jrod82** » Fri Apr 09, 2004 8:57 pm

I've ran my '82 jap import on 91, 96, and 98.. 98 seems to be the best by far, better performance and economy. I haven't ran her on 91 for over a year now, but I'll give it a go in a week or 2 when I next fuel up and let you know.

SpidersWeb · Post by **SpidersWeb** » Fri Apr 09, 2004 10:32 pm

Wouldnt suprise me man.

My car doesn't make any sense.

Its a weird bastard.

I used to run 96 in the past. I found more power up high, but less power down low. The car would do its cut'n splutter if I held it in gear for too long, e.g. 5th gear, 155KPH top speed basically.

For some reason, using 96 of late, really caused some havoc. But running 91 I can hold her in gear as long as I want with no problems, I test this by accelerating in 3rd gear. Start at 2000rpm and go to 6250rpm. Did it the other day when running 91 for the first time since Ive owned the car it didn't cut or splutter. I now feel its capable of its 200KPH top speed.

grrr so confusing
Well anyway, if anyone has a Jap staz, and its running like crap on 96, try 91 and see if it improves.

Also mine is a very late model intercooled JB, and yours is an early JA, so possibly some differences there as well.

Paradoxx · Post by **Paradoxx** » Sat Apr 10, 2004 7:04 pm

Cam just put up a post that may help you...
Might be ur answer to changing the mixtures

ProZac · Post by **ProZac** » Sat Apr 10, 2004 7:30 pm

All 3 of my jap imports starions have run fine on 96. On 91 they would ping like mad under max load.

C Fernance · Post by **C Fernance** » Sat Apr 10, 2004 8:05 pm

Just a side note. I was pulling the fuel tank out of my JB today, and inside the fuel door there is a sticker saying "97+ Octane".

Powerslave · Post by **Powerslave** » Tue Apr 13, 2004 11:55 pm

As ricethief said , just putting in higher octane fuel alone does not really improve performance alone. There are 2 things you can do to supplement the higher octane fuel. 1: Increase boost without detonation or 2: Advance your ignition timing. I have advanced mine 5 degrees (8deg btdc - 13deg btdc). This does not give huge power gains but it 'moved' my power range down by 1500-1800 rpm , and makes the car drive more like a grunty 6 cylinder (ie not having to rev the shit out of it to get max power). Try advancing the ignition timing by a few degrees at a time and take it for a test drive. If it does not ping , increase it more , if it pings , back it off. Just make sure your cooling system is up to the task cause it will make your engine run hotter. Hope this helps ....

:beer

SpidersWeb · Post by **SpidersWeb** » Wed Apr 14, 2004 2:31 am

Yep and 96 can handle more compression before exploding. With the 91 compressed, a tiny spark can set it off.

With that in mind, and the fact I have Iridium TX plugs, 8mm leads, and they've only driven <500Km, (in 2 years my car has travelled only 2000Km, as it spends more time off the road, than on the road), I am thinking possibly an old dying coil?

Is there an easy way to test the coil? e.g. voltmeter?

Problem seems to be getting worse from age and not use. So might be a simple case of oxidized contacts or something. Ideas welcome :)

Hint for NZ owners, use http://www.partsworld.co.nz website to find parts. There is a Starions (both autos!!) in Te Puke and NP being dismantled, it has a listing for every part on the site (well almost).

SpidersWeb · Post by **SpidersWeb** » Wed Apr 14, 2004 2:34 am

Cooling system is mint, big viscous belt driven fan up front. Never overheats or comes close.

Id also like to add that my ignition timing will be advanced, considering I seem to have a huge amount of power at 3500-4000rpm instead of 5500-=6000rpm. As you hit 6000 something sounds bad.

I'd rather set mine up for peak power at 6000rpm to be honest, because the faster the engine is spinning the more air/fuel it can process, and more power, and quite frankly I just want more power :)

I'm an idiot, and don't have a timining light, so might just have it cheaply dynoed and have the Ign Timing adjusted. But don't wanna fork out for that, if something else is wrong with the car.

Austarion

Japanese Starion - Fuel Advice

Japanese Starion - Fuel Advice

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