High Powered Sports Cars

[Viper]

Does anybody know exactly what the fuel availability is at the pump stations regarding octane levels? If you are familiar with high performance vehicles, and the way in which poor fuel can affect performance, and in some cases there have been reports of engine siezures due to detonation. Most high performance cars have an ECU which is mapped for high octane fuel such as super unleaded commonly known as 97-98 RON as purchased in eupeon countries, but ive noticed Thailands fuel is very poor and ive only ever seen octane levels up to 95 unleaded. Is there a solution here in Thailand?

[koratsteve]

Viper,

I have only seen three different fuels available in the local forecourts 95, super which I understand to be 97 octane and gasohol 97 which is a mixture of 10% alcohol and petrol, most local cars and motor bikes are designed to run on 95, high performance cars bikes and older cars run on super as for the gasohol I never use it but a friend of mine put it in his Yamaha R1 by mistake and it basically ground to a halt and would not start until we drained the tank and refilled it with regular 97 and I keep reading that the super will be fazed out and replaced by the gasohol which means that if you have a performance vehicle you will have to use 95 plus an expensive octane booster.

[Viper]

Beware of octane boosters, as many contain lead or lead-like substances which will damage the catalytic convertor and oxygen (Lambda) sensor..

t seems that the Engine Management System will react to a lower quality fuel by detecting the onset of knocking. In this case, it will retard the engine timing and reduce the maximum boost available from the turbo. It will then run on these lower settings until such time that the system is reset, though the system should eventually re-adapt to the higher quality fuel. Resetting the ECU simply speeds up this process.

You may obtain gradual improvements by simply running on the higher spec fuel, but most will find that although it is not any faster: the engine will be slightly smoother and the economy increased marginally (by about 5%).

I would suggest remapping a programmable ECU, or visit an Ecutek center and have the OEM ECU checked out.

[moonoi]

Koratsteve...where do you find 97 Octane in Thailand? I've driven all over thailand and never seen a forecourt selling 97 anything.

What I have found is 91 Octane petrol, 91 Octance Gasohol, 95 Octane petrol and 95 Octance Gasohol. The only problems I've found with Gasohol (95) is that as it doesn't create as much energy I get around 50km less milage out of my car.....its works out to be cheaper to buy 95 Octance petrol at the more expensive pump price never heard of a vehicle failing to start because of it....normally the only problem associated with gasohol (apart from crappy milage) is it can course some vehicles fuels systems to degrade (the alcohol desolves seals, pipes etc)

Some places still don't sell Gasohol though.....and I've only seen 91 Gasohol at Lemon Green stations. The other places I use are PTT,Shell,Jet and Esso.

EDIT: It is true that last year the gov send it would phase out 95 petrol in favour of gashol...although like all things here is been very quiet regarding this recently......

Edited April 1, 2006 by moonoi

[Viper]

Koratsteve...where do you find 97 Octane in Thailand? I've driven all over thailand and never seen a forecourt selling 97 anything.

What I have found is 91 Octane petrol, 91 Octance Gasohol, 95 Octane petrol and 95 Octance Gasohol. The only problems I've found with Gasohol (95) is that as it doesn't create as much energy I get around 50km less milage out of my car.....its works out to be cheaper to buy 95 Octance petrol at the more expensive pump price never heard of a vehicle failing to start because of it....normally the only problem associated with gasohol (apart from crappy milage) is it can course some vehicles fuels systems to degrade (the alcohol desolves seals, pipes etc)

Some places still don't sell Gasohol though.....and I've only seen 91 Gasohol at Lemon Green stations. The other places I use are PTT,Shell,Jet and Esso.

EDIT: It is true that last year the gov send it would phase out 95 petrol in favour of gashol...although like all things here is been very quiet regarding this recently......

I think what Koratsteve is trying to say, is that the fuel labeled 95 super on the pumps is actually a 97 octane. Ive seen this in some stations, and if thats the case then 97 octane would be sufficiant for a high powered vehicle. Ive actually found out that 100 octane fuel can be purchased but is quite expensive - I would only recomend using this fuel if you are participating in circuit racing to obtain maximum power. Jet and caltex are my prefered choice. I used a ptt station in the south once which left my vehicle with a miss fire, poor detonation.

[koratsteve]

Sorry I got a bit muddled up with the octane numbers, What I meant was 91 and regular 95, The gasohol is rated at 95 octane.

[PeaceBlondie]

The formulae for calculating octane are different in some countries. I think USA uses an average of the two methods, and Thailand uses the formula that results in the lower number. The owner's manual for my Thai-built Honda CBR150R says it runs on 91 octane, but has a compression ratio of 11:1. You can't run that high a compression ratio in the USA on 91 octane, but you do in Thailand. So, I don't run 95 in my motorcycle, but a bike like a Yamaha R-1 might have an even higher compression ratio, and need the Thai 95 number. The R-1, however has electronic fuel injection with an ECU that can adjust the timing; the carbureted bikes probably don't have that.

[Skyline]

Fuel in Thailand is really poor quality,I have a tuned B16 VTEC engine with a modified ECU and have had lots of trouble with the fuel here.So much so that I have had the injectors serviced 3 times in 1 year:(

It seems I need to have the engine retuned reguarly to keep it running well!!!!!....wish Id stuck to a standard engine now!

My boss has a 1 year old Merc and he has been through 2 fuel pumps because of poor 95 fuel too.Thailands really not the place for hi-performance cars,bad fuel,poor roads and other factors make it unenjoyable.

[PeaceBlondie]

I still can't believe my owner's manual. Eleven to one c.r., and 91 octane gas? But it doesn't ping (pre-ignite, detonate) on 91 octane.

Could injectors have much smaller clearances in their nozzles, than carburetors have?

[Viper]

Fuel in Thailand is really poor quality,I have a tuned B16 VTEC engine with a modified ECU and have had lots of trouble with the fuel here.So much so that I have had the injectors serviced 3 times in 1 year:(

It seems I need to have the engine retuned reguarly to keep it running well!!!!!....wish Id stuck to a standard engine now!

My boss has a 1 year old Merc and he has been through 2 fuel pumps because of poor 95 fuel too.Thailands really not the place for hi-performance cars,bad fuel,poor roads and other factors make it unenjoyable.

I would say that Thailand has some of the best conditions for rally going cars such as subaru's. However if you are a ferrari, porche, or lambogini enthusiast then Thailand is most deffinatly a NO! NO!

I think ive found my solution now. There are some really good garages that I did not think would exist, with engineers that have excellent knowledge of high performance vehicles. My answer was as i presumed replacing the stock ECU for factory programmable ECU and tweaking it to suit conditions, temperature, fuel, etc.

Sounds like something is very wrong if you had to service your injectors 3 times in 1 year. Try using only the same fuel from the same station if possible, and use "redex" (made in UK) fuel injector cleaner, purchased from Tesco Lotus.

Different grades of fuel burn at different temperatures, some have lead and some dont. Ping comes form pre ignition or detonation. High performance vehicles have knock sensors that alter the timing ever ?? number of knocks.

[kruudontrii]

As for the question in your post's title (which seems to be different than in the body of the post), high ambient temperature reduces performance because the colder air is, the more dense it is; the more dense it is, the more oxygen is ignited on each firing of a cylinder, creating a more powerful explosion, thrusting it down faster. That's why short-distance intakes are often marketed as 'cold air' intakes.

As for gas purity affecting power, that's basically the same explanation... higher purity means a more powerful explosion. Particle contaminants can also affect injection nozzles, wreck piston rings, weaken ring seal, etc etc, but a fuel filter will surely grab these.

[típ-yá-jàk-sòo yaan]

I know this isn't just an octane post but I am confused. Back home in Canada premium fuel is rated at 91 octane (average of RON & MON - Thai/European equivalent 95 RON octane). 94 octane (Thai/European equivalent 98 RON octane) is available but not common outside urban areas. I have run many different types of high performance vehicles (carbed V8s, blownV6s, 13,000 RPM bike engines)on 91 (95 Thai) octane for years with no maintainence/service issues and negligible performance degradation on the street.

So is the issue here in Thailand that the manufacturers/distributors are misrepresenting their octane figures or that the quality of the product supplied is so inferior that it can cause issues?

If fuel quality is the issue a high performance fuel filter, regularly maintained and/or changed, should remove (most) contaminates.

If the octane ratings are outright lies then there is no recourse other than resorting to a non-lead based octane booster, or live with the fact that your ECU is going to reduce performance to eliminate knock and save your engine from an expensive rebuild.