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Old 4th January 2005, 08:01   #46
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I was told that Speed (regular) was 90 Octane & 93 was 93 (duh)!
Not sure about that, coz speed has additives and not necessarily octane boosters. I didn't find any diff in performance from Speed, but IOC Xtra Premium did wonders for my car. Now, the car pulls better from low rpms, car feels more torquey and smooth.

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Old 4th January 2005, 09:42   #47
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can we get some brew this weekend for the drag
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Old 4th January 2005, 09:44   #48
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Speed /Power is the regular 87octane petrol with additives.
but IOC xtra Premium is 91 octane fuel.
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Old 4th January 2005, 16:01   #49
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Octane rating of the fuel to be used in the vehicle is directly propotional to the Compression ratio. Some facts:
1. Fuel octane requirements for gasoline engines vary with the compression ratio of the engine
2. The higher an engine's compression ratio, the greater the amount of heat generated in the cylinder during the compression stroke.
3. The higher the octane rating on fuel the less volatile (evaporative qualities) and the slower the fuel burns.
4. Higher octane fuel contains more POTENTIAL energy but requires the higher heat generated by higher compression ratio engines to properly condition the fuel to RELEASE that higher potential energy.

High octane fuel does reduce knocking due to the delayed ingition. But engines with low compression ratio are not able to utilize the potential of the high octane fuel and actually the performance may reduce using high octance fuel.


Suggested Compression Ratios for Street Driven Engines
(Source: http://www.ford-trucks.com/article/i...ion_Ratio.html)
With cast iron heads, 9.0-9.3:1 is considered the maximum C/R for regular (87 octane) pump gasoline. 10.5:1 is about maximum for todayís premium (91-94 octane) pump gasoline with a cast iron head. And thatís assuming you keep the rpms up without lugging the engine, youíve cleaned up the combustion chambers of sharp edges and rough spots to reduce the possibility of pre-ignition and use a zero deck clearance, or close to it, to enhance quench.

Aluminum heads will generally allow 11.5:1 C/R on premium pump gasoline, again assuming you have clean combustion chambers and a zero deck clearance.

If you run A/C, take .5 off the maximums.
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Old 4th January 2005, 19:49   #50
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Originally Posted by Domnic
go to the dealer and ask them to connect the OBD and interface and increase the octane type in the ecm. This will make a difference.

.
hey Dom,
now with 87 octane being replaced by 91,will it help if the octane type is changed.
can u list the cars in which this can be done.
wat abt the mpfi zen.
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Old 4th January 2005, 22:39   #51
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Yes,
mpfi cars will benifit from the higher octane. You can use 91 on all the indian cars, no problem whatsoever...

Cheers
Dom
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Old 5th January 2005, 13:02   #52
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hey Dom ,i am talking abt changing the "octane type" in the ECM.
can u list the cars in which this setting can be changed.
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Old 5th January 2005, 13:08   #53
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you need to check the comp ratio of your engine, any thing above 9 will work well with 91 octane gas...generally the car manual will tell you what octane rating works the best. but the fuel we get here is not the best...so 87 octane might not actually be 87....thats the only danger.
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Old 10th January 2005, 13:44   #54
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well guys i used dom's mixture in my car and the response is almost immediate and the car burns better and is much more crisper...got an excellent mileage of 19.7 on the highway in my baleno...dom was sittin with me to prove it!!!
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Old 10th January 2005, 14:36   #55
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wat mixture ?????????
are u talking abt the toluene.
wat was te ratio uused and with wat fuel.
how much did u get the toluene for?????????


satya
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Old 10th January 2005, 14:46   #56
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dom did all for me...so u need to ask him and the mixture too is somethin he calculated according to the compression of my engine
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Old 10th January 2005, 17:57   #57
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hey dom
will it be possible for you to send us some of it or like will we have to make it ourselves
anyone here sell toulene or get it ???
was thinking of using it on my palio or ikon
how much does it cost per litre ???

will there be anychange in performance of the carb if 91 octane is used .
i mean FE and performance wise
thanx
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Old 10th January 2005, 21:28   #58
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Hi,
No probs, let me know how much qty you guys want, or else let me know the car type, amount of mods done.... ill get it when i come to bombay.

Cheers
Dom
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Old 10th January 2005, 21:53   #59
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hey lambo,
u can get it through a chemist.or u can search for one at Dava Bazaar near CST
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Old 11th January 2005, 03:04   #60
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thanx for the offer dom
satya happy bday
will check it out after my exams
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