Listen up NA guys (octane rating)
01-24-07 | 12:57 PM
#1
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From: idaho
Listen up NA guys (octane rating)
Here is a technical service bulletin I found that confirms the use of lower octane gasoline in NA engines.
Category Applicable Model/s
4 All Models
w/o Turbocharger
Subject:
USE OF REGULAR UNLEADED GASOLINE
Bulletin No. 054/89
Issued 2/20/89
Revised
DESCRIPTION
It is recommended that REGULAR UNLEADED gasoline be used in all Mazda vehicles NOT equipped with a turbocharger. All non-turbocharged Mazda vehicles are designed to perform best when REGULAR UNLEADED fuel is used.
Due to the low volatility of some SUPER UNLEADED fuels, an overlean air-fuel condition may occur especially when cold. This may result in start and driveability problems.
We urge you to NOT recommend the use of SUPER UNLEADED gasoline to your customers. Also, if a customer complains about a rough idle after starting, inquire as to what type of fuel the customer has been using as a first step in troubleshooting.
So for all you non believers, there it is, straight from Mazda.
Category Applicable Model/s
4 All Models
w/o Turbocharger
Subject:
USE OF REGULAR UNLEADED GASOLINE
Bulletin No. 054/89
Issued 2/20/89
Revised
DESCRIPTION
It is recommended that REGULAR UNLEADED gasoline be used in all Mazda vehicles NOT equipped with a turbocharger. All non-turbocharged Mazda vehicles are designed to perform best when REGULAR UNLEADED fuel is used.
Due to the low volatility of some SUPER UNLEADED fuels, an overlean air-fuel condition may occur especially when cold. This may result in start and driveability problems.
We urge you to NOT recommend the use of SUPER UNLEADED gasoline to your customers. Also, if a customer complains about a rough idle after starting, inquire as to what type of fuel the customer has been using as a first step in troubleshooting.
So for all you non believers, there it is, straight from Mazda.
01-24-07 | 01:04 PM
#2
I really Schruted it
Joined: Sep 2006
Posts: 573
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From: Grand Rapids, MI
If this was cut and pasted, isn't it a little strange that they used:
"4 All Models"
I just would have assumed the people that write TSB's don't substitute "4" for the word "for". I don't know, seems a little unprofessional.
Brian
Rx7's 4 ever
"4 All Models"
I just would have assumed the people that write TSB's don't substitute "4" for the word "for". I don't know, seems a little unprofessional.
Brian
Rx7's 4 ever
01-24-07 | 01:11 PM
#4
I have an ISB (Icemark Service Bulletin).
Originally Posted by Icemark
If LittleCon had searched he (or she) would have found that anything more than 87 octane on a stock FC motor actually is more likely to cause problems, and will actually result in less HP.
See the octane rating has absolutely nothing to do with BTU or power output. The only thing higher octane numbers do, is make it harder to pre-ignite. It makes the burn slower. Higher octane does not contain any additional power or performance unless the motor was designed or tuned to run on a higher octane (and even then the additional power is only a result of higher compression or boost along with computr processing).
In fact (more so on a non-turbo) you want the gas to ignite as easy as possible. Lower octane on a rotary with less than a 10:1 compression actually burns cleaner and faster than a higher octane.
So using higher octanes on a stock motor will result in increased deposits on the rotor faces(which could result in pre-mature engine failure), less power, and less money in your wallet.
So why would you waste the money and buy anything but 86 or 87 octane???
See the octane rating has absolutely nothing to do with BTU or power output. The only thing higher octane numbers do, is make it harder to pre-ignite. It makes the burn slower. Higher octane does not contain any additional power or performance unless the motor was designed or tuned to run on a higher octane (and even then the additional power is only a result of higher compression or boost along with computr processing).
In fact (more so on a non-turbo) you want the gas to ignite as easy as possible. Lower octane on a rotary with less than a 10:1 compression actually burns cleaner and faster than a higher octane.
So using higher octanes on a stock motor will result in increased deposits on the rotor faces(which could result in pre-mature engine failure), less power, and less money in your wallet.
So why would you waste the money and buy anything but 86 or 87 octane???
01-24-07 | 01:37 PM
#5
Very Simple, like ICEMARK said
Lower the Octane the easier it is to ignite (NA)
Higher the Octane the harder it is to ignite (Turbo)
I thought this was some given info that everone should no.
Lower the Octane the easier it is to ignite (NA)
Higher the Octane the harder it is to ignite (Turbo)
I thought this was some given info that everone should no.
01-24-07 | 04:04 PM
#6
Thread Starter
Senior Member
Joined: Oct 2003
Posts: 732
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From: idaho
Originally Posted by RX7Tuner.
If this was cut and pasted, isn't it a little strange that they used:
"4 All Models"
I just would have assumed the people that write TSB's don't substitute "4" for the word "for". I don't know, seems a little unprofessional.
Brian
Rx7's 4 ever
"4 All Models"
I just would have assumed the people that write TSB's don't substitute "4" for the word "for". I don't know, seems a little unprofessional.
Brian
Rx7's 4 ever
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01-24-07 | 05:59 PM
#8
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Joined: Oct 2003
Posts: 732
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From: idaho
Originally Posted by NoviceRotaryTech.
Thread Fails.
01-24-07 | 06:01 PM
#9
I have a 90 GTU and I can't run anything but 91 or 93. If I put a lesser octane in it, it runs like ****. And 89 is worse than 87. I get a loud tapping sound when I use cheap gas. And whenever i use 91 or 93, it goes away.
01-25-07 | 09:13 AM
#16
Originally Posted by gxlspeeder
Is that so? I tend to disagree. This is real proof it's better to run 87 octane over a higher octane in na applications. People can now use this information however they want.
https://www.rx7club.com/showthread.p...t=octane+n%2Fa
https://www.rx7club.com/showthread.p...t=octane+n%2Fa
https://www.rx7club.com/showthread.p...t=octane+n%2Fa
https://www.rx7club.com/showthread.p...t=octane+n%2Fa
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