reg gas ?
11-16-2010, 11:55 AM
#3
1% evil, 99% hot gas.
iTrader: (21)
Lower octane does not equal lower power. That is a common fallacy. In fact it can often make more power. It merely has less resistance to detonation. That is all.
The engine might make less power if it detects detonation and retards the timing, but it is the retarded timing
reducing the power, not the gasoline. The RX-8's knock detector is deaf as a post and unlikely to do anything.
I run regular frequently when I'm not at the track and feeling poor. No problems. 40k miles so far, thousands of which are on the track, and good compression. (I have a Twisted Rotors compression tester.) Note that when I'm running regular, I consciously don't stand on the pedal at every green light and on-ramp.
And where in the world did you get the idea that the engine would "run a little warmer"?
The engine might make less power if it detects detonation and retards the timing, but it is the retarded timing
reducing the power, not the gasoline. The RX-8's knock detector is deaf as a post and unlikely to do anything.I run regular frequently when I'm not at the track and feeling poor. No problems. 40k miles so far, thousands of which are on the track, and good compression. (I have a Twisted Rotors compression tester.) Note that when I'm running regular, I consciously don't stand on the pedal at every green light and on-ramp.
And where in the world did you get the idea that the engine would "run a little warmer"?
Haven't noticed any gains though, either...
11-16-2010, 01:33 PM
#5
I purchased and want my baby forever so I take good care of her.
11-16-2010, 01:56 PM
#6
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[quote=wankelbolt;3785443]Lower octane does not equal lower power. That is a common fallacy. In fact it can often make more power. It merely has less resistance to detonation. That is all.
The engine might make less power if it detects detonation and retards the timing, but it is the retarded timing reducing the power, not the gasoline. The RX-8's knock detector is deaf as a post and unlikely to do anything.
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If the ECM retards the timing due to sensing Knock, because you run lower octane fuel, the root cause is the lower octane. So why does the decal on the gas flap state not to use anything lower than 95.
The engine might make less power if it detects detonation and retards the timing, but it is the retarded timing
reducing the power, not the gasoline. The RX-8's knock detector is deaf as a post and unlikely to do anything.----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
If the ECM retards the timing due to sensing Knock, because you run lower octane fuel, the root cause is the lower octane. So why does the decal on the gas flap state not to use anything lower than 95.
11-16-2010, 06:59 PM
#11
very cold intake air temperature is akin to very low altutide and is one of the causes of detonation and pre-ignition if your car is tuned under "normal" conditions, in these situations you are better off using a higher level of octane.
ait is more of a factor than I previously thought.
been looking over my logs from home in the summer, fall, fall in high altitude (smokey mountains), and now the colder weather.
it is usually 100% humidity where I live and that probably adds a factor but that would take a whole different approach of data logging.
premixing also affects your octane level.
ait is more of a factor than I previously thought.
been looking over my logs from home in the summer, fall, fall in high altitude (smokey mountains), and now the colder weather.
it is usually 100% humidity where I live and that probably adds a factor but that would take a whole different approach of data logging.
premixing also affects your octane level.
11-16-2010, 07:54 PM
#12
Yup I meant Intake Air Temperature not the sensor ..... sorry for the confusion.
IMO lower air temps reduce the chances of detonation thus allowing you to use a lower octane fuel.
The mass air flow sensor will pick up the increase is flow density and adjust the fuel accordingly ...
IMO lower air temps reduce the chances of detonation thus allowing you to use a lower octane fuel.
The mass air flow sensor will pick up the increase is flow density and adjust the fuel accordingly ...
11-16-2010, 07:56 PM
#13
(I guess technically we are Maf base and Closed loop based)
How very cold are you talk'n anyway .... like 0 Kelvin or something? lol
Last edited by wcs; 11-16-2010 at 08:10 PM.
11-16-2010, 10:29 PM
#15
Lately, it's been cold outside and I've used the 89 octane a few times. I also started premixing the last 500 miles I've driven and kind of experimented. I get 16-17 mpg with 91 octane and more than 17 mpg with 89 octane, both are premixed with Valvoline TC-W3 and driven the car on the same route everyday. The exhaust smells stink though, premixed with Valvoline!
11-17-2010, 04:22 AM
#18
well considering most engines are tuned at an ambient temperature of let's say 70F. When your FI engine is running hot you use an intercooler to lower that temperature to the "tuned" more stable air temperature. I have thought about it much and drove my 1994 TT RX7 in the summer and winter, and you don't even need an intercooler in the winter because the air mass in dense and cold already. Think about it.
Premix doesn't lower the octane much but you are adding a combustible fluid to your gas.
The oil is not 91 octane. Add an ice cube to a drink and it gets a bit watered down, get it?
Premix doesn't lower the octane much but you are adding a combustible fluid to your gas.
The oil is not 91 octane. Add an ice cube to a drink and it gets a bit watered down, get it?
11-17-2010, 06:57 AM
#19
11-17-2010, 08:20 AM
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11-17-2010, 12:52 PM
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11-17-2010, 01:01 PM
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The 8 is not a snowmobile. Of course an intercooler would not be needed in most cases in winter,unless running high boost, air pressure causes heat.Heat causes detonation.
Last edited by FastFreddy61; 11-17-2010 at 01:08 PM.