Why Premium Gas?
#1
Why Premium Gas?
Hi all,
I'm new here, but not new to rotary engines. I had an '84 GSL-SE (13b) several years ago. I was told by my mechanic who knew rotaries well that the normally aspirated rotaries liked low octane gas since the engine has a longer burn time and is a low compression engine. My 13b ran great (I used to race the thing) with regular gas. I tried premium, but noticed no difference.
So now I'm looking into an '06 and I read that Mazda suggests premium. Why? What has changed with the Renesis? Anybody have the answer?
Thanks!
Daniel
I'm new here, but not new to rotary engines. I had an '84 GSL-SE (13b) several years ago. I was told by my mechanic who knew rotaries well that the normally aspirated rotaries liked low octane gas since the engine has a longer burn time and is a low compression engine. My 13b ran great (I used to race the thing) with regular gas. I tried premium, but noticed no difference.
So now I'm looking into an '06 and I read that Mazda suggests premium. Why? What has changed with the Renesis? Anybody have the answer?
Thanks!
Daniel
#3
Seriously.. FML..
If you want your engine to last longer, use premium.
Well, not really but it helps in some way.. I wouldn't dare use regular on my 8.. Not even if I was outta gas and the only available octane was regular!
Plus, you go fast with premium..
Well, not really but it helps in some way.. I wouldn't dare use regular on my 8.. Not even if I was outta gas and the only available octane was regular!
Plus, you go fast with premium..
#4
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Hi all,
I'm new here, but not new to rotary engines. I had an '84 GSL-SE (13b) several years ago. I was told by my mechanic who knew rotaries well that the normally aspirated rotaries liked low octane gas since the engine has a longer burn time and is a low compression engine. My 13b ran great (I used to race the thing) with regular gas. I tried premium, but noticed no difference.
So now I'm looking into an '06 and I read that Mazda suggests premium. Why? What has changed with the Renesis? Anybody have the answer?
Thanks!
Daniel
I'm new here, but not new to rotary engines. I had an '84 GSL-SE (13b) several years ago. I was told by my mechanic who knew rotaries well that the normally aspirated rotaries liked low octane gas since the engine has a longer burn time and is a low compression engine. My 13b ran great (I used to race the thing) with regular gas. I tried premium, but noticed no difference.
So now I'm looking into an '06 and I read that Mazda suggests premium. Why? What has changed with the Renesis? Anybody have the answer?
Thanks!
Daniel
#6
Registered User
#7
Hi all,
I'm new here, but not new to rotary engines. I had an '84 GSL-SE (13b) several years ago. I was told by my mechanic who knew rotaries well that the normally aspirated rotaries liked low octane gas since the engine has a longer burn time and is a low compression engine. My 13b ran great (I used to race the thing) with regular gas. I tried premium, but noticed no difference.
So now I'm looking into an '06 and I read that Mazda suggests premium. Why? What has changed with the Renesis? Anybody have the answer?
Thanks!
Daniel
I'm new here, but not new to rotary engines. I had an '84 GSL-SE (13b) several years ago. I was told by my mechanic who knew rotaries well that the normally aspirated rotaries liked low octane gas since the engine has a longer burn time and is a low compression engine. My 13b ran great (I used to race the thing) with regular gas. I tried premium, but noticed no difference.
So now I'm looking into an '06 and I read that Mazda suggests premium. Why? What has changed with the Renesis? Anybody have the answer?
Thanks!
Daniel
I ran 87 without issue too.
#8
Registered
I don't know what the earlier rotaries were, but the Renesis has a compression ratio of 10:1. That usually means you need more than regular. Mazda's spec is 91, not the 92 or 93 that (depending where you live) is the highest grade on the pump.
Because of engine sensors and electronic management, you can run most modern cars on lower than the recommended octane. The spark just gets retarded to avoid knock. Mazda requires at least 87, and recommends 91 for best performance. A lot of people here report using 87 and are very happy with it. Some report knocking if they don't use premium.
I use premium. Too low an octane might cost performance or (long shot, these days) damage the engine. The worst you can do using too high an octane is waste money. But if I was going to worry about that, I'd have gotten a car that got better than 18 mpg.
Ken
Because of engine sensors and electronic management, you can run most modern cars on lower than the recommended octane. The spark just gets retarded to avoid knock. Mazda requires at least 87, and recommends 91 for best performance. A lot of people here report using 87 and are very happy with it. Some report knocking if they don't use premium.
I use premium. Too low an octane might cost performance or (long shot, these days) damage the engine. The worst you can do using too high an octane is waste money. But if I was going to worry about that, I'd have gotten a car that got better than 18 mpg.
Ken
#9
Rotary , eh?
iTrader: (1)
its all about the tune.
Last edited by mac11; 07-18-2007 at 09:43 AM.
#12
This is a car by car issue, many on this board run fine using 87 with no lose of performance or mpg. I am one of those. I have used premium and have recorded no difference at all so 87 is the call. Some on the board have had knocking using 87 and have moved to premium, this makes sense. Many on the board have just used premium with out even checking, it is their money and if it makes them happy who am I to say they are wrong.
As for the rotary by the nature of the engine's combustion chamber it will run better on low octane fuel. Many rotary race cars have been running with octane as low as 80. I have read a few posts on this board were an RX-8 ran at higher HP with 87 then premium.
The problem is that there seems to be a very inconsistent quality control with the manufacturing of the Rotary engines by Mazda. One guy runs great on 87 the next guy knocks. The only advantage that premium will give you is it will prevent knocking and may allow an advance on the engine timing. I have seen no tests, dyno sheets, or other evidence to support the fact that premium will give you more power. Maybe they is some but I have not seen them. I did see the dyno with 87 showing improved HP.
So, if your car is not knocking with 87 there is no reason to move to premium. Mazda probably recommends it as a safety net for the few cars that do knock with 87, it is cheaper for them to do this then fix the problem.
As for the rotary by the nature of the engine's combustion chamber it will run better on low octane fuel. Many rotary race cars have been running with octane as low as 80. I have read a few posts on this board were an RX-8 ran at higher HP with 87 then premium.
The problem is that there seems to be a very inconsistent quality control with the manufacturing of the Rotary engines by Mazda. One guy runs great on 87 the next guy knocks. The only advantage that premium will give you is it will prevent knocking and may allow an advance on the engine timing. I have seen no tests, dyno sheets, or other evidence to support the fact that premium will give you more power. Maybe they is some but I have not seen them. I did see the dyno with 87 showing improved HP.
So, if your car is not knocking with 87 there is no reason to move to premium. Mazda probably recommends it as a safety net for the few cars that do knock with 87, it is cheaper for them to do this then fix the problem.
#13
Out of NYC
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I cant use 87 because I use Premix, which lowers the AKI of the gas, and everytime I use 87 /w premix I got some hesitating issue.
We have 93 in NYC, so Im just gonna stick with it.
#14
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You cant really compare a 10:1 rotary compression to a piston 10:1 compression, they're different beast.
I cant use 87 because I use Premix, which lowers the AKI of the gas, and everytime I use 87 /w premix I got some hesitating issue.
We have 93 in NYC, so Im just gonna stick with it.
I cant use 87 because I use Premix, which lowers the AKI of the gas, and everytime I use 87 /w premix I got some hesitating issue.
We have 93 in NYC, so Im just gonna stick with it.
Hmmm...again I guess we all just have different engines as I also premix and use 87.
#15
Living In The Past
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Our Subaru, on the other hand, will run just fine on 85 octane no matter how hot the weather or how heavy the driver's foot is.
I agree with those who point out that a few cents at the pump is worth it just to remove this issue from the table. I always use premium in my 8.
#17
No need if you do this, https://www.rx8club.com/rx-8-discussion-3/no-more-detonation-%2Amiac%2A-121249/
#18
Registered
My Accord has a compression ratio of 8.8:1 and runs on 87.
Ken
#19
Rotary Wanker
#20
Rotary , eh?
iTrader: (1)
What of these vehicles/motors? Anomalies for sure.
Hyundai 2.0L 4cyl BetaII engines as found in the 03+ tiburon, accent....maybe more have a 10.3:1 compression ratio and run on 87
Hyundai 2.7L v6 Delta engines as found in 03+ Tiburon GT, 02+ Santa Fe + more have 10.3:1 compression ratio and run on 87.
Chevy 5.3 liters V-8 as found in 07+ Avalanche and others 9.9:1 compression ratio run on 87.
Again, its all about the tune.
As an example:
Honda 1.3L 4cyl as found in 2006 civic hybrid 10.8 compression ratio runs on 87
Honda 2.0L 4cyl as found in 2006 civic SI 11.0:1 compression ratio runs on 91
does2/10s a point of compression make THAT much a difference? When you take a look at how each motor is tuned, it does. But then what is really the determinant there? The compression or the tune?
Last edited by mac11; 07-18-2007 at 07:38 PM.
#22
Registered
Yes - anomalies. Every one.
You're right - tune.
Thanks for putting all those examples up. I remember the days when it was primarily compression ratio...but it looks like memory isn't all its cracked up to be.
Ken
You're right - tune.
Thanks for putting all those examples up. I remember the days when it was primarily compression ratio...but it looks like memory isn't all its cracked up to be.
Ken
#23
Zoom-Freakin'-Zoom
iTrader: (5)
There it is, scientific proof.
What of these vehicles/motors? Anomalies for sure.
Hyundai 2.0L 4cyl BetaII engines as found in the 03+ tiburon, accent....maybe more have a 10.3:1 compression ratio and run on 87
Hyundai 2.7L v6 Delta engines as found in 03+ Tiburon GT, 02+ Santa Fe + more have 10.3:1 compression ratio and run on 87.
Chevy 5.3 liters V-8 as found in 07+ Avalanche and others 9.9:1 compression ratio run on 87.
Again, its all about the tune.
As an example:
Honda 1.3L 4cyl as found in 2006 civic hybrid 10.8 compression ratio runs on 87
Honda 2.0L 4cyl as found in 2006 civic SI 11.0:1 compression ratio runs on 91
does2/10s a point of compression make THAT much a difference? When you take a look at how each motor is tuned, it does. But then what is really the determinant there? The compression or the tune?
What of these vehicles/motors? Anomalies for sure.
Hyundai 2.0L 4cyl BetaII engines as found in the 03+ tiburon, accent....maybe more have a 10.3:1 compression ratio and run on 87
Hyundai 2.7L v6 Delta engines as found in 03+ Tiburon GT, 02+ Santa Fe + more have 10.3:1 compression ratio and run on 87.
Chevy 5.3 liters V-8 as found in 07+ Avalanche and others 9.9:1 compression ratio run on 87.
Again, its all about the tune.
As an example:
Honda 1.3L 4cyl as found in 2006 civic hybrid 10.8 compression ratio runs on 87
Honda 2.0L 4cyl as found in 2006 civic SI 11.0:1 compression ratio runs on 91
does2/10s a point of compression make THAT much a difference? When you take a look at how each motor is tuned, it does. But then what is really the determinant there? The compression or the tune?
87 good gas.. premix.. 70k + miles...
it depends on how your drive it.. that damn ecu is smart..
beers