The specifications on the RX-8 website recommends PREMIUM gas. Is fuel grade going to be important with the Renesis engine?

I have driven my 1st Gen RX-7 over 256,000 miles on regular unleaded. Can hit and git as good today as when I drove it off the lot in '85. I even seem to recall an article in the old Roatary Rocket magazine about 15 years ago that recommended NOT using premium.

Since the Renesis is not turbo-charged wouldn't it do just as well on regular?

Besides, gas prices have jumped 10-15 cents/gallon here in the last week! :mad:

i think the general consensus is that yes, you probably would be wise to choose premium (91/92 octane). this is mostly due to the fact that the renesis has something like a 10:1 compression ratio,

if that means nothing to you then look at it this way...crotch rockets are generally like 11-11.5:1 and your regular piston motor family four banger is probably in the order of 8:1

using a lower octane gas will cause knocking, and supposedly knocking is especially bad in a rotary (this i don't know why but would be most grateful if someone would care to elaborate)

-nate

knocking is bad period, but the weakest links in the Wankel-type engine are the seals at the apices of the rotor, which are pretty darn thin, and would (usually) give out before anything else (like the rotor warping or something)....

but like i said before, knock/ping is just awful in any engine.

If you can afford this car, you should be able to afford premium gas. End of story.

Can you really have a knock without pistons? Seriously, I don't know. What does a rotor knock sound like?

And it is not a matter of affording premium. As I said, 17 1/2 years of driving a wankel nearly every day on regular and it is still the original engine, now with 257,000 miles on it. I've pumped 7954 gallons of regular unleaded. Premium has probably ranged from ten to twenty cents a gallon above regular over this period of time. So assume the maximum of twenty cents and the increased cost would have been $1590 or less than $100 per year. Kinda like a government tax break:)

Why pay for higher octane if there is no real benefit. Higher is not always better. Comression ratio on my 1st gen is listed as 9.4:1, so that's not too far off from 10:1, right?

Ignition timing is also a factor in whether or not you use Premium gas or not. Go ahead and run regular you can be amoung the elite few with Renesis rebuilds. Man I bet it will be a while before you can get parts...

The ECU would probably "dumb down" advance and other operating parameters to keep detonation at bay. Well, there goes the performance the Renesis is (or hopefully will be) famous for! I wouldn't try running regular myself though.

$100 a year savings? That's chump change .. :) Besides most likely the ECU would retard timing and reduce power.. Looks like the Renesis will use premium gas for optimal results = hp.

well, at least one could hope for a computer controlled (variable) ignition that could handle a lower octane if if if... i'm pretty sure that with normal daily driving (slow acceleration, low rpm operation) you wouldn't run into problems on 90 octane, even 89 octane gas, but for peak performance you'd really need to be on +91...

anyhoo, the deal with knocking is that it can be from pre-ignition combustion, or (i believe) from the fuel not burning so much as exploding all at once (not the way it's suppost to happen)... so yeah, it doesn't matter how the compression and expansion is generated, you can still have knock, rotary, piston or otherwise ;)

Originally posted by TreknMazda
Can you really have a knock without pistons? You betcha, and how. And while apex seals aren't as "fragile" as some people make them out to be, they are the weakest link, and will be defreated with repeated and/or strong knock, which is a significant issue with forced induction. ...Comression ratio on my 1st gen is listed as 9.4:1, so that's not too far off from 10:1, right? It is, actually. That's the kind of difference between factory Normally Aspirated and factory Forced Induction engines in the same car.

Although lower octane gas was actually better for the FBs, this is a major redesign in the engine (and we're talking about fuel injection vs. carburetors). And if they're recommending premium, then it's probably for a reason.

BTW, nice car. Gotta love those FBs!

---jps

Originally posted by wakeech
...you wouldn't run into problems on 90 octane, even 89 octane gas, but for peak performance you'd really need to be on +91...

89 - 90 - 91 octane???? :eek: :confused: :eek:

Does that exist??? :eek: Thats SO LOW !!! Here in Belgium they only sell 95 octane and 98 octane... For me 95 octane is already low, I'll only be using 98.

I know that my friend Formula Atlantic 12A Peripheral. Uses, guess what? 93 octane w/oil premix. And I've seem, most of the SCCA Rx-7 ITS cars run 93 octane w/oil premix too on their 13B's. And, a SCCA GT1 20B Peripheral uses 93 octane w/oil premix. All those mentioned race cars are Normally aspirated race engines. Also, even if they used the 13B 2nd Gen highest compression Mazda production rotors, they still use 93 octane w/oil premix. But, then they can use ATF as an octane booster too.

I assume that now that the exhaust ports on the RENESIS are no longer a peripheral port (ex. peripheral throws out all the hydrocarbons exhaust gasses, have more overlap & have a cleaner intake charge after the exhaust cycle) & being side ports to recirculate unburned hydro-carbons. Using higher octane than recommended will just cause the engine to build up more carbon deposits in a stock normally aspirated trim (all-motor).

Spending money on higher octane (>97) will just cause more hydrocarbons in the new Rx-8 RENESIS, thus affecting emissions & maybe performance will diminish in the long run.

Originally posted by Beemer


89 - 90 - 91 octane???? :eek: :confused: :eek:

Does that exist??? :eek: Thats SO LOW !!! Here in Belgium they only sell 95 octane and 98 octane... For me 95 octane is already low, I'll only be using 98.

Beemer,

There are three octane rating systems: research octane, motor octane and the average of research and motor (R+M/2). Most of the world uses research octane while the USA uses the average method.

An equivalent fuel will have a higher research octane number than a motor octane number by about 10 points. Basically 100 research octane is 95 average USA octane.

Since my head is a bit foggy at the moment I may have switched research and motor but it still does not make a difference to the point that USA fuel does not really have a lower detonation resistance. Now sulfur content is a different story.

According to this, in terms of Fuel grades, a Rotary engine is suppose to be able to use a lower grade of fuel without any issues.

Take a look at this article in the Fuel Efficiency Section [EDIT] and let me know what you think.


The Renesis Rotary Motor (http://www.carmemories.com/cgi-bin/viewexperience.cgi?experience_id=624)

Well, So can we just use our pain old regular unlead fuel for this engine or what ?

sorry for this rater cheesy answer- use the fuel grade recommended in the owner's manual. and since we haven't seen one yet no one can say(unless they get some info from mazda) what that recomendation is. :)

Post the section on Fuel Consumption. All I see is a fuel efficiency section and it only talks about running on a leaner mixture not a low octane mixture. Both the press pack and Mazda website say premium. So I would assume that premium is what your supposed to use. You can be the first to try the low octane stuff if you want I don't care.....

Would Chevron with Techron keep a rotary engine cleaner also?

Originally posted by fritts
Post the section on Fuel Consumption. All I see is a fuel efficiency section and it only talks about running on a leaner mixture not a low octane mixture. Both the press pack and Mazda website say premium. So I would assume that premium is what your supposed to use. You can be the first to try the low octane stuff if you want I don't care.....

A leaner mixture is more prone to detonation/knocking than a richer mixture. This may be the reason for the Renesis to use premium

Would Chevron with Techron keep a rotary engine cleaner also?

Driving the car and hitting redline a couple times a day will keep a rotary engine clean :)

Reciprocating piston engines generally use a richer fuel mixture under high-speed and high-load conditions to prevent knocking. In contrast, rotary engines do not require a particularly rich fuel mixture under these conditions due to their special combustion characteristics. In addition, the RENESIS achieves nearly complete combustion over the entire speed range thanks to its high compression ratio and the use of new fuel injectors designed for improved fuel atomization. These enhancements allow the RENESIS to run on a leaner fuel mixture than conventional rotary engines from the low to the high-rev range. The result is the power and performance of a sports car engine and reduced fuel consumption.

So what I'm hearing is that leaner fuel can be used, but this is not officially from Mazda. Then again, are we going to adhere to everything they tell us???

Originally posted by VWjet


So what I'm hearing is that leaner fuel can be used, but this is not officially from Mazda. Then again, are we going to adhere to everything they tell us???

leaner doesn't mean lower octane, leaner means a higher ratio of air to fuel (or conversly a lower ratio of fuel to air)... the average buyer has nothign to do with the fuel:air ratio, the ECU determines that.

because of the higher compression ratio (10:1 i think), it's very adviseable to use only Premium gasoline, especially if you're planning on revving it (which one ought to, if they buy the car).

Folks, I got my car and I got my owners manual. And here's what is says about Fuel, page 4-2:

"Your Mazda will perform best with Premium Unleaed Fuel, Octane Rating 91 [(R+M)/2 method] or above (96 ROM or above).

You may use a regular unleaded fuel with Octane Rating from 87 to 90 (91-95 ROM) but this will slightly reduce performance. Fuel with a rating lower than 87 octane (91 RON) could cause the emission control system to lose effectiveness. It could also cause engine knocking and serious engine damage."

They also say use nothing with more than 10% ethanol or any fuel system additives or cleaning agents not specified by Mazda.

I will use a maximum of 89 octane, and I'll probably use 87 octane on occasion. Knowing how these books are written, they are being most cautious and recommend premium to give you the optimum driving experience. Slightly degraded performance of an 8 far exceeds anything I have ever driven so I'll still be happy. With MPG shaping up to be as poor as it appears, I'll offset with 89/87 which according to their manual will still be ok.

Put what the manual suggests. Premium.

Originally posted by vudoodoodoo
Put what the manual suggests. Premium.

I will do what the manual suggests, to wit: "You may use a regular unleaded fuel with Octane Rating from 87 to 90 (91-95 ROM)." That is exactly what I will do.

I've read your other post explaining why you will do this and I guess for your situation 87 will do. But I don't understand the money saving motivation. Unless you drive 1000 miles a week, with the cheap cost of gas in the US, how much $ can you really save? :confused: $10 a week? Pittance. I just don't see the point of buying a sports car and detuning the engine right away with lower octane gas. Also don't forget the Renesis is a high compression engine and I'm sure the premium will work much better than the regular. To each his own I guess...

does the rx8 have a knock sensor?

Originally posted by Efini 8
does the rx8 have a knock sensor?

yes, IIRC of course.

Originally posted by Quick_lude
I've read your other post explaining why you will do this and I guess for your situation 87 will do. But I don't understand the money saving motivation. Unless you drive 1000 miles a week, with the cheap cost of gas in the US, how much $ can you really save? :confused: $10 a week? Pittance. I just don't see the point of buying a sports car and detuning the engine right away with lower octane gas. Also don't forget the Renesis is a high compression engine and I'm sure the premium will work much better than the regular. To each his own I guess...

Let's take the emotion out of it and look at the facts. One, 87 octane (R+M)/2 falls within the recommended fuel by the manufacturer. Two, it does no harm to the car. Three, at most I will give up 2-3% of performance. Let's say I'm down to 240 HP. My question remains: So what? I just unloaded a Honda minivan with 140 HP and more curb weight than the 8. I am so far ahead of the power equation it isn't funny. Call me frugal, I don't buy stuff I don't want or need. I want the 8, but I don't need the extra gas bill and I will gain nothing from it. Why should I spend $30-40 more per month to satisfy a non-requirement? If you got $30-40 per month you'd like to fritter away I'll give you my PayPal address and you can set up a monthly deposit to my account. I'll add that to the money I'm saving on gas and I can do something with an extra $70-80 per month. I'm enjoying the car as-is and I don't need to spend extra money to demonstrate my macho. I didn't buy the appearance kit for the same reason. One could argue, why buy a $30,000 and not spend a little more on the appearance kit? My answer: It's all window dressing and I'm just not into that. The car, even with this minor reduction in performance, far exceeds my expectations in just about every way. I'm a happy camper.

Originally posted by 8_wannabe


Let's take the emotion out of it and look at the facts. One, 87 octane (R+M)/2 falls within the recommended fuel by the manufacturer. Two, it does no harm to the car. Three, at most I will give up 2-3% of performance. Let's say I'm down to 240 HP. My question remains: So what? I just unloaded a Honda minivan with 140 HP and more curb weight than the 8. I am so far ahead of the power equation it isn't funny. Call me frugal, I don't buy stuff I don't want or need. I want the 8, but I don't need the extra gas bill and I will gain nothing from it. Why should I spend $30-40 more per month to satisfy a non-requirement? If you got $30-40 per month you'd like to fritter away I'll give you my PayPal address and you can set up a monthly deposit to my account. I'll add that to the money I'm saving on gas and I can do something with an extra $70-80 per month. I'm enjoying the car as-is and I don't need to spend extra money to demonstrate my macho. I didn't buy the appearance kit for the same reason. One could argue, why buy a $30,000 and not spend a little more on the appearance kit? My answer: It's all window dressing and I'm just not into that. The car, even with this minor reduction in performance, far exceeds my expectations in just about every way. I'm a happy camper.

well said

From that paragraph in the manual it sounds like the 8 is equipped with a knock sensor.

However I don't know if challenging the knock sensor to work its hardest is what you want to do all the time. First off, it's a reactionary device which will retard timing after it detects vibration from pre-detonation. Of course any actual long-term damage threat of constantly using 87 would depend on things like how sensitive the KS is, and how exactly the ECU remembers and changes ignition timing over a period of car shut-offs, etc.

Second off, my somewhat limited experience with researching knock sensors is that over time they can become a finicky sort, where it's hard to tell if they're actually failing in conjunction w/other sensors in the car...and can be hard to test due to location...so they can wrongfully retard performance sneakily with the driver (at that time with mileage on the car) having a lot of possible causes for the performance degredation. Of course, you can by-pass the sensor with a resistor mod, etc, but my point here is, making it work more often isn't going to help out on longevity.

But if you're always running 87 you won't notice anyway :) Personally I'm w/quicklude, I dunno why you'd buy a smooth, high-revving machine just to retard it to 85% or something.
Even if you're not driving around at 9k all day every day, that still seems like just as much a relative 'waste' as the $ spent on premium.

Bliz81 is right. You don't rely on the knock sensor. It wasn't designed as a tuning device, it was designed to help protect the engine in the event that something is wrong.

---jps

Originally posted by blizz81
From that paragraph in the manual it sounds like the 8 is equipped with a knock sensor.

However I don't know if challenging the knock sensor to work its hardest is what you want to do all the time. First off, it's a reactionary device which will retard timing after it detects vibration from pre-detonation. Of course any actual long-term damage threat of constantly using 87 would depend on things like how sensitive the KS is, and how exactly the ECU remembers and changes ignition timing over a period of car shut-offs, etc.

Second off, my somewhat limited experience with researching knock sensors is that over time they can become a finicky sort, where it's hard to tell if they're actually failing in conjunction w/other sensors in the car...and can be hard to test due to location...so they can wrongfully retard performance sneakily with the driver (at that time with mileage on the car) having a lot of possible causes for the performance degredation. Of course, you can by-pass the sensor with a resistor mod, etc, but my point here is, making it work more often isn't going to help out on longevity.

But if you're always running 87 you won't notice anyway :) Personally I'm w/quicklude, I dunno why you'd buy a smooth, high-revving machine just to retard it to 85% or something.
Even if you're not driving around at 9k all day every day, that still seems like just as much a relative 'waste' as the $ spent on premium.
Well said.

Originally posted by Sputnik
Bliz81 is right. You don't rely on the knock sensor. It wasn't designed as a tuning device, it was designed to help protect the engine in the event that something is wrong.

---jps
Well said x 2. :)

Besides how do you know the loss of power is 3% only? Once again, if it was my high compression engine I would feed it the 92 octane and not have to worry about the knock sensor compensating for the lower octane.

I don't remember the link but I posted this copy/paste in another thread:

If your car requires high-octane gasoline and you habitually use regular gas because the engine exhibits no sign of knock, you’re outsmarting yourself. Most modern, computer-controlled engines include a knock sensor that detects knock and retards the ignition timing, causing the spark plugs to fire slightly later in the cycle. This typically prevents abnormal combustion and knock, which allows vehicles specified for premium fuel to run on lower-grade gasoline if it is all that’s available. While this removes the immediate hazard, it’s a bad idea to make a habit of running a vehicle on gasoline of lower-than-recommended octane. Retarding the spark causes a richer fuel/air mixture, which decreases fuel economy, increases emissions, causes the engine to run hotter, and reduces the longevity of both the engine itself and the catalytic converter. The money you save by pumping low-grade fuel into a car that demands higher octane is lost anyway, in decreased fuel economy and possibly gradual damage.

Wow, all of these high powerd discussions of fuel octane make me giddy. I have a Honda Van that recommends premium and I will run whatever suits my fancy at the time I fill up. Nearly 70 thousand miles and no problems yet.

I must say that with the recent reports on this car being tested out on a dyno at a horsepower loss of 29% at the wheel and then they are recommending premium fuel I am thinking real hard about waiting for something a little bit better. If I am going to use premium, I should be getting better performance than this engine has so far demonstrated. I know it is early but I take delivery in late August and if the news doesn't get better I might spend 30 grand on something with a little more uuumph than this thing has. The difference in cost is not the issue, it is a car that as we find out more and more, just is not cutting it!!!

Jury is still out.:(

As you said commentator; "the jury is still out". It all depends on what you are looking for. I think this car is cutting it and exceeds my every desire. No car is perfect, but if you want a tight looking car with fairly good performance, the 8 has it. If you want mad power, then get and Evo or something (though I can't stand there looks). As for wannabe, hey man, it's your car. You put whatever you darn well please in it. I seriously doubt running it from time to time on a lower grade fuel is going to end the world or your car. Maybe give it premium once a month as a treat?! :D

Folks, I know most of you ain't agonna like this, and I was almost convinced from your discussion of knock sensors and delayed timing on the octane issue. For those of you who took the time to really explain the mechanics (as opposed to responding from sheer emotion) I thank you. I am certainly better educated now than I was. Not ready to concede yet, I sent an inquiry to Mazda over the weekend about fuel grade for the 8. They just sent the following reply:

"Thank you for contacting Mazda North American Operations. I appreciate the opportunity to respond to you.

Mazda does recommend 91 octane gasoline for the 2004 Mazda RX-8. Because the rotary engine is a high performance engine it has been determined 91 octane gasoline will provide the best performance for this vehicle. 87 or 89 octane gasoline will not cause engine damage, but please keep in mind it will not provide the best performance and could cause engine noise. The type of gasoline you use should not affect the gas mileage the vehicle will get.

Again, thank you for contacting Mazda. It has been my pleasure to assist you. If for any reason this response has not completely
satisfied you, please feel free to reply to this message. You may also contact our Customer Assistance Center toll-free at 1-800-222-5500.

Please take a moment of your time to give us your opinion about our e-mail service. Click the link below to complete a brief, online
survey.

Regards,

Heather Drake
Specialist, Customer Assistance E-Business"

The subject line of this response had some kind of code: KMM113833V95443L0KM. So there you have it: No damage, no decrease in mileage, but yes a decrease in performance. I am gratified that they answered exactly what I asked. Second, I'm gonna take 'em up on it and post my results. After a another tank of 91, I will shift to 87 and let y'all know what I think. Of course, if I ever do hear "engine noise" I will go up a grade permanently.

My driving style is moderate. I am being told by local rotorheads to keep the RPMs low, around 4000, except of course when I want to kick butt. Shifting guidelines in the owners manual tend to confirm that. I've not yet had it above 7000, though some have said to redline it periodically (after break in) to clean out deposits. My point is, it's not in my nature to try to milk every last horsie from this engine so I really won't miss the power delta from lower octane. I know this is troubling to some of you, but it makes perfect sense to me. Happy cruising and I'll let you know how it all works out.

Originally posted by Quick_lude
If you can afford this car, you should be able to afford premium gas. End of story.
Well after affording the car I can't afford the gas...:p


The owner's manual says basically the same thing the above E-mail says.

Originally posted by TJRX8
Well after affording the car I can't afford the gas...:p

The owners manual says basically the same thing the above E-mail says.

Thank you, TJRX8, for stating that so succinctly. I feel so validated! You're right, the owners manual does say that but if you read the sometimes emotional thread many people just don't want to believe. They got me concerned enough that I decided to go right to the source.

Originally posted by 8_wannabe

Thank you, TJRX8, for stating that so succinctly. I feel so validated! You're right, the owners manual does say that but if you read the sometimes emotional thread many people just don't want to believe. They got me concerned enough that I decided to go right to the source.
No problem. After going through 2 1/2 tanks of gas in less than 400 miles I'm thinking of going to Regular every now and then.

If your knock sensor is ever used, i suspect you wont have a motor anymore. Rotarys greatly dislike detonation. I suspect mazda recommending 91 octane is to cover there backside. 89+ NA rx7's were 9.7 to 1 compression, and ran 87, i fail to see how a .3 increase in compression matters that much. Also its VERY hard to get a NA rotary to detonate. Such abuses as turning the crank angle sensor twards advance, untill the engine stumbles a little at idle, then backing it off a tad and leavign it like that have been documented without detonation in the second gens(not recommended).

I see a thread like this on every car site I visit. Here's a good FAQ (http://www.seansa4page.com/resource/octane.html) on Automotive Gasoline. Well worth the read.

Bottom line is, engines make the most power using the fuel for which they are tuned. My GSL-SE was tuned for 87 octane and it never made a single extra hp on 93 octane. Higher octanes do not magically carry extra power ... they simply make using a higher state of tune safer. This is one of the reasons why the JDM versions of many engines are more powerful: they are tuned for Japan's higher octane fuels.

Run your 8 on whatever you want. It won't blow up on 87 and it will get a bit more power from 91, because the ecu can take advantage of it. Good times.

Hmmm... let me gather up the facts here and form up some sort of logic here:

-So if we choose to use lower grade fuel, the performance of the engine will decreases.

-Performance decreases because the ECU retards the engine timing to prevent knocks.

-The ECU retards the engine timing because it detects knocks in the engine through the engine knock sensor.

-The ECU would periodically go back and use the default optimal timing just in case you start using High Octane fuel once again for the engine.

So..... that means if we are using a lower grade of fuel, the ECU will use the Optimal Timing until it hear a *knock* in the engine, then it will slow down the timing. But then once in a while (don't know how often) it will just check to see if you are using its recommendated High Grade fuel again by setting the timing back its Optimal setting. Since we still using Lower grade fuel, engine will *knock* again, and the timing will be adjusted back to the slower setting again.

So what I'm seeing here is that, by using a lower grade fuel we are actually letting the engine continue to have *knocks* over and over again while the ECU periodically check to see if it can advance the engine to the most optimal timing ??!!!

That's nuts !!! We know knocking is bad for an engine and EXTREMELY bad for the Apex Seals in a Rotary Engine. No way in hell we should allow our engine to get "knock" around all the time and every time when we step on it.

I dunno man, but since Mazda acknowledge the fact that performance will decrease with a lower grade of fuel, and that means some knocking will occur when you drive it, that's good enough of a reason for us to stay away from lower grade fuel.

(if they say no difference in performace, then that's a different story)

Allow me to quote the Mazda rep's email from earlier in the thread:

87 or 89 octane gasoline will not cause engine damage, but please keep in mind it will not provide the best performance and could cause engine noise.

The threshold between optimum performance and pre-detonation is more than 4 octane points. How low do you have to go before you see knocking? We don't know. 87 is safe according to mazda, so don't be afraid of using it. Decide for yourself if the difference in performance is worth the $2.50 or so per fillup difference in price.

When the turbo kits arrive, even 91-93 won't be enough ... you'll see more threads on toluene and xylene and water injection. For now, enjoy the fact that your gf or wife could fill up your car with 87, against everything you've told her, and it wouldn't be the end of the world.

I'd love to see a dyno of 87 vs 91, i bet there would be no differance. As far as im concerned the ecu has no way of telling what kind of gas you put in it. If it used knocks to tell, mazda would have LOTS of engines to replace real fast. Mazda woldnt do that again (learned from 3rd gen hopefully). I really think mazda is just covering there behind, knowing that if your putting 91 in it and you get a bad tank of gas, say 1-2 octane points lower then spec, the motor is still well withing its safty net, where as a bad tank of 87 could push it a little. They know that by saying 87 "reduces performance" that most people will use 91+, thus less chance of damage from a bad tank gas, thus less warrenties they have to make good on.

Thanks, 86rx7. My feelings exactly. If you read back through this thread I've been the antagonist all along, but I don't have the technical background to put my feelings into words. You've captured what I suspected all along was the truth. Mazda is just covering their 6, as they say.

Good story in USA Today entitled "Why use premium gas when regular will do?" (http://www.usatoday.com/money/autos/2003-07-30-premiumgas_x.htm).

More fuel for the fire, so to speak.

Some extracts: "Engines designed for regular fuel don't improve on premium and sometimes run worse. And today's engines designed for premium run fine on regular, too, their makers say, though power declines slightly."

"'I personally use regular even though my owner's manual says you'll get better performance with premium,' says Lewis Gibbs, 45-year veteran at Chevron oil company. He's chairman of Technical Committee 7 on Fuels, part of the Society of Automotive Engineers (SAE) Fuels & Lubricants Council. Gibbs knows gas."

"The main advantage of premium is that it allows automakers to advertise a few more horsepower by designing and tuning engines to take advantage of premium's anti-knock properties. But auto engineers generally agree that if you use regular in a premium engine, the power loss is so slight, most drivers can't tell."

"Burning regular when the owner's manual specifies premium won't void the warranty, nor damage the engine, even the most finicky automakers say. "You're giving up perhaps just a little bit of performance that a customer wouldn't really even notice, it's so slight," says Furey. Some auto engineers estimate that power declines roughly 5%."

Originally posted by 8_wannabe
"You're giving up perhaps just a little bit of performance that a customer wouldn't really even notice, it's so slight," says Furey. Some auto engineers estimate that power declines roughly 5%."

So by using regular I'm losing aproximately 12 hp (5% of 247). To me that's a HUGE loss.

Originally posted by neit_jnf
So by using regular I'm losing aproximately 12 hp (5% of 247). To me that's a HUGE loss.

That's why it's such a personal choice. To me, the 12 HP is utterly inconsequential.

I think I'll start putting in regular save the $120-$150 per year and move up from milk and crakers for lunch to PBJ sandwichs. Have to contend w/the triple regestration fees in CA! Plus the SF Bay Area has the highest gas prices in the USA.

spoken like a true (bay area)californian

Originally posted by antman_x
I think I'll start putting in regular save the $120-$150 per year and move up from milk and crakers for lunch to PBJ sandwichs. Have to contend w/the triple regestration fees in CA! Plus the SF Bay Area has the highest gas prices in the USA.
Haha.. you wouldn't last 5 min in Europe.

Originally posted by 8_wannabe


That's why it's such a personal choice. To me, the 12 HP is utterly inconsequential.
Then why don't you buy the low power version and lose some more "inconsequential" horsepower? The saving on the purchase price would pay for all your fuel for the next year or two at least.

Here in the UK we have a choice between Premium (95 RON) and Super (97/97 RON). Super costs the equivalent of 25c per (US) gallon extra. But if the difference is 12 hp I'll pay it.

Originally posted by ChrisW
Then why don't you buy the low power version and lose some more "inconsequential" horsepower? The saving on the purchase price would pay for all your fuel for the next year or two at least.


Because in America you can only get the low-power version with automatic transmission, and I want stick.

Look, 238 hp is enough for me; why do so many folks here feel compelled to impose what they want on others? Can we not realize and accept that many of us have different priorities, and that for each of us the RX-8 gives us what we want? I've put 200 miles on the car with 87 in the tank and I utterly cannot tell the difference. Maybe some of you could. Some people can tell great wine from good, some can't and furthermore they don't care. Some audiophiles can tell superb audio quality from ordinary; others can't and don't care. Let's not try to mold each other into model images of one another; there's room enough here for all of us. Celebrate the differences! (and no, I'm not gay.) ;)

Originally posted by 8_wannabe
Look, 238 hp is enough for me; why do so many folks here feel compelled to impose what they want on others? Can we not realize and accept that many of us have different priorities, and that for each of us the RX-8 gives us what we want? I've put 200 miles on the car with 87 in the tank and I utterly cannot tell the difference.
Sorry, it was probably a bit of cheap shot, but I just couldn't resist :D.

I still think it's irrational to spend all that money on a high performance car and then and then compromise the performance to save a tiny amount of money. But then with the price of fuel over here I may well be just as irrational the other way - I am probably paying out way too much for hard to detect performance imcreases.

Originally posted by ChrisW
I still think it's irrational to spend all that money on a high performance car and then and then compromise the performance to save a tiny amount of money. But then with the price of fuel over here I may well be just as irrational the other way - I am probably paying out way too much for hard to detect performance imcreases.

It's all a matter of expectations. Most people who are disappointed in the RX-8's performance are coming from other high-performance cars and have high expectations. I'm coming from a Honda 4-cyl minivan with 140 hp and more curb weight than the 8, so to me this thing just kicks butt, even with slightly reduced power. I'm a happy camper.

As to getting what you pay for, what's under the hood is just part of the equation. I find the design of the total car so appealing that's it's worth the price. Besides, look at bragging rights: Of all the people who have admired my car (I've given over 100 "tours" of the car by now) maybe 20% understand what a rotary engine is. After I explain it, they still ask "So is that 6-cylinder or a 4-banger?" And no one asks what kind of gas I'm putting in. My point is, this car has a wide appeal and that goes for people with zero understanding of engine mechanics. Maybe calling it irrational is not too far off the mark -- It has a visual appeal that goes to our baser instincts. It looks fast even while sitting at the curb. Zoom zoom!