here in canada too we just go to the airport and fill up on avgas!!! lol

 

in a 2nd gen n/a use regular 97 i believe and then premix!

 

Bad idea on the Avgas if you have cats. No cats, then knock yourself out (just don't tell the EPA I said so )

PaulC

 

Also bad for O2 sensors as I recall. Don't recommend this unless you have a heated 4-wire O2 sensor.

 

Well, in the manual and on the gas tank cap it clearly says "95 Oct Fuel Only", so I guess this is the minimum...

I now put in 96Oct, but I used to use 98Oct, and I DID see a difference (might have been the different gas stations...)

 

in my owners manual of my 87 TII it says use a 91 octane or higher fuel.

 

no 87 - there's no such thing as 97, I think you meant 87

EDIT: I could be wrong about 97, but I never heard of 97...only 87, 90 ( I think) and 93.... hmmm

 

Well it definitely made a difference for my emissions, when I used 94 as opposed to 87. This means that the combustion in my engine is more complete.

Please explain to me why less complete combustion nets the same or more power than more complete combustion, because I am honestly curious to know.

Thank you,

/F/

 

Just to convert that value for the stupid Americans (LOL), 91 RON is roughly 87 PON, which is what you put in your S4 RX-7.

Once again, for the lazy Americans, 95 RON is roughly 91 PON, which is what you put in your S5 RX-7.

Yes, the gas formula also has a lot to do with the power, however the octane rating in itself has absolutely no bearing on power, complete combustion, or any other magical powers. Aromatic additives will add to both power and octane rating, while iso-octane and other additives will raise the octane rating but reduce power. If that 98 octane had benzene in it, for example, you would have seen an increase in power. Unfortunately, the environmentally-conscious Americans will generally not allow aromatics in pump gas, so we are pretty much stuck with the power-reducing octane enhancers.

Please explain to me why you think that the higher octane gave you more complete combustion? I guess that what is difficult for people to understand is that octane is a desensitizer, which basically "waters down" the fuel so that it doesn't detonate as easily.
http://www.ftc.gov/bcp/conline/pubs/autos/octane.htm
http://www.exxon.com/exxon_gas/index.html

 

Good info Evil Aviator.

Thinking back, most concrete evidence supports the idea that higer octane than reccomended does not improve performance. There seems to be a lot of Psychosematic evidence towards the opposite though.

I've been supporting the idea that higher octane than reccomended will not gain performance for quite some time. Then I was challenged by some psychosematic evidence the other day:

I ran out of gas in my Nissan Primera (SR20DE) on the freeway. I happened to have a 32 oz. can of "100 Octane Booster" in my car, so I just poured the whole thing into the tank hoping I could get to a gas station. I drove the car very lightly to get to a gas station, then I added 5 gallons of 91 fuel. When I left the gas station, I drove the car pretty hard and it drove noticeable smoother. I normally use 87 fuel. It's been two days now, and it seems to be driving quite nicely.

The only reason I doubt myself is that I have no concrete evidence to support the smoother feeling. Nor do I have a 100% understanding of the octane system and the effects on combustion. Someone offered an explanation of, "Yeah, they wouldn't have the higher octane available for no reason," but that's a pretty empty support.

I'm going to continue to research this until I can understand the process and number ratings fully. Thanks for the links!

 

Aromatic additives are a whole different story than pump gas. Check out the MSDS sheet on "Go Go Octane Boost" (I love that name, LOL)
http://www.berrymanproducts.com/msds/1516.pdf

There's a lot of high-power suff in there that makes pump gas look pretty lame in comparison. There are many ways to increase the octane rating of a fuel. Most of the "boost in a bottle" additives use more powerful methods to increase the octane rating, as does racing fuel, while most pump gas uses methods which either maintain or reduce the power potential of the fuel. The bottom line is that the octane rating is an anti-detonation rating, and nothing more.

Confused yet?

 

Okay, just because we HAVE higher octane does not mean we NEED to run higher ocatane. We also have 87 and 89 here too!

 

I got a suggestion for your new sig: How about changing it to V6 mustangs and giving credit where credit is due? Any decent 5.0 or 4.6 will beat your listed cars.
You wouldn't respect a geo 3 cylinider saying "objects in mirror? those are NA RX-7's", so why should you be so blasphemous?

Where does all this hate for mustangs come from? Me thinks it is jealousy for their straightline power.

Me? I drive a killer car, but respect mustangs for what they are: Straight line cars. They were never meant to handle (solid rear axle, but Cobra IRS is a step in the right direction), but the perform wonderfully in the straight line.

Modified mustangs are about the only cars I am wary of, and I put 400+ to the tires when drag racing. You are not making near that much, so tell me your secret to keeping in front of them?

Sorry for the rant, but this ignorance and bigotry is pissing me off.

 

Thanks for the post evil Aviator.
That was more of the information I was looking for.

I made the assumption, that since my emissions were higher with 87, (especially the CO), and lower with 94, that the combustion is more complete, as there existed less incomplete products (CO, NO) during my emissions test. (don't know about CO2 NO2, SO2).

I think the key point is that using higher octane fuel that manual recommends won't give you power increase and it's in the formula of the gas.

So what does everyone here use/not use?

/F/

 

Man, this might anger some people, i dont use it cus i got an n/a, but about 45 min south of me the gas stations sell 105 on the pumps,

everyone from southern nh on tehre way to NED buys ther gas along the way i suppose

 

we can get avgas in australia, thats why real fuel is.

 

Yes, too bad we "suckers" don't have any airplanes in our country, otherwise we could also get AVGAS just like you lucky people in Australia.

 

that "corn" gas?

 

I know Sunoco adds 10% ethanol to their gas to raise the octane rating of thier fuel, all the way to 94 for premium.

Is ethanol a power adding octane increaser, or does it also reduce power?

 

how about an 91 n/a with 12 degrees of advanced timing? wouldnt that require more octane so it wont detotonate??

 

We used to put 6 to 8 unscented moth ball in 5 gal. of gas for drag racing. This didn;t leave any deposits on plugs or valves and 30 of them in 5 gal. could pop the head off a V8. In a 4 cyl. chevy prod. It raised MPG by 3 and they were a cheap boost. I haven't used them in my GTU yet. Older now not into that much speed.

 

damn thats low 91 .... in Canada we have 94 and i think Shell has a 96.

or we can just stop at the airplane strip for personal planes and fill up with some 103 or 105 i think.

 

everyone thinks that NAs should use higher octaine for some reason. i dont understand why they come up with this idea. even heavy moded na rotaries dont need that high of octaine.