Eriks85Rx7

I know this has been beaten to death but my reasons for asking are different. 93 octane is supposed to burn cleaner than 87 therefore having clean internals thus extending the life of the car..( you would also have cleaner injectors) but I also heard that the rotary can't burn off 93 all at once and there is excess fuel left over after the combustion stage.

So in the long run which is better to run 87 or 93?
This is just my understanding so please give me your insight thanks!

jjwalker

93 doesn't burn slower, it is just harder to ignite. This is how it prevents spontaneous ignition before the plug fires (pre-ignition).

So basically in your N/A motor, not seeing the high pressure of boost, is a total waste of money.

cluosborne

The rule of thumb in regard to octane for an RX-7 is this:

87-octane for non-turbo
93-octane for turbo-charged

I've run regular fuel (87) in my non-turbo for years with no problems, and it's perfectly fine even with mild modifications such as exhaust and intake.

Icemark

For more power in a stock port non turbo, (or stock boost turbo) go with the lowest octane you can buy 86 or 87 is fine.

Remember the octane level has nothing to do with the BTUs (power) of the fuel, but is instead the amount of resistance to prematurely igniting or detonating. If your non turbo is tuned and running fine, 85 or 86 is all it will ever need and it will run better as well as save you a few bucks at the pump.

87FCna

iTrader: (3)

93 octane feels like it pulls harder in a na rotary

Marshessn

iTrader: (-1)

yeah.... No. It does not.

Icemark

You need to re-calibrate your butt dyno.

jjwalker

His wallet being lighter on one side is throwing the whole thing off.

93rx74lyfe

iTrader: (1)

NAs dont "pull" at all.

mark86

im using 91 pump gas and on cold mornings the car run a lot rougher than if its warm .
Does using 87 octane would minimize this issue

mark86

sorry 1986 rx7 gxl na

Spock

iTrader: (2)

yeah most likely because it doesn't need the 91....stop wasting your money

Evil Aviator

The octane rating is an anti-knock rating, not a cleanliness rating. If you want a clean engine, then use a top-tier rated fuel.
http://www.toptiergas.com/

Totally false.

In the long run, it is better to use whichever grade of fuel that keeps your engine from knocking. If your engine is in good shape, then 87 will work fine. If your engine is in bad shape and has a lot of deposits, then a higher octane rating may make it run smoother. The only significant differences between the various octane grades of pump gas are the anti-knock quality and the price. Just as long as you are using gasoline from a reputable US gas station, there will be no harm to your car regardless of the octane rating. However, if knock is not an issue, then using higher octane is just a waste of money.

If your 91 octane is ethanol-enriched, then switching to 87 octane with less ethanol may help. Simply changing to a different brand may also help if the new brand happens to have a higher vapor pressure. Unfortunately, you never know exactly what kind of mixture the manufacturer uses in their fuel, so you usually need to just shop around and see what works. If your local gas stations happen to post the"RVP" of their gasoline, then the highest number will help cold starting and engine operation below the normal operating temperature.

Evil Aviator

No, the TurboII is rated for 87 just like the non-turbo cars.

Roen

iTrader: (2)

Thread closed; this information can be found in the FAQ of this section.