ludedude1995

Whats up guys.

I have a 1986 RX7 with a N/A street ported 13b in it. Dual exhaust and intake.

Should i be running 87, 89, or 93 octane in it for optimal performance. The previous owner claims 93 makes it run better...but i dunno i went down to 89 and it seemed to pull harder.

Any suggestions?

No_love_for_pistons

iTrader: (4)

I'm not an n/a guy, but from what I've read, go with the lowest octane. 87 should do it for you.

ludedude1995

Yeah thats what ive read from researching on here but i didnt know since it was a street ported 13b

Turbo II

iTrader: (1)

From what I understand the only reason to run higher octane is to prevent detonation.

LargeOrangeFont

iTrader: (7)

I have an 86 street ported NA, and it seems to run better with 87.

RotorBalls

iTrader: (1)

Before I knew anything about rotaries I tried race octane and it really didn't do **** for the car. I'd go with the cheap stuff

MMoore4545

iTrader: (7)

yeah man
87 is all you need.
drove on both 87 and 89
and there isn't a difference, maybe a very slight MPG difference on the highway
but for daily stuff
notta. Atleast on the N/A motors

importtuner137

Is it the same thing for TII engines?

Turbo II

iTrader: (1)

The manuals for both the NA and Turbo models say 87 octane. The reason a lot of us run higher octane is to prevent detonation on cars that are moderately modded. There is no power benefit in running higher octane.

ludedude1995

Sweet so 87 it is for my street ported 13B....let me tell you...there was 93 in the tank when the previous owner sold it to me....i ran it all out and filled the car up with lower octane and the car definitely hauls out better!

Evil Aviator

The porting, exhaust, and intake make no difference. The big factors in octane requirement are the ignition timing and the condition of the engine.

For general optimal performance, just use a Top Tier gas.
http://www.toptiergas.com/

Then the previous owner is either ignorant, he advanced the ignition timing, or he knows the engine is in bad shape and has hot spots.

It's your mind playing tricks on you. The performance difference between the various octane grades of pump gas is insignificant. For example, the energy content difference between Chevron regular and super unleaded is 0.136%, which would not even show up on a $30,000 chassis dyno, let alone your butt dyno.

The octane rating has nothing to do with MPG.

ludedude1995

The previous owner is ignorant....he was under the impression that the higher octane fuel would make the car run better. The motor was rebuilt by KDR Performance 4,000 miles ago!