Supra Forums banner

Mixing gas - How to calculate octane?

4K views 11 replies 6 participants last post by  Twin Turbo 
#1 ·
Hellooooooooo,

I usually only run 112 octane gas in my car and i was thinking about mixing in some 93 for the winter since i wont be doing any high boost stuff with the cold weather. Since my low boost setting is 23lbs i will need enough octane to cover that. Straight 112 is overkill since i've run 32lbs on that gas fine.

The 112 is as follows
Antiknock Index (R+M)/2 - 112
RON, Research Octane - 114
MON, Motor Octane - 110

I'm wondering how much 93 octane pump gas i can mix in to be save for the boost im running. I'm thinking maybe 3/4 112 and 1/4 93, anyone know what the 93 octane stats are? :scratch:

:)
 
#3 ·
HotSoup said:
110+93=203/2=101.5 50/50 mix that should be enough for the boost you want to run.

Jason

Are you sure 93 octane has a MON of 93?

Im not sure 101octane is enough for 23lbs, might have to datalog it some to watch for knock.
 
#4 ·
From logging timing on my '97 T78 car I've found that 100 MON is sufficient for around 25psi (~600rwhp). This is with leaded high octane pump mix. In addition, I've found that a leaded/pump mix performs better then the equivalent MON unleaded/pump mix.

I'd watch your knock sensors since you have that capability though.
 
#7 ·
StokerSix said:
From logging timing on my '97 T78 car I've found that 100 MON is sufficient for around 25psi (~600rwhp). This is with leaded high octane pump mix. In addition, I've found that a leaded/pump mix performs better then the equivalent MON unleaded/pump mix.

I'd watch your knock sensors since you have that capability though.

Thanks! Im still trying to find the MON of 93 pump gas. :)
 
#10 ·
Mad TKD said:
you should be able to do do 1/2 tank 110 and 1/2 pump for 23 easy. I run that sometimes with mine no problems.

Ok good! Im actually running 112 octane (110 MON).
 
#11 ·
HotSoup said:
110+93=203/2=101.5 50/50 mix that should be enough for the boost you want to run.

Jason
i dont mean to steal the thread but i've been wanting to ask you this for a while now, what gas are you running??? whats your mods??? how much psi and whats your #'s????
 
#12 ·
dyno #'s i mean with mixed gas and with just 93
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top