wrong gas
03-16-11 | 11:22 AM
#27
This is exactly how I read it. Replacing the stock exhaust with aftermarket parts no longer makes the car stock.
Unfortunately even a small boost spike can lead to detonation without proper fuel modifications.
Unfortunately even a small boost spike can lead to detonation without proper fuel modifications.
Last edited by RotaryRocket88; 03-16-11 at 11:25 AM.
03-17-11 | 09:57 PM
#34
so heres an update car actually got about 50miles more out of the tank with the mixed gas. only prob now is ive been overboosting for a bit and today i gave it a little to much pedal in third and ping ping boom. now i need a rebuild sucks *** to beacuse this motor only had about 30k on the rebuild now. :0(
i was reading this and reading all the shitty replies hoping i could get in a response before something such as this happened.
i have thoroughly tested the US market gas grades in rotary applications and 87 octane is only good for about 8 psi of boost before you will start noticing alarming amounts of knock from the engine. add in the variable of mixed gas unknowns and it was a bad idea to push even stock boost levels on a car with freeflowing exhaust.
i tested the values due to commuting about 150 miles per day to save on fuel as it was about $4/gallon during the start of the war several years back. now that fuel price is standard but i have no choice in low grade fuels as i now have about twice the horsepower as i did then.
even with 91 octane it will buy you a bit more knock resistance but the AFRs from the stock fuel system will generally start to lean out at around 10psi, just an FYI. if you were pushing 8+ psi on 87 then bad idea, if you were pushing more than 10psi on the stock fuel system, also bad idea. combine the 2 and you have a guaranteed dead motor.
i have even had customers lie to me, claiming to run 91 octane. when i could audibly hear their engine detonating at 9-10psi i could tell them otherwise.
Last edited by RotaryEvolution; 03-17-11 at 10:06 PM.
03-17-11 | 10:31 PM
#35
talking head
Joined: Apr 2008
Posts: 2,775
Likes: 14
From: Perth, WA, OZ
man....
i was reading this and reading all the shitty replies hoping i could get in a response before something such as this happened.
i have thoroughly tested the US market gas grades in rotary applications and 87 octane is only good for about 8 psi of boost before you will start noticing alarming amounts of knock from the engine. add in the variable of mixed gas unknowns and it was a bad idea to push even stock boost levels on a car with freeflowing exhaust.
i tested the values due to commuting about 150 miles per day to save on fuel as it was about $4/gallon during the start of the war several years back. now that fuel price is standard but i have no choice in low grade fuels as i now have about twice the horsepower as i did then.
even with 91 octane it will buy you a bit more knock resistance but the AFRs from the stock fuel system will generally start to lean out at around 10psi, just an FYI. if you were pushing 8+ psi on 87 then bad idea, if you were pushing more than 10psi on the stock fuel system, also bad idea. combine the 2 and you have a guaranteed dead motor.
i have even had customers lie to me, claiming to run 91 octane. when i could audibly hear their engine detonating at 9-10psi i could tell them otherwise.
i was reading this and reading all the shitty replies hoping i could get in a response before something such as this happened.
i have thoroughly tested the US market gas grades in rotary applications and 87 octane is only good for about 8 psi of boost before you will start noticing alarming amounts of knock from the engine. add in the variable of mixed gas unknowns and it was a bad idea to push even stock boost levels on a car with freeflowing exhaust.
i tested the values due to commuting about 150 miles per day to save on fuel as it was about $4/gallon during the start of the war several years back. now that fuel price is standard but i have no choice in low grade fuels as i now have about twice the horsepower as i did then.
even with 91 octane it will buy you a bit more knock resistance but the AFRs from the stock fuel system will generally start to lean out at around 10psi, just an FYI. if you were pushing 8+ psi on 87 then bad idea, if you were pushing more than 10psi on the stock fuel system, also bad idea. combine the 2 and you have a guaranteed dead motor.
i have even had customers lie to me, claiming to run 91 octane. when i could audibly hear their engine detonating at 9-10psi i could tell them otherwise.
even though i dont experience your fuel grades i gave my warning on what i think of an 86 combined RON/MON
and left it to the OP to prudently keep out of it while on the low octane
when i was in colledge i had a lecturer explain exactly what happens when you blend two octanes to a perfect 50/50 ratio
the result is not as expected,, and the discussion on the matter was lively
( i will point out this bloke was teaching us the petroleum industry processes )
i was at that point advocating what you wrote,, but apparently it is not so ,, and the reasons complicated
( something to do with hydrogen bonding / van der waals ratios )
for the OP,, it will not matter that much,, drive it for a short distance conservatively ,, and refill with your normal choice
where i am in western austraila,, octane is rated in RON ,, and so the numbers don't co-relate with your grades
-- however,, on any aftermarket tuned rotary,, using the standard 91 RON
( about 86 combined ron/mon )
can be engine lethal in hot ( 100 F + ) conditions
here,, the better tuners tune for 8/10's cause the petrol quality from the pump can vary in hot conditions
- pulling 2 degrees out of the optimum timing is considered normal practice
the result is not as expected,, and the discussion on the matter was lively
( i will point out this bloke was teaching us the petroleum industry processes )
i was at that point advocating what you wrote,, but apparently it is not so ,, and the reasons complicated
( something to do with hydrogen bonding / van der waals ratios )
for the OP,, it will not matter that much,, drive it for a short distance conservatively ,, and refill with your normal choice
where i am in western austraila,, octane is rated in RON ,, and so the numbers don't co-relate with your grades
-- however,, on any aftermarket tuned rotary,, using the standard 91 RON
( about 86 combined ron/mon )
can be engine lethal in hot ( 100 F + ) conditions
here,, the better tuners tune for 8/10's cause the petrol quality from the pump can vary in hot conditions
- pulling 2 degrees out of the optimum timing is considered normal practice
03-18-11 | 01:11 AM
#36
ya it was a combo of the two i had already been having overboost issues when i ran 91 but then i had the 87 mix in there and was behind a slow driver got impatient and gunned it and boom but eh you live and learn. so does anyone reccommend a rebuild kit. i was looking into super seals. also can i run the a factory ecu with a street port not going for any huge hp numbers just a fun daily. thinking of also upgrading the injectors to some 720's of course the fuel pump and def that fcd. eventually gonna get the rtek and a bnr but prob not till next tax season.
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