Which octane to use @ 10psi?
#1
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Which octane to use @ 10psi?
S4 TII engine pushing 10psi stock otherwise from FCD, Full RB Turbo-back exhaust and ported wastegate.
What octane should I be running?
(searched, did not find straight answer)
What octane should I be running?
(searched, did not find straight answer)
#2
97 pump gass. and if i were u i would look into atleast a fd fuel pump if not that and some time of fuel mang cause i dont think ur motor will last to long runin 10 psi without it, but thats just me. good luck
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To get the same AFR with ethanol blend you need to inject more gas volume. This will result in leaner afr values if you use a fuel map designed for pure gasoline. This may be a factor if you are pushing the limits of the stock fuel system/computer.
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Originally Posted by nik
To get the same AFR with ethanol blend you need to inject more gas volume. This will result in leaner afr values if you use a fuel map designed for pure gasoline. This may be a factor if you are pushing the limits of the stock fuel system/computer.
Thanks, I'll switch to 91 octane with no ethanol.
#10
mazda recomends 87 octane for stock rx7's. any higher octane on a stock rx7 is just wasting money, fuel and lower power. 91 is fine for modified 7's depending on how much boost you have. at 10psi 91 octane will do just fine.
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I would recommend even a stock T2 should run 91. The (stock)cars have a knock detection box and will pull timing if you get some knocking, which would translate to lost power.
#15
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Originally Posted by nik
All the more reason to run 91 , then again, detonation lives at low rpm, so maybe it's meant to be that way.
Last edited by R_PROWESS; 11-04-06 at 08:38 PM.
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Originally Posted by keithrulz
well my understanding is it only happens severly enough to cause damage in boost and normaly you don't even enter boost until 3k rpms or higher depending on your setup. we all know you dont blow apex seals unless you are in boost. boost is where we are most vulnerable and thats exactly where the knock sensor stops working
Also I am interested how you determined the knock sensor stops working above 4000rpm?
#21
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Originally Posted by rogrx7
I heard that the 7 was designed for 87 use and that a higher octane will promote carbon buildup.
actually N/A's were designed around 80 octane, but since you cant find it anywhere, 87 will have to do for N/A's and like everyone else explained, with a turbo setup like you'res 91 - 93 octane will be fine, as this is the highest you can find at most pumps
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Originally Posted by rogrx7
Meh.
Carbon equals pre-ignition which can turn to detonation.
Carbon equals pre-ignition which can turn to detonation.
A car with functional closed loop O2/proper tuning (which the stock EFI should have both) and correct heat range plugs will not have significant carbon-build up problems.
#23
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Just redline it once a week and you wont get carbon buildup.
Also tournapart, you think the stock fuel pump is good enough for 10 psi, thats what i run on my 88 TII, stock turbo, and I was told on here to get a walbro 255 pump, so thats what i got along with the rtek 1.7 which makes me run 720cc secondaries, so your saying that the 255 is too much?
Also tournapart, you think the stock fuel pump is good enough for 10 psi, thats what i run on my 88 TII, stock turbo, and I was told on here to get a walbro 255 pump, so thats what i got along with the rtek 1.7 which makes me run 720cc secondaries, so your saying that the 255 is too much?
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The Walbro 255 will over run the stock fuel pressure regulator. I would go with an FD fuel pump. The FD pump flows 15%-20% more than the stock turbo pump and will not over run the stock FPR. This will be a great set up for your 720's and Rtek 1.7 ecu.
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Originally Posted by keithrulz
well my understanding is it only happens severly enough to cause damage in boost and normaly you don't even enter boost until 3k rpms or higher depending on your setup. we all know you dont blow apex seals unless you are in boost. boost is where we are most vulnerable and thats exactly where the knock sensor stops working
not true, i run full boost in fifth at 2000 rpm if i floor it