Octane for high compression. . .
07-06-2008, 07:22 PM
#1
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Octane for high compression. . .
I'll use race fuel if i really have to, but i'd like to be able to use premium (Shell 91 in Canada). . .
Nismo heads and valvetrain, S1 cams (276/256). . . 12:1 CR. . .my original goal was to make 300whp but I don't think i'll be able to at our altitude (2,191.6 FT). . .just going to see how much I can get with what i've got . . .
How realistic/safe would premium be to run with this setup? Would the Nismo VTC pulleys be of any help? This will be a drift/auto-x car but would like to keep it somewhat streetable . ..
Nismo heads and valvetrain, S1 cams (276/256). . . 12:1 CR. . .my original goal was to make 300whp but I don't think i'll be able to at our altitude (2,191.6 FT). . .just going to see how much I can get with what i've got . . .
How realistic/safe would premium be to run with this setup? Would the Nismo VTC pulleys be of any help? This will be a drift/auto-x car but would like to keep it somewhat streetable . ..
07-08-2008, 01:44 PM
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not really. youd just run a little less timing and more fuel. would still make more power than a 10.3:1 engine. but it wouldnt be good for the gas mileage
07-09-2008, 02:10 AM
#7
[QUOTE. .
How realistic/safe would premium be to run with this setup? Would the Nismo VTC pulleys be of any help? This will be a drift/auto-x car but would like to keep it somewhat streetable . ..[/QUOTE]
The VTC pulleys do give a big increase in power in the midrange but you will need a Haltech to tune them unless you have someone in Canada that can suitably reflash the OE ECU.
As Z1 has pointed out "its all in the tuning"
Don't even think about using 12/1 CR with pump gas in a screaming drift motor without tuning.
The OE Ecu is fully retarding the inlet camshaft & is adding up to 40 deg of Ign advance at 6K+ rpm, an instant killer of pistons.
I unfortunatly know this from personal expierance.
How realistic/safe would premium be to run with this setup? Would the Nismo VTC pulleys be of any help? This will be a drift/auto-x car but would like to keep it somewhat streetable . ..[/QUOTE]
The VTC pulleys do give a big increase in power in the midrange but you will need a Haltech to tune them unless you have someone in Canada that can suitably reflash the OE ECU.
As Z1 has pointed out "its all in the tuning"
Don't even think about using 12/1 CR with pump gas in a screaming drift motor without tuning.
The OE Ecu is fully retarding the inlet camshaft & is adding up to 40 deg of Ign advance at 6K+ rpm, an instant killer of pistons.
I unfortunatly know this from personal expierance.
Last edited by Nathan; 07-09-2008 at 03:47 PM.
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07-09-2008, 02:50 PM
#8
Originally Posted by Z1 Performance
it's all in the tuning
I'm not sure of that. My ign timing goes from 15-31 (stock c/r BTW) and I ping occasionally at WOT using 91
. I'm at a lower elevation (1200ft) than the OP. I would think 12 to 1 would require at least 93 or a mix of 91 & racegas.My previous car had a 12.5 to 1 NA build and would run hard on 93 but this was at sea level.
07-09-2008, 02:56 PM
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Originally Posted by Frostydc4
I'm not sure of that. My ign timing goes from 15-31 (stock c/r BTW) and I ping occasionally at WOT using 91 . I'm at a lower elevation (1200ft) than the OP. I would think 12 to 1 would require at least 93 or a mix of 91 & racegas.
My previous car had a 12.5 to 1 NA build and would run hard on 93 but this was at sea level.
. I'm at a lower elevation (1200ft) than the OP. I would think 12 to 1 would require at least 93 or a mix of 91 & racegas.My previous car had a 12.5 to 1 NA build and would run hard on 93 but this was at sea level.
I could write a 87 octane **** gas map if I wanted to for my Z if I wanted to. The car doesn't know what octane you put in - the tune is telling the ecu the whats and whens of the ignition and fuel
Last edited by Z1 Performance; 07-09-2008 at 03:00 PM.
07-09-2008, 03:26 PM
#10
Originally Posted by Z1 Performance
then you're car is not tuned properly. If your car runs at substantial levels above sea level and only on 91, then it should have a conservative tune done on 91
I could write a 87 octane **** gas map if I wanted to for my Z if I wanted to. The car doesn't know what octane you put in - the tune is telling the ecu the whats and whens of the ignition and fuel
I could write a 87 octane **** gas map if I wanted to for my Z if I wanted to. The car doesn't know what octane you put in - the tune is telling the ecu the whats and whens of the ignition and fuel
True. I'm not going to argue with you here.
It is tuned properly but it is not the map I use during the summer (I have another map just for the 110+ summer temps).
The ign tim. map for an 87 oct tune would probably go from 10-25 (at high load).
My answer was based on the OP desire to break 300whp.
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