will 317s on Ls1 allow for 87 octaine?
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will 317s on Ls1 allow for 87 octaine?
I have an opertunity to buy some ported 317s (unmilled) for my Ls1 that im putting in my ford ranger. The truck is my DD and if i can drop the CR enough to use 87 it would all be worth it to me. I log a **** load of miles on my truck and to some it may sound stupid, but hey it all adds up over time. thanks
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If you don't plan to beat on it, running 87 octane on a lightly loaded ls1 will not hurt a thing. Even if you do push it some, the stock ECM will have high & low octane spark tables to save you from detonation.
I would not lower your compression in the quest for economy. It could actually cost you a MPG, and you aren't likely to see any return on your investment for the cost of the heads.
I would not lower your compression in the quest for economy. It could actually cost you a MPG, and you aren't likely to see any return on your investment for the cost of the heads.
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Yeah the lack of compression will reduce efficiency and mileage, so your gains at the pump might not be justified. A 10.9:1 LS2 can be ran fine on 91, so your 10.1:1 LS1 does not need any lower compression, and a set of ported 317s will lower that into the 9s and make your car feel like a dog down low. It will take more throttle to keep the car going at a steady rate of speed thus negating any savings you might get from buying cheaper octane.
I prefer a higher compression engine that may need 91 but will get better mileage due to the better efficiency.
If anything, tune for the lower octane but keep the higher compression for better efficiency.
I prefer a higher compression engine that may need 91 but will get better mileage due to the better efficiency.
If anything, tune for the lower octane but keep the higher compression for better efficiency.
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Yeah the lack of compression will reduce efficiency and mileage, so your gains at the pump might not be justified. A 10.9:1 LS2 can be ran fine on 91, so your 10.1:1 LS1 does not need any lower compression, and a set of ported 317s will lower that into the 9s and make your car feel like a dog down low. It will take more throttle to keep the car going at a steady rate of speed thus negating any savings you might get from buying cheaper octane.
I prefer a higher compression engine that may need 91 but will get better mileage due to the better efficiency.
If anything, tune for the lower octane but keep the higher compression for better efficiency.
I prefer a higher compression engine that may need 91 but will get better mileage due to the better efficiency.
If anything, tune for the lower octane but keep the higher compression for better efficiency.
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In the back of my head i thought something along those lines might be an issue. I will have to dyno tune the engine for sure, im gonna cam it (228 on .580ish lift), Ls6 intake, ported TB, custom LTs, full exhaust, no cats, and cold air intake. I could have the tuner pull a little timing out of it just to be safe. Then again, if i see a dramatic drop in HP, maybe 91 isnt such a bad idea for the extra .12 cents a gallon, lol.
If you want to make horsepower, settle for a 91 octane tune and cough up the extra $2.00 or so per tank. If that's going to break you, forget the performance parts, or just stick to bolt-ons and forget the cam.
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Wild truck!
Is the front track as wide as the pictures make it look? It looks 15% wider than the rear...
Is it stable at freeway speeds?
What is tire life on that set up?
That critter deserves the late 6.2 truck engine...
Maybe with cylinder deactivation if you were really looking for FE.
I'm not a Ranger fan but that one is truly tough looking...
Is the front track as wide as the pictures make it look? It looks 15% wider than the rear...
Is it stable at freeway speeds?
What is tire life on that set up?
That critter deserves the late 6.2 truck engine...
Maybe with cylinder deactivation if you were really looking for FE.
I'm not a Ranger fan but that one is truly tough looking...
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dont get me started on my 2300lb Ls1 pt88 RX7
Last edited by Hi Volume; 02-12-2012 at 08:30 AM.
#18
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Wild truck!
Is the front track as wide as the pictures make it look? It looks 15% wider than the rear...
Is it stable at freeway speeds?
What is tire life on that set up?
That critter deserves the late 6.2 truck engine...
Maybe with cylinder deactivation if you were really looking for FE.
I'm not a Ranger fan but that one is truly tough looking...
Is the front track as wide as the pictures make it look? It looks 15% wider than the rear...
Is it stable at freeway speeds?
What is tire life on that set up?
That critter deserves the late 6.2 truck engine...
Maybe with cylinder deactivation if you were really looking for FE.
I'm not a Ranger fan but that one is truly tough looking...