will 317s on Ls1 allow for 87 octaine?

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Jan 31, 2012 | 10:58 PM

Hi Volume

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From: NoCal

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

Feb 1, 2012 | 02:22 AM

hammertime

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From: Smithton, IL

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.

Feb 1, 2012 | 04:13 AM

bww3588

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From: Chillicothe/Lima, Ohio

More than likely, you will lose fuel mileage, so what little bit you save at the pump each fill up will be negated in number of fill up's.

Feb 1, 2012 | 08:53 AM

redtan

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From: Belmont, MA

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.

Feb 1, 2012 | 09:09 AM

trans_am7935

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From: Glen Burnie, MD

here is an example, my wife's Colbolt is 10:1 compression and regular gas is recommended. it is not just the compression but the timing tables you will have to retard. you can not run as much spark safely with out risk of detonation on regular gas

Feb 1, 2012 | 09:20 AM

smok'nZ

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From: OKLAHOMA

you would be better off getting a tune than buying/installing heads

Feb 1, 2012 | 09:22 AM

Slowhawk

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From: Bridgewater,Ma

Quote:

Originally Posted by smok'nZ

you would be better off getting a tune than buying/installing heads

I agree.87 is no problem if the tune is adjusted for it. You will lose 15-25rwhp with the lower octain gas.

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Feb 1, 2012 | 05:30 PM

Latch

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From: Mechanicsville, VA

Would going the other way - going to higher compression and having it tuned appropriately - improve mileage? This would be on 93 of course. I've always wondered about this.

Feb 2, 2012 | 08:04 PM

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garygnu

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what cam will you be using ?

Feb 2, 2012 | 08:43 PM

#11

hammertime

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From: Smithton, IL

Quote:

Originally Posted by Hi Volume

A cam of that size is going to bleed off some of your compression anyway, and could end up costing you fuel economy as well. You'll have better part throttle performance (and city fuel economy) with more compression to offset what you lose with a cam.

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.

Feb 3, 2012 | 11:53 AM

#12

PREDATOR-Z

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From: BFE

Why own a 8 cyl for fuel economy. Ya'all logic is flawed.

Feb 3, 2012 | 12:28 PM

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01ssreda4

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From: Turnin' Wrenches Infractions: 005

Quote:

Originally Posted by PREDATOR-Z

Why own a 8 cyl for fuel economy. Ya'all logic is flawed.

I was thinking the same thing. Shoulda kept the Ranger 4 banger.

Feb 10, 2012 | 09:17 PM

#14

Hi Volume

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From: NoCal

Quote:

Originally Posted by PREDATOR-Z

Why own a 8 cyl for fuel economy. Ya'all logic is flawed.

Ls1 will be way more fuel efficient to power my truck than the 4.0 or a 2 banger in it. I get about 9-10MPG currently with the 4.0 Shes not a stock ranger btw...

Feb 10, 2012 | 09:28 PM

#15

fknsmshn

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From: Puyallup

That DD makes me lawl.

Its bad ***, dont get me wrong. But definitely a different kind of DD.

Feb 10, 2012 | 11:34 PM

#16

technicalninja

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From: Ft. Worth

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...

Feb 12, 2012 | 08:22 AM

#17

Hi Volume

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From: NoCal

Quote:

Originally Posted by fknsmshn

That DD makes me lawl.

Its bad ***, dont get me wrong. But definitely a different kind of DD.

thanks! for the record... i drive it everyday! hence,,,, just kidding you know where im going with this!

-should- i post a picture of my -3 lowered busa (whooops just did) with no rear brake and only one front brake, 40 shot, tuned on oxy fuel, +8 swingarm which is an air tank in itself that supplies air to my air shifter which is wired to my shift light sooo when my shift light blinks it sends 12+ to my air shifter. (autoshifted under WOT),,, which i daily rode for 5 months or soo... people's feelings might get hurt when they hear me say "daily driver"

dont get me started on my 2300lb Ls1 pt88 RX7

Last edited by Hi Volume; Feb 12, 2012 at 08:30 AM.

Feb 12, 2012 | 08:29 AM

#18

Hi Volume

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From: NoCal

Quote:

Originally Posted by technicalninja

Its 89" end of tire to end of tire up front and once i start the rear end/axle/suspension build it will match the front. its probably more stable that most "road cars" under hard cornering. It seriously rails corners super scary well for a truck. trust me, scary like its on rails (tried some sketchy ****) and it tracks straight on side streets or 90mph. Front suspension cycles 16 inches, the soon to be started rear will pull 20 inches.