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Here comes the 2nd part of teat from 7700' to 9800' and the cabin. Fired right up...but not surprised. Jus getting back from the Avs game and and a fun nite out with a buddy!!! #GoAvs
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I had a HELLUVA time gettin my rig to run smoothly at the differing altitudes i routinely drive at...an IMPOSSIBLE time of it actually!! Converting to EFI beat thing ever!!!At higher elevation, lower octane works better because of the "rarified air" so 85-87 is just fine. At lower elevation, lower octane can cause detonation or pinging. I usually don't get much below 4000 ft and 87 is fine all the way up to 12,000ft or more in my FJ60.
The Toyota mechanics in Denver had some issues tuning my then new 1980 pick up for life in Leadville (10,000ft). (It was the last model year you could still run the cheaper leaded gasoline.) When I brought it down to Moab, I had to retune the carb and retard the timing a couple degrees.
Nite + Day! Best thing EVER!!Hell yeah! I'm putting the Sniper on this weekend.
Im over in Clear Creek County and dont get emission tested. Ive been wanting to test it anyway....jus to see whats up. I keep forgetting lolI'm counting on it. Mine did well enough for me with full emissions BS intact but all those vacuum hoses gave me too much anxiety. The engineering that went into the carb is impressive to say the least. Seems the emissions system is the weak link and the Sniper fixes that.
FTR...im not revisiting 85oct for better fuel MPG...im just a cheap ole bastid and if i can save $4-$6/fill up...ill give it a go!!!Fuel injection and a modern adaptive ignition would provide the biggest performance gains. I once got 18mpg on a tank in the 60 but that was all down hill coming East out of the mountains in Colorado. That in itself tells me that for normal driving there is likely no way to get 18mpg with any amount of modifications short of a diesel or an engine with a lot more low end torque and a 5 or more speed.
I’m picking up what you are laying downFTR...im not revisiting 85oct for better fuel MPG...im just a cheap ole bastid and if i can save $4-$6/fill up...ill give it a go!!!
On a longer trip today....85oct. Dsnt seem to be having a negative impact on MPG. Also, still purring like a lion...driving GREAT!!I've run 87, 89, and 93 octane fuel in my truck and calculated the mileages for multiple tanks of fuel and not seen an appreciable difference in mileage. Mostly i run the higher octane now and then as I have desmogged and my dizzy curve is still set for the emmissions.
Math wise if I use from the AAA website:
View attachment 2184698
There is a 27.5 cent difference per gallon between regular and mid grade. In a full 25 gallon fill up thats a $6.87 difference in cost from regular to mid grade. So I can buy 2.5 more gallons of regular for the same price of Mid-Grade. If I'm basing my decision on mileage then I better be getting an increase in mileage that offsets this 2.5 gallon buffer. In my case my mileage always varies between 13.3 and about 14 mpg regardless of whether I filled up with 93 or 87. If I can get 13mpg with 87 octane then I need to to get at least 14.3 mpg to equal the cost difference from regular to mid grade.
All this said there is no mechanism in the 2F engine that is capable of optimizing for higher octane fuel. There is no system measuring knock and adjusting the ignition to maximize advance like on a modern system. Also the higher octane fuel will produce less power for a low compression engine like the 2F. The only thing the higher octane will do is bandaid the preignition/detonation issues like I have because of my ignition advance curve or because carbon buildup etc.
Now in my 1999 Saab 9-5 I always run 93 octane fuel when I can get it because it is high compression engine and also turbocharged running a reasonable amount of boost. With the higher octane fuel the computer can maximize the timing and boost and get more torque out of the engine which in turn allows me to run a lower gear with less rpms and use less fuel. If I run 87 in this car I can feel the power the difference and the car drives much worse. I also see a significant drop in mpg because I can no longer run the boost.
SniperSorry if I missed this elsewhere but what EFI are you running ?