t2d2

iTrader: (8)

I'm guessing that was mostly highway miles, to have filled up again already?

It'll be interesting to see how this experiment plays out in the winter with different gas blends...

oldManTan

yea mostly highway, drove 120 miles on one of the days. But lots of town driving as well, stop and go traffic as well. i commute 36 miles everyday so it adds up quickly.

Ali SC3

iTrader: (10)

sounds like it even went up a hair, getting jelly of these high MPG's.. might have to put mine back to stock haha

oldManTan

yea i can't believe how much better mileage i'm getting lol. i do drive like a granny but if traffic ticks me off i tend to floor it and weave around it lol. i still have to do my timing belt, distributors, fuel filter and change tranny ans PS fluid. so there's probably more MPGs to squeeze out of this car. oh and removing cats and resonators, that should free up at least a solid mile per gallon.

t2d2

iTrader: (8)

Come back to The Force, leave The Dark Side behind.

oldManTan

i've noticed it's a little slower lately especially on the highway when trying to speed up going 65mph or something. that might just be due to the crazy heat and humidity lately. it's been in the 90s the past few days. MPGs still about the same. I've been pulling some crazy timing too, had 52 degrees at one point when cruising on the highway, again, probably just the heat. it's supposed to rain tomorrow so it will cool off, i'll see what kind of timing i'm getting. no knocks or anything so far.

t2d2

iTrader: (8)

What are using to monitor timing? Wouldn't any octane-related pulled timing be more likely to be at lower speed / higher RPM? We have to be going double the speed limit to wind out these A/T's enough to raise the RPMs on the highway.

oldManTan

i'm using OBDIREAD, search TOYOBDI on facebook. it's an OBDI bluetooth logger.

litesoarer

Low RPM, high load tends to be the hard on the engine unless your fuel management actively tosses more fuel at it (rich condition) to prevent pre-detonation.

High RPM, High load has the potential for more destructive results if more fuel isn't added or timing isn't pulled with the onset of pre-detonation. Usually stock tune is rich enough up top to handle poor quality fuels.

t2d2

iTrader: (8)

Aha. I've followed it a bit.

What about it would make it high load? I'm not really solid on that concept. Wouldn't the RPMs climb fast enough to make it medium load almost instantly? And being so far below the car's top speed, does it even qualify as high load in the first place? I think of low RPM, high load as pertaining more to a M/T going slow in a high gear, but a stock SC400 has no control over that.

Ali SC3

iTrader: (10)

The part of the timing map with the most timing will be low load and over 2.2k rpm's.
Generally the timing increases with rpm, and the timing decreases with load. 2.2k rpm is right above the timing "ramp" from idle to cruise.

you can knock anyhwhere in the timing map with the wrong fuel, cause the timing map is tuned to be close all over, but I doubt you will see knock anywhere other than maybe a bit at idle on a hot day.

oldManTan

So i just started knocking, wondering if it's the gas. Car sputtering randomly at idle, running lean, and this horrible knocking sound when revving in Park.

t2d2

iTrader: (8)

I haven't experienced anything like that yet, but then you've cycled through a lot more tanks of Regular than I have.

Ali SC3

iTrader: (10)

maybe you got bad gas or have some carbon buildup. that is pretty odd though.

oldManTan

I think i blew a spark plug, gonna check tomorrow but it sounds like one cylinder is just spewing air and gas now, no misfire, just pure shaking and poof poof poof poof poof.

I really hope the threads weren't ripped out. Otherwise I'll be researching for a spark plug channel repair kit and what size to get, unless anyone here knows?