just curious.

 

I run 89 octane during long road trips, the ADSPARK value drops to ~90% so it's pulling some timing but it's a happy camper. No point burning the good stuff on long part-throttle cruises.

I'm running an '02 Vette spark map with some increases in the high rev high MAP area. An F-bod map shouldn't even need to ADSPARK-out advance w/ 89 octane.

 

Running 89 octane, computer still set where it was at like 24* at idle and 45* full advanced, no problems or pinging here.

 

If you have EFILive or something else that has this PID, check the ADSPARK value...it's GM's adaptive spark multiplier, or long-term spark retard. If it shows 100, you're getting 100% of your spark map.

 

my computer setup is strictly 99. with the way gas prices are i've been thinking of trying to at least run mid grade to see what happens but i'd hate to mess something up. i know plenty of people do it with their normal cars, yet my luck something would happen.

 

That adaptive spark multiplier is stored between runs, similar to fuel trims, so it does a good job of keeping the engine out of trouble.

Much nicer than the older ECM's design of just managing KR as a temporary event. I wouldn't worry about it, in fact my next tank will be 89 octane for street use...93 is just too darn expensive.

 

why do they say premium only then... other then the money for them what benefit does it have?

 

It just better matches the factory programming in conjunction with the high CR that those motors have. They sorta play the worst case senerio card incase a load of fuel is so bad the engine can't compensate for it.

 

which is what i figured, in the end i'm sure the gas mileage more then makes up for the .20 cent difference but it's always a thought. the fact gas is $4 a gallon now is an incentive enough to want to really bump the motor and run race gas.

 

Well, my LS2 stroker is set up for 9.5:1 compression for adding boost in the future, so I will be having the initial tune set up for 87 octance. Might as well save a few bucks.

 

my 383 was 9:7 and it wouldn't run on anything other then 93+ with the most curved programming. cam was quite large though, good luck. every penny counts as long as the mileage follows.

 

Yeah, I've got a mid-sized cam for the engine size since this is going to be a daily driver. I'm willing to take a bit of a hit right now on performance to save a few bucks until gas prices come back down to reality. This is really just stage 2 of 3 anyway...... the REAL performance is gonna come when we throw on the turbo! :devil:

But that won't be till probably next year.

 

I figured out the difference in a tank for me to run 87 vs running both 89 and 93

87 = $35.75
89 = $37.05
93 = $38.35

difference is $2.60, if I have to wory about 2 and a half bucks, then I just need to park the car and ride a bicycle.

 

It depends on how much you are driving your car, though.

When you start talking about 4 or 5 fill-ups a week for a high-mileage daily driver, then you aren't talking a difference of $2.50 anymore..... and $10/week starts to add up pretty quick.

It's also a bigger difference in various places. 87 to 93 in my town is .35 apart right now...... so you're talking closer to $4 per fillup anyway.

 

It's usually about 320-350 miles a week on the car, about a tank a week.

Right now regular is 2.75 and premium is 2.95

 

You're lucky. Here regular is $3.49 and premium is $3.83.

I've been know to put close to 1000 miles on in a single week sometimes, although I'm cutting that down considerably right now.

 

wow premium at it's highest is $3.10 for the most part.

 

i paid 3.49 for two tanks, but its been steady at $3.19 for awhile now....

kinda sucks though, gas was at a much lower then avg price around here until recently..............

 

Ah well, doesn't really matter to me now since I spun a rod bearing today driving home from the post office. All I can say is I'm really glad it's an LT1 instead of an LS1, 500-700 bucks for a rebuild vs about 1200 for the LS1. May even think about putting a CC306 in it while it's out.

 

oh yea because the _____ is so much more expensive..




umm, could you fill in the blank?

 

...labor and non-reuseable fasteners...

Most experienced chimps with a mic set can build a gen 1 or 2 SBC bottom-end that will be reliable.

Shops with the knowledge and tooling to build a gen-3 aren't bottom-feeders in terms of pricing for their services, generally speaking.