Hey a local gas station USED to have LEADED 107. I know thats BAD for your O2 senors and other things.

Question 1: Now this gas station has 100 UNLEADED GAS. Now I assume thats it's leaded I could run a full tank everyday and shouldn't have any issues right? I'm not going to do this since its 5.99 a gallon, but just thought about getting 5 gallons for my ls1 and lt1 cars and don't want to hurt anything. I figured it would be the same as adding octane booster or something.

Thanks

 

Why would you assume that fuel labeled "unleaded" is "leaded"?

100-octane unleaded will not hurt anything (except your wallet), and will not provide any benefits, unless the engine requires it and is correctly tuned to use it. Save your money.

 

oopss sorry..had a brain fart. They used to heave leaded 107, now it is unleaded 100.

Yea I know the octance is can be kinda snake oilish if your car don't need it....


I had my car tuned. So I don't know what it really needs. I know on my LT1 87 runs fine....

Thanks

 

NO LT1 runs "fine" or to it's potential on 87 octane, PERIOD !
The knock sensor and knock module WILL be pulling timing when under ANY sort of load.
The only way one could make an LT1 (w/10.5:1 factory compression ratio) run without knock retard on straight 87 octane unleaded would be to have the PCM DE-TUNED to limit the total spark advance. This would reduce the total horsepower produced as well as reduce the mileage.
Under typical light throttle/light load highway cruise conditions most (as mine does) LT1's will run fine on 89 octane, but one should not be revving it up too high.
I run 89 during the week (due to my 125mi. daily round trip to work) and 94+ on the weekends.

 

I have ran it hard and usually just run 89...I do have the LT4 knock module in it though. But never had any issues been running mostly 87 and maybe every 5th tank or so do 93....but here lately its been mainly 87.

I have ran only 93 in my ls1 car, but going to check and see what the tune is from tsp...

 

Your LT1 has the HPP III..... as useless as it is, even Hypertech tells you not to run low-octane fuel with their tuning. Unless you have run a data log on several WOT passes, in the heat of summer, you have no idea if and how much knock retard is being pulled. You could be throwing away HP, and never know it.

And running the LT4 KM means nothing with regard to low octane fuel and true knock. The LT4 KM is little more than a filter to remove the false knock signals from the LT4 roller rockers. It does not filter or diminish "true" knock retard.

If you are happy with running 87 in the car, why would you even be asking about 100? There is nothing "snake oilish" about octane... it a pretty well developed science that can provide HP gains, IF (and only if) the engine needs it. And a stock LT1 with the mods you have listed does not in any way need 100-octane fuel. My 500HP stroker, at almost 11:1 did not benefit using 100-octane fuel, based on numerous engine dyno pulls, using wide variations in timing advance and air/fuel ratio. At 94-octane, it was making max power. It wasn't until adding another 135HP of dry nitrous that the 100-octane fuel allowed more power.

 

That pretty much sums it up.

 

Thanks for your help!

On my LT1 I have a HPIII but didn't install the tuning, just changed the fans and gears...

I have a LS1 and been running 93 (just had it less than a week) its pushing 400ish HP...and I was thinking of adding 2 gallons of race gas 100 instead of adding any octane booster. I do that every once in a while on my cars.....

Thanks again.

 

first off...you realize that "octane booster" additive is junk. they say it raises octane "4 points"...well that's actually point 4...
so adding it to 87 octane would make it 87.4 octane.

very big waste of money.

as for adding 2 gallons to the tank. assuming you run a full tank...say 15gal...the 2 gallons of 100 octane added to 13gal of 93 would make your final octane rating 93.9

so basically you're getting 1 more octane for your $12

:blah:

 

I do agree it's junk. The torco fuel addative works well but screws your plugs and o2 sensors. I read a test they did on octane boosters and learned some intresting stuff. Yes they only boost you octane up a point or so but they still allowed for more timing to be added and boost etc, etc. I wish I could find the article because reading it made more sence then me trying to explain it. Point is thought it doesnt change your low octane fuel into super fuel it still helps alot. Ive used addatives and seen less knock, ALOT less knock so it has to be doing something right.