16 gallons of 89 octane!!

D

Dartastic

Dedicated LVC Member
Joined
Mar 15, 2005
Messages
505
Reaction score
0
Location
SF Bay Area
Guess I was day dreaming when I did it but I just filled up my 2004 LS V8 with 16 gallons of 89 octane. 30k miles and never put anything in it under 91. Ill run this till empty and post on any performance difference. Geez, went to the same gas station I go to every week or so. Dont know how I screwed up on the pump. LOL!!:p :mad:
 
Let me introduce you to the remedy...

fuel_oct_boost.jpg
 
lmao the remedy think that stuff will work with a full tank?
 
You don't need that much of a boost going from 89 to 91. And you could use 2 bottles if needed.
 
Don't know about the STP brand of booster, but on the other brands I have played with, you have to read the tiny print. Usually you will find that it takes something like a full bottle for every 10 gallons to boost the octane 1 point.

For an 18g LS fuel tank, that means probably 2bottles(for18g) x 2(91-89=2) which means you only need 4 bottles of what I would guess costs between $2 and $4 booster. This is the reason I quit trying to use booster when using my truck for towing. It was just cheaper to buy premium when needed.

By the way, 89 isn't going to hurt your engine. At most you might get an occasional slight ping under heavy load or high temperatures. 87 octane does ping more often, so I would avoid that.

I would do one of two things, just drive the 89, or when I get down about 1/4 tank I would fill it back up with premium.

Good Luck,

Jim Henderson
 
That's not entirely true, 89 or 87 one time can hurt the motor. It's happened before.
 
2001LS8Sport said:
In this cool weather with reasonable driving techniques, you will be fine.
Click to expand...

I just drove 15 miles to work and noticed no difference. I still plan on always using the 91 octane chevron gas though.
 
Did that in my wife's Cobra - ran like crap within 30 minutes. Had to put 2 cans of 104 Octane boost to get it to act normal. She has the superchip, CAI, etc, etc so it is really picky about the gas, cant even use premium at the cheapo stations, Only Sunoco 94 (which they are ending production or already have - so I will have to get the chip redone) works - othewise I have to use my stash of CAM2 purple.

Anyway just take it easy and when you get down 1/4 tank fill up with your regular brew. If you get a lot of 'pinging' before - then start putting premium in or a booster to help.
 
nashmage said:
ouch...frat man that mustang must be costing you a pretty penny on gas.
Click to expand...


Damn skippy... we use the gas gauge as a tach!

Every vehicle I own goes fast and gets really :q er crappy milage. but it sure is worth every penny...sctarch that... dollar!
 
haha well thats good that you think its worth it. This is my first car that isnt a "economical car". The gas money isnt that bad but nothing like my first car.
 
if you don't go into the throttle too much I doubt you'd get any knock..

I'd keep it under half throttle till it's gone and you'll be fine.

The colder the weather the better chance of knocking you have any ways..

cold air =more dense..
more air + lesser octane = knock
 
As long as you know goin' in it really is not all that bad. If you take it easy and keep a Lincoln tuned they get decent milage. My TC got 23 but my Mark only gets 18 - I get on it pretty hard too. I dont even bother with the Mustang - to scared to find out the truth...the tree huggers might blow it up.:eek:
 
ignorant prodigy said:
if you don't go into the throttle too much I doubt you'd get any knock..

I'd keep it under half throttle till it's gone and you'll be fine.

The colder the weather the better chance of knocking you have any ways..

cold air =more dense..
more air + lesser octane = knock
Click to expand...

What you say makes sense on paper...but is not accurate. You are more likely to see detonation when it's good and hot out than in cooler weather.
 
BTW, I run 89 probably 70% of the time on my daily 60mile RT commute. I run probably 80% of that at 70+ and the rest at stop and go with not a lot of street driving. My engine hasn't blown up yet, but then I have only had the car for about 14,000 of its 28,000 miles. Strangely none of my other "91 recommended" vehicles blew up either and those averaged about 100K before I got tired of them. I do usually switch to 91 in summer when the AC is on and the temps are up and if I notice pinging.

There is very little economic reason to use lower octane gas since at least for now the difference is about $1.70 a tankful. I just do it because I am cheap and my experience over about 20 years with high octanne cars with computer controls has shown the computer can adjust. Of course my old 12.5:1 Mopar didn't care much for anything less than 92, but then that was not a normal engine. Prior to the mid 80s, engines were much more finicky.

89 will run fine, you just may not be taking advantage of the maximum performance and you will be decreasing the margin that the computer has to work with. The lower the octane the more load, speed, and temperature sensitive the engine will be. Of course if you get some Mexican "superior" 80 octane gas, all bets are off.

An engine that blows with octane just a couple points low has other problems including some that increase the octane requirement. My theory is that engines that are driven like a "Sunday go to church mobile" usually "carbon up" and will need higher octane because they are closer to the edge. That is why I make sure I blow out the carbon regularly. I had a 79TA that required regular romps on the pedal, way back in the 55 stay alive days, otherwise it would start to run sluggishly and stumble etc.

Just drive it sensibly and you will be fine.

Jim Henderson
 
What you say makes sense on paper...but is not accurate. You are more likely to see detonation when it's good and hot out than in cooler weather.
Click to expand...

I wasn't going by paper actually.. I was going by personal experience.

My previous car had a supercharger so maybe my numbers were a little more extreme... but I did have a water to air intercooler. With the exact same setup all year I saw consistently more knock in the winter months, with colder air and winter blend gas..than I did in the summer months..even during the 89-90* weather and high humidity.

The car was definitely faster and more responsive in the winter.... but unless my knock sensors were lying to me.. I'm convinced the higher boost with the colder air generated more knock. :D
 
ignorant prodigy said:
I wasn't going by paper actually.. I was going by personal experience.

My previous car had a supercharger so maybe my numbers were a little more extreme... but I did have a water to air intercooler. With the exact same setup all year I saw consistently more knock in the winter months, with colder air and winter blend gas..than I did in the summer months..even during the 89-90* weather and high humidity.

The car was definitely faster and more responsive in the winter.... but unless my knock sensors were lying to me.. I'm convinced the higher boost with the colder air generated more knock. :D
Click to expand...

I forgot about winter blend gas. Crappy stuff!

I don't think the WBG is distributed to everyone, only high population or pollution areas ?!?!?!?!? I also thought (no facts just remember a news report) due to production issues, in the Gulf, this year they were not going to distribute the WBG this season -?!?! Anyone know for sure? I just called a local Mobile station and they were clueless - no suprise there.
 
ignorant prodigy said:
I wasn't going by paper actually.. I was going by personal experience.

My previous car had a supercharger so maybe my numbers were a little more extreme... but I did have a water to air intercooler. With the exact same setup all year I saw consistently more knock in the winter months, with colder air and winter blend gas..than I did in the summer months..even during the 89-90* weather and high humidity.

The car was definitely faster and more responsive in the winter.... but unless my knock sensors were lying to me.. I'm convinced the higher boost with the colder air generated more knock. :D
Click to expand...

That sounds strange! I see how your physics makes sense, but I have never seen it work out that way on a fuel injected car. I have an 04 Cobra with a Diablo Revolution flip chip in it. I have three tunes. The stock factory, a summer tune, and a winter tune. The winter tune is MUCH more aggressive. More timing and more fuel...and it's a huge difference in performance. What you say is absolutely true if you don't have control over your mixtures and the car stays as lean as it does in summer, but the ECM (or the tune) should compensate for that. The lower inlet temperatures of winter driving supress detonation like you can't believe. Even with our intercoolers, there is no comparison to summer and winter performance. I'm wondering if you're other car was on the ragged edge and just couldn't compensate enough to richen the fuel enough to prevent detonation? Or maybe it was carbureted?

By the way...the 03/04 Cobras don't even have knock sensors. Nada...nothing. They use timing control based off the AIT temps after the intercooler...but no knock detection.
 
and it's a huge difference in performance
Click to expand...

Definitely, I'm not arguing that at all..

I drive a Grand Prix btw. The seem like completely different management systems.

In the Grand Prix the IAT (inlet air temperature) sensor is located just before the Throttle body in front of everything... just after the air box. So basically... useless

So the air temp it's reading does not reflect the air entering the pistons.. infact its not even close.

The PCM or ECM in the Grand prix doesn't use fuel as much to compensate for any knock(pinging) it see's.. it reduces the timing more so..

We would have to compensate for additional other fuel ourselves with a tuning device..

I guess the only way to truly know would to understand how the Lincoln compensates for the colder air... and if it kills the knock by adding fuel like the mustang must then what you say might be true.

Like I said I'm only going by my experience.. but if everything were to stay consistent except for the colder air and winter blend gas then I would see it as causing more pinging.
 
I've done that before, it didn't hurt my car any. It ran just fine, it did rev just a little higher at times but that's about all. If you EVER put the cheap stuff in the engine will start knocking and skipping...My friend's LS8 (Which was stolen, but later recovered just this week) put 87 in for about 2 weeks of ownership and I drove it...big difference between mine and his. I told him to use the premium and he can tell a difference too. But the middle grade will not hurt too much, so your fine bud! Oh yea, has anyone filled up on premium and put in the octane booster? Does it make much of a difference?
 
J3FF said:
I've done that before, it didn't hurt my car any. It ran just fine, it did rev just a little higher at times but that's about all. If you EVER put the cheap stuff in the engine will start knocking and skipping...My friend's LS8 (Which was stolen, but later recovered just this week) put 87 in for about 2 weeks of ownership and I drove it...big difference between mine and his. I told him to use the premium and he can tell a difference too. But the middle grade will not hurt too much, so your fine bud! Oh yea, has anyone filled up on premium and put in the octane booster? Does it make much of a difference?
Click to expand...



Im more than halfway thru the tank and all is well. Thanks for all the posts guys. Just going to make sure I dont do it again.
 
ignorant prodigy said:
Definitely, I'm not arguing that at all..

I drive a Grand Prix btw. The seem like completely different management systems.

In the Grand Prix the IAT (inlet air temperature) sensor is located just before the Throttle body in front of everything... just after the air box. So basically... useless

So the air temp it's reading does not reflect the air entering the pistons.. infact its not even close.

The PCM or ECM in the Grand prix doesn't use fuel as much to compensate for any knock(pinging) it see's.. it reduces the timing more so..

We would have to compensate for additional other fuel ourselves with a tuning device..

I guess the only way to truly know would to understand how the Lincoln compensates for the colder air... and if it kills the knock by adding fuel like the mustang must then what you say might be true.

Like I said I'm only going by my experience.. but if everything were to stay consistent except for the colder air and winter blend gas then I would see it as causing more pinging.
Click to expand...

Good post. No argument from me. And I also agree about the Pontiac engine management system...it's just horrible. I don't understand how they can get away with that...and I've read several complaints. My Cobra measures air temps before the supercharger and after the intercooler both. You can actually log them both and see the efficiency (or lack of) the intercooler.
 
You must log in or register to reply here.

Members online

No members online now.
Total: 91 (members: 0, guests: 91)
Back
Top