Hi guys and gals,

Back in January I asked this question:
ETHANOL-E10 and my 1983 Camaro Sport Coupe?

Today (and I'll bet not the first time this question has been asked)
I'd like to ask about the ramifications and possible potential problems of using Regular gas instead of Premium in a
1983 Camaro (5-Liter, V8, 305, 5-Speed)...just over 100k miles.

This is a one-owner (me), never had any engine problems, and for all the years I've owned it, I have always used high octane Premium...
(California) Arco for the first 20 years or so and now that I've moved to Oregon, I've been using Chevron Premium.

As we know, regular gas has an octane rating of 87, mid-grade gas is 89, and premium is 91 or 92...plus the difference in price at the pump is dramatic.

The reason for this question is obvious to anyone who has filled up their tank recently...with no sign of relief in sight.

So, what would happen using fuel with a lower octane rating?
knocking, noticeable loss of power...EVENTUAL ENGINE DAMAGE?

Choices:
1. I wouldn't recommend using Regular...because..
2. You won't notice any difference in performance
and you'll save money at the pump.
3. What are you...NUTS! for even considering such a thing?

Thanks for any and all comments.

Gene

 

I dont know the specifics of that engine, timing, comrpression etc. but I will almost gaurentee it will run fine.

Please dont tell me you get sucked into the 'premium cleans your engine and it wil make more power' bs.

Octane changes on the same engine will NOT affect power. More octane = harder to detonate.

If it sounds like rocks in a can, try midgrade, but like I said it will be fine unless youve done engine work to up the compression ratio to over 10:1

 

Ambient temp makes a difference too. My intrepid would ping in the summertime on 87, but run fine on it in the winter. This was due to a 9.4:1 compression ratio, stock. I wound up running 89 in the summer, and it would run fine. The hotter the incoming air is, and the hotter the engine is, the more likey it is to detonate.

 

The '83 LG4 had 8.6:1 CR. No way it needs 87 octane in proper tune, let alone 91.

If you had been investing the money you've wasted on premium the last 20 years, you'd have plenty of money now to buy all the regular you need.

Since premium (higher octane) resists pinging by burning slower, you've had less power and economy over the last 20 years on top of the higher price you've paid per gallon.

 

That's exactly. Unless you build & tune the motor to run on the higher octane, then you're wasting time & horsepower.

With my measly 8.8:1 compression, aluminum headed 355, it made 310 RWHP on 87 octane running 34* timing without any pinging.

 

Thanks for your input everyone!

So, what I'm gleaning from all your comments is:

1. YES..I can start using Regular gas with NO worry about
engine damage, pinging, missing or loss of power or compression.

2. For 20+ years I have wasted money buying Premium gas.

3. No way it needs 87 octane in proper tune, let alone 91.

but then I read:
"Unless you build & tune the motor to run on the higher octane,
then you're wasting time & horsepower."

which really speaks to the core of my question...

didn't I purchase the car with a factory engine "built and tuned"
to run on Premium?
I seem to recall the dealer, the manual or some source advising
me at the time of purchase to...
"always be sure to only use Premium".

Was that advice not right?
What makes it ok to switch to Regular at this juncture and not
when I first bought the car?

Guys, I'm just playing Devil's Advocate here as I prepare to go
fill up my tank in the next day or so and really want to use Regular
and start offsetting the rising price of fuel but also want to be sure
I won't be regretting it "down the road" (so to speak).

If y'all are that sure, I'm going to trust your advice and start using Regular.

And, you realize of course, that if the word gets out to America that
it's ok NOT to use Premium, this could be the biggest boost in our economy
short of the Arab oil-producing countries lowering the price of crude back to $50 a barrel.

I'm just sayin'...

Many thanks,

Gene

 

It's all about the compression, and a little about advance. You're setup for regular. And the vast majority of america (probably over 98%) use just regular already. You're livin in a little Premium only gas bubble or something.

 

Perhaps you're right.

I believe I've simply been under an impression instilled in me over twenty
years ago by those who seemed to be knowledgeable at the time, to use
what was recommended as being best for my high-performance car's engine.
And now, all that has apparently changed...and what you're hearing from
me is just the slightest bit of hesitation on my part to acknowledge
something that wasn't true then but now seems to be the rule that a large
percentage of Americans once having faithfully used Premium have now
switched to Regular.

I've just always lived by the rule of good 'ol Davy Crockett:
"Be sure you're right, and then go ahead".

 

worst case senario, you put a tank of regular in and it pings a little, then ASAP pick up some lucas octane booster for like $10 and dump it in. or you could just possibly retard timing a little bit.

my mustang needs premium for reasons that i do not know, and i put 87 in it once and it pinged at WOT. i put half the bottle of the lucas octane booster in and it was fine.

 

A properly running stock engine, 350 to V4 for this car uses regular. Improper spark plugs, timing, temperature, or malfunctioning computer may all get masked by using premium over regular. Bad regular gas may also be the culprit. Only engines built around higher compression really take advantage of premium.

 

Now impaled, you know where I'm going to go with that and that is to
ask the first question that comes to mind:
"Why spend $10 on an octane booster when I'm trying to save a few bucks
here by using a lower octane and less expensive fuel and seeing if I can
"get away with it".

For the sake of argument...
let's say I put in 13 gals @ $4.00/gal. of Premium = $52.00.
but, say I put in 13 gals @ $3.75/gal. of Regular = $48.75 (diff: $3.25)

and then add an octane booster @ $10?

I may as well just keep using Premium.

 

I think he means to stop the ping immediately while you get to a premium pump to fill back up.

 

It wont ping. Don't worry.

 

I also have an 83 Camaro, although mine has a 350 crate. Anyway I use Regular everytime. After about ten tanks I get a bottle of Octane Boost and dump it in the tank on a half tank to burn out any build up.

 

lol..you guys are gonna hate me for being argumentative which I'm not
at all trying to be but, too many years in manufacturing has cursed me
with an inquisitive dark side which prompts me to ask questions that
arise during the process to prevent bigger problems from cropping up
at the end.

For example, to that I could say, "ok, but I just filled up my tank so I'll be
driving around for quite sometime with pinging before I am able to refill my
tank back up with Premium."

Ok, I'll shut up now...I think I'm wearing out my welcome.

 

If your car starts pinging because of gas it is a deeper problem than just the gas. I have a better idea anyway. DUMP THE 305 and get a 350!!!!

 

Worst case for your 305 when switching to regular is pre-ignition (pinging) under load and detonation under WOT. Retarding your base timing slightly may be required with lower grade fuel. An '83 LG4 did not come with a knock sensor to my recollection.

Try a tank of regular and listen for pinging under light load at cruise. With the motor hot and in a high gear, get to around 35-45mph and give it enough throttle to load the engine. If it pings try reducing your base timing a few degrees.

If you DO have to reduce your timing your engine may get slightly less mileage, although you probably won't notice the difference. It will certainly be outweighed by the benefit from the cheaper fuel.

Premium fuel will allow an engine to run with slightly more timing which 'generally' makes it more efficient (when compression ratio isn't an issue-and it's not for your 305).

 

My 305 is just fine thank you! and has put down plenty of 350's so you don't want to go there...unless it's to the nearest track to meet me.

As for pinging...the car has never emitted even one ping in her long
history..so, if there were to be any pinging, it would be the direct result
of using a lower octane gas. (hey, am I answering my own question here?)

 

LOL. Very Nice. Well I live in Battle Ground and I am ALWAYS up to racing.

 

You just hit the nail on the head, if it pings after you fill up with 87 octane just drive it mellow to keep it from pinging and then fill up with 91 octane on your next fill. I had a 1983 Z-28 5-speed and it works fine on 87 octane fuel because it is only 8.6 to 1 compression.

The only reason to run a higher octane fuel in your car is to eliminate pinging, if there is no pinging run the 87 octane fuel.

 

LOL...sorry but I'm originally Philly born and raised and I see by your
screen name...well, you know how Eagle fans feel about the Cowgurls.

Sorry man, you know I just couldn't pass that up....

 

My car pings on anything lower than 93, and its a bone stock LO3. I hate it. I replaced my EGR, I regularly sea-foam the car, and clean the TB with carb spray. I keep great maintenence on it, and it has a 180* Tstat. I can even make it ping on 93 if I try.

I pulled one of my plugs a week or 2 ago, and even though they were put in last fall, the little "rapid-fire" tip on the end of the electrode was completely missing.

 

Eagles fan. That explains the 305 and no 350 LMAO. Just playin' all good with football banter. I mean the stats say the truth. See you avoided the whole race thing.

 

Before I saw your post, I said to myself "I bet he comes back and says
that's why I have a lowly 305"...

Avoid the "race thing"? ...I'm not a racist!

 

jeez...ya know...
after reviewing all the posts above, I don't get a warm and fuzzy feeling
that there would be much advantage going to Regular considering all the
"potential" problems I could encounter, not to mention the uneasy feeling
I'll always have in the back of my mind as I kick her into 5th gear and start
expecting to hear pinging "at any moment".

Perhaps whoever said, "if it ain't broke, don't fix it!" was right after all.

I DO appreciate everyone's input though...
yes, even from those who might be a fan of the 'BOYS.

 

Come on I know a good little place by Vancouver Lake!!!!!!

Its law that when you have a Camaro you must be a raceist just like if you love football you must be a Cowboys fan!!!!!!!!!!!!!!

 

dude i ran mine on 86 and it was fine in 80* heat i only got one ping when i almost stalled it no worries bro 87 all the way

 

haha...you really need a Cheesesteak!

Check it out... http://heylaydee.files.wordpress.com...heesesteak.jpg

 

Nah, if that were a universal truth, we'd still be living in caves.

If you're worried, pick up a bottle of octane booster (save your receipt) run a tank of 87. Drop your timing if it pings. Take back the octane booster for a refund.

It will likely run just fine with no worries.

 

My friend..that's just one ping too many for me.

I think for the 15 cents or so per gallon I might save, I'll probably just
stick with Premium for now...

Now...once Premium gets to $8/gal and Regular is say $1 less, I might
be looking more closely at my decision.

 

dude if your car is running like it is supose to it will be fine on 87....you are totally wasting your time on 93 half these guys wouldnt no a ping if they were inside ure engine... five7kid hit it right on the head....i run 87 in my 99 v6 camaro 9.4:1 cast iron headed engine no problems in the texas heat.....and yes i know its can retard its on timing and all that bs but still no problems and she will run....at 8.6:1 compression 87 octane has plenty of octane for ure motor.....save the cash buy the 87 drive and enjoy most cars are designed to be able to function properly on low buck fuel, especially early 80s models. only higher end cars will sometimes require premium.
----------
o and i wouldnt knock the idea of changin to a 350 one day think about this my 3.8 v6 makes 50 more hp and only 15 ftlbs tq less then ure 305....

 

Oh...ok dude!
btw...did I not mention mine is a "MODIFIED" 305?

sorry 'bout that!

 

if you can get it to ping on 93, you have some issues, especially if it is a bone stock LO3. i would retard the timing a little bit, or figure something else out.

 

Hey guys (any gals in the mix?)

Really enjoyed all your posts and I appreciate everyone's input.

And I know if ever I have questions about my Phantom 305
(well, that's my Track name), I know where to come for great
advice and a little fun...ThirdGen.org

Y'all have a great weekend now, ya hear?

 

GeneL for the amount of money I would save on gas each year i bet that I could buy a semi built sbc 355 off craig's list every year untill the end of time one ping is fine with me now i know the thresh hold and it is low and i can git'r where she needs to be to be safe 100% of the time not to mention that now that i know where the thresh hold is I could drive on 86 all the time and be safe just don't start in second gear without using the skinny pedal and not have to worry about knock because that is basically what it takes man detonation isn't even a problem 87 is recommended by gm these cars were built in the eighties remember that gas crises remember the eighties nova now think about the seventies nova i'll run on 86 all day and you'll be a fool all day for putting 93 in just listen to five 7 no way it needs 87 let alone 91 give itt a break worst case do what some one else already stated keep a bottle of octane boost in the car or do what i do and keep a timing light and wrench and stop being naive and maybe then i'll start using grammar

 

No, if you did that, the world might stop turning.

 

i own a 1990 GTA 350 TPI

factory says run 91 or above only

every tank has been 87

never had a problem with pinging or knocking

same with my built 305, both of them have always ran on 87

 

Ok, I came here to inquire whether or not going to a lower octane
from the Premium 91 I've been putting in Phantom 305 for all these
years would be a bad idea and you've given me honest answers based
on your own experiences.

The majority of you have said "no", and I could go ahead and start
putting in 87 with no worries.

And, like I said before, I've never heard ping one out of her so
I'm going to go ahead and on my next stop at Chevron to gas up
I'm going to put in their mid-grade 89-octane gasoline and see what
happens..whether I get a "pinging" or "knocking" sound or any
noticeable loss of pickup or power and whether or not I can
continue shutting down those arrogant 350's that dare me to a race.

In addition, monitor the savings per tank full compared to what I
would have spent for Premium.

Just as an FYI:
The prices spotted today May 31 using www.gasbuddy.com:

CHEVRON: Portland Oregon area
Regular.....$4.15

Midgrade ....$4.19

Premium....$4.41
(so, quick math would tell us a savings of
around .22 cents/gal equating to around $2.86 for 13 gallons.)

Thanks again guys for all your input.

 

Now what if he advanced his timing and ran premium. Would he not get a performance increase and also need the premium?


Just trying to educate myself here.

 

Stop giving it so much thought and just buy some 87. Nothing bad is going to happen. If you do ping something is wrong considering the LG4 engines compression and soft spark advance. I would try some top engine cleaner and check the base timing.

 

Some say high octane premium burns slower. That is NOT true. Oxygenates and other octane enhancers interfere with the PRE-combustion reactions taking place in the end gases BEFORE the flame front arrives, to prevent self-ignition at that point. That's ALL. ( oxygenate = already burnt. A pile of ashes is an oxygenated house, or garage, or... )
If the flame front arrives before detonation can take place ( which is true of ALL gasolines ) then the gases are burnt before they can detonate, and no detonation can take place. One of the objectives of swirl chambers, fast burn heads, and such, is exactly that. Burn it before it can self combust. ( explode is another almost correct word )
If the flame front does not arrive before self-ignition occurs, your kick start sportster throws you over the handle bars, or breaks your leg. This is especially true on a kicker that doesn't fire at all. No flame, so it detonates.
Nitroglycerin burns slow, and smokey if you light it with a match. Once burnt, it can't explode. BUT rapidly compress it to a high ratio, say by hitting it with a hammer, and it'll self-ignite. ( detonate ) Hit it with a hammer after it's burnt, and nothing happens.
LIGHT detonation ( you can't hear it ) on the edge of incipient knock can be a good thing, as it will blast away build up of almost everything giving a very clean engine with no damage. MODERATE detonation ( you can hear that if your listening ) will eventually cause problems, but it may take a few or several thousand miles.
Almost everything Detroit ever built can stand some degree of moderate detonation, and some will survive short periods of heavy detonation ( SHORT periods ) with no damage. HEAVY detonation, when it sounds like a diesel, can cause seizure, broken pistons, and such in relatively short order.
A slight rattle at very little throttle is seldom a cause for concern in the short run. ANY rattle at WOT can become very expensive very quickly. BACK OFF !
Some engine designs make more power with lower compression and more advance. This is strictly related to detonation, and the quality of fuel.
Black specs on the spark plug insulator is carbon being blown off the combustion chambers by detonation. Silver specs are piston being blown off the piston by detonation ! Look closely.
Now, if I were you, I'd run it near empty, then buy 1/4 tank of reg. If it knocks ( detonation, which is the spontaneous combustion of the end gases before the flame front arrives ) then immediately go fill it with premium.
The final octane rating of what's in the tank is almost a direct proportion of the mix. Half 87 and half 91 and you have all 89. 1/4 87 and 3/4 91 and you have all 90. There's enough tolerance in ratings that you won't hurt anything that way, unless you try and drive it the whole time ratteling like a can of marbles. Then, you'll have scuffed pistons, broken spark plugs, all sorts of things caused by the very high heat and sudden pressure rise caused by detonation.

 

Its possible that could happen. The idea is to ignite the mix at the right moment to burn all of the fuel and have that happen at the right moment to get the most downward force on the piston.

 

Quote:

Originally Posted by RED86Z28

"Stop giving it so much thought and just buy some 87.
Nothing bad is going to happen."

Now RED, that's why I come here, not only for the pleasant banter
but also, to get informed so I can make intelligent decisions based on
reliable input from you guys.

I hear what you say, and I had pretty much already made up my mind
to try a tank of Mid-grade and then, someone like Cflick who presents
a very believable argument, comes along with this:
This then takes me to the core and purpose of my original question and
whether there is too much risk involved to try and save $2.86 for 13 gallons?

And, as I am prone to do as you folks share your experience and
knowledge, I look for certain buzz-words, like those mentioned by
Cflick above, scuffed pistons, broken spark plugs, etc. (I know, this
is worst case condition) but, if there's the slightest chance, I'm just
not willing to take it..not to be able to pocket $2.86 anyway.

Good stuff everyone!

 

OK, listen when you bought your car 20 years ago you could of used 87 and your car would of ran great. The only reason some of us use 93 is because old egr's wear out and other stuff goes wrong which makes pinging and then we start using 93. whoever told you, you had to use premium was lying and you have been wasting your money. if you put regular in and it pings, oooo nooo, put premium back in for the rest of your life! you are over analyzing all of this just try it and if you don't like it then don't use it. if everything is good with your engine it should run great if not better because that is how it was supposed to run. if it does ping your little 305 is not in as good of shape as you thought it was. sorry. something is broken then.

 

TRUE.
Too much advance, and you get a LOT of downward force, but the piston is still trying to move up the bore. Compression pressures go WAY up, and so does heat, and power out goes down, usually accompanied by audible knock but not always.
We want the LEAST advance consistant with performance, and with the LEAST octane that will sustain that level in that engine. More advance is less performance, and more fuel cost, while too much octane is simply money for no reason at all.
----------
Yes, if, but only if, timing is too late now, due to having been retarded to use lower octance than the engine really requires.
If the engine is already at minimum best torque, then more advance equals less performance in all cases, but would also need premium in spite of lower performance and greater wear.

 

Im not trying to give jerky answers but it seems that as a group we are making the question more complicated than it needs to be and focusing too much on the negative results of prolonged or severe detonation rather then our own experiences running 87.

 

usually people or over simplifying things but here it is definately not the case. on the risk of sounding like and ***. your motor is far from a high performance motor that would need 93 octane...i dont care what u have done to it anything shy of raising the compression or advanceing the timing to an outrageousdegree witch i highly doubt you have done. it only needs 87. stop with the well it might ping, and all that bs i swear it will not,

 

Agreed.
My ( former pro-gas ) 70's iron head big block runs 87 all the time. At 6-8 MPG ( heavy truck ) I'm looking almost at dollars per mile. Yeah, sometimes the logs record light detonation. 3 or 4 pings per hour. I'm not worried. Been that way more than ten years, and many thousands of miles.
I'd do what I said I'd do. Run it near empty, put 1/4 tank of regular, and a 5 gallon can of premium in the trunk just in case. ( if your worried about it )
If you listen, and hear no knock, I'd run regular.
For $2 no big deal, but for me it's more the difference between $120 and $160 fill-up.
Now, the guy who posted he has broken spark plugs, THAT I'd worry about.

 

GeneL
I've looked thru this post and I don't see any detailed info on your car. Do you have ANY mods at all? If it's bone stock, run 87. My 92RS pinged under load when I first got it. A tune up, including EGR, O2 sensor,cap,rotor,plugs and wires and timing adjustment cured all and got me 2 more MPG. Notice i didn't even do either coil. They're both the originals (ignition coil and pick up coil).That was over 2 years ago and now it's a 50 mile per day driver. Never a hiccup. Starts up quick, too.
Also, have you tried to calculate cents / mile? Just another perspective.

 

You got me that was just a regrettable trash-talking embellishment.
The car is just as it came from the dealer, I have a pretty good mechanic
who does maintenance and tune-ups for me A/R. When something breaks
it gets replaced (last event..two years ago needed the Alternator replaced),
which is why I suppose the car's been around so long.
To that I'd say, "yes, pretty much the boner".
You can blame me for much of that RED, with each claim or comment
someone makes it inevitably proposes another question in my mind..
and then, here we go again. And RED, your answers are un-jerky.

Overanalyzation (is that a word?) is what I believe this thread should and
has been all about...there are reasons manuals suggest using High-octane
and to go counter to that advice requires thorough justification before any
expensive repairs become necessary to fix damage done, which was the
sole purpose of my question, to ensure I'm not heading down the road to
self-destruction just to save a few bucks.

So, the bottom-line: when all is said and done, it's MY car, it's MY risk to take.
But you've all given me plenty of food for thought and reasons to consider
all the pros and cons, and I thank you all for that.