Whats the highest compression you can run before it will ping and you have to then by higher octan fual???

 

There are SO MANY "IT DEPENDS" situations to that answers.
SOME new vehicles are up to 10 compression.
Some new engines also have NEW IGNTION SYSTEMS TO COMPENSATE for fuel.
SOME new vehicles run with aluminum heads to help prevent detonation.
Stick with 9-ish, you'll be better off.
FYI SOME MAGAZINE ENGINES RUN UP TO 400 plus HP & use 87 octane fuel (these are V-8 engines).
I use 87 all the time I can.
IF I COULD RUN AN ENGIEN ON WATER & GET POWER, I WOULD!!!!

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Chat Soon,
KED85
Karl
1985 Firebird 2.8 to 3.4 swap project for Smog Happy LA, CA

 

Call me crazy, but I've put in high octane fuel for the heck of it and didn't notice anything. Then one of my friends, that happens to work at BP, suggested their Super 93. I said "what the heck, why not?" I actually noticed a little difference! Go figure...

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2.8 mpfi
My only mod: Flowmaster 40 series
check my home page for pics

 

Black 86 'bird
You are 110% right, REMEMBER our 60 degree engines only have 8.5 to 1 compression SO HIGHER OCTAN fuel won't do sh*t for us. ALL OCTAN does it prevent pre-dentanation of the fuel in higher compression engines.

IF you do notice a difference, YOU STILL can't justify the cost because you payed more for the fuel and it's NOT saving you the extra cost.

 

I tell you what I noticed when I ran higher octan: I spend more fuel

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www.marion-becker-nidda.de
91 Firebird 3.1
Modsynomax ultra flow stainless steel -americanracing rims (ar26) rear 15x8 255/60
front 15x7 235/60
www.members.aol.com/tramphorst/pontiacpics

 

Very true...

 

Black 86 'bird
Thats why you have to laugh when people come up to you and tell you they get 2 MPG more with 90 octan that they payed 2 bucks a gallon for and tell you it's a better deal.

LOL

 

I disagree with you. Yeah, I know that higher octanes are designed to prevent pre-detonation, but I really do notice a difference when using 93 than when using 87 or even when using 89. The ride seems smoother. I'm willing to pay a little more for a smoother ride. I also have this theory that may hev no factual basis whatsoever that higher octane fuels are cleaner which is better for my engine. In conclusion, I'm still going to buy higher octane fuels.
Kevin

 

There are two cases where using higher octane gas helps. The first is where you have borderline pre-ignition. This is where it's not strong enough to make a ping or a real knock but it's still a bit rough. The family bus is an '86 and it does this. If I put in a tank of better gas it runs a bit smoother up hills and a slight ticking (like a small exhaust leak) goes away.

The second case is if the engine has a knock sensor that retards the timing if the octane is too low. I've found that when this happens the knock or ping goes away but the engine is still rougher than if better gas is used.

Cheers,

Duane

 

I used to use 87 in my Car and one day tred 92 Ever since then my Gas milage went up so i tried it on m moms 3.1 HGer milage went up. But now all you can get in cali is 91 octaine

 

F_Bird89
I'm not saying it's going to hurt, just saying that it costs more, BUT if you need it for a smoother ride go for it. And I agree that if your engine is under load, your more likely to ping, expecially because the 2.8/3.1 don't have MAFs.

 

In all honesty, I don't see why I (or anyone else) would run a higher octane fuel unless they need to. I understand you would if your engine detonates an lower octanes, but other that that. I usually run the cheap stuff and have no problems. I like to "clean out" the engine every once in a while getting on the interstate and I've had no problems with detonation. For some reason, I did however notice something with the Super 93. Maybe it's all in my mind, but I'd only run it if I go to the track or something... Not a constant thing due to the $$$. BP is high, but Shell is insane!

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2.8 mpfi
My only mod: Flowmaster 40 series
check my home page for pics

[This message has been edited by Black 86 'bird (edited September 10, 2001).]

 

Here is what I have noticed...

My car likes 93, period. With the chip, without the chip, doesn't matter. It likes (and has since brand new) 93. What do I mean by "likes"?? Smoother take off, smoother passing power, and I do get about 1-2 MPG better.

When I used 87 in it (when I first got the car), I said "this thing feels fine, I don't know why my mom always used 93 in it). Then I put the chip in and DAMN, it was smoother. Remember, the chip DID NOT cause this, as the chip only adjusts WOT.

Now I need to use 93 anyways, as without it the chip is of little to no value, as it calibrates the car for 93 octane. Do you NEED it? No. But some cars like it...mine does.

The funny thing is how technology changes things. I can run 89 all day long in my Z28 that is recommended for 93, and throw 93 back in and there is NO difference...and that's a 10.5:1 engine too

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Jason E

'89 Camaro RS
-Medium Grey Metallic
-2.8, A4, T-tops, 94k miles
-Hypertech chip, Accel wires/coil/K&Ns
-Alpine 60x4 and Bostons

'97 Z28
-30th Anniversary package (white with orange stripes)
-LT1, M6, t-tops, 45k miles
-Eclipse CD and 10" Aluminum sub in JL Audio Stealth box, Boston RM speakers, Xtant 403a amp

Speed Kills...Wanna live forever? Drive a Ford.
Long Live #3...

 

BTW, keep in mind that there is only a .15 difference between 87 and 93 (at least around here). For a $1.50-2.00 difference on full tank fillup, I'll take the smoother power. I fill up once a week, so for a maximum $100 difference per year, I'll give the little 2.8 any help it needs

 

umm higher octane does more then cost more . It also increases the mialge of the car because it raises the ignition(flash) point of the fuel. With the higher octane I get more milage. I get 350ish with 12 gallons running 93 oct. I put in 87 I get maybe 270ish if I am lucky. So that extra 8 cents gets me 70 more miles to the tank, so I think its worth it.

 

Camaro_hunter_d
BULL **** there is no WAY you can get 350 miles on 12 gallons of GAS, what the hell you driving a HONDA. THAT would make the mileage 29.16 MPG, there is no way you got 29 MPG with a 3rd Gen. Camaro, what do you have the 4 banger. Man when your going to post something that is BS, do the math first. I don't think you got the tank full. And 93 octan isn't 8 cents more then regular, your thinking of 89 octan, try like .25 cents, AND I LIVE in Houston the GASOLINE capitol in the world.

 

I'm gonna have to call BS on the difference of 70 miles... you may be able to get 350 miles on a tank IF AND ONLY IF you drove straight highway miles for the entire 350 miles... that is not very common, but my mom's honda civic gets 50 MPG on long distance trips (much better than it's 40 MPG normal driving).

There is no way switching ratings will do that. So, what does the higher octane offer? It will smooth out higher compression engines, it will not give you any performance boost at all... the only thing it will do which "boosts" the performance is that your car will drive to the specs that it was designed... that is of course if it needed the octane, otherwise it would not do anything. Last time I checked (may be different due to certain circumstances now) 87 was going for $1.44 and 93 @ $1.58 (NY prices) Since I have a V8, I just buy the 93... I notice no power gain over 87 though (LG4 = low compression V8) but it does seem to smooth out the mid range and idle.

I do not believe 93 is better for the environment... the rating is based on purity of the gas itself... relating to how much octane is actually in the gas (versus pentane, hexane, heptane, nonane, decane etc.) In that sense, the engine will like the consistency better. As always someone that knows better is free to put thier $.02 in... I always welcome more educated info.

 

Camaro_hunter_d may be very correct.
Here's why.
IF the engine is more efficent (POWER/TORQUE wise) then you use less gas pedal to do the work.
Recently I achived 25-28 MPG plus on my 3.4 swap. Freeway milage & high speeds did the job! Plus the torque of my 3.4 engine.
BUT, I only use 87 or the cheapest gas I can use.
Again, I'd run water if I could make it work.

PS That A$$HOLE GOUGER in the midwest (charging $5/gal of gas!) has lost his business. Would you ever, again, patronize a place that does that to the customers? OT ME, I'd drive much further for gas just to let him whistle in the wind, until silence!
WHAT A CROOK!!!

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Chat Soon,
KED85
Karl
1985 Firebird 2.8 to 3.4 swap project for Smog Happy LA, CA

 

It is very possible to get 30mpg with a mix of intown and highway (mainly hwy). I do it every week with 87 gas. Actually I got better than that on my last trip from home to MTU. The roads around here are very hilly and I tend to pass a lot of people. On a straight road with few other cars, I may get better.

If I drive the car hard for a while, I get about 25-27 mpg.

I never tried any higher octane, I feel it is not worth it. Yes I have a 2.8 it has 119K miles on it.

Dale

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1986 FireBird
2.8L MPFI
1/2 CAI
Gutted Cat, No muffler
Was 700-R4 --> Now T5

Great cars aren't bought, they are built

[This message has been edited by 86Chicken (edited September 12, 2001).]

 

You guys aren't getting the tank full each time, your dividing a smaller number then what you should be.

 

No, I am measuring how much fuel I use between fill-ups divided by the number of miles I drove.

I fuel up at the same pump at the same gas station and fill it until the handle clicks once then when I fill up the next time at that pump the amount I put in is how much I used.

Dale

 

Do you all ever Pack your tanks every fill up, try it some time I bet your mileage will go down, BECAUSE one click on the pump or two means nothing, the best way is to pump it each time till you see the full at the top. That way you know you got it full.

I can understand, 25 MPG if you drove highmiles and/or if you have a manual and NOT an Auto and you have the 2.8L but anything after 26 is just not right.

 

Ok you guys do the math. Last time I filled up was yesterday. I was at half a tank(almost exactly on the guage) I out in 7.285 gallons. I have driven 215.9 miles. I regularly get over 330 miles to the tank. And that is with some city driving. straight highway I get closer to 400 maybe a little more depending on the gas I get.

And as I said I also keep a very close eye on my plugs, and timing to make sure both are in the best condition possible. As a matter of fact I checked it(the timing) yesterday to find it 5 degrees out. I out it back into time as well.

You people get up in arms when someone actually gets this type of performance but instead of that you need to see what YOU need to do to get that performance yourself. And just FYI my engine just flipped 104k 2 days ago.

I fill my tank about every 10 days and I always ge over 330 miles and that is not dry or even fumes yet so I know I have another 20 maybe more miles that I can push it if need be. Oh and when I do fill my tank it will usually take around 12.3 gallons.

EDIT I also have a 5 speed trany so yes that DOES make a differance.

[This message has been edited by Camaro_hunter_d (edited September 12, 2001).]

 

When I swapped in the manual my mileage went up 5mpg. I used to average 25 with the auto. I also don't ride the gas too hard like most people I know.

I see your point but if look at the mileage over the past year the average is right around 30 so I am pretty confident in my method.

If you do not want to believe me, that's fine. My friend with a high mile carbed 307 gets 23mpg with a 4200lb Olds. If he would clean the junk out of his trunk he could probably get 24+mpg.

In fact 30mpg with a small displacement V6 in a pretty aerodynamic car is not as good as it should be, I think that with some extensive PROM tuning, 35mpg should be possible.

Dale

[This message has been edited by 86Chicken (edited September 12, 2001).]

 

I cannot justify the use of 93 octane fuel, however if I ever get a job I'll try it. However, the reason why I use plus (89) is because my timing is pretty advanced, and I use the higher octain fuel to quiet the pinging...

Since fixing some major problems, I have yet to calculate my gas milage... however with my timing very far retarded, and the connection on my O2 sensor a little fritsy, I was getting just about 15 MPG...

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1985 Camaro SC - 2.8L, auto.

http://www.xenodrgn.f2s.com/Frontright.jpg

 

Case in point. my car is IN TUNE. If you fix whats wrong you will see an obvious improvement. I'm not raggin on ya or anything but just sayin.

 

To quote a friend of mine... "It's an American car!! It's made for sh*t gas!"