: How much does fuel matter?



bsteven43
02-04-06, 04:13 PM
Will I notice a performance drop by using 87 or 89 octane versus premium?

1MEANV
02-04-06, 04:16 PM
Yes

1MEANV
02-04-06, 04:29 PM
Run 87 In A Race Car

1MEANV
02-04-06, 04:29 PM
Run 87 In The V Shit I Dont Even Run 87 In My Yamaha Raptor

04CTSVFLA
02-04-06, 04:47 PM
why would u do that

V Amazed
02-04-06, 04:50 PM
may start to notice knocking.

Ben

heavymetals
02-04-06, 05:09 PM
Don't use any additives in the fuel either.:thepan:

A couple of guys here did that and thought they killed their ride.

verbs
02-04-06, 05:21 PM
Don't use any additives in the fuel either.:thepan:

A couple of guys here did that and thought they killed their ride.

Depends on the additive.....Torco and Toluene/Xylene (in small doses) won't do anything.....but everything else, yeah I agree.

verbs
02-04-06, 05:24 PM
Will I notice a performance drop by using 87 or 89 octane versus premium?Your car will go into "low octane" mode and your PCM will reduce the timing in your car which equals less power.

Think of it this way, high octane is like bottled water and 87 octane is like Mexican tap water. ;)

rand49er
02-04-06, 06:26 PM
... your PCM will reduce the timing in your car which equals less power ...:yeah:

Florian
02-04-06, 07:26 PM
You have the high octane table and low octane table in your PCM, if you run the crappy low octane, timing gets pulled and you effectively lose HP/TQ as a result. Spend the extra 20 cents/gal and treat your car right.


F

dqw1
02-04-06, 07:47 PM
What Octane are you guys running? I use 92

Koooop
02-04-06, 07:49 PM
The display will light up with a warning that states...

BUY A HONDA!

Geno
02-04-06, 09:26 PM
The display will light up with a warning that states...

BUY A HONDA!


:yeah:
How bout a Chinese Cherry!

CIWS
02-04-06, 10:00 PM
The display will light up with a warning that states...

BUY A HONDA!

That's pretty funny...:histeric:



Try to run at least 91 octane. If you run the math there really shouldn't be that much of a difference per tankful. 10c difference at 17 gallons would be the difference between paying 39.00 for a fill up vs 40.70. Fill her up three times a week and your talking one trip to a Starbucks for a single cup of fancy java.

04CTSVFLA
02-04-06, 10:11 PM
ive added gumout before (one occasion) and it worked great! I almost felt my car being cleaned while I drove it. And gas mileage is slightly improved.

cts-v ls6
02-04-06, 10:54 PM
The difference in price in Memphis between 93 and 87 octane is 20 cents per gallon. I've had the V 1 year and put 51k miles on her. I took her to DTE in Ft. Wayne, IN and had her dyno tuned to run on 87 octane. She pulled 361 rwhp, and runs like a top--no knocking and no detonation, even in 6th gear at 40mph. Most of my driving is highway, and at 70 mph, 2k rpm, I'm getting 25-26 mpg. If you average in the city driving, I'm probably averaging around 22 mpg. The math shows a savings of $460 plus per year. I keep the car 5 years, I've saved $2300. Phil at DTE told me I gave up about 10 rwhp by using 87 octane instead of 93 octane. Big deal. This car is amazing, and if you put thought into your mods, you can have your cake and eat it too. My .02.


Jack

verbs
02-04-06, 11:32 PM
The difference in price in Memphis between 93 and 87 octane is 20 cents per gallon. I've had the V 1 year and put 51k miles on her. I took her to DTE in Ft. Wayne, IN and had her dyno tuned to run on 87 octane. She pulled 361 rwhp, and runs like a top--no knocking and no detonation, even in 6th gear at 40mph. Most of my driving is highway, and at 70 mph, 2k rpm, I'm getting 25-26 mpg. If you average in the city driving, I'm probably averaging around 22 mpg. The math shows a savings of $460 plus per year. I keep the car 5 years, I've saved $2300. Phil at DTE told me I gave up about 10 rwhp by using 87 octane instead of 93 octane. Big deal. This car is amazing, and if you put thought into your mods, you can have your cake and eat it too. My .02.


Jack

[Devil's Advocate]

Correct me if I'm wrong, but in theory, less timing=worse gas mileage. I'm sure it's not THAT big of a difference but that probably cuts into your "savings" on gas.

I'm also thinking that the difference in timing one can run between 6 points of octane (87 to 93) should equate to more than 10rwhp. Just curious, how much timing are you running now, and how much timing were you getting stock?

[/Devil's Advocate]

arr0gant
02-04-06, 11:51 PM
Might as well just poor 16 gallons of water in it.

Stangar
02-05-06, 10:05 AM
BUY A HONDA!

. . . . and then you won't have to see the inside of a Cadillac service waiting room again.

6104696
02-05-06, 10:22 AM
I put 87 in my car by accident once. I felt a noticeable decrease in performance from the change in the timing map. I suppose that you could have the car "tuned" to have a slightly better timing map for the cheap gas....but if I wanted to optimize the car for lower performance I might as well have gotten a V6.

I'm glad that you are getting "good" performance from your detuned car, but whatever you are getting, if you optimize it for 93 octane your performance will be improved, and so will your fuel mileage to some extent, thereby "mitigating" any savings.

Saving a few cents on gas by detuning a 400 hp performance car, where you are paying over $10K for the performance aspects, is an interesting economic analysis.

CIWS
02-05-06, 11:39 AM
The difference in price in Memphis between 93 and 87 octane is 20 cents per gallon.

Jack

I was referencing running at the minimum of 91 octane. As of today where I live it's about 12c betwen 87 and 91. To 93 it is 20c. But still looking at what I personally spend every day /week on non-essentials, coffee, energy drinks, BS snacks, etc or for that matter even one time ordering out a pizza once a month. Any of those could be easily "sacrificed" if I had to in order to spend the few cents difference at fill up. But that's just my personal take on how I run my car.

verbs
02-05-06, 12:06 PM
The difference in price in Memphis between 93 and 87 octane is 20 cents per gallon. I've had the V 1 year and put 51k miles on her. I took her to DTE in Ft. Wayne, IN and had her dyno tuned to run on 87 octane. She pulled 361 rwhp, and runs like a top--no knocking and no detonation, even in 6th gear at 40mph. Most of my driving is highway, and at 70 mph, 2k rpm, I'm getting 25-26 mpg. If you average in the city driving, I'm probably averaging around 22 mpg. The math shows a savings of $460 plus per year. I keep the car 5 years, I've saved $2300. Phil at DTE told me I gave up about 10 rwhp by using 87 octane instead of 93 octane. Big deal. This car is amazing, and if you put thought into your mods, you can have your cake and eat it too. My .02.


Jack

If I saw you putting 87 in a CTS-V I'd steal your cake :yup:

Koooop
02-05-06, 05:36 PM
. . . . and then you won't have to see the inside of a Cadillac service waiting room again.

My brother in law blew 3 transmissions (among other things) in his '01 Acura, his wife's '04 Pilot pooweed a tranny already...

I'm happy I don't have the see the inside of a HONDA waiting room, they probably have hard plastic chairs!

Vdrenaline
02-06-06, 12:26 AM
The manual says it can run on 87 octane but when I tried it, the engine knocked terribly. I then tried 89 and it still knocked. 91 was OK but not great. I don't want to damage the engine so I now use the highest octane I can get. Suggest you do the same.

Mat347
02-06-06, 02:51 PM
The knocking should have auto-corrected itself. I run Shell 93...I can feel a difference in part throttle performance when compared to Mobile/Exxon 93..WOT seems the same though.

I've used 87/89 and find myself using much more throttle to get on the freeway and passing people.

atdeneve
02-06-06, 03:05 PM
Mat347, which was better: Shell or Mobile/Exxon? Shell s'more expensive, right?

verbs
02-06-06, 03:36 PM
Shell is better from a study I read a while back, but more importantly don't fuel up if you see a tanker leaving the gas station as you're pulling up, or if the tanker is adding fuel. You'll get a bunch of deposits in your tank as a result.

M5eatr
02-06-06, 03:57 PM
Alot of myths being propogated here. Do a google/yahool search and you will come up with that higher octane doesn't equal more power. Actually the contrary could be true. Octane rating means that the fuel is less likely to detonate, so sometimes you will need a higher energy ignition to fully burn the fuel. I have used 87 without any problem. Will can attest that my car "ran well." Here is an excerpt.

Effects of octane rating
Higher octane ratings correlate to higher activation energies. Activation energy is the amount of energy necessary to start a chemical reaction- since higher octane fuels have higher activation energies, it is less likely that a given compression ratio will cause knocking.

It might seem odd that fuels with higher octane ratings burn less easily, yet are popularly thought of as more powerful. Using a fuel with a higher octane lets an engine run at a higher compression ratio without having problems with knock. Compression is directly related to power (see engine tuning), so engines that require higher octane usually deliver more power, though this is not a product of the fuel, but rather the engine. Some high-performance engines are designed to operate with a compression ratio associated with high octane numbers, and thus demand high-octane gasoline. It should be noted that the power output of an engine also depends on the energy content of its fuel, which bears no simple relationship to the octane rating. A common myth amongst petrol consumers is that adding a higher octane fuel to a vehicle's engine will increase its performance and/or lessen its fuel consumption; this is mostly false—engines perform best when using fuel with the octane rating they were designed for and any increase in performance by using a fuel with a different octane rating is minimal. On the other hand, using the recommended octane for a modern engine makes a huge difference compared to a lower than recommended octane. Here is a white paper that gives an example: http://dinancars.com/whitepapersFile.asp?ID=9 .

The octane rating was developed by the chemist Russell Marker. The selection of n-heptane as the zero point of the scale was due to the availability of very high purity n-heptane, not mixed with other isomers of heptane or octane, distilled from the resin of the Jeffrey Pine. Other sources of heptane produced from crude oil contain a mixture of different isomers with greatly differing ratings, which would not give a precise zero point.

M5eatr
02-06-06, 04:02 PM
Also, Gasoline is all the same. Shell, Chevron, BP etc all fill up their tankers at the same distribution centers. They then put all the additives to increase the octane and cleaners and whatever other additive they may advertise. If you look at the mec exchange, prices are only for unleaded gas, not 87, 91, 93 or whatever. All gas is the same and has the same energy. Different fuels such as alcohol, top fuel, jet fuel is different, it is not "unleaded gasoline" and does have higher potential energies.

cts-v ls6
02-06-06, 07:54 PM
M5etr,

Right on, right on, right on!!!

Jack

CIWS
02-06-06, 08:08 PM
snip

Thanks for passing on all of the fuel info.

Now tell me honestly when you fill up your performance cars you have listed. Do you always use 87 octane ? If not then which ?

M5eatr
02-07-06, 01:03 AM
Honestly, I first start with the higher octanes and then work down. No knock or ill effects, I use it. My V is on 87. Any brand, Getty, BP, Shell, Citgo, whatever. I met Will at a gas station last week and I was filling with 87.

The CPU's are designed to sense knock not octane amount. I would assume that a knock would have to occur before the computer would step in, much like the other stuff like abs, traction control, and stability control. So if there was going to be a remap, you would at least hear or feel one knock.

Luna.
02-07-06, 01:15 AM
I use premium unleaded and would only use such, regardless of whether my V was blown or not.

It has nothing to do with performance, but more to the point reliability.

Knock will seriously screw up a performance motor in a hurry if it's not monitored.

And, oh by the way, not all knock is audible...

Yes, I agree that fuel prices are egregious. Yes, the amount of refining that the oil companies do to the fuel to up the octane is minor and not necessarily worth the additional ~$0.20/gallon, but come on---what are we talking about here---~$3.40 per fill up, if that?

I'm all in favor of controlling costs, but I'm not sure this is where I'd necessarily cut my budget...