Road trip question

2210 Views 25 Replies 12 Participants Last post by CavemanB52, Mar 9, 2015

caveman728

Discussion Starter · Mar 2, 2015

I'm headed from Tampa to Knoxville for a funeral this weekend. I think I'm taking my V. Here's the question: Do you have to put 92 octane gas in the V's, even if you're just on the highway? Saving that $.50 per gallon will add up on a long trip like that. I know it will rob power, but will it hurt anything? I know my Escalade used to call for Premium, but we always put 87 in it, no harm done.

Thoughts?

Thanks all.

CAVE

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Crystal Red CTS-V

· #2 · Mar 2, 2015

Not a problem as long as you don't hammer it, but your mpg's will be worse as it will try to make up for the lower octane by reducing efficiency. Why would anyone who's driving a V not feed it what it deserves?

vfaninva

· #3 · Mar 2, 2015

You didn't scrimp on the car, don't scrimp on the gas.:tisk:

Reactions: 1

caveman728

Discussion Starter · #4 · Mar 2, 2015

it seems to me to be a total waste of money to use premium gas when you're on cruise control at 75 mph. THere's a difference between scrimping and being frugal. I've never put anything in it but premium, but it's never been on a long trip like this either.

garfin

· #5 · Mar 2, 2015

Consider it from the standpoint of the cost of fuel now vs. what the cost was a year ago! That might put it in a different perspective.
We returned to the Toronto area during the 1st week in Feb. after 6 weeks in Englewood/Cape Haze and did the Knoxville-Tampa run on I-75... a drop in the bucket compared to the Toronto-Tampa drive. I didn't take the V on the trip because I didn't want to be driving that length of time in FLA on my winter tires and I wasn't gonna change over to the PSSs before the trip, just in case we ran into bad weather. (which we did - had to hole up in Erie PA for 2 nights because of the storm at the beginning of Feb.)
We took our '07 SRX (AWD V8) which yielded 18 mpg (U.S gallon) at 80 mph completely loaded down, which is actually a bit worse than my manual V. I was almost laughing at the gas prices (We were paying about $1.95 a gallon for 87 Octane in FLA/GA etc.). At home, we're been paying around 95-98 cents a liter which is a bit less than $4.00/U.S. gallon and I still ain't complaining! 94 octane is approx. $1.25 liter here.
Take the V and put in the highest octane you can - that way you don't have to think twice about flooring it if you have (want) to!
Drive safe!

Best regards,

Elie

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caveman728

Discussion Starter · #6 · Mar 2, 2015

while I'm venting, why is premium so much more expensive that regular? I can remember when ratings were only separated by $.10 per gallon. Granted, It may have been quite a while ago!

And, thanks for the responses. I guess what I'm hearing is that I'm being a cheap ass, and it doesn't matter if I'm throwing away some money.

vfaninva

· #7 · Mar 2, 2015

caveman728 said:
it seems to me to be a total waste of money to use premium gas when you're on cruise control at 75 mph. THere's a difference between scrimping and being frugal. I've never put anything in it but premium, but it's never been on a long trip like this either.

You're right. Nothing wrong with being frugal. Being frugal is what helped many of us to acquire our V's.
Having said that, I doubt it will cause any damage to your V. It will at least rob power though.
Figuring the round trip from Tampa to Knoxville is about 1,500 miles, at 20 mpg it should take about 75 gallons of gas. With a savings of fifty cents per gallon you keep about $37.50 in your pocket.
For that amount of savings I'd go with premium and keep all 556 horses kicking.

Reactions: 2

caveman728

Discussion Starter · #8 · Mar 2, 2015

well, shit. when you put it that way, what's $37.50? Maybe I'll even kick it up a few MPH. After all, gas is cheap these days.

CVP33

· #9 · Mar 2, 2015

Agree with everyone above. I'd also add that your car will also 'learn' the low octane fuel tables once it starts experiencing repeated spark knocks. No damage, but not good from a performance standpoint as you will lose some power.

CTSVsport

· #10 · Mar 3, 2015

X2 on doing the math - it's not that much money.

If you had a NA engine, the discussion would be different

neuronbob

· #11 · Mar 4, 2015

vfaninva said:
You're right. Nothing wrong with being frugal. Being frugal is what helped many of us to acquire our V's.
Having said that, I doubt it will cause any damage to your V. It will at least rob power though.
Figuring the round trip from Tampa to Knoxville is about 1,500 miles, at 20 mpg it should take about 75 gallons of gas. With a savings of fifty cents per gallon you keep about $37.50 in your pocket.
For that amount of savings I'd go with premium and keep all 556 horses kicking.

You and your logic and your math and your common sense!

This is exactly the argument I use for always using premium. I've done several major (4k mile plus) road trips in my wagon, always used premium, and it really doesn't add significant cost.

tdyguy2k

· #12 · Mar 7, 2015

Over half of the mileage on my V is from road trips. One from Ohio to VA Beach, and two from Ohio to Florida. One of the trips to Fla. was circuitous, Ohio to VA Beach to Jacksonville. On the way back we took the long way through New Orleans and up the Natchez Trace Parkway. All toll about 4000 miles. Never used anything but premium. You just never know when you'll strike a fancy to have some highway fun with the loud pedal. And returning from a funeral, that may be just what you need to lift your spirits.

Reactions: 1

the blur

· #13 · Mar 7, 2015

The computer will retard the timing if it hears detonation. No harm done. You can even alternate from regular to premium fuel. I do this with my Hemi. Never heard detonation. You can be sure the engineers planned for this, as they don't want to be replacing motors every time someone can't find premium fuel.

CTSVsport

· #14 · Mar 7, 2015

the blur said:
The computer will retard the timing if it hears detonation. No harm done. You can even alternate from regular to premium fuel. I do this with my Hemi. Never heard detonation. You can be sure the engineers planned for this, as they don't want to be replacing motors every time someone can't find premium fuel.

Yes, at the expense of power and mileage. If you have a high compression engine and are experiencing detonation, you need higher octane (and that's the only time)

the blur

· #15 · Mar 7, 2015

CTSVsport said:
Yes, at the expense of power and mileage. If you have a high compression engine and are experiencing detonation, you need higher octane (and that's the only time)

I do not believe MPG will drop with lower octane. In fact, MPG drops 25% with Ethanol, which is much higher octane.

Trapspeed

· #16 · Mar 7, 2015

the blur said:
Never heard detonation.

And some of it you'll never hear. Gotta love knock sensors!

CavemanB52

· #17 · Mar 8, 2015

the blur said:
I do not believe MPG will drop with lower octane. In fact, MPG drops 25% with Ethanol, which is much higher octane.

Mpg drops with ethanol for a whole different reason. Ethanol does not hold the same amount of hydrocarbons for a given volume. Thus you need more of it to burn for a given fuel/air combustion cycle. This is true of regular vs premium also. Thus the confusion of why premium results in a bit better mpg over regular and even more so over E85. Bringing Octane into the discussion to compare mpg just confuses the matter. Octane can be better discussed as the higher the octane the higher the stability the fuel has and therefore the more pressure the fuel can take before detonation prior to the addition of spark. Thus some tend to say high test or when speeking of race fuel burning colder.

----------

BTW i agree... Trying to save money by putting 87 in a V is a bit like taking an hour to plan a perfect route that saves the most time. But when you finally come up with your plan you realize it saves you an hour. The hour already waisted getting the perfect plan.

CTSVsport

· #18 · Mar 8, 2015

The knock prevention is what will decrease mileage.

You should always run the lowest octane fuel that won't pre-detonate.

CTSV UT

· #19 · Mar 8, 2015

^^^Ethanol doesn't have as much energy per pound as gasoline but, has a higher octane rating. Octane has basically nothing to do with MPG unless the computer has retarded the timing with the same fuel type. The Octane rating is basically the flame front speed (there is a little bit more to it than that). The higher the Octane the slower the flame front and therefore the higher the compression can be because the higher compression, the faster the flame front is with the same type of fuel. Typically (everything else being the same) the higher the compression the more power the motor will generate. If you want to run 87 octane try to make sure you never go into boost. Yes, the computer will retard the timing when it detects knock but, any knock puts extra stress on the rings, pistons and bearings and the knock has to occur before the computer can detect it. Personally, I would just always run 91 octane or better and not ever take the chance.

CTSVsport

· #20 · Mar 8, 2015

Actually, flame front speed is a result, not a cause. Octane rating is a representation of the fuel's resistance to detonation. It's more accurately looked at as a "flammability" rating. Lower octane fuels generally make more energy available during a combustion cycle, but may detonate at higher compression ratios, which creates huge stress on the engine.

"Compression ratio cures all". Higher compression both increases power and efficiency.

At the extreme, look at Diesel engines. Lower energy fuel, but very high octane and very high compression ratios lead to much better torque and efficiency, but the engines have to be built very heavy in order to be strong enough to withstand the detonation.

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