Hi!
I just got my Crossfire only a week ago, so I have a gasoline question for all you knowledgeable owners out there.

I know the gas cap says "Premium Only". Gas station has 3 choices. Unleaded, Unleaded PLUS, and Premium Unleaded. Can I get away with using the Unleaded PLUS or do I truly need to stick with Premium Unleaded? Question of economics, ya know.

Thanks in advance.

 

See earlier thread:

https://www.crossfireforum.org/forum...ead.php?t=8460

 

Thanks Maxxm for fast reply!...still leaves me wondering what I can get away with though. Hmmm..."fuel for thought".

 

Before you consider saving 10 - 20 cents per gallon, check the price of a new cat converter.

Pete

 

Thanks Pete. I am beginning to regret asking this question. I was serious about it. I am not cheap, but since Premium is over $3.15 a gallon, I wanted to consider other options. That's all. I truly wanted to know...not just to save money, but wondering if it can be done, that's all. I thought it was a reasonable question. If I had seen the previous thread, I would not have asked a question that has been discussed before...especially when someone suggested that people who wanted to save "a few cents" were cheap. Anyway...

Thanks for your reply.

 

I've been using 87 octane in my "premium" cars for a number of years. There is a very slight (and I do mean slight) performance change, but that's all. No problems of any sort.

 

Yeah depending how you drive and where and how much!!! I would never except in case of emergency! Put reg -gas is a premium recommended car! Besides the knock damage why? You WILL GET BETTER GAS MILEAGE with premium and the 10% or less difference will be $0 in cost except for engine damage and warranty!

 

Hey, that's My Thread!!!

Glad to know I make a difference...

 

I sell these things and let me tell you I have people call me asking the same question. I tried it in mine and there was a serious difference/drop in performance and mileage as well. I refer to the owners manual in the Audi book and it states that there will be a drop in performance when dropping the points of the octane.

I have learned to curtail the use of the A/C, drop the windows at lower speeds and raise them as you go faster. Or if you Need the A/C use it with the recirculate button and cycle. Meaning, when the interior temp is comfortable turn the A/C button off and the recalculate button on. After a while the interior temp will drop and you simply repeat this process.
It helps a lot let me tell you. I've tested it several times. But the best way to save gas is to roll the windows down a little and cruise. Especially if you're the only one in the car.

 

This may or may not save you gas. Rolling the windows down will disrupt the airflow over the car and increase drag, causing your gas mileage to drop. It will depend on the efficiency of your A/C system as to whether the increase in gas mileage will offset the drop from having the windows down.

 

Sure. You can get away with using Plus...or even Regular. And...you'll save at the pump doing so.

In fact, you'll save a lot of money...that is until you destroy the engine due to the increased knock/detonation and significantly higher internal operating temperatures caused by that lower-rated fuel. At which point you will spend even MORE money on overhauling that engine several years before you'd otherwise have needed to.

I've not had to do an overhaul in quite some time. But, my guess is that an O/H on one of our engines will run somewhere in the $4000+ range...assuming it is done properly, of course.

We won't even mention all of the additional damage to the engine and transmission which was incurred because you were at (or well above) speed on the motorway when it all packed up, locked up, and took a powder.

Gee. Saving a dollar or three at the pump suddenly doesn't seem quite so much the bargain now, does it?

Nice cars are like pets: If you can't afford to feed them, then perhaps you shouldn't have taken one home in the first place. If you just want to destroy something...focus on the neighbours kids instead. They're undoubtedly more deserving.

...sT

 

We had an eclipse 2002, it said to use premium. We used regular, well in about 3 week time we were bringing the car in for service. A sensor went bad from using regular. My .02C

 

When we bought our cars it said premium only. We accepted this extra cost for fuel at that time.

 

CISSY, darling... if you don't plan on keeping the car much after the warranty expires then go ahead and burn 89 octane. I just feel bad for the person who buys your used car.

 

It's like...

Buy all your clothes at K-Mart and WalMart...

BUT DON'T got to Pennys or The Gap...

NO WAIT!!!...

Buy your clothes at a "Welfare Used Clothing Shop"...

it doesn't matter how you look...RIGHT???

Save a few dollars...

 

Washington Post ran article that debunks premium myth. Cars have computers that sense octane and readjust. They said, that only noticeable change may be slight hesitation at high speed passing. I have been using regular gas for two months and can see no difference.

 

Oh Boy, you'll get alot of debate over this one. Especially when it comes to pre-firing caused by lower octane and the engine parts that will fail with repeated pre-firing... Get ready for some serious engine repair at 50,000 +/- miles.

Post your VIN # in the forum so we can track the life of your engine after you sell the car... And hopefully warn the poor bast*rd that buys it...

 

I watched that report from DC, and it was and is WRONG. Its true that sensors can make small adjustments for a limited time, but not enough for you to continually run lower octane. If you don't see a difference, your car and it's sensors do. The last thing an auto manufacturer wants to do is tell you to spend money on something they don't sell or control. If it didn't require premium, they wouldn't tell you to buy it. Someone said it very well above, If you can't afford one, maybe you shouldn't have taken one home. If you need to save money on gas, GO BUY A PRIUS!!!

 

I believe the following explanation by the makers of Powerchip speaks to what a factory tune on the ECM will accomplish....

Is Powerchip smarter than the manufacturers?

Most vehicle manufacturers these days have multi-billion dollar research and development budgets, and great people with a passion that can create cars that are reliable, well built, and enjoyable to drive. A good example to use in this situation is BMW Motorsport, in particular with their M3 and M5 models.

The software engineers have produced a great software program, with impressive power and torque. But it is a still, unfortunately, a compromise as all production (road) cars are.

Powerchip has the ‘easy’ task of only improving a tiny element of the cars overall operation, by tweaking the already good mapping that has been created by the factory.

The engine management system itself, no matter how fast the processor, or how high the resolution (size) of the maps, is only as good as the values in the lookup tables for ignition advance angle (timing) and injector duration (fueling).

And those tables are compromised to allow for poor fuel, excessive carbon buildup, poor servicing and maintenance, fuel economy, California emissions, production tolerances to allow for vehicle aging, minimizing warranty claims, and varying markets around the world, and even driving abuse.

That said, BMW are not alone in building-in production tolerances, Powerchip also must make allowances for the above, it's just that we can specify more aggressive tolerances because we only sell to enthusiasts.

Performance chip companies all around the world have been producing performance chips for over 15 years that can increase power through modifying the ignition and fuel.

So the concept of changing a chip to effectively gain power, performance, acceleration, throttle response raised rev and speed limits and improved drivability can really not be questioned. As long as the chip is well designed, and from a reputable company, most people would agree that the number of positive reports far outweigh those people who are dissatisfied after having purchased a performance chip.

The question that needs to be addressed is, specifically, can Powerchip improve a particular vehicle type, by changing the engine management software?

So the argument is not "are Powerchip smarter than the vehicles manufacturer?", it is simply, "can Powerchip do what we say we can do?"

Let’s pick an example: the 1999-2001 BMW M5 4.9 V8 software is compromised in the following areas -

• The ignition timing is not advanced to an optimum level on part throttle for maximum power and torque.
• (The ignition timing is not advanced to an optimum level on full throttle on 92.5 octane or above fuel for maximum power and torque. Not relevant for California drivers)
• The air fuel ratio is not set at an optimum level on full throttle for maximum power and torque. (The stock car runs a touch rich)
• The throttle response is not aggressive and can be improved on "sport" or "normal" mode
• The car is not as smooth in transient throttle conditions as it can be
• The engine rev limit is set slightly below its safe level
• The speed limiter restricts the vehicles top speed
• Some aftermarket modifications change the vehicles requirements for ignition, fuel or adaptation

All of these statements are true, even on 91 octane fuel

The claims made by Powerchip for the BMW M5 software are -

• Improved power on part throttle (2-5 hp at 75% throttle on 91 octane)
• Improved power on full throttle (7 hp on full throttle on 91 octane)
• Improved throttle response in both sport and normal modes because the rates at which the throttles open is increased
• The car acceleration feels smoother
• The engine rev limit is raised by a few hundred rpm
• The speed limiter is removed, allowing the car to attain a natural top speed
• The software is designed specifically for each M5 owner, and is adjusted slightly for cold air intakes or free flow exhausts

An argument is put forward that the M5 (and many other late model electronically fuel injected vehicles) "automatically adapts" to each fuel type or grade that is used.

The assertion is that when 91 octane gas is used, the car produces adequate power. When 93 octane is used, it produces more power than 91, and when race gas (say 100 octane) is used, the car produces more power yet again.

Powerchip has found that the M5 does adapt (somewhat) to the octane rating of the gasoline being used at the time in question, and can and does advance or retard the ignition timing, according to preset algorithms contained in the software and knock sensor feedback.

Where the specifics need to be explained is in the M5’s ability to optimize the ignition curve for fuels above 92.5 octane.

I am sure that most of us are aware of the confusion that exists in regard to octane ratings, mainly because North America uses a unique measurement system for measuring this fuel quality. Pump octane is a measurement of two important measures of the fuel’s ability to resist knock (pinking, pre ignition, detonation etc), RON and MON.

In Europe, the M5 is designed to use 98 RON fuel exclusively. A label is placed on the filler cap, and on the instruments, and owners manual, MINIMUM 98 RON. In North America, the equivalent fuel is 92.5 pump octane. Basically, US pump octane is (RON+MON/2)

Those wanting specifics and formulas can go to http://www.powerchipgroup.com/articles/PET0605.pdf

In my research, I am yet to find a fuel in Europe higher than 98 RON, and the M5 is not DESIGNED to use fuel that is not readily available in Europe.

In our testing on 98 RON fuel, (In Australia) Powerchip has found that the car will develop more power by using advanced ignition timing.

This is the reason that the Powerchip for 91 and 93 octanes produce different power and torque.

By running 93 or 94 pump octane fuel, which is readily available in most states except California, we have found that small but important changes can be made to the ignition advance to improve power on full and part throttle.
If the question is specifically, will the M5 produce more power by using fuel higher than 92.5, the answer is yes.

If the question is will the M5 automatically adjust (advance) the ignition timing for fuels above 93 octane, the answer is no, as the car is not designed to run on fuels above 98 RON in Europe. Using 93 pump octane, an M5 will not be ‘pulling ignition retard’, as the knock sensor is not requesting the car to retard the timing, it will be requesting to run the timing value in the lookup table, and not adjusting or adapting it downward like it is always doing when poor quality gas is used.

The knock sensing abilities on the M5 (and M3, in fact any late model BMW engine) are so good, that the driver cannot feel the ignition timing being retarded continually.

But if you were to ask "can the difference be felt or measured in running 91 compared to 93 or 100 octane", the answer is a definite YES.

The last point to be clarified is if the car is not advancing the timing by running 100 octane as opposed to 93 octane, how the heck can it be producing more power? 100 octane fuel is better quality, and has different properties such as density that changes the flame front and the way the fuel burns. Unless the engine is high compression, and running significant amounts of ignition advance, the benefits of very high octane fuel are lost on most ‘normal’ engines. The M5 engine for example, however will produce slightly more power by running 100 compared to 93, but not significantly more.

As an aside, the air fuel ratio is unchanged by running 91 gas compared to 93 gas.

For those considering running the Powerchip Gold 93 software, should they decide to run 91 octane for whatever reason, the ignition timing will automatically retarded, and the car will run the correct amount of ignition advance to suit.

When 93 gas is used, the car will advance the ignition timing up to the level requested by the Powerchip. Under no circumstances does Powerchip reduce the built in safety, and allow the car to detonate or ping if 91 gas is used on a 93 program.

 

My dealer said, you can use the mid-grade with no bad effects as long as you are at sea level.

San Diego Bob