Rincewind

i filled up my car from empty to full with sunoco 94 octane super premium gas!

holy crap. i noticed faster accel off the get go right away...

anyone know if theres any downsides of using it? the manual says 93 octane is recommended and im just wondering if using higher octane would do any harm.

Rincewind

and my spare is sitting in my garage btw!

JAM

There are some Sunoco stations that have 100 Octane racing fuel. I've tried it in a few of my cars.... no ill effects, just lots of power... Very noticeable difference.

2~s0L~t

I sell them by the family, Rince... You can place them at the rear wheels and they will run like crazy adding an amazing 20-30hp boost. Just slightly more than the amazing TORNADO!

$30.00 includes 2 parents, 3 siblings, and two wheels -- Shipping is free on a group buy!

Rincewind

rofl

davis449

Since this is a posting about fuel, I was gonna ask if it was ok to add OCtane booster to my C. Of, course the manual says not to do it, but I think that's just B.S. cause almost every manual I've seen to cars tells you you don't have to/shouldn't use fuel additives. If it just increases the octane level of yougasoline, what's the problem? This isn't something I would do on a regualr basis, but I was thinking of putting Chevron 93 (93 is the highest available where I live) octane and a bottle of octane booster, just to see what it does.

2~s0L~t

i will give you the kleemanized package. this guys makes that pulley vrrooooooooooooooooom! only 99$ plus s/h...

final offer bro... this is the last kleemanized rat i own... he is dyno'd at 132hp!!!

mr_man12

Does higher octane fuel really increase your HP though? If you use fuel that is too low in octane % for your engine, you'll get knocking (combustion on compression instead of at spark from the spark plug) ... but I didn't think using higher octane % increased HP?

JAM

Not sure if it gives you more HP, but definately more OOMPH, of course it very well be in my mind, considering I paid $3.50 per gallon for the 100 Octane, maybe I just made myself believe it was better.... Perception is Reality

E55AMG99

Example...Higher octane will allow your engine to make maximum power but only to a point. In other words, if max power is achieved with 94 octane, using 100 octane is just a waste of money. If you use 91 octane, the engine will detonate (ping) and the ECU will retard the timing resulting in less than maximum power.

As for octane boosters, I'd stay away from them. Since it is impossible to bottle pure octane, they resort to a variety of methods to increase the octane rating of the gasoline. Some of these methods include extrememly harsh chemicals that if spilled or not mixed properly can cause damage to all sorts of things. I've used it in several race cars over the years when fuel quality was suspect without harm but I pre-mixed it in a fuel jug before filling my fuel cell.

If you have access to the good stuff (93+) at the pump, use that instead of the boosters.

mr_man12

Yeah I think all high octane means is that the gas won't blow up when compressed as easily as lower octane gases. Engines with a high compression ratio (air is compressed in the cylinder at a relatively high level) need high octane gas to match the compression ratio. Excess octane doesn't hurt, but it doesn't help either I don't think unless you're getting knocking with lower octane fuel. Somebody correct me if I'm wrong on this.

Diesel gas is just the opposite, it is supposed to blow up under compression ... diesel engines have no spark plugs but much higher compression ratios than engines with spark plugs. Just thought I'd throw that in here ...

E55AMG99

You get the idea

C280Sportster

Hmmm, higher octane shouldn't make a difference in our cars (from what I've read). Now, in cars with a new CPU that is programmed to adjust, you might see something. If you read all those threads (which always turn into arguments, lol) about this chip or that chip, they have different dyro result using different octane.

I don't really know if our stock cars are faster, but I'll say this, in my J30, I put in 94 octane and did get 20 mpg instead of the normal 19...now of course, there might have been other factors (less city driving), but, I believe my driving habbits are the same week to week.

I am doing MPG test with my J30 and I'll be glad to keep everyone posted, I just changed my oil to mobil 1 10w-30, next I will add a cold air intake with a cone filter...

Then i will replace the snow tires with real tires (probably be winter when i get around to this).

I'm trying to get 24 MPG out of this car.

Maybe I'll test out Boush 4 plugs, etc.

As far as more power with our MBs, I'd like to get EVOsport's underdrive pully(s) to start with...I'd also chip it, if I could get 8-10 HP, but I don't think that's possible.

E55AMG99

What Rincewind experienced when running lower octane fuel is an indication that his car was experiencing enough detonation that the ECU retarded (adjusted) the timing to compensate. The higher octane he filled up with allowed the engine to achieve maximum power as tuned.

According to MB, both my CLK430 and E55 require premium fuel of at least 91 octane. However, many factors like temperature, load, altitude, humidity, engine tune, etc. will have an impact on real world octane requirements.

Best of luck in getting another 20% mileage improvement. MAy I suggest a lighter set of shoes?

C280Sportster

LOL! Thanks...

Well, Edmonds says the car gets 18/23 average.

I think the snow tires are killing my MPG...I think I can get up to 24...I've been doing some quick starts and parking has been a b!tch to find in the city lately. So, along with a slight change in driving habits and some mods, I'll get it. I'm at the city range and I'm doing more highway driving...and damn, the AC is on all the time, I forgot about that. So, 24 is an obtainable goal.

DMXtremeZ

Rincewind, what octane did you use before trying Sunoco 94?

Right now I use Sunoco 93 everytime i fill up...i figure another .10 to each gallon and only 1 more octane wont make much of a difference...i may try it a few times though...

E55AMG99

They claim my E55 will get 16/23 but the best highway tank I've ever had is 20. Then again, I wear lead sneakers!

DMXtremeZ

Hahahah, I know what you mean... I seriously have lead in my right foot