Andy0331

It seems that most "standard" tunes are geared for 91 octane since it's available everywhere. I live in FL & 93 is available at all the gas stations here. I'd like to have my Kleemann tune switched out for a 93 octane tune.

The real question is how damaging would it be to the engine if I were forced to use 91 octane? It won't happen here, but I do occasionally drive up the east coast & could possibly encounter 91 somewhere out there.

The next question would be "is it worth it"? Would there be a noticeable improvement in performance going from a standard K2 to a 93 octane tune?

Thanks!

storm

[quote=Andy0331;3366974]It seems that most "standard" tunes are geared for 91 octane since it's available everywhere. I live in FL & 93 is available at all the gas stations here. I'd like to have my Kleemann tune switched out for a 93 octane tune.

The real question is how damaging would it be to the engine if I were forced to use 91 octane? It won't happen here, but I do occasionally drive up the east coast & could possibly encounter 91 somewhere out there.

The next question would be "is it worth it"? Would there be a noticeable improvement in performance going from a standard K2 to a 93 octane tune?


well its not damaging, as the ECU will adapt but you will notice the different if you car is tuned for 93 and you run 91.

best thing to do is tune your car for 93, and put 91 in along with 2 gallons of 100 octane racing fuel.. what I do,, runs perfect
averages out to around 93-94 oct, and runs perfect..

here in cali we dont have 91, but we do have racing fuel lol at 100,
so it will boost the octane..

works great

Andy0331

I'm assuming that if I'm out of town & can't find 93, that I might not be able to find 100 easily either.

I've never been a fan of "octane boost", but I could keep some in the trunk if it would actually help.

chiromikey

it won't help so get that idea out of your head right now!

TMC M5

Not to derail the topic...but this was an interesting test of octane boosters:

http://www.europeancarweb.com/tech/0...ted/index.html

Based on the chart the NOS Octane booster resulted in a boost of 2.5 AKI (RON+MON/2). That seems real (although the MMT additive isn't doing wonderful things to the cats)...

Tom

Carl Lassiter

If you have 55 or 63 then it's already tuned to perform best on 93 AKI. My M5 is too but it has to cope with 91 AKI. It even says on the fuel cap that 91 is the minimum (equivalent to 95 RON) so we are certainly losing a certain amount of our horsepower here in cali.

Ohbev

im from australia i put 98 octane from the pump lol

TMC M5

That is a 98 RON octane rating. Here in the US octane is rated based on AKI (anti-knock index). It takes the RON (Research Octane Number) rating and averages it with the MON (Motor Octane Number) rating. Apparently in Australia, the Shell V-Power 98 is 91.5 AKI ((98 RON + 85 MON)/2). The Shell V-Power Race 100 is 94.5 AKI ((100 RON + 89 MON)/2).

Most parts of the US have 93 AKI available.

Tom

NSX2NV

I only get my gas from one station in town and it is rated at 94. On the test that they run every few months the owner says it usually test out over 94. Mostly high 90's even over 100 a few times.

What should I do when I get my car tuned? I'm planning on driving up to Chicago to LET and having them do it, which is 8 hours away so I won't have the gas I usually run on.

AMGfan

On my VR700 tune, I tried the Shell racing fuel and 93 Octane fuel w/10% ethanol mix and I kept getting CEL's.

I'm back to Mobil 93 Octane (no ethanol...at least it is not posted anywhere...it is damn harder to find) and I haven't had any CEL's.

Performance wise on Shell RF, I really didn't get to the point I could notice since I kept worrying about the CEL's.

TMC M5

I find that hard to believe....I think he just wants to have enthusiasts use his pumps thinking they are getting more for their money.

Tom

storm

its not octane boost,, that is a crap product that is not gas,,TOTALLY DIFFERENT. NOT WHAT I SAID AT ALL..

this is real 100 octane RACING GAS,, that $400,000 race cars and bikes use

IT IS GAS from the OIL company UNION 76 and it made from the same oil batches your 91 is made just to a higher octane lol at the same refinery

and any chemist knows when you take some chemical at a certain strength,, like 91 octane and mix it with identical chemical 100 octane,, it averages out,, to around 94 and is stable..

same exactly gas as if you got 93-94 out of the pump..

here is the math for you
10 gallons 91 octane,, when you add 2 gallons of 100 octane, thats a 20% percentage, so 2 gallons of 100 octane RACING GAS when diluted in 10 gallons of
91 octane will make the gas about 2 octane higher or around 93-94..

thats a just a fact

storm

thats cause you used ethanol, and that you likely put too much racing gas in and it thinned the mixture too much
higher octane gets better gas milage and pollutes LESS as it burns more thouroughly

try 91 REG GAS, NON ETHANOL, and add 2-4 gallons of RACING 100 gas

know 20 people that do this works fine, on $250,000 ferrairs and lambos'
and mercs

what do you think all the racing cars use and racing bikes?

NSX2NV

I don't know. All my friends were the ones that told me about it. I think he showed them the data sheets too. Either way I know for a fact that the pumps say 94. That's the only place in town that says that. Most others say 91 with some that have 93.

HYEPWR

to answer the original question....

It depends on the tune...

Normally---the higher the octane---the more timing you can run before detonation. The stock ECU has all sorts of safety mechinisms. For example---In the orginal tune made for 91 octane---the max timing advance would be set at 22degree(guess)......if the AIT/oil temp/engine temp/transmission load/knock sensor output are all within safety parameters---> the ECU will advance timing to 22 degrees and give you X power.

If someone were "tuning" the same car with 100octane----they could set the max advance to 27degrees. Now under the same conditions---the ecu will advance the timing upto 27 degrees and gain 20-30 hp.

Now heres the fly in the ointment----if any safety parameters are exceeded---like ait's or knock sensor counts---the ecu will back out timing. It wont matter what the "max" is set to because it will never get there.

For example--->Lets say you run 104oct AND your cars max timing is set to 30 degrees. You punch the gas and the car makes crazy HP....the engine is fine...ait's are nice...all temps are good...there's no knock.....BUT.....the tranny senses a HUGE overrunn in its "torque limit"----> Guess what....your timing will drop like a rock.

So unless ALLLLLLLLLLLL the parameters that control timing are KNOWN to the tuner and are adjusted----tuning your car for higher octane is a waste of resouces.

As we all are aware---we have yet to tame the "ECU SHREW"

E55Pilot

And it's a fact your math is wrong. Just like everything else you post.

here's the math:

(10*91)+(2*100)
------------------- 92.5 octane
12


Let me break it down incase you don't get higher math

10 gal of 91 is 910 points

2 gal of 100 is 200 points

200+910 is 1110

now divide that by TOTAL gallons (12 gal) and you get 92.5 octane.

I'm not even going to get into blending aromatics like Toluene (112octane) or Xelene (116 octane) with pump fuel in order to get 100 octane

Anyone who is a test driver for Porsche or GM would know that.....

TMC M5

Lol...ouch.... but you're right, his math was off...unless he meant 8 gal of 91 and 10 gallons total...which isn't what he said...

Tom

Andy0331

Somehow I missed some of these replies.

Anyway, I can see the logic of mixing racing gas with the 91, but I'm operating under the assumption that if I'm traveling and can't find 93, race gas will probably be just as hard to find. And no, I'm not keeping a couple of gallons in a can in my trunk. Visiting my parents in the mountains of N. Carolina... I'm not chasing around for racing fuel.

My question, was only based on the "damage" that could be done running 91 if you were tuned specifically for 93.

I doubt I'll mess with it at all, as the difference in performance is probably minor (at least in relation to cost & risk).

E55Pilot

if you are that worried just add 2 Gallons of Toluene to 20 gallons of 91 octane gas. that will get you 92.9 Octane

Vadim @ FD

93 octane allows several more degrees of timing, which is typically on E55 is worth around 15RWHP. Not a whole lot, but if you can get the gas, get the tune.

ChicagoX

Actually, most "race gas" comes from completely different base stock than road gas.

Please feel free to PM me if you would like more info.

storm

[quote=E55 ButtPilot [B]And it's a fact your math is wrong. Just like everything else you post.[/B]

actually, I was only off by 1/2 of 1 octane, I said you would get 93 and you said 92.5 ... douchbag..
and that is because I was merely approximating and giving a rough idea to the guy as a example.. not as an exact science..

every ECU tuner, from EVO, THE BRABUS, to KLEEMAN, ro POWERCHIP all say you can add 100 octane a few gallons to get the 93 needed for the tuned ECU

bottom like it works, and your way to ****, or wound up to be
having a fit over 1/2 an octane rating..

TMC M5

[QUOTE=storm;3410315]
ClayJ:

I think the problem is that you definitively said here is the math....and your math was wrong. If you are an engineer...you should just take your lumps and walk away because saying you were only off by 1/2 an octane point isn't going to help your cause.

Tom