How much premium gas affect performance ?

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NICAT

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Azerbaijan
Hi.
In my country, So Called Regular gas is AI-92 And Premium Gas is AI-95
My question is, is it possible to gues how much percent performance difference there would be if we are using 95 octane gas instead of 92 gas ?
Regards
 
Unless you drive a turbo higher performance car or one that requires high octane like MB, you will see zero improvement.
 
Some numbers for modern cars that "recommend" but do not "require" premium fuel (95 RON/91 AKI):

"Fuel economy for test vehicles averaged a 2.7 percent improvement. Individual vehicle test result averages ranged from a decrease of 1 percent (2016 Audi A3) to an improvement of 7.1 percent (2016 Cadillac Escalade)."

"Horsepower for test vehicles averaged an increase of 1.4 percent. Individual vehicle test result averages ranged from a decrease of 0.3 percent (2016 Jeep Renegade) to an improvement of 3.2 percent (2017 Ford Mustang)."

https://newsroom.aaa.com/2017/12/dont-fueled-premium-not-always-worth-price/

If your car does not "recommend" or "require" premium fuel there is usually no performance gain.
 
It depends on the compression ratio and how the engine/ECM are tuned. The difference may be very significant or none at all. If the owners manual spec's premium using lower octane fuel will probably result in lower performance.
If regular is spec'd it will run okay on it but its possible the ECM will allow increased settings and may provide additional performance. The best thing is to try it and decide.
 
My G35 recommends premium, but does not require it. When I first got it, I put regular in it "by accident" every so often just from habit of using regular fuel. It ran perfectly fine. I did it again, put regular in, not too long ago and I could absolutely feel a difference in acceleration. Not drag-strip, racing acceleration, just going from 35 mph to 60 mph, for instance. It is "smoother" with premium fuel while with regular fuel I could feel it was as smooth. I didn't do any 0-60 runs with either fuel for comparison though.
 
I have a HP Tuners and I will tell you probably can't feel the difference in some cars, but in the Caprice, Truck and Trans Am I can see the timing being pulled back depending on grade of fuel and even brand to brand.

You can't just say there is no difference, The data for my cars shows differently at WOT. The ECM is compensating so you probably won't notice, but your car knows.

The Caprice is a bone Stock 6.0/6L80E. The truck is a tuned for torque converter lock up 6.0/4L80E. The Trans Am is a Heads/Cam/intake/full exhaust 5.7 LS1.
 
Originally Posted by Danno
Unless you drive a turbo higher performance car or one that requires high octane like MB, you will see zero improvement.

So you've driven over 20 cars and tried a bit of higher octane and saw no difference.

Odd.


Me, I HAVE to blend in about 3 gallons on a tank to get rid of low speed ping and regain snappy throttle response and have good full throttle high rpm torque.


the NISSAN QR 25 DE is a moderate compression engine - but it has effectively high cylinder pressure due to GIANT intake ports and VVT cam phasing.

The only car that Ive owned that ABSOULTELY NEEDED high octane - or it would hard knock - was a 1993 Lincoln MK Viii with the 300 HP intec DOHC V8. A Fast pre -OBDii car. After 1995/96 OBDii killed a lot of peppy ford engines, IDK why.
 
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Thanks for replies,
But i can't understand why many people reported that they haven'y felt any difference with higher octane fuel?
Doesn't premium gas let the ECU to safely advance ignition timing to most optimal level ? So shouldn't there be considerable performance boost ?
 
Originally Posted by NICAT
Thanks for replies,
But i can't understand why many people reported that they haven'y felt any difference with higher octane fuel?
Doesn't premium gas let the ECU to safely advance ignition timing to most optimal level ? So shouldn't there be considerable performance boost ?


Really depends on the car I guess. You can tell the most in my truck. The Caprice doesn't care. The WS6? Well it does not like anything but premium but the list of modifications is long.
I have not done any data logging on the Malibu, but we run premium in it so I guess it really doesn't matter.
 
Many cars, especially basic low performance models, use a fixed timing profile. If this is set up for the use of regular gas, there will be absolutely no change upon using premium.

If the system does not have a knock sensor, it can't adjust due to knocking.
 
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Originally Posted by NICAT
Thanks for replies,
But i can't understand why many people reported that they haven'y felt any difference with higher octane fuel?
Doesn't premium gas let the ECU to safely advance ignition timing to most optimal level ? So shouldn't there be considerable performance boost ?


What you're referring to actually happens sort of reverse order of how you're thinking of it and will only occur on engines equipped with factory knock sensors. The higher the octane number, the slower the fuel burns, when timing advance is factored in, this is why a higher octane fuel is "more resistant to knock". The "knock" people refer to is detonation. On cars which have knock sensors, yes, if there is no detonation detected by the sensor then no timing will be pulled due to knock, however the ECU has a maximum timing table which is never exceeded, it just may not pull as much timing. Heat, humidity and density altitude also have a roll.
 
Originally Posted by mk378
Many cars, especially basic low performance models, use a fixed timing profile. If this is set up for the use of regular gas, there will be absolutely no change upon using premium.

If the system does not have a knock sensor, it can't adjust due to knocking.


I can't think of an OBDII car without one. Do you know of any? I looked a bit on line and can't find anything OBDII without one.
 
Originally Posted by thastinger
The higher the octane number, the slower the fuel burns, when timing advance is factored in, this is why a higher octane fuel is "more resistant to knock".


I thought this was a myth and octane merely refers to resistance to knock, and not how fast the fuel burns?
 
Premium gas at many stations in Ontario has no added ethanol. (for the moment). I see slightly better gas mileage when I fill with permium in my Civic, but not enough to justify the difference in price.

Having said that, the OP is in Azerbaijan, so I don't know if their various gas grades are ethanol-free...
 
E0 yields more BTU per gallon than an ethanol blend. This could lead to a slight increase in mpg apart from octane effects.
 
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In this video they run both 87 E-10 Shell and 91 E-0 Shell V-Power in a Chevy cruise and find no difference in performance for a vehicle not requiring it.
 
Originally Posted by ls1mike
I can't think of an OBDII car without one. Do you know of any? I looked a bit on line and can't find anything OBDII without one.

For starters, my 2001 Mercury Sable doesn't have one. For some reason, Ford Mo Co decided to do away with the knock sensor on the Sable a few model years prior.
 
Originally Posted by ls1mike


I can't think of an OBDII car without one. Do you know of any? I looked a bit on line and can't find anything OBDII without one.

My jeep 4.7 doesn't have one. The HO version does though.
 
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