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Reading an article in the paper today about the 2013 Hyundai Genesis coupe, and they were talking about power increase from the previous model. The statement was about the turbocharged 4 cylinder: "Those changes plus other engine mods contribute to a 30% increase in output, 274 on premium gas (260 when running on low-octane regular fuel)." Just caught my eye that they would quote the difference. This works out to 5.1% reduction in hp. Is this an industry standard? Do you think they actually did a dyno on this?

They did not list a fuel comparison for the other engine option(normally aspirated V6). This makes me wonder if as a rule are turbocharged engines more affected by lower octane fuel?

The V6 makes 348 hp btw.
 

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I don't know what you're getting out... The outgoing Theta engine only made 210hp. On premium the new Theta makes 270hp~. Lower octane fuel usually lowers the boost and if it's got variable valve timing it can compensate so the engine makes less power with lower quality fuel.

I'm not sure where and why you think it's a reduction.

When they do "dyno" testing on engines it's kind of a benchmark engine they based all their other engines off of. And it's measured on an Engine dyno as opposed to a mustang Dyno or anything that measures WHP.

All turbo engines generally benefit from premium fuel. Most sporty cars that use turbos require it. Sometimes they can run with lower quality fuel but mostly in cars where fuel economy is the main concern (IE: Volvo's LPTs, GM's 1.4Ts, VW's TwinCharged engines, etc etc).

Back in the day any remotely "sporty" engine REQUIRED premium fuel because the ECUs couldn't compensate or change the timing to make up for the lower quality fuel.
 

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Well, it is a reduction in output.

On a basic level (and you may already know this) using lower octane fuel means that ignition timing needs to be retarded to reduce heat and compression. Otherwise, the low octane fuel (which is easier to ignite) could cause uncontrolled detonations called preignition, potentially damaging the engine.

When timing is retarded to accommodate the lower octane fuel, performance is reduced. So is the speed at which exhaust flows. Turbochargers are driven by exhaust. If the flow of exhaust is slower, the turbocharger's performance will be reduced. As a result, turbocharged engines can be more heavily effected by a reduction in timing when the engine is not tuned for that lower timing.

Source: I made this up, but it sounds good to me. Normally, you retard timing to accommodate higher boost pressures, but whatever. I don't see what that has to do with anything.

:thumbup:
 

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Matt is correct. My experience with ECU's compensating for lower octane is based mostly off older turbo systems from Ford.
 
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