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Premium fuel for turbos!

How to go faster, stop quicker, and turn harder. Chips, exhaust, larger turbos, bigger/slotted/drilled rotors, high performance brake pads, manual boost controllers, performance shocks/struts/springs, airbox mods and more! Also discussion on HID and Xenon lights, aftermarket foglights and other exterior lighting.
northernlights
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Premium fuel for turbos!

Post by northernlights » Fri Sep 26, 2014 8:18 am

This isn't Volvo specific, but here's a really interesting quote from Edmunds review of the 2015 2.3 Ecoboost (i.e. turbo) Mustang:

http://www.edmunds.com/ford/mustang/2015/road-test1.html

It's an interesting option, generating 310 horsepower and 320 lb-ft of torque while delivering better fuel economy than the slightly less-powerful entry-level V6 offering....

There is one catch, however: the EcoBoost engine needs premium fuel to deliver its peak horsepower ratings. Put in regular gas and the EcoBoost can only muster 270 horsepower, although its torque output remains unchanged according to the engineers at Ford.


This is from a 9.5:1 engine, with about 1.2 bar boost during acceleration peaking at 1 bar at redline.

That's a huge loss of horsepower! I'm a premium fuel buyer for any performance engine, so I'm a little biased in favor of good gas even without knowing details like this, so that's all my 94 Turbo burns.

rmmagow
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Re: Premium fuel for turbos!

Post by rmmagow » Fri Sep 26, 2014 10:26 am

This phenomenon is primarily caused but the knock sensors right? They dial back advance when sensing knock. I know my V70 has a sensor, but how about early turbos, maybe before high end ECUs were in use? They'd benefit a lot from premium fuel and using crap gas can actually damage them due to knock. My v70 runs OK on mid-grade (91) but I don't run a tune. Premium does feel better but I'm not sure if this is real or just because I want to think it made a difference because I paid a 20 cent premium for it. I put a tank of regular in it once due to zero gas and the station had no better available, car ran like crap, felt like the e-brake was dragging.
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matthew1
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Re: Premium fuel for turbos!

Post by matthew1 » Fri Sep 26, 2014 11:00 am

Engineers can do anything they want with engine management now. I suspect this huge drop in hp is fully intended. They've got warranties to honor, so as an engineer, I'd want this huge margin. There is crap gasoline out there. Old, water, etc.

But yea, it's a shocking difference however you try to explain it.

I'd also suspect it might be a low "sample" data point. Test a hundred more and you'd find the average hp drop w/ 87 octane to be less drastic than this. Just a hunch.
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rmmagow
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Re: Premium fuel for turbos!

Post by rmmagow » Fri Sep 26, 2014 11:59 am

I had an old Mazda 929 and a test for the knock sensor involved tapping an area of the block with a ball-peen hammer and watching the timing marks change. It was pretty obvious watching that happen on that motor.
1998 V70 AWD 228K - Daily Driver
1985 Mercedes Benz 300D - 197K Off Road For Now Brakes Failed
1998 S70 135K - FOR SALE
2003 GMC Sonoma - 114K - POS
1958 Mercedes Benz 220S 66K Original and never to be restored.
2006 Saturn ION 5-Speed - 150K Son's weird little easy to fix car

northernlights
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Re: Premium fuel for turbos!

Post by northernlights » Fri Sep 26, 2014 2:35 pm

matthew1 wrote:Engineers can do anything they want with engine management now. I suspect this huge drop in hp is fully intended. They've got warranties to honor, so as an engineer, I'd want this huge margin. There is crap gasoline out there. Old, water, etc.

But yea, it's a shocking difference however you try to explain it.

I'd also suspect it might be a low "sample" data point. Test a hundred more and you'd find the average hp drop w/ 87 octane to be less drastic than this. Just a hunch.
You are absolutely correct regarding the degree of control available from engine management. And on that note...the more I think about it, it's funny that the claimed torque is the same at reduced power. I wonder how much they are limiting it via engine management to make sure it doesn't step on the V8's toes!

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Re: Premium fuel for turbos!

Post by brad850 » Mon Oct 27, 2014 12:27 pm

I swear by high octane. The higher cost is worth it, especially for a turbo and or high miles Volvo, I can tell the difference in performance and the fuel economy is a little better with high octane as well.
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Ben850
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Re: Premium fuel for turbos!

Post by Ben850 » Sat Dec 27, 2014 4:41 pm

brad850 wrote:I swear by high octane. The higher cost is worth it, especially for a turbo and or high miles Volvo, I can tell the difference in performance and the fuel economy is a little better with high octane as well.
I agree and go a little step further with every other tank full and add some octane boost/fuel conditioner to the 93 octane I always buy.
I spoil the cars, and it may be over kill but it makes me feel comfort in an area that is easily doable.

I must say, as a result of this regimen, my turbo and intake hoses appear clean, as well as my spark plugs. I realize these are not all related and it may be a placebo affect to me, but I know the octane level is not the cause of related issues.
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