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Discussion Starter · #1 ·
i was told when buying the car at the dealer that it is designed for regular and higher gas wouldnt make a difference. it so happens that when i went to fill up today, they only had premium. i dont know if its psychological or what--BUT the car felt much faster. ESP. after 4500 revs. felt much more responsive then the usual stubborn pick-up.<br>not to say the car's <I>fast</I> or anything---but compared to NA s60 standards....
 

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I did the same thing on my NA.<br>and it really didn't make a difference. Gas milage was about the same. Detonation is detonation. As long as you don't have pinging you don't need more than 87 octane.<p>But, again, I do have stubborn pick up as you said. I live with it.
 

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Nope! The only engines that benefit from high octane gas are turbo, supercharged and high compression engines. The naturally aspirated S60 is neither of these.
 

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Re: (fredmc)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>fredmc</b> »</i></TD></TR><TR><TD CLASS="quote"><br>But, again, I do have stubborn pick up as you said. I live with it. </TD></TR></TABLE><p>yeah, same here. as long as i dont drive my friends faster cars, i think the s60 is not that bad. plus with today's gas prices, its pretty good. ha, my justification.<p>prob was psychological, always wanted a faster car deep down.
 

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Re: (arvmister1)

For a better idea of what the octane rating actually means and why you dont need a high octane in a normally aspirated car read this article:<br><A HREF="http://auto.howstuffworks.com/question90.htm" TARGET="_blank">http://auto.howstuffworks.com/question90.htm</A>
 

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Re: does premium gas make a difference in a NA S60 (arvmister1)

Just for comparison, the engines in Honda's 06 Civics (except the si) all have 10.5:1 compression ratios (same as Volvo 2.4L NA) and are spec'd to run on regular unleaded gasoline.<p>I wondered about this at first with my v70NA and did some testing when it was new. After a few tanks of regular it seemed that my gas mileage was about 10% better with the premium. So, as long as premium was less than 10% more than regular that's what I have burned. However, it has always been in the back of my mind that regular would be ok, and as I have read more about it, including other anectdotal info, I have decided to run another test of several tanks of regular. I always try to use major brand gas, but blend variations--certainly over the seasons--may and can be accounting for the difference that I attributed to premium.<p>All this said, when I worked for a company that made fuel additives for all the US refiners amongst others, it was common knowledge that the premium fuels had better additive packages than regular and certainly most of the low price independents. This may not be as much the case anymore, when was the last time a car manufacturer reported a major valve or injector clogging problem caused by the gasoline? The additive packages had to improve, i.e. carburetors are more forgiving than fuel injection, and, today, no one today would (or should) tolerate fouling caused by a low grade regular fuel.<p>One guy that I worked with always recommended using premium every 3rd or 4th tank full, he said their their lab results showed that this was almost as good as running 100% premium gasoline as far as clean engine internals went. I had a company car, Ford Taurus, that ran rough (after 25 or 30K miles) and would always smooth out after a tank of premium. I tried the every 3rd or 4th tank full routine and never had a problem after that.<br><BR><BR>
<i>Modified by MrTippy at 7:18 AM 7-18-2006</i>
 

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Re: does premium gas make a difference in a NA S60 (arvmister1)

A good article about octane requirement. <A HREF="http://www.usatoday.com/money/autos/2003-07-30-premiumgas_x.htm" TARGET="_blank">http://www.usatoday.com/money/...x.htm</A><p>Notice the comment from the Honda tech.
 

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Re: (T5Killa)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>fredmc</b> »</i></TD></TR><TR><TD CLASS="quote"> Detonation is detonation. </TD></TR></TABLE><p><TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>T5Killa</b> »</i></TD></TR><TR><TD CLASS="quote">Nope! The only engines that benefit from high octane gas are turbo, supercharged and high compression engines. The naturally aspirated S60 is neither of these.</TD></TR></TABLE><p>Careful now, your comments are too general. One way of increasing power to weight ratio of an engine is to increase compression ratio. Volvo uses higher compression ratio, EVEN in N/A engines, then most auto manufacturers. In this case, detonation is NOT detonation. As you increase pressure of any gaseous medium, you also increase it's temperature (adiabatic system) - this is basic thermodynamics. The higher the compression ratio, the higher the temperature of the air-gasoline mixture. For design performance (max power), you want the spark plug to ignite the mixture at its maximum pressure. At high compression ratios, you run the risk of getting the air-gasoline mixture above its combustion temperature with low octane gas. All that higher octane does is raise the combustion temperature. I believe Volvo uses a NOX sensor to determine if a lower octane gas is used - if so, it will ignite the mixture before its full compression cycle thus providing lower power AND avoiding knocking and pinging to protect the engine.<p>I have a N/A S60 and have compare performance of different octane levels. I notice a power difference when comparing 87 and 93, and also have measured a difference in mpg. However, the difference in mpg was not enough to make up for the price difference between these octane levels. I still run 93 octane (91 is not generally available where I live unless I mix proper proportions of 87 and 93, but that is a pain in the a$$) basically to have the engine perform the way it was designed. Then again, I'm an engineer and may be compulsive about such matters.
 

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Re: (samulsoon_0503)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>samulsoon_0503</b> »</i></TD></TR><TR><TD CLASS="quote">...I have a N/A S60 and have compare performance of different octane levels. I notice a power difference when comparing 87 and 93, and also have measured a difference in mpg.</TD></TR></TABLE><p>Samulsoon: I measured a difference too (above), but I've always suspected I that it was overestimated. How much of a difference did you observe?<p>The energy content (btus/gal) of premium is close to that of regular gas (only 2-5% more). All things being the same, the mpg's should reflect that; but since they are not, higher compression should produce better results with premium fuel. However, an additional 5-8% beyond what the energy content provides seems like a lot. I'll be using regular the next few weeks and see what I get...
 

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Re: (MrTippy)

What I measured:<p>Highway mpg increase is about 0.7 mpg<br>Overall mpg increase is about 0.5 mpg<p>I don't have a trip computer, but calculate it the old fashion way. Highway mpg was measured several times during my numerous trips back and forth across the PA turnpike. Overall mpg was measured over the course of a week of "normal" driving - did this quite a few times as well. Numbers are small (subject to error, not highly scientific), but were quite consistent when I repeated the "tests' several times.<p>Originally did this when gas was well under $2/gallon - at that time, the cost of premium did not offset the increased mpg. But at the higher cost today ($3/gallon range) even with a modest increase like this, the cost of premium is more closely offset.<p>For me, just running the numbers made me more aware of things modestly affecting mpg. I routinely check tire pressure, etc. Not so much for the cost savings, but more to do my part to reduce consumption.<p>Steve
 

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Re: (samulsoon_0503)

Steve,<p>I measure mileage the same way and use the trip computer for every tank. I'm hardly OCD, but mileage changes are a good tip off when something is wrong. I've got data for all tanks, just about, since the car was new; eventually I'll plug it all into Excel and see what it looks like.<p>From the start, I figured that test condition variances (e.g. weather, road conditions, traffic) and systematic errors (tank fill level--or would than be random?) would probably wash out any real differences in mpg, but why not take a SWAG.<p>I keep my tires at 40psi. They wear very evenly, handle well, and yes, the ride is a little harder, but we don't mind. On thing about that is even if they lose some air, seasonal changes or whatever, I'm still well over 34psi by the time I usually catch it and pump them up.<p>I typically get 30-33mpg on the highway, up to 70mph, and my wife (it's really her daily driver) gets 22-24.5 during the week (local/hwy/stop&go mix). Not bad for 3600lb car. Crosswinds can drop the highway numbers 2-3 mpg, especially with a canoe on top!<p>peter<p>p.s. PSU or Pitt?<br>
 

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Re: (samulsoon_0503)

Me too. MS+ Chemistry. My neighbor is moving to State College, he was just appointed to PSU's new Knight Chair in Sports Journalism (College of Communications); interesting guy, maybe I can get some inside lines. <IMG NAME="icon" SRC="http://www.vwvortex.com/vwbb/sly.gif" BORDER="0">
 

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Re: (samulsoon_0503)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>samulsoon_0503</b> »</i></TD></TR><TR><TD CLASS="quote">PSU all the way!!! BS 1988, MS 1991 - both Aersp. Engineering.</TD></TR></TABLE><p>threadjacked!<p>woohoo: PSU 2000-2006 (don't ask) Electro-Mechanical Engr.
 

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Re: (phuz)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>phuz</b> »</i></TD></TR><TR><TD CLASS="quote">threadjacked! woohoo: PSU 2000-2006 (don't ask) Electro-Mechanical Engr.</TD></TR></TABLE><p>I was on the 5 year plan myself. Nothing wrong with that! Getting your MBA at night while working full time, on the other hand, is not very fun. At least is was free! Gotta love tuition reimbursement! <IMG NAME="icon" SRC="http://********************/smile/emthup.gif" BORDER="0"> <IMG NAME="icon" SRC="http://www.vwvortex.com/vwbb/smile.gif" BORDER="0">
 

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Re: (samulsoon_0503)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>samulsoon_0503</b> »</i></TD></TR><TR><TD CLASS="quote">I believe Volvo uses a NOX sensor to determine if a lower octane gas is used - if so, it will ignite the mixture before its full compression cycle thus providing lower power AND avoiding knocking and pinging to protect the engine.</TD></TR></TABLE><p>Steve, I think the timing is retarded when knocking is detected.
 

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Re: (MrTippy)

How about premium for T5? I used to run with premium for the first few months i had mine, but havn't really noticed much of a difference since i've switched to regular, but then again i'm not much of a gear head and I havn't done any quantitative studies. I switched after my mechanic told me it didn't matter.
 

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Re: (alphasigmookie)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>alphasigmookie</b> »</i></TD></TR><TR><TD CLASS="quote">How about premium for T5? I used to run with premium for the first few months i had mine, but havn't really noticed much of a difference since i've switched to regular, but then again i'm not much of a gear head and I havn't done any quantitative studies. I switched after my mechanic told me it didn't matter. </TD></TR></TABLE><p>You can use mid-grade (89) with out much concern. I have noticed that the car seems to accelerate from idle a bit quicker with the lower octane, but it doesn't maintain it's power at higher rpms as well (once the turbo kicks in)...
 
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