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Luxury Performance Sedans

10006 messages,  Last post on Nov 26, 2009 at 6:59 AM

You are in the Sedans Forum. Your Hosts are pat & karens

What is this discussion about? Lexus GS 430, Acura RL, BMW 5 Series, Volvo S80, Audi A6, Infiniti M35, Infiniti M45, Mercedes-Benz E-Class, Cadillac STS, Sedan


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#7881 of 10006
Re: Sudden Acceleration [markcincinnati] by shipo
Jul 24, 2006 (2:24 pm)
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Replying to: markcincinnati (Jul 24, 2006 12:42 pm)

The fact that the computer attempted to save the engine from internal damage via retardging the spark may well have been the case -- but even my 1982 Audi 100S with the 2.8 V6 REQUIRED 91 octane."
 
Mark, that must have been some rare car (as in one made in entire world). I bet you wish you still had it.
 
Best Regards,
Shipo
#7882 of 10006
Re: Octane by warthog
Jul 24, 2006 (2:39 pm)
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Replying to: markcincinnati (Jul 24, 2006 12:42 pm)

A related question: Have you ever seen a street car that required more than 91? In North Carolina, premium is routinely 93; mid-grade is 89, and regular is 87. In other states, premium seems to usually be 91.
 
 Anyone know why.
#7883 of 10006
Re: Octane [warthog] by james27
Jul 24, 2006 (3:00 pm)
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Replying to: warthog (Jul 24, 2006 2:39 pm)

Go up into the high mountain areas, say Santa Fe, NM which is somewhere around 7500' or so, depending on where you are in the city, and see what the octane levels are. The altitude limits the amount of air you can stuff into the engine (unless you have a supercharger or turbo), so they won't ping on the lower octane. Couse, they don't have the same power, either. Prior to electronic fuel injection, cars just didn't run well up there without adjusting the carburator, either. Most cars are power rated at sea level. They can make significantly less at altitude, regardless of that the computer does.
#7884 of 10006
Re: A Premium experience. . . [markcincinnati] by james27
Jul 24, 2006 (3:36 pm)
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Replying to: markcincinnati (Jul 24, 2006 6:45 am)

This is a quote from the Infiniti owner's manual, page 9-3 Printing March 2005, number OM6E-0Y50U0 (I might have the o and 0's mixed up - hard to tell) for the M-series, 2006 model year:
 
VK45DE engine
In order to maintain engine and exhaust system durability and performance, unleaded premium gasoline with an octane rating of at least 91AKI number must be used."
 
It goes on to say in an emergency, use 87 to get you to the next gas staion with the minimum amount of 87 you can get by with and to avoid full throttle accelerations and abrupt acceleration.
 
FOr the VQ35DE engine
 
"Use unleaded regular gasoline with an octane rating of at least 87 AKI number.
 
For improved vehicle performance, INFINIT recommends the use of unleaded premium gasoline with an octane rating of at least 91 AKI number."
 
So, The V-8 REQUIRES premium, the V-6 RECOMMENDS premium. I can tell you from personal experience that I notice the difference in merging on the interstates around here where they are often going at 80-85. With premium, it just goes, with regular, you have to plan ahead (not much, but more). I think it idles smoother with premium.
 
I no longer have the Audi, so I can't look up their recommendations, but seem to remember it being almost exactly the same as Infiniti's is for the V-6.
#7885 of 10006
Re: Sudden Acceleration [shipo] by markcincinnati
Jul 24, 2006 (4:36 pm)
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Replying to: shipo (Jul 24, 2006 2:24 pm)

Er, oops, 1992.
#7886 of 10006
HiPerf V8 Octane req by jmess
Jul 24, 2006 (7:19 pm)
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Some of you may get a kick out of GM's recommendations for my C6 Corvette (V8,400HP)
 
"Use premium unleaded gasoline with a posted octane of 91 or higher for best performance. You may also use middle grade or regular unleaded gasoline rated at 87 or higher, but your vehicle's acceleration may be slightly reduced"
 
I have used mid grade several times and you can't feel any change. The car is so responsive that losing 10-15HP doesn't register in daily driving; and yes I stomp on it from time to time.
#7887 of 10006
Re: HiPerf V8 Octane req [jmess] by lexusguy
Jul 24, 2006 (8:18 pm)
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Replying to: jmess (Jul 24, 2006 7:19 pm)

have used mid grade several times and you can't feel any change. The car is so responsive that losing 10-15HP doesn't register in daily driving; and yes I stomp on it from time to time.
 
How about mileage? Have you noticed any differences there? I've read that using regular in a car that recommends premium can not only cost you horsepower, but also may make mpg suffer as well, which could potentially render any savings at the pump moot.
#7888 of 10006
NBC. . . by markcincinnati
Jul 25, 2006 (4:37 am)
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Replying to: lexusguy (Jul 24, 2006 8:18 pm)

. . .must have sold the rights to the Premium fuel story to the local affiliates. Last night, 11PM news on the local NBC TV station here in Cincinnati, they had a story about when to and when NOT to use Premium. It was only slightly different than the one from the Today show -- but they interviewed a "mechanic" who said the long term effect of using Regular in a car that requires Premium is "a melted engine." Then the plucky news anchor said that she'd bet a new engine costs a lot more than could ever be saved by using Regular vs Premium ($.20/gallon here.)
 
The "mechanic" also said that the use of Regular means lower mileage so there is a negative benefit to using Regular -- "it costs more."
 
Of course this still leaves some consumers (and that is not meant to be a slam) in the dark since their car's manufacturer's seem to not want to use words like REQUIRED or MANDATORY (and were I the author of the owner's manual, I would give a "warning" that using more than one tankful in a row of regular will cause damage to the engine and possibly risk your warranty (assuming of course that any failure would be related to the fuel chosen.)
 
After reading here and elsewhere, it seems that engines with higher compression ratios are more efficient overall; it seems that fuel injected engines are better than carb'd engines overall; and, it seems if cars deploying Fuel Stratified Injection can have yet additional increases in efficiency.
 
These increases seem, over time and miles, to translate to lower costs, higher performance and even lower emissions -- therefore it begs the question, "why not build modern IC engines to have the highest "reasonable" compression ratios, multiple valve layouts (3,4 or 5 valves per cylinder), dual exhaust systems, dual pathway intake systems and both small turbo chargers with "booster" electric helper motors (or superchargers that disengage above a certain RPM to avoid robbing power)?" All of these things, one would imagine would allow physically smaller engines, lighter engines, and fewer cylinders doing the work -- a 4 could perform like an 8 and probably have the economy of a 5, kind of thing.
 
Or, take this up to having these technologies all applied to diesels and really knock our MPG's outta the park all the while giving us Americans (at least) the torque we so covet.
 
Now, of course I am girding my loins for the response: "the reason is cost! you idiot." Well, OK, if it is cost, then it must be acquisition cost, not total cost of ownership -- yes? Why not edumacate the customers about the benefits that would accrue if we were to begin using super-turbo-charged, multi-valve, fuel-stratified, ultra high compression engines?
 
Big ones, small ones, fat ones, short ones -- seems we would kill several birds with few stones.
 
 
#7889 of 10006
Re: NBC. . . [markcincinnati] by lexusguy
Jul 25, 2006 (11:21 am)
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Replying to: markcincinnati (Jul 25, 2006 4:37 am)

Why not edumacate the customers about the benefits that would accrue if we were to begin using super-turbo-charged, multi-valve, fuel-stratified, ultra high compression engines?
 
VW seems to be the only one testing the super-turbo concept with production cars at the moment. The thing is though, yester-tech engines like GM's 3.5L, 2 valve per cylinder pushrod V6 is rated 23\32 in the Malibu. If they can make one of those for $1.73, why should they spend huge amounts on forced induction and direct injection?
#7890 of 10006
Re: NBC. . . [lexusguy] by markcincinnati
Jul 25, 2006 (11:28 am)
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Replying to: lexusguy (Jul 25, 2006 11:21 am)

You'd get no quarrel from me on that -- there must be a "gotcha" there somewhere (or a pony) for if what you say is accurate (and I assume it is), why not use economical engines across the board.
 
And, for clarification, I mean economical engines that do not make performance seem to be an afterthought.
 
 

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