Gas Grade and Mileage

SouthArk370Z · 03-31-2013, 10:14 PM

Quote:

Originally Posted by RoshDawg

Nice that makes sense. Judging from your other posts I take it you're an engineer? If so, what kind?

Oh and op, use 91 at least.

Not an engineer but spent many years as an Instrument Tech at a hazmat incinerator, so I know a little bit about combustion and heat. I also paid attention in Science classes when attending high school.

I also spent some time in mechanical maintenance, so have been around pumps, valves, flow, &c.
I was always asking the engineers "Why'd ya do it that way?" and most of them LOVE to splain stuff to others. heehee

BlueDog007 · 03-31-2013, 10:24 PM

I have read a little about FI but not sure what that is. Please explain. Thanks!

Baer383 · 03-31-2013, 10:31 PM

Quote:

Originally Posted by BlueDog007

I have read a little about FI but not sure what that is. Please explain. Thanks!

Forced Induction,as in Superchargers and Turbos

JARblue · 03-31-2013, 10:44 PM

To save on gas costs, I just siphon gas from my neighbors' lawnmowers

that is, the neighbors I don't borrow gas from for my own lawnmower...

RoshDawg · 04-01-2013, 01:04 AM

Quote:

Originally Posted by SouthArk370Z

Not an engineer but spent many years as an Instrument Tech at a hazmat incinerator, so I know a little bit about combustion and heat. I also paid attention in Science classes when attending high school.

I also spent some time in mechanical maintenance, so have been around pumps, valves, flow, &c.
I was always asking the engineers "Why'd ya do it that way?" and most of them LOVE to splain stuff to others. heehee

Nice! Haha spot on!

EndyKwon · 04-01-2013, 03:04 AM

Quote:

Originally Posted by RoshDawg

Something interesting, Porsche (at least on the 991) runs temps of 210-220 for oil when in normal mode to reduce emissions and in turn (I think) increase gas mileage. When selecting sport, oil temp goes down to 180.

Higher oil temp apparently has something to do with emissions.

So running an oil cooler would make the engine run less efficiently as far as MPG goes?

xxAGAVExx · 04-01-2013, 08:27 AM

Quote:

Originally Posted by EndyKwon

So running an oil cooler would make the engine run less efficiently as far as MPG goes?

That makes a little sense, the viscosity of oil would be affected by the temp, less so with a synthetic, but I think the temp changes would have to be fairly big to see a diff.

Nismo89 · 04-01-2013, 09:11 AM

Quote:

Originally Posted by BlueDog007

I have read a little about FI but not sure what that is. Please explain. Thanks!

Forced Induction. (in other words) SuperChargers or Turbos.

KERMIT · 04-01-2013, 09:18 AM

Quote:

Originally Posted by EndyKwon

So running an oil cooler would make the engine run less efficiently as far as MPG goes?

Heat energy flows from hot to cold and based on the difference in temperature from one side to the other (delta T) and the material properties, it will determine how fast energy is transmitted through the material.

That being said, the heat energy is generated by fuel energy. You want to have more of that energy end up turning your crankshaft as opposed to going into the atmosphere as heat. Running hotter reduces the delta T in the combustion chamber allowing more of the heat to stay in as opposed to going into the coolant. (this is super basic overview).

as a rule of thumb your fuel energy is 30% crankshaft power, 30% cooling losses, 30% exhaust, and 10% friction.

What they are attempting to do with running hotter is take some of the cooling % and put it back into crankshaft power. We are talking very small amounts... but every bit helps to meet the future regulations.

SouthArk370Z · 04-01-2013, 10:05 AM

Quote:

Originally Posted by EndyKwon

So running an oil cooler would make the engine run less efficiently as far as MPG goes?

Not really. The oil has very little to do with cylinder/gas temps and, as KERMIT points out, the effects of engine temperature on efficiency can be subtle.

It's not really something the average weekend mechanic wants to mess with as there are a lot of other variables involved. Changing the engine temp (eg, by installing higher/lower temp thermostat) can affect how the ECM reacts. Plus there are limits to how far you can go before pre-ignition becomes a problem - especially with a high-compression engine.

kenchan · 04-01-2013, 01:35 PM

Quote:

Originally Posted by JARblue

To save on gas costs, I just siphon gas from my neighbors' lawnmowers

that is, the neighbors I don't borrow gas from for my own lawnmower...

KERMIT · 04-01-2013, 04:02 PM

for an interesting read about controlling coolant temps...

Audi EA888 Gen 3

geddy lee · 04-02-2013, 09:14 AM

You need to premium grade gas and you will only get 17 mpg. That is all.

But it sure is worth it.

Cmike2780 · 04-02-2013, 09:49 AM

Quote:

Originally Posted by BlueDog007

Just doing research and didn't really want your non-helpful comments. This will actually be my 3rd car. I'm not too worried about the costs. However, I'm not so sure I'm going to buy a Z if it only gets 15 mpg. That's a joke. My current daily driver is a 2010 Tundra that gets 16-17 mpg. That big truck weighs a lot more, is fast, and has more horsepower. It makes no sense at all that a little Z gets similar mileage as compared to a Tundra. Don't get me wrong, I'd love to have a 370Z, but it needs to get over 20 mpg.

In regards to premium vs. regular, my Tundra definitely gets better MPG running premium. The costs of the premium gas + the more miles per tank I get is pretty much a wash compared to buying regular grade gas.

A COI would pay off in the long run and should provide more HP...at least both are true with the Tundra.

That comparison is a bit silly don't you think.

First off, max hp has very little to do with mpg's. There is no way in hell you're getting 16-17 mpg in a V8 Tundra at wide open throttle all the time for example. It all depends on driving habbits, and let's face it, you're more likely to want to hit the throttle a bit more driving a sports car. Basically, I've averaged anywhere from 30 mpg cruising on the highway, to 12 mpg with a stupid grin on my face. You're going to spend money on a car that has tires that last about 15k miles and cost about $1k to replace. The difference between using regular gas and premium gas is about $0.02 more per gallon....spending an extra $100-200 a year on premium fuel isn't something to really worry about.

Just as an example, if you're driving a Civic and are on a budget & fuel savvy, premium fuel wouldn't have any real benefits for you since you're not really after the performance aspect. You're gonna drive that thing like a grandma to get the most mileage. The opposite is gonna be true (with me anyways), driving the Z.

I always go with 93 octane and average 22-28mpg of mixed city and highway driving.

Airwalk · 04-02-2013, 06:41 PM

Listen dude, get the Z. I drive an F150 all day at the Pool company I run. When I get done work and get in my NISMO, my bad day just disappears. You having a truck too so let me tell you there is nothing more satisfying to tear up a back road on the way home after driving a big cumbersome vehicle all day. I really appreciate the car more to feel the agility and speed of the car. I know the Tundra is quick for a truck, but believe me it doesn't have **** on the Z.

03-31-2013, 10:44 PM	#19 (permalink)
JARblue A True Z Fanatic Join Date: Mar 2011 Location: Austin, TX Age: 43 Posts: 36,449 Drives: 11 Z34, 98 E36 M3 Rep Power: 2684440	To save on gas costs, I just siphon gas from my neighbors' lawnmowers that is, the neighbors I don't borrow gas from for my own lawnmower... kenchan, SouthArk370Z and DEpointfive0 like this. __________________ 2011 370Z 6MT Sport Gun Metallic \| ARC \| CJM \| Ecutek \| FI \| Fujimura \| R2C \| SPL \| Stillen \| TWM \| Z1 \| ZSpeed \|

04-01-2013, 04:02 PM	#27 (permalink)
KERMIT Enthusiast Member Join Date: Apr 2012 Location: Republic of Wadiya Posts: 301 Drives: Ms. Daisy Rep Power: 13	for an interesting read about controlling coolant temps... Audi EA888 Gen 3 __________________ Steering wheel with Z emblem, keyless entry, 3.7L with dual overhead cams, am/fm radio, ABS brakes, windshield, air in tires

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03-31-2013, 10:24 PM	#17 (permalink)
BlueDog007 Base Member Join Date: Jul 2012 Location: Charleston, SC Posts: 35 Drives: Not yet Rep Power: 12	I have read a little about FI but not sure what that is. Please explain. Thanks!

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04-02-2013, 06:41 PM	#30 (permalink)
Airwalk Base Member Join Date: Feb 2013 Location: norristown Posts: 52 Drives: 2009 Nismo 370Z Rep Power: 12	Listen dude, get the Z. I drive an F150 all day at the Pool company I run. When I get done work and get in my NISMO, my bad day just disappears. You having a truck too so let me tell you there is nothing more satisfying to tear up a back road on the way home after driving a big cumbersome vehicle all day. I really appreciate the car more to feel the agility and speed of the car. I know the Tundra is quick for a truck, but believe me it doesn't have **** on the Z.