The standard 5.6-liter DOHC Endurance V8 produces 315 horsepower and 390 lb-ft of torque in the QX56.

Why does the QX56 have more hp and torque? Is it just the ecu or are there mechanical reasons for the difference? If it's the ecu, would swapping a QX56 ecu with the Titan's give us those same numbers?

After most of the dyno's that I've seen I believe Nissan underrated the Titan anyways and those numbers are probably more on par.

 

The QX56 also requires premium fuel. There was a thread on this some time ago. It could be that the QX56 is tuned for premium fuel. Some peole feel that premium fuel gives the Titan more power. The performance numbers in tests seem to show that the Infinity may have more power than the Titan.

 

So is premium not required for the Titan?

I have been filling mine up with Premium just because anything high-powered and over 300hp just seems it would do better on premium? I know premium is a waste on anything that it is not required on but something like the Titan with this size motor and displacement seems like it would need premium...

 

nope

So is premium not required for the Titan?

I have been filling mine up with Premium just because anything high-powered and over 300hp just seems it would do better on premium? I know premium is a waste on anything that it is not required on but something like the Titan with this size motor and displacement seems like it would need premium...

Nope. It "seems" your wrong. Ok, ok.. you just flat out wrong. Do your home work. :flamed: Premium isn't required or recommended and it runs 85 great at high alt.

 

Nope. It "seems" your wrong. Ok, ok.. you just flat out wrong. Do your home work. :flamed: Premium isn't required or recommended and it runs 85 great at high alt.

Premium is not recommended? This is where YOUR wrong...

No car company does not "recommend" premium, they may suggest using regular because a higher octane will not improve performance, but they would not recommend against it. All premium is is a higher cleaner burning octane, not harmful by anymeans.

Now, Im not saying its necessary to run premium on the Titan by any means, I do not run premium on my Honda (there is no point).

 

Premium is not recommended? This is where YOUR wrong...

No car company does not "recommend" premium, they may suggest using regular because a higher octane will not improve performance, but they would not recommend against it. All premium is is a higher cleaner burning octane, not harmful by anymeans.

Now, Im not saying its necessary to run premium on the Titan by any means, I do not run premium on my Honda (there is no point).

Much of the money you would spend on premium if you added it up you could get some new exhaust system to enhance fuel efficiency. Or at least buy one part of it.

 

I was under the understanding that premium was required for high compression engines because of early/pre detonation. The higher octane fuels can withstand the compression without detonating prior to TDC.

If this is in fact true, and the engines are the same why would the compression on the Infinity engine be greater than the Titan 5.6L

Thanks.

 

I was under the understanding that premium was required for high compression engines because of early/pre detonation. The higher octane fuels can withstand the compression without detonating prior to TDC.

If this is in fact true, and the engines are the same why would the compression on the Infinity engine be greater than the Titan 5.6L

Thanks.

Im wondering the same thing.

 

If this is in fact true, and the engines are the same why would the compression on the Infinity engine be greater than the Titan 5.6L

Its not. Its probably just a different timing and fuel curve in the Computer that boosts the specs or Nissan had to show a power difference in the QX56 and the Armada just to make the Infinity buyers feel like they were getting something better for the extra 10k......so they just gave the Nissan Titan and Armada engine a real conservative hp and torque rating. But this is a good question because I have seen somewhere they have the Armada as having more torque than the Titan. Anyone seen this?

 

"Armada is powered by an impressive 305-horsepower, 5.6-liter aluminum-alloy V8. With an easy-breathing 32-valve double-overhead-cam design that utilizes lightweight aluminum components and a highly advanced variable intake, for instantaneous power at any rpm. Plus 385 lb-ft of torque".

Yep.

 

This is a pretty good writeup in USA Today about premium fuels. http://www.usatoday.com/money/autos/2003-07-30-premiumgas_x.htm

 

I was under the understanding that premium was required for high compression engines because of early/pre detonation. The higher octane fuels can withstand the compression without detonating prior to TDC.

I meant to say recommended, not required. Also the knock-sensors in today's engines allow to run a lower grade fuel.

 

the reason that companies have upscale divisions, is because they tend to offer a little more lux, for people who want it. so with the higher price, comes more immenities, which may take the form of more lux, and that extry power, seperates it from the armada. most likely, it's in the ecu.

 

Be carefull if you've only been using premium...

I read somewhere a long time ago, that if you run more than 3 tanks of premium through your engine your stuck with using premium. If you switch back you'll have issues...

Not sure how true it is, but might be worth doing some homework on before you switch back to regular...

 

I wouldn't be surprised if the computer's fuel maps are very similiar for both vehicles.
Remember the Nissan Tech article released at about the same time as the Titan (no, I can't find it, so don't ask me to scan it... )? It was explaining how Nissan wanted to bring a truck to market that could be compared to the domestics, and they felt that introducing a gas-guzzling pickup that required premium fuel would not be very well accepted .. I am totally paraphrasing an article I read 6 mos ago so please correct any inconsistencies...

Anyways, when you run premium in the Titan, the timing does advance. See Juma's thread:
http://www.titantalk.com/forums/showthread.php?t=13805&highlight=octane+timing+advance
So you will see a power gain. I got better times at the track with premium fuel, it was a minor difference, but it is there.
Maybe if the Titan REQUIRED premium fuel it would also be 315 hp??

As stated, the numbers are under rated. I like that. Its modest. You can roast any other stock production pickup other than the lightning, srt-10, and sc'd harley davidson f150s. That's saying alot. Its a proven hemi-eater either way.

 

Like many have said, premium fuel will NOT improve performance in a vehicle that has compression ratios below 10.5-11. It's simply a waste of money. 87 octane has the same amount of detergents as the 93 does as required by law. 87 octane actually has more potential power than does 93 because it burns much faster. Higher octane and power is a common thought. However, if your car requires premium and you use 87, the engine can lose as much as 8-10hp. Maximas require premium fuel and you can definately tell the butt dyno difference. If you use 87 in a Maxima, the computer will retard your timing to compensate for the lower octane fuel. Since 93 octane burns much hotter than 87, you could actually cause damage to the cylinders if you continue to use premium fuel in the Titan. If the Titan says 87, use 87.

 

I vote for pciley. juma

 

Like many have said, premium fuel will NOT improve performance in a vehicle that has compression ratios below 10.5-11. It's simply a waste of money. 87 octane has the same amount of detergents as the 93 does as required by law. 87 octane actually has more potential power than does 93 because it burns much faster. Higher octane and power is a common thought. However, if your car requires premium and you use 87, the engine can lose as much as 8-10hp. Maximas require premium fuel and you can definately tell the butt dyno difference. If you use 87 in a Maxima, the computer will retard your timing to compensate for the lower octane fuel. Since 93 octane burns much hotter than 87, you could actually cause damage to the cylinders if you continue to use premium fuel in the Titan. If the Titan says 87, use 87.

Sorry, you have most of your "facts" bass-akwards. This is silly how many octane debates there are on this list between the few who know what they are talking about, the the rest that choose to spread mis-information.

First, where did you come up with this arbitrary 10.5:1-11.0:1 (which is quite a spread) rule? There are many aspects of engine design that influence knock propensidy, compression ratio is just one of them.

Second, you correctly state that 87 octane has more energy content and burns faster. But because it is fast burning it is more prone to pre-ignition. Then you contridicted yourself and said 93 burns much hotter... after you said 87 has more power potential and burns faster.

The icing on the cake was when you wrote that running 93 octane "could actually cause damage to the cylinders." Do you have any clue what you are talking about? Which part of "the cylinders" are in harms way? The walls?

While I belive that there is an advantage to using premium fuel over 87 in our trucks, for me it is not enough of a difference to justify the added expense on a daily basis. It is not easy to feel the difference between 305 and 315hp in a 5000lb. truck. But there is a difference, and you certainly will not hurt your truck using premium fuel. The other myth of "once you switch, you can't go back" is also unfounded b.s. When switching either way, you need to allow time for the ECU to re-adjust. Or reset it and speed up the process.

Jason K.

 

Be carefull if you've only been using premium...

I read somewhere a long time ago, that if you run more than 3 tanks of premium through your engine your stuck with using premium. If you switch back you'll have issues...

Not sure how true it is, but might be worth doing some homework on before you switch back to regular...

I read the same thing a while back.... My wife's 99 Pathfinder is a perfect exampe of this.

 

The infinity has a higher compression ratio than the the titan look on msn.com autos they state displacement and compression there.

 

http://www.carseverything.com/content/article/1497.3 From what I have seen ALL the endurance engines show to be 9:8.1

 

I agree with JMC. All the info that I have seen shows the QX56 and the Titan to have 9.8 compression ratio. I used 87 octane for 20K miles and I had no problem with it. I ran one tank of premium and I could not tell much difference. I now have driven over 4K miles with 91 octane and over that many miles I have found it does seem to have more power. I also have kept close records of fuel economy and I have seen about 7% increase in fuel economy. Where I live it is about a trade off with the extra 10 cents a gallon and the extra MPG.

 

I agree with JMC. All the info that I have seen shows the QX56 and the Titan to have 9.8 compression ratio. I used 87 octane for 20K miles and I had no problem with it. I ran one tank of premium and I could not tell much difference. I now have driven over 4K miles with 91 octane and over that many miles I have found it does seem to have more power. I also have kept close records of fuel economy and I have seen about 7% increase in fuel economy. Where I live it is about a trade off with the extra 10 cents a gallon and the extra MPG.

Ditto .

 

I BUY PREMIUM FUEL BECAUSE IT GIVES ME MORE MPG , and it smeels better,and taste better. :jester:

 

Yeah smell and taste :jester: