De-Tune a QX56 Engine?

[SFBayQ45]

I like the QX56, but the premium requirement is a big turnoff considering gas prices these days. Is there a way to de-tune the QX56 engine to make it run on regular gas instead (so as to prevent the "knocking" associated with using 87 octane)? I don't care about the extra 10+ horsepower at the expense of premium gas.

[elwesso]

Im sure most people run 87 in them. the newer ones you probably wont hurt so mcuh. you can turn the timing back a few degrees and that will take care of it.

[Skibane]

Less horsepower from a gallon of gas = more throttle required to provide the same amount of acceleration = lower fuel economy = zero net reduction in fuel cost...

[maxnix]

Less horsepower from a gallon of gas = more throttle required to provide the same amount of acceleration = lower fuel economy = zero net reduction in fuel cost...

BINGO!

Difference in cost maybe $300 per year? On a $56K vehicle?

Might try to trade for a Honda.

[qship96]

Disable knock sensor which will retard timing to below 87 octane state of tune,if it works like a g50-or just wait as Nissan uses crappy knock sensors which all seem to fail sooner or later resulting in the above

[bullittandy]

Run 87, and the engine will detune itself. Take it easy on the engine and it probably won't even notice.

[SFBayQ45]

Less horsepower from a gallon of gas = more throttle required to provide the same amount of acceleration = lower fuel economy = zero net reduction in fuel cost...

That's already known, but like I said I don't care for the additional horsepower because acceleration is not what I'm after (considering I already have a Q to serve that purpose). There's no need to spend premium on two vehicles when the Q is already getting pampered. I'm more interested on the technical side of the equation: what separates the Armada from the QX56 in terms of modification to make the difference in horsepower and if there's any way to detune the QX engine to run regular? Despite what is being said about running regular, I strongly believe prolong use of regular gas in a engine engineered for premium will result in direct/indirect damages and/or shorten engine life. I noticed that the Armada and the QX56 gets the same MPG, so how is this possible? What can be done to the QX56 to make it run regular without suffering potential damages down the road?

[elwesso]

Is the extra money really the problem? How can (lets call it $300/year to be ultra safe, more like $250) matter in the long run? drop in the bucket IMO.

The QX56 only makes 3 more HP than the armada (317 in the armada), they both have 9.8:1 compression ratios.... Its definitely in the ECU that makes it run premium...

I tend to think you might be able to use an armada ECU.

Personally, what I would do if I was hell bent on doing this (which I wouldnt be), I would just turn the CAS back 2 degrees.

[Skibane]

That's already known, but like I said I don't care for the additional horsepower because acceleration is not what I'm after

It's not just a matter of acceleration.

You aren't going to save any money on gas, either. What you save in a lower price per gallon will be more than made up by the fact that you will be using more gallons.

Getting less energy out of a gallon of gas means that you have to use more gas to get the same amount of energy.

[bullittandy]

I'm sympathetic to the fact that noone is answering your question.

I'm also in disagreement that running 87 will damage the engine. Unless there are actual mechanical changes between the Nissan and Infiniti engines then the only thing that is different is the timing and fuel and fuel is likely correlated with the timing. Octane requirements are very conservative because of all the gas/load variables across owners, geopgraphy.

Less octane, engine pings, K/S "hear it," less timing, no damage. Hell, its not even a certainty that the engine will ping on 87. There's alot of experimentation with timing and octane on 5.0 Mustangs. The factory timing is 8 degrees BTDC and an easy way to get some H/P is to bump the timing. Some guys run 12 degrees on 91 octane, some 14 and some 15, ping free, every engine's different. But I could be wrong....

[dsagers]

Another alternative is water injection.

Snow Performance makes a kit for naturally aspirated engines, and it is adjustable, so you can fine tune it.

[elwesso]

I'm sympathetic to the fact that noone is answering your question.

I'm also in disagreement that running 87 will damage the engine. Unless there are actual mechanical changes between the Nissan and Infiniti engines then the only thing that is different is the timing and fuel and fuel is likely correlated with the timing. Octane requirements are very conservative because of all the gas/load variables across owners, geopgraphy.

Less octane, engine pings, K/S "hear it," less timing, no damage. Hell, its not even a certainty that the engine will ping on 87. There's alot of experimentation with timing and octane on 5.0 Mustangs. The factory timing is 8 degrees BTDC and an easy way to get some H/P is to bump the timing. Some guys run 12 degrees on 91 octane, some 14 and some 15, ping free, every engine's different. But I could be wrong....

agreed totally. thanks andy.

[Q45denver]

You could install a thicker head gasket. The trade off for your high compression engine is that it gets better mileage than a similar low compression engine running on regular.

[SFBayQ45]

I'm also in disagreement that running 87 will damage the engine. Unless there are actual mechanical changes between the Nissan and Infiniti engines then the only thing that is different is the timing and fuel and fuel is likely correlated with the timing. Octane requirements are very conservative because of all the gas/load variables across owners, geopgraphy.

I see where you're coming from in terms of your disagreement with regards to 87 not causing any damage, so you could take that risk but I'd rather play it safe. Everyone has his own interpretation.

It's unfortunate the answer is not apparent how both the Nissan and Infiniti get the same EPA Estimated Fuel Economy (4WD: 12 mpg city / 17 mpg highway) but the Infiniti reguires premium gasoline. I guess only a Nissan engineer could shed some light into how the engine is designed differently.

[maxnix]

Another alternative is water injection.

Now we are into serious degradation of performance. First we'll lower the flash point, then we'll replace fuel with water!

If you don't want to run it the way it is designed to run, get something that is.

A bicycle will give you great mileage, and tone you too!

[elwesso]

it should be obvious to most that its not in the engine, but in the tuning.

[SFBayQ45]

I'm also in disagreement that running 87 will damage the engine. Unless there are actual mechanical changes between the Nissan and Infiniti engines then the only thing that is different is the timing and fuel and fuel is likely correlated with the timing. Octane requirements are very conservative because of all the gas/load variables across owners, geopgraphy.

I see where you're coming from in terms of your disagreement with regards to 87 not causing any damage, so you could take that risk but I'd rather play it safe. Everyone has his own interpretation.

It's unfortunate the answer is not apparent how both the Nissan and Infiniti get the same EPA Estimated Fuel Economy (4WD: 12 mpg city / 17 mpg highway) but the Infiniti reguires premium gasoline. I guess only a Nissan engineer could shed some light into how the engine is designed differently.

[SFBayQ45]

I'm also in disagreement that running 87 will damage the engine. Unless there are actual mechanical changes between the Nissan and Infiniti engines then the only thing that is different is the timing and fuel and fuel is likely correlated with the timing. Octane requirements are very conservative because of all the gas/load variables across owners, geopgraphy.

I see where you're coming from in terms of your disagreement with regards to 87 not causing any damage, so you could take that risk but I'd rather play it safe. Everyone has his own interpretation.

It's unfortunate the answer is not apparent how both the Nissan and Infiniti get the same EPA Estimated Fuel Economy (4WD: 12 mpg city / 17 mpg highway) but the Infiniti reguires premium gasoline. I guess only a Nissan engineer could shed some light into how the engine is designed differently.