Infinity QX

tagjet · 01-24-2005, 10:50 PM

does anyone know the differance in Engine in the Infinity vs the Titan?
How do they get 10 more horse and 10 more torque?

Horsepower 315 hp @ 4,900 rpm
Torque 390 lb-ft @ 3,600 rpm

Potroast · 01-24-2005, 11:00 PM

tuning. It all comes down to how the ECU is programmed. If it were 100% efficient, then "chips" wouldn't work.

Armada · 01-25-2005, 07:35 AM

I don' think there is any difference whatsoever. The Infiniti uses premium fuel. The ECU just advances timing until it senses knock. Premium fuel lets that happen with our smart ECU's. That extra power is only going to show up at WOT and is really not usable in normal driving conditions.

There is at least one other thread here where it was proven that premium fuel does permit timing advance at WOT. So put premium in and give the ECU time to reset and you have an Infiniti engine! This is a very small increase in power and probably does not justify the significant increase in fuel cost, unless you are at the drag strip and trying to get every ounce out of the engine in competition.

Infiniti owners are an "upscale lot" and probably want to feel they are getting something extra. They are, but at a pretty high cost in price of the vehicle and in fuel costs. BTW, they can run regular without any problem and then have the same bhp and torque that we have. Then they can save a few bucks. Engines are the same.

Armada · 01-25-2005, 10:01 PM

Ctuck13, what is your source of info that the compression ratios are different? They are both 9.8 to 1.

The ECU's are identical and are of the new generation Nissan design. They are "smart" in that they will absolutely continue to advance spark until knock is detected. That will produce a small gain at wide open throttle.

Here is the Infiniti web site specs on the engine.

http://www.infiniti.com/content/mode...,75031,00.html

I say there ain't no difference at all in these engines. Put premium in and get about 10 more horses and 10 more lbs. of torque, after you give the ECU a little time to adjust. Or run the Infiniti on regular and get the same as ours.

It's just a way to make people with more money to spend feel more "special." And they get to enjoy being special when they fork out the extra money at the pump.

If anyone can show me that as much as one bolt is different on the Infiniti engine and the Armada engine and back it up, I'll stand corrected. They even build both trucks in the same plant here in Mississippi, about three hours north of me.

Besides the advance curve objective testing done by others on threads here, I can tell you that using an accelerometer (specifically a G-Tech Pro Competition model), and repeated testing, I can produce 8-10 more horses and about the same amount of extra torque by running 93 octane as compared to 87 octane, here at sea level.

There should be chassis dyno numbers posted here by others which bear out the same thing.

In trucks that weigh almost 6000 lbs, this is not going to make any meaningful difference, and none at all except at wide open throttle. It's not enough, however, to change quarter mile times by even one tenth, but could give you a few feet edge in a close drag race.

JS02 · 01-29-2005, 08:04 AM

There have been other threads on this topic. No one has shown that there is any difference in the engines. No one has been able to show if there is any difference in tuning. I think that from the info we have so far that the premium fuel could make the difference with the ECU adjusting for it. There doessn't seem to be anyone that can tell us if the tuning is the same or not.

**HudsonValleyTitan** · 01-29-2005, 10:33 PM

I'm with Armada on this one. I know the engines in the QX, Armada and Titan are identical. Even the ECU mapping are mirrored in each vehicle. The added "PREMIUM FUEL RECOMMENDED FOR MAXIMUM PERFORMANCE" is all that differs according to a few people at Nissan I know quite well. I've been using 93 octane since new just for this reason.

RockyMtnTitan · 01-30-2005, 03:48 PM

I just received a copy of the "Nissan Armada and Titan New Model Training" from a member at ClubTitan. This is not the Shop Manual, but is much more detailed than the owners manual. Anyway, it shows 305 HP/ 385 TQ for the Armada and 305/379 for the Titan. Does the Armada recommend premium like the Infinity? If not, then I'm wondering why the torque rating is a little higher on the Armada, kinda like the Infinity. With the exceptions of the xfer cases, I thought the powertrains were the same, although this would only affect rwhp and not bhp. Just curious.

Potroast · 01-30-2005, 08:40 PM

the exhaust on the armada has higher backpressure which results in a little more torque.

PuvMan · 01-31-2005, 12:09 AM

Speaking of the QX, little off topic.

My aunt has a QX, with the 7 seating option....and a lovely golden retreiver named Destiny....well Destiny's nails dont get along with the leather very well, and she is looking for seat covers. Needs them for the 2 center row captain's chairs, and the 3rd row bench. Any help is appreciated!

thanks

puv

Armada · 01-31-2005, 10:22 AM

Quote:

Originally Posted by Potroast

the exhaust on the armada has higher backpressure which results in a little more torque.

Interesting. Do you have part numbers or other info on how the exhausts are different? I'd really like to know the specific differences.

I know the vehicles have different wheel bases and that the pipes from the muffler back are different because of that, but are there any other differences?

I thought everything from the exhaust manifolds to the muffler are the same. What's different?

The Armada manual does not specify premium fuel. Same fuel recommendations as Titan. Same rated horsepower.

I wonder if the very slight difference in torque (6 whole lb/ft.), which is well within testing range of error, might just be how the numbers worked out for averages done on different test days.

Potroast · 01-31-2005, 10:28 AM

I'll see if I can get part numbers for ya. I had asked my GM a few days ago about the difference in torque between the armada and titan and he was very confident in his response regarding more backpressure. Considering that they are different exhausts, but ecus and engines are the same, this would seem a reasonable explination. I know the part #'s are diff for the titan and armada, but I don't know how that will help you determine the backpressure between em. If you had both you could flow-test them, other than that.....

*dilleyoshemp* · 01-31-2005, 11:42 AM

this is from motortrend magazine

"...The QX56 shares the Armada's 5.6-liter DOHC V-8 and five-speed automatic transmission, but engine compression is bumped from 9.8:1 to 10.0:1, boosting power output to 315 horses and 390 pound-feet of torque--10 additional ponies and five additional pound-feet of twist. Off-line 0-to-30-mph acceleration is inspiring, and we're especially impressed with the 30-to-50-mph passing power, which will truly be appreciated when towing..."

JS02 · 01-31-2005, 04:08 PM

Here are Infiniti's spec's:

http://www.infiniti.com/content/mode...,75031,00.html

They do not show the increased CR. Maybe the magazine guys had it wrong.

RockyMtnTitan · 02-03-2005, 02:29 PM

Quote:

Originally Posted by dilleyoshemp

this is from motortrend magazine

"...The QX56 shares the Armada's 5.6-liter DOHC V-8 and five-speed automatic transmission, but engine compression is bumped from 9.8:1 to 10.0:1, boosting power output to 315 horses and 390 pound-feet of torque--10 additional ponies and five additional pound-feet of twist. Off-line 0-to-30-mph acceleration is inspiring, and we're especially impressed with the 30-to-50-mph passing power, which will truly be appreciated when towing..."

Also from Motortrend:

Infinity QX56
0-60 in 6.8 sec
1/4 mi in 15.2 sec

Car and Driver tested the Armada with a 0-60 time of 7.0 secs, but no 1/4 mi time. Both Armada and QX56 tested faster than C&D's 0-60 time for the Titan 4WD SE CC at 7.6 sec. Seems like a pretty big spread to attribute to only premium gas and running more timing, especially given the weight of the QX and the Armada. Does make you wonder about the possibility of different CR's, or something else.