Gear Ratio for Towing

I was looking at a Dyno chart for the Armada at the K&N web site. According to their Dyno chart the Armada gets into it's serious torque ratings starting at 3,500RPM up until 4,000RPM. But with my gearing (06 LE 4x4 with Tow package), 3,500RPM in 2nd gear is 40MPH while 3,500RPM in 3rd gear is 70MPH. Now while towing a trailer I would like to be able to tap into my prime torque curve when going up long uphill grades, but I don't want to have be traveling or trying to maintain 70MPH in 3rd gear or drop down into 2nd gear and maintain 40MPH. I would really like to have gearing that gives me around 50MPH or 60MPH at 3,500RPM.

Do I have any options available for changing my final gearing? Has anyone else been concerned about this?

I was looking at a Dyno chart for the Armada at the K&N web site. According to their Dyno chart the Armada gets into it's serious torque ratings starting at 3,500RPM up until 4,000RPM. But with my gearing (06 LE 4x4 with Tow package), 3,500RPM in 2nd gear is 40MPH while 3,500RPM in 3rd gear is 70MPH. Now while towing a trailer I would like to be able to tap into my prime torque curve when going up long uphill grades, but I don't want to have be traveling or trying to maintain 70MPH in 3rd gear or drop down into 2nd gear and maintain 40MPH. I would really like to have gearing that gives me around 50MPH or 60MPH at 3,500RPM.

Do I have any options available for changing my final gearing? Has anyone else been concerned about this?

RiverOne - I'm towing about 5500 lbs or so, and I can handle most any grade in 3rd gear at around 60 mph, turning around 3,200 rpm. This includes the Grapevine out of Bakersfield, Sherwin Summit north of Bishop, and other like grades. You might be towing heavier, so you need the extra torque / hp, but there is plenty of umph for towing at rpms outside of 3500 to 4000.

Keith

I don't have a TT yet, but I'm looking. What prompted my original question was that I test towed a 25' TT which had a listed UVW of 5660 (listed in the TT, not brochure). It had about a 1/4 tank of water but I do not know its actual weight. Actually it towed (and stopped) very well, but I only had the chance to tow on the flat freeway. It did however, feel better power wise, towing in 4th at 70MPH than 60MPH. I really don't like traveling that speed with a trailer but that is where the gearing felt best.

BTW, the Service Manager for the RV dealer went with me on the tow test. He was not at all familiar with the Armada. He came back very impressed. When we first hitched the trailer he watched in amazement as the air suspension nearly raised the rear end to regular ride height. When we pulled out the driveway at dealership he commented that this is a spot where many people have their hitch scrape the ground. We went through it without a scrape. As I accelerated onto the freeway he asked what kind of engine it had. When I told him he commented that he had no idea Nissan had an engine with this much power. Once on the freeway he had me put on the cruise control at 60MPH because he said most of the smaller vehicles have trouble holding the steady speed on cruise. He was impressed when it settled right in.

When we got back to the dealership he went over to a couple of salespeople that were standing around. I could overhear him telling them how impressed he was with that "Nissan" and how it wasn't anything like the Tahoe's that he had done test rides with.

So yes, I was happy with the power, put looking at the Dyno chart I see this extra 40-50ft lbs of torque just sitting there at 3,500 - 4,000 RPM. It's so close, I just wish I could more easily get into it in 3rd gear. At least I know it is there, and if need be, I would imagine that a steady 3,500 RPM in 2nd gear (40MPH) would carrying me over just about the steepest thing I would face.

There are only two options for the ratios in the Armada. The non-big tow is 2.94 and the big tow/off road is 3.36. There are no aftermarket gears available. Even if there were, changing the ratio causes problems. The Armada's computers are looking at vehicle speed from two sources; the sensor in the transmission and the wheel sensors. If these two signals don't match it causes problems, such as incorrect transmission operation and failure of the cruise control system. If you change final ratios, these two signals will not match.

I'm not sure I'd place a lot of value in that dyno chart. I'm attaching an excerpt from Nissan's technical paper on our engines as presented to the Society of Automotive Engineers.

Nissan says that maximum torque is at 3600 rpm and that 90% of the torque is there at 2500 rpm. From looking at the chart (I've posted this paper elsewhere on this board), it looks like about 70% of the torque is available as low as 1500 rpm.

I tow an 8,000 lb. equipment trailer and do not think this engine is underpowered for towing that load. It's not a turbo diesel, but it is one hell of a fine gas engine for towing in my humble opinion.