MPG Breakthrough - Nissan Armada Forum: Armada & Infiniti QX56 Forums
User Tag List

 1Likes
Reply
 
LinkBack Thread Tools Display Modes
post #1 of 22 (permalink) Old 11-09-2017, 11:44 PM Thread Starter
SHIFT_Hardcore
 
SGreenlyn's Avatar
 
Join Date: Apr 2015
Posts: 276
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 68 Post(s)
 
MPG bump?

Armada/Titan gurus,

Has anyone tried heating up the thermostat a bit to give a little bump to MPG?

Reason I ask:

Yesterday, my thermostat failed full open. Its a little chilly, around 50F ambient, so the motor is now running full-cold-needle on the road. My awesome little $10 (Amazon) ODB2 Bluetooth interface says the coolant is running about 125F on the highway, and then as high as 140F while going slow or stopped for a while.

I've noticed an MPG drop with the full radiator cooling, begging the question, might we get an MPG increase by installing a slightly higher temp thermostat?

I know that my BMW twin turbo's tune won't even kick-in for safety until the coolant temp reaches 200F. Contrast that to OEM Armada thermostats which are set to 170 degrees, and my gauge vs ODB2 readout confirms that 170F corresponds to a needle about 40-45% of the way from Cold to Hot, where the needle usually sits. I've noticed there are both 170F and 180F thermostats are commonly available for our truck stating they are both "OEM replacements."

Questions:

1) Is there a reason our engines want to run at 170? A quick scan of Amazon turns up 170s and 180s as direct OEM replacemnets, though OEM is 170. There are also 195, 200, and 205 "performance options" for a lot of similar vehicles--SUVs, trucks, etc.
2) Is there a case for running 170 vs say 180-190, assuming oil viscosity is matched, etc?
DanF. likes this.

2005 Armada LE 207K miles,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
, rear cats deleted and replaced with 2 x Vibrant 1792 resonators, Magnaflow 22", stock pipes, dual tips, home made K&N RU-3270 intake,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
with 6000K 75W HIDs,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
, 36W LED projector fogs, LEDs all around,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
, 400W rear amp + Bose 161s in back,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
, 'Armada' emblem wrap for the hamburger,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
for interior exhaust fans and continuous battery charging.

Last edited by SGreenlyn; 11-10-2017 at 09:06 AM.
SGreenlyn is offline  
Sponsored Links
Advertisement
 
post #2 of 22 (permalink) Old 11-11-2017, 07:31 PM Thread Starter
SHIFT_Hardcore
 
SGreenlyn's Avatar
 
Join Date: Apr 2015
Posts: 276
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 68 Post(s)
 
MPG Breakthrough

When my thermostat finally failed full open after 200K miles, I noticed a precipitous steady state coolant temperature (125F) and MPG drop. The colder the coolant temp, the lower the MPG.

After some Amazon shopping, I noticed the OEM thermostat was rated at 170F. There was another aftermarket option or two which claimed to be OEM spec, but listed 180F. A lot of other trucks and cars had 190F, 195F, 200F, and 205F "performance" options.

This begged the question, could our motor be running too cold for best MPG, from the factory? The Armada options were so much cooler than my BMW's 230F normal coolant temp, so I did a little digging. I found a good article noting that modern BMWs go for fuel efficiency instead of power, so they run their engines warmer. Hmmm, could Nissan have been trying to bump that critical HP # above 300?

After a little research, I decided that up to 200F was perfectly safe, if not safer for the motor than running on the cool side. So I bought a Stant 14128 180F Thermostat (plus Gates 33658 Engine Coolant Thermostat Seal) specifically because the reviews said this Stant ran a little hot, between 190 and 195.

Total cost: $15 for parts, $18 for a gallon of Nissan coolant premix, and 15 minutes installation time.

With engine cold:
1. Remove engine top cover: remove two 10mm bolts straddling throttle body
2. Slide off intake forward/off at throttle body for more room: loosen 1 screw clamp with standard screwdriver
3. Remove thermostat under throttle body: three 12mm bolts
4. Top off coolant through radiator top cap until expansion tank is at fill line: ~3 quarts.
5. Squeeze a large radiator hose repeatedly to burp bubbles before buttoning up the radiator cap.
6. Optional: after closing coolant system, spray-clean throttle body flap with throttle body or carb cleaner
7. Drive, let cool, burp again.

Well, here are the first results from a closed 14 mile loop with mild rolling-hills. I've never seen MPG like this from my truck. Could it really be this simple?
Attached Thumbnails
Click image for larger version

Name:	MPG1.jpg
Views:	201
Size:	518.8 KB
ID:	42145   Click image for larger version

Name:	MPG2.jpg
Views:	216
Size:	74.4 KB
ID:	42153   Click image for larger version

Name:	MPG3.jpg
Views:	222
Size:	549.9 KB
ID:	42161  

2005 Armada LE 207K miles,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
, rear cats deleted and replaced with 2 x Vibrant 1792 resonators, Magnaflow 22", stock pipes, dual tips, home made K&N RU-3270 intake,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
with 6000K 75W HIDs,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
, 36W LED projector fogs, LEDs all around,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
, 400W rear amp + Bose 161s in back,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
, 'Armada' emblem wrap for the hamburger,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
for interior exhaust fans and continuous battery charging.

Last edited by SGreenlyn; 11-12-2017 at 09:05 AM.
SGreenlyn is offline  
post #3 of 22 (permalink) Old 11-12-2017, 12:06 AM
Zad
SHIFT_Lurker
 
Join Date: Sep 2017
Posts: 20
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
 
Holy crap, Id love 22+ mpg! I dont know the first thing about what youve done and Im looking forward to hearing from people that do, yourself included. Nice detective work. Lets hope that what youve discovered is just that simple.
Zad is offline  
Sponsored Links
Advertisement
 
post #4 of 22 (permalink) Old 11-12-2017, 09:03 AM Thread Starter
SHIFT_Hardcore
 
SGreenlyn's Avatar
 
Join Date: Apr 2015
Posts: 276
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 68 Post(s)
 
Quote:
Originally Posted by Zad View Post
Holy crap, I’d love 22+ mpg! I don’t know the first thing about what you’ve done and I’m looking forward to hearing from people that do, yourself included. Nice detective work. Let’s hope that what you’ve discovered is just that simple.
Its pretty straight forward - this simple mod runs the engine about 20F degrees hotter than stock. The engine temperature gauge moves maybe one needle width to the right compared to the OEM position, if that. More testing today.

2005 Armada LE 207K miles,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
, rear cats deleted and replaced with 2 x Vibrant 1792 resonators, Magnaflow 22", stock pipes, dual tips, home made K&N RU-3270 intake,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
with 6000K 75W HIDs,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
, 36W LED projector fogs, LEDs all around,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
, 400W rear amp + Bose 161s in back,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
, 'Armada' emblem wrap for the hamburger,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
for interior exhaust fans and continuous battery charging.
SGreenlyn is offline  
post #5 of 22 (permalink) Old 11-12-2017, 07:07 PM
SHIFT_Enthusiast
 
Join Date: Oct 2014
Posts: 205
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 31 Post(s)
 
I am all over this - can't wait to see a larger sample size. Please do some hand calculations on the MPGs next fill up.

My 06 is at 150k and I average 14-15 mpg in mixed driving 17-18 is the best I get with easy highway driving. I'd swap in a t-stat tonight in the dark for a 2mpg gain. MPG is about the only thing I don't like about my Armada.

Please keep this post updated.
staplebox is offline  
post #6 of 22 (permalink) Old 11-12-2017, 09:16 PM
SHIFT_Enthusiast
 
Join Date: Mar 2014
Location: ATL
Posts: 162
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 33 Post(s)
 
Quote:
Originally Posted by staplebox View Post
I'd swap in a t-stat tonight in the dark for a 2mpg gain. MPG is about the only thing I don't like about my Armada.
Please keep this post updated.
Seriously, this.
amaff is offline  
post #7 of 22 (permalink) Old 11-13-2017, 06:32 PM
SHIFT_Newbie
 
Join Date: Aug 2010
Location: San Diego
Posts: 97
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 18 Post(s)
 
What was your MPG before you swap the thermostat?

Have you noticed any performance difference?

If you run the engine hotter does that mean you need to swap out your oil for a lower viscosity?

Subscribed!

08 Armada SE 4x4
Front: Bilstein 5100s, Rear: 2" PRG spacers, Bilstein 24-187077, Firestone Coil-Rite Air Springs (W237604150)
Volant (Gen 1) CAI, Nitto Terra Grapplers (275/70/R18), Bully Dog GT (10/2017), Hayden 678 Trans Cooler (12/2017)
Bulkhead is offline  
post #8 of 22 (permalink) Old 11-14-2017, 01:07 AM Thread Starter
SHIFT_Hardcore
 
SGreenlyn's Avatar
 
Join Date: Apr 2015
Posts: 276
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 68 Post(s)
 
So after 150 miles or so, the verdict is around +2 MPG. I just returned from mixed driving with 20.0 on the display. That's never happened to me in 200K miles. There is no noticeable change in engine power. It surprises me too.

For reference, Bluetooth ODB2 reader temperature readings:

Heat soaked idle: 196
30 mph: 194
50 mph: 191
75 mph: 188

The temp needle on the dash looks the same as before, maybe a needle width to the right. It parks on the left side of the thermometer symbol. I think I'm going to try a 190F thermostat, just to see what happens.

One downside is the front electric fan runs all the time, at least whenever I'm able to hear it. That should be an easy fix, Hayden makes some temp-adjustable fan relays that Amazon says are a fit.

2005 Armada LE 207K miles,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
, rear cats deleted and replaced with 2 x Vibrant 1792 resonators, Magnaflow 22", stock pipes, dual tips, home made K&N RU-3270 intake,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
with 6000K 75W HIDs,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
, 36W LED projector fogs, LEDs all around,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
, 400W rear amp + Bose 161s in back,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
, 'Armada' emblem wrap for the hamburger,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
for interior exhaust fans and continuous battery charging.

Last edited by SGreenlyn; 11-14-2017 at 01:13 AM.
SGreenlyn is offline  
post #9 of 22 (permalink) Old 11-14-2017, 09:02 AM
SHIFT_Lurker
 
happycamper's Avatar
 
Join Date: Oct 2017
Location: Chicago, IL
Posts: 20
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
 
Garage
What's the thermostat specification for our 5.6L engine? The only info I've found is below for a 08 QX56.

http://www.nicoclub.com/manuals/QX56/2008/CO.pdf

Valve opening temperature: 80 - 84C (176 - 183 F)
Maximum valve lift: More than 10 mm/95C (0.39 in/203F)
Valve closing temperature: 77C (171F) or higher

08 QX56 4WD towing 2012 Rockwood Roo 233s TT
MODS: Bilstein 4600 HD front shocks + Moog 81085 rear springs, General HTS60 Load Index 119 tires, Rockville RW10CA subwoofer, more to come...
happycamper is offline  
post #10 of 22 (permalink) Old 11-14-2017, 09:39 AM Thread Starter
SHIFT_Hardcore
 
SGreenlyn's Avatar
 
Join Date: Apr 2015
Posts: 276
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 68 Post(s)
 
Quote:
Originally Posted by happycamper View Post
What's the thermostat specification for our 5.6L engine? The only info I've found is below for a 08 QX56.

http://www.nicoclub.com/manuals/QX56/2008/CO.pdf

Valve opening temperature: 80 - 84C (176 - 183 F)
Maximum valve lift: More than 10 mm/95C (0.39 in/203F)
Valve closing temperature: 77C (171F) or higher
Great question. It's listed as 170F, which is confirmed by your 171 closing temp, but its impossible to know the temp it actually maintains without testing. If the info in your quote is right, this thermostat is 13F degrees hotter than stock. I threw my OEM thermostat away because it was broken full open. If someone could read their heat soaked idle temperature with an OEM thermostat using a $11 ODB reader like the one below, that would be helpful. I use the $5 Torque Pro app to connect it to my Android phone, there is also a free version.

A little additional info from the Stant website:
Quote:
THERMOSTAT FAILURES
A thermostat fails “open” if the return spring breaks or debris prevents the thermostat valve from fully seating or closing; allowing a steady flow of coolant to the radiator, overcooling the engine. This results in poor warm up and heater performance, increased engine emissions and reduced fuel economy. An engine should never be operated without a thermostat, even in extreme temperatures.

OE & ALTERNATE TEMPERATURES
OE recommended temperatures should be used in nearly all situations. Alternate temperature thermostats are available and can be used in some applications
- Alternate temperatures are often applicated for older, pre-1995 vehicles where they can be used without causing problems
- Alternate temperature are not applicated for most newer vehicles
- Using an alternate temperature thermostat in a newer vehicle would require changing computer setting and possible additional modifications
Search Amazon for: B01BY2CK32
Attached Thumbnails
Click image for larger version

Name:	51z7L6z0ZfL._AC_US218_.jpg
Views:	43
Size:	13.5 KB
ID:	42218  

2005 Armada LE 207K miles,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
, rear cats deleted and replaced with 2 x Vibrant 1792 resonators, Magnaflow 22", stock pipes, dual tips, home made K&N RU-3270 intake,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
with 6000K 75W HIDs,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
, 36W LED projector fogs, LEDs all around,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
, 400W rear amp + Bose 161s in back,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
, 'Armada' emblem wrap for the hamburger,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
for interior exhaust fans and continuous battery charging.

Last edited by SGreenlyn; 11-14-2017 at 09:51 AM.
SGreenlyn is offline  
Reply

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome