2018 Chevy Colorado Z71

[great08]

A link to a vid that gives some great detail/insight onto some of the build features of this truck. This is an old vid from 2015 so some things have changed over the years. For instance the entire drive train was replaced in 2017... and a portion of the front frame was re-enforced to get better frontal offset crash test ratings.

 

[great08]

Today I parked next to a co-worker with the new gen Tacoma TRD Off-Road.

I noticed that his truck had the exact same tires as my Z71. Possibly even the same size. Even did a double take to make sure the rims were not the same pattern. They were the same grey with silver trim colors.

It makes sense that the auto mfr of both brands chose to put these tires on their vehicles.
1 - They score high owner/real-world reviews.
2 - They are super quiet
3 - Fuel efficient (got 30.1mpg on the way home today in a 4x4 truck with a little traffic breaking wind)
4 - Wet and dry pavement traction is amazing. (Still need to test in mud, snow, ice, and deep sand.)
5 - The sidewalls are pretty stiff which would help the vehicles achieve higher payload/tow ratings(that great street traction helps here as well)
6 - They have a large "Kevlar" stamp on the side stating that they are tough, which all truck buyers want
7 - They are not super expensive
8 - Tread wear life expectancy is decent

My all-time favorite tires have been another... possibly the most popular all terrains. Start with a BF. Been running those since high school... around 1998 actually. lol About time I tried something else for a while.

https://www.goodyear.com/en-US/tires/wrangler-all-terrain-adventure?cta=BBCardTireName

 

[great08]

Front and Rear Diff. Breather Mod:

Not Required!

I swear... the longer I have this truck... the more I keep finding little things about it that I really like. It really does seem that GM put some serious effort into thinking about making these trucks awesome little functional machines. It's in the details.

I just went out to take a look at my front and rear diff. breather tubes. To see how high they are for some fore-knowledge of their whereabouts(height) before making any sort of water crossing. In my case I tend to have to ford deep water on pavement when we get hard rains. I passed many flooded out Jeeps in my old 2WD Colorado on the way to work the last time I lived here. Not because my truck was better... but I understood it mechanically and was able to adjust speed to make the water wake not flood out/hydro lock my engine. My neighbor did destroy his vehicle.

Anyways.... Both diff breathers have a vent cap that is Spring Loaded to allow air in and out... but will close when trying to suck in water! On another plus note... they are already super high as well!!! Nice. The front diff breather ends up in the engine bay next to the battery. The rear diff breather is clipped up to the fuel port in the LH fender well. The tubes are clipped off every foot or so... and remain up out of snag range the whole way as well. Perfect!!!

Any deeper and my truck will be floating away... and hydro-locked anyways.

Good Job GM!

Photographic evidence...

View attachment 69562
Front diff. breather. TAKE NOTE... GM also put in bolt locations near the battery/fuse box (and marked with stickers) so that mods can have good grounds! Lower right...
View attachment 69563
Rear Diff. Breather... comes out just above the right side of the pumpkin... routes over the top of the diff... then routes up behind the fuel tank... along the frame... then up to the fuel port. If water gets this high... water will be entering the fuel system as well.
View attachment 69564
You can faintly see two of the clips. They are every 6 inches to 1 foot apart.
View attachment 69565

This is looking up through the inside of the frame/fender area to the fuel port. As you can see the last clip is up there nice and high.

Look at that heavy duty stainless steel fuel fill tube for the tank. Maybe dry-rotting and leaking tubes are a thing of the past. Maybe...

My mechanic eye also notices that the EVAP system tube is attached to the Top. It has a nice vertical bend in it as well. So that is also an awesome detail GM did a good job on. A lot of vehicles get issues with these systems when owners top off and get solid fuel into it. This should keep solid fuel/issues away.

View attachment 69566


Well... I suppose I will not be doing any mod to this system.

 

[great08]

Xfer Case and Transmission Breathers....

Someone on Coloradofans.com asked me if there are breathers for the Xfer case and Transmission. So I looked. Yes... there are!

I was not able to find the ends of either one though. However, they both rout along the top of the transmission and start heading up vertical when they reach the bell housing/engine/fire wall area. So they likely end on the same vertical plain.

On a side note... BOTH of the Xfer Case and the Transmission have cooling lines that head up to the radiator area.

The Xfer Case vent in the top left side... heads forward...
View attachment 69572
Then the Xfer case vent hose flops along the top of the Transmission before turning upwards and disappearing.
View attachment 69573

The transmission vent is hard to see. On the top right side of the transmission and turns forward... then turns up and disappears...

View attachment 69574

 

[great08]

Found a cool 100th Anniversary for Chevy trucks on YouTube. It inspired me to do a little bit of reading up on the history of GM. It does indeed have an interesting past.

Here is the 1st vid...

2nd Vid...


The first time Hydraulic Automatic transmissions were used in automobiles... was by GM. They first put them into Oldsmobile vehicles in 1940. Then made their automatic transmissions and installed them into GM built tanks during WWII. After that it became part of their marketing as having transmissions that were "Battle Tested".
Link...
https://en.wikipedia.org/wiki/Automatic_transmission

Here is a link that contains the specs of GM C/K series of trucks from 1960 through 1998. There were a LOT of firsts done to their trucks during this time period.
It is neat to see that the old...
1986 7.4L V8 454 for instance had...
240 hp (179 kW) @ 3800 RPM 375 lb⋅ft (508 N⋅m) @ 3200 RPM... more torque but a lot less hp and a lot less gears in the transmission (which adjust torque at the wheels technically)
The old 1987 5.7L V8 (350) made...
185 hp (138 kW) @ 4000 RPM 295 lb⋅ft (400 N⋅m) @ 2400 RPM... Same tq and drastically less HP.

https://en.wikipedia.org/wiki/Chevrolet_C/K

 

[Zillon]

Fantastic info documented in here, nice work.

I knew about the diff breathers and where they extended to, did not know about the transfer case and trans breathers and that they were extended as well. That’s great.

I agree, though - there are a lot of nice little touches that shows GM was thinking when they designed the trucks. And still some questionable ones that make you scratch your head (plastic front skid plate, anyone?).

 

[great08]

Fantastic info documented in here, nice work.

I knew about the diff breathers and where they extended to, did not know about the transfer case and trans breathers and that they were extended as well. That’s great.

I agree, though - there are a lot of nice little touches that shows GM was thinking when they designed the trucks. And still some questionable ones that make you scratch your head (plastic front skid plate, anyone?).

Yeah. Transfer Case and Transmission breathers had not even crossed my mind for some reason. Good thing that guy had asked on the coloradofans.com website.

I thought the plastic front skid plate is funny as well. Sadly it is not the first mfr. that did that and won't be the last. Maybe they thought it would be protected by the giant plastic air dam hanging 4" below/in front of it? lol

It does look like there is a lot of dead air space above it though. Maybe I will check that out next. They did throw some cheezy sacrificial skids below the steering gear and the Xfer case though. Those are at least made of steel to protect those cast aluminum parts.

 

[great08]

That right there is worth more than any overland trip in the world!

There are some good magazines out of Australia all about 4WD that I enjoy -- really good on the iPad or tablet as they have a lot of interactive features. With that Wifi in the truck it could give him something else to enjoy, and the Colorado's (Holdens) were really cutting their teeth in Oz before coming here, as I understand it (but I may be mistaken). This is one I really like: http://unsealed4x4.com.au

I just went through that link you provided in an earlier post to do some digging around. I don't know if the Australian Holden version is exactly the same as our Colorado trucks here in the states. However, I found a review they did on the 2017 Holden Colorado. Long story short... the reviewer is 6' 10" and loved it. Said he was not tired after a 5hr drive. Here is one quote from his review followed by a link...

"Will this truck outsell the HiLux? Probably not, but only due to the innate HiLux love we Aussies seem to have. Is it as good a 4X4 as the HiLux? You bet your arse it is."

http://unsealed4x4.com.au/factory-pimped-2017-holden-colorado/

 

[great08]

Tire Deflaters....

Boulder Tools
$26 on Amazon


These are not rapid tire deflators.

With these you set them once... then when ready to air down you screw them on and wait. I timed them and it took 10 to 12 mins to deflate down to 20psi. The lower the air pressure got the slower they bled the air. I have them all set to 20psi. I am going to set them again down to 15psi so they will drain the air faster. My gauge cluster states the exact air pressure in each tire. So deflating is going to be a breeze now.

I will screw them onto all of the valve stems and then start up the truck... watch the air pressure drop on my cluster... then unscrew them as their perspective tire reaches the desired level. Easy Peasy. I plan to go the beach and do some camping/fishing over night out there. Should be a lot of fun!

Tested out/timed the new Tsunami inflator. It took about 1min 50sec to re-inflate each tire back up to 35psi. My Z71 tire size is 255/65R17... which translates into around 30.5 inch tall tires.

Pics of the kit that will be living in my center consol....
View attachment 69840


View attachment 69841

 

[great08]

Vehicle Alert system:

Just some more observations so far that I think will be good info. for those who don't have one yet....
These things are just some more of those "little details" I like about this truck.

1) When I was airing down yesterday that little info. screen on the gauge cluster made life so easy. I can put the deflaters in and just watch the screen for the EXACT tire pressure. No popping them on and off to see where the tire pressures are at. That speeds things up considerably. It is likely even faster than one of the speed deflators that removes the valve stem since you are able to do all 4 tires at the same time. The truck gave off warning alarms for each tire as it went below 30psi. A little tire light lit off in the dash as well. And... I found out later.... that Chevy actually sent me an ALERT email about a tire that is to low on pressure. How cool is that? Made a little chime noise as the pressures fell as well.

Look at the pic below. When the tire pressures got below 30... the white box turned red and had a red flag next to that tire.

View attachment 69898



2) That same little info. screen gives all kinds of surprise alerts. It will tell you when the hood isn't latched properly, or when your windshield washer fluid is getting low. I go through a tank about every two to three weeks and it gives me the warning in enough advance that I have a few days to refill it. Also shows you a pic of which door is open as well.... of course.


3) I get a report card email every week from GM. Saying how well/far I am driving and things I can do to improve fuel economy. Even tells me how many hard accelerations and stops I did during that time frame. lol


4) I like the fuel economy page as well. You can set it to see what your average has been for either the last 25, 50, 100, or 400mi if I recall correctly. Whatever you have the setting to... it also will show an instant reading... and a best score reading for that setting... as well as show you when the engine is switching from V6 to V4 mode... which is super smooth. Unless you are cruising through a neighborhood and set the cruise @ 25mph or something. The truck will downshift and go into V4 mode.


5) There are a MASSIVE amount of info. screens you can choose. I disabled most of them so I only have 6 pages to scroll through to get to the fuel economy, tire pressure, and transmission temp pages with ease.

6) The "Miles to Empty" screen is continually adjusting the range based on fuel mileage you are currently getting. Which is awesome. When I am getting horrible economy on slow/rough roads... I will be able to better guess.


I suppose I am easily amused. lol

 

[madcratebuilder]

I didn't want my driving habits to make it to my insurance company and found that if you have a scan tool plugged in to the ALDL it can't be read remotely. I use a Scangauge II to watch engine timing and temps.

 

[great08]

I didn't want my driving habits to make it to my insurance company and found that if you have a scan tool plugged in to the ALDL it can't be read remotely. I use a Scangauge II to watch engine timing and temps.

That is something good to know. Thank You!

I think it is kind of creepy that all you have to do is call OnStar if it gets stolen... and that they can shut down the vehicle remotely. What about hackers?

 

[great08]

I live in the land of GIANTS.

Parked at work earlier and noticed that the bottom of my rear bumper is the same height as the front end of some lifted full sized trucks. Good enough... though I bet my departure is not quite as good as theirs... maybe. Should b fine for super rough roads though. Most of them anyways.

View attachment 69933

 

[great08]

Fuel Economy Test #2: Air Dam Removed

OK. I am not done with this portion of the test yet. It is only Monday and I have two more days worth of driving left till it's complete. It has been a few weeks since I last completed the first portion of the tests with the Air Dam Installed. So the weather has cooled down slightly for now... with that hurricane that blew through.

Anyways, with the air dam removed I have notice a slight decrease in fuel economy of around 2mpg when cruising @ 70mph. On a plus note that is only a 5 or so mile section of my 52.7 mile commute. So far it is looking like I will leave the air dam OFF most likely!!!

Today was the first two of six legs. The very first leg(out of 6) is the only one starting with a warm drive train. That is the result in the first pic. 27mpg! Not bad... The rest will be starting with a Cold drive train that will take about maybe 15mins for the oils to warm. I watched this awesome 27mpg PLUMMET to 24.4mpg within just the first few miles. It took the rest of the trip home to slowly climb back up to the result you see in the second pic. The temps dropped down to 75degF on the way home as well... which also took a cut out of the fuel economy since cold air is more dense. The engine may be having to put out just a little more fuel to keep the air/fuel ratio proper... and the oils will be running a just a little thicker in the drivetrain... and the air the vehicle has to push though will be just a tid bit thicker... and the tires will have just a tid bit higher rolling resistance... (OK very little differences but they accumulate dang it! lol )


View attachment 69972

The fuel reading when I got home. It took the whole trip to slowly climb back up to here after dropping to 24.4mpg on a cold drive train.

Looks like my trip each way is around 52.7 miles... and the gas station is about 1.7miles from the house.

View attachment 69973

 

[great08]

View attachment 70036

Found another Bumper for the Colorado. This would be the one to get if the apocalypse ever came. Found it on...

https://www.rocky-road.com/chevy-colorado-bumper.html

It is an ARB bumper.

EDIT: In case you have not noticed yet. Anyone who starts throwing this kind of armor onto a vehicle also has to upgrade the suspension... and sometimes even the drive train. For a reason. Bumpers like this can weight 700lbs sometimes. This one says it weights only 185lbs. So it may not be that tough.

 

[great08]

3.6L V6 Engine Info:

Since I just bought this truck and plan to do all of my own work on it over the next 1 to 3 decades... I am reading up on my engine. It is hard to dig around and find info. However, I just came across a gold mine that someone else discovered over @ coloradofans.com!!!

From what I am reading... this engine has alllllll of the makings of something that is going to LAST. I know a little about engines. Lets just say that all of the internals they designed into this engine are for strength and durability. So... providing that the companies that built the parts did a good job... and the builders on the GM product line did a good job. This engine should be around for many hundreds of thousands of miles if I take care of it. Many of the internal features are the SAME features that make diesel engines last soooo long. When combined with the 8spd transmission this engine does not have to rev.... just like a diesel... so it may very well make it. Lets get into some of the details. First a few links to two pages I have been reading from...

Link #1.... is to a thread of a guy doing an oil catch can test over 10k miles so far. Spoiler... there is no oil in his can so far. GMs design is spot-on...
https://www.coloradofans.com/forums/385-2nd-gen-how-tutorials/380673-moroso-oil-catch-can-2018-lgz-1-a.html

For those of you out of the loop... all manufacturers had issues with their vehicles when they began switching over to Direct Injection many years ago. The oil/carbon blow by from combustion on the piston rings works it's way up through the PCV system and back into the intake in the form of and oil/fuel/carbon vapor. Old fuel injection systems kept the intake valves clean by spraying fuel on them at all times. The DI engines did not have that self cleaning feature anymore.

It took some time to show up... but massive buildups began to form on intake valves on these DI engines (again all Makes/Brands) that were no longer multi-port (or other) fuel injection. This caused massive issues. So long story short Every mfr. has been coming up with ways to keep this from happening. Guys with older Direct Injection engines began installing Oil Catch cans into the PCV lines to save their engines(they usually have to drain it every couple of oil changes). Some companies now have a catch can design built into the engine. Others use Both DI & Multi-Port fuel injection in unison.

This engine (2017 and Later) has a built in catch can. (EDIT: It has two catch can stages it turns out)

Link #2... is to an article that gives SUPERB detail about the internal build features of the engine. You have to scroll down a ways to find the section on the new 3.6 that was first introduced into the 2016 Cadillac CT6 and Camaro with the same 8speed. The engines and transmissions in my truck have a slightly different tune for the truck with less HP but more TQ. (I do wish they brought the paddle shifter over. lol I am sure someone will do the mod)

http://camaronews.com/camaronews-bloggers/gm-reveals-twin-turbocharged-lgw-3-0l-v6-and-3-6l-lgx-v6-engines/

The truck variant of this engine is known as the LGZ.

It is a REALLY good read. With lots of info. I will try and break it down tomorrow. There are a Lot of features that a diesel engine has... like spraying oil directly onto the cylinder walls for one. Read up and Enjoy!

You will notice in the pic below that the oil filter is on the bottom of the engine. However, mine is remote located inside the engine bay and accessed from the top of the engine. Which for an Overlander who will have skid plates... is a GREAT THING. lol Anybody who has had to change oil on a motorcycle or any vehicle with skids understands.

I read that the oil pump is actually in the oil pan now to make the engine quieter. I don't care about that! I just want to know if I can do the timing chain one day without having to drop the oil pan now. Most engines have an oil pump in the timing chain cover... which means the pan has to be removed first... which means the steering linkage has to be removed...etc. etc. etc. It can snowball and be a pain depending on the vehicle. (Especially 4WD vehicles) I shall try to find out.

 

[madcratebuilder]

The LGZ is a techno marvel. Lot of power in a small package.

One thing that puzzles me is the wide spread in gas mileage with the LGZ in Z71's and ZR2's. My ZR2 is rated 16/18 city/hiway. I'm lucky to get 14.5 in town, on the hiway I have had 50 mile segments up to 30 mpg, most are around 26 mpg. I saw a minor increase in mpg after installing a Trifecta tune.

 

[great08]

The LGZ is a techno marvel. Lot of power in a small package.

One thing that puzzles me is the wide spread in gas mileage with the LGZ in Z71's and ZR2's. My ZR2 is rated 16/18 city/hiway. I'm lucky to get 14.5 in town, on the hiway I have had 50 mile segments up to 30 mpg, most are around 26 mpg. I saw a minor increase in mpg after installing a Trifecta tune.

I am pretty confident that it is all about (well the main thing anyways) right foot/throttle position. I have noticed that just a few mm difference in foot position can make a massive difference in fuel economy. Cruising at low RPMs will enable the engine to lean itself out and run more efficient as well. That is for hwy though.

Around town down in Mobile, AL I was getting around 20 to 22 mpg pretty consistent. Up here in Virginia Beach I am getting drastically less. Seems like the lights are mean to catch you in front of businesses on purpose here.

Way back when I was getting my Free Black Bowtie upgrade and dropped the truck off at the dealer... they gave me a Loaner 2018 Z71 Silverado. It had almost the same fuel economy rating as my truck but with a much more massive V8 and a much larger/heavier truck. How is that possible? Tune. (Note they may have had it in Teen driver mode or something) That truck had nowhere near the same level of pep. I had to go down to half throttle to keep up with traffic. I have no doubt that the power was there. It was just not easily accessible due to the tune for the throttle/transmission. I used to have a 00' Silverado with the first 5.3 V8. That thing was probably 2 to 3 times faster @ 1/4 throttle with a much weaker motor.

I tried to write my own Fuel Injection Air/Fuel ratio map for a conversion on a Motorcycle I used to have back in the day. (Ended up not getting past an engine that would idle since the daughter was born a month early... just threw the carb back on there) I learned a LOT about fuel injection back then. The things that will effect Proper Air/Fuel ratio are.... Engine Temp, Air Temp(Density), Throttle Position, Altitude/Humidity, Time it takes for the selected injector to put out enough fuel for that stroke, and RPMs. When you throw in some Sequential timing(Spark advance/retardation is now controlled by the computer) then you have what is called a 3D fuel curve map... and things get Super complicated. I would like to see that map for this engine.

 

[madcratebuilder]

Back in the day I did a lot of OBDI tuning on the second gen LT1's. I did a heads, cam, converter, injectors engine and I think the tune made as much difference as the old school speed equipment.

I use a ScangaugeII in my truck and one thing I monitor is total timing, The differences from a oem tune, the Trifecta sport and eco tune are considerable. Another thing about the Trifecta is I see V4 mode more often, or at least it seems that way, maybe it's just my driving.

 

[great08]

Back in the day I did a lot of OBDI tuning on the second gen LT1's. I did a heads, cam, converter, injectors engine and I think the tune made as much difference as the old school speed equipment.

I use a ScangaugeII in my truck and one thing I monitor is total timing, The differences from a oem tune, the Trifecta sport and eco tune are considerable. Another thing about the Trifecta is I see V4 mode more often, or at least it seems that way, maybe it's just my driving.

After the talk we had this morning I decided to take a look at what Trifecta has to offer for the Colorado with the 3.6 (saw an option for the 4cyl as well). Looks like for the 2017-later 3.6 V6 there are three options.

https://www.trifectaperformance.com/store/category/1309-36l/

The base program cost $329

The top program cost $688

Says that the Colorado can be about .5secs faster 0 - 60mph time. Cool... def better than most bolt on parts.

Also says... "Gains of up to +41 ft-lbs and +28 WHP under the curve (and +18 ft-lbs and +10 WHP peak on 91 octane)"

Not for me though. I am happy where I am at.