Project Polar Bear: '89 V2500 Suburban

[Larry]

Lot of damn work just to adjust the driver’s door! After getting Rob’s ZooK5.3 door adjusted so nice I really couldn’t stand the Polar Bear anymore. I had replaced the bushings a few years ago but I couldn’t get to the fore/aft bolts without yanking the fender.....so the time had come just to dig in deep. All fixed up now and operates like new. Just have to put the fender and inner fender back on

Did the same thing to Rob’s K5 a while back

 

[Larry]

Burb back together (driver’s door shuts nice too!) and Rob’s ZooK5.3 loaded for its ride to Canon City for exhaust and to have the interior bed lined. It will be a good road test for the Burb. The Burb only has about 120 miles on it since the re-cam.

 

[Greg Ducato]

I love that Burb, that's what mine wants to be when it grows up

 

[Kay86K5]

Let me know how you think that 8.1/nv4500 combo tows that load. Since a similar load is what mine will end up towing for the majority of it's life. Your burb really is freaking sick! Its such an awesome all around rig. Can tow, can haul a lot of people and gear....good hunting rig....and to cap it off its really clean too. Doesn't get much better

 

[blazinzuk]

I just wanna know about the evil 3 -4 shift.

Thirds revving to the moon. 4th is not enough revs to pull the load. If any motor can overcome that its an 8.1.

 

[Larry]

Let me know how you think that 8.1/nv4500 combo tows that load. Since a similar load is what mine will end up towing for the majority of it's life. Your burb really is freaking sick! Its such an awesome all around rig. Can tow, can haul a lot of people and gear....good hunting rig....and to cap it off its really clean too. Doesn't get much better

Thanks! That was what I envisioned with this thing from the start. A good all around modernized classic for all occasions

I just wanna know about the evil 3 -4 shift.

Thirds revving to the moon. 4th is not enough revs to pull the load. If any motor can overcome that its an 8.1.

You know, I really don’t notice any big crazy gear ratio change from 2nd to 3rd or 3rd to 4th like the old SM465’s. Both the K10 and Burb have the second gen NV4500’s (yeah, the one with the sucktastic granny gear) but the gear splits seem to fit the 8.1L’s well. It doesn’t fall out of is power-band at all. The NV4500 is definitely better matched to the 8.1L over the awkward shifting ZF-S650 behind the 8.1L in my Silverado. Those gear ratios are too close together where you shift a lot like a damn 18 wheeler and go nowhere fast.

The K10 weighs in 8,000 lbs. when loaded for our annual desert trip once the camper is loaded with food, water, propane and the rest of the gear for the week and the 8.1L, 4:56, 35” tires and NV4500 peddle it around pretty athletically so that is almost like pulling a load all the time. I don’t expect the Burb pulling this trailer with a K5 on it to be too much different.

I’ve only driven one first gen GM NV4500 that I recall and if I remember right, it did have a bigger more noticeable gear split between 2nd and 3rd almost like a SM465 more so than the later gen NV4500's. I sure miss that deep 6.55 granny gear of the 465 though but having overdrive is a beautiful thing!

 

[blazinzuk]

All of my time with one has been a first gen 4500. And it was the same as a 465 too much gear in 3rd too little in 4th. Then again most of that was hauling around 12000 lbs with several 7% grades up and down up and down. Always wanted a 4500 with a gear vendors. That would have been the cats meow

 

[Kay86K5]

I just wanna know about the evil 3 -4 shift.

Thirds revving to the moon. 4th is not enough revs to pull the load. If any motor can overcome that its an 8.1.

You know, I really don’t notice any big crazy gear ratio change from 2nd to 3rd or 3rd to 4th like the old SM465’s. Both the K10 and Burb have the second gen NV4500’s (yeah, the one with the sucktastic granny gear) but the gear splits seem to fit the 8.1L’s well. It doesn’t fall out of is power-band at all. The NV4500 is definitely better matched to the 8.1L over the awkward shifting ZF-S650 behind the 8.1L in my Silverado. Those gear ratios are too close together where you shift a lot like a damn 18 wheeler and go nowhere fast.

The K10 weighs in 8,000 lbs. when loaded for our annual desert trip once the camper is loaded with food, water, propane and the rest of the gear for the week and the 8.1L, 4:56, 35” tires and NV4500 peddle it around pretty athletically so that is almost like pulling a load all the time. I don’t expect the Burb pulling this trailer with a K5 on it to be too much different.

I’ve only driven one first gen GM NV4500 that I recall and if I remember right, it did have a bigger more noticeable gear split between 2nd and 3rd almost like a SM465 more so than the later gen NV4500's. I sure miss that deep 6.55 granny gear of the 465 though but having overdrive is a beautiful thing!

This is always what I envisioned with the NV4500 behind an 8.1 as well. Most of the guys who really complain about the gear splits in them are the Cummins guys. Since those motors are designed to have the power come at lower RPM's, they seem to have trouble with those splits cause they are hunting for the right gear to get the correct power to the ground. With a higher revving motor like the 8.1, and then couple that with a second gen GM NV4500 with a little better gear splits, I would think that it wouldn't be as noticeable. Especially if you are building a rig to be a good all around rig like Larry has done with the Polar Bear (can tow pretty well, but gets driving empty a lot too), I think the second gen NV4500 would be better, even if you have to "sacrifice" by having a steeper granny gear

 

[Larry]

Well, the towing verdict is in…. Hwy 50 is pretty hilly between Pueblo West and Canon City (both cities are around 5100 ft. elevation) and there was a strong headwind to buck the entire way but it ran down the road 65-70 MPH without much of an effort nor a need to downshift out of 5th gear (65 MPH speed limit). I wouldn’t go so far to say that K5 on a trailer wasn’t noticeable as that load would be noticeable with any tow rig especially on a windyass day like today.

It’s way too soon to say how the fuel economy was but we’ll know what this tank delivered in a few weeks as the gauge is still on full. Discovered it doesn’t like to start well after a heat soak though. Starts fine if restarted immediately after shutting it off but between 15 minutes to 45 minutes in a heat soak it has prolonged cranking before it will start. After it sits for about an hour it fires right up. I suspect a fuel tank vent issue….I had a similar issue on the K10 as well. Anxious to see if that annoyance persists as the fuel level goes down.

 

[campfire]

Well, the towing verdict is in…. Hwy 50 is pretty hilly between Pueblo West and Canon City (both cities are around 5100 ft. elevation) and there was a strong headwind to buck the entire way but it ran down the road 65-70 MPH without much of an effort nor a need to downshift out of 5th gear (65 MPH speed limit). I wouldn’t go so far to say that K5 on a trailer wasn’t noticeable as that load would be noticeable with any tow rig especially on a windyass day like today.

It’s way too soon to say how the fuel economy was but we’ll know what this tank delivered in a few weeks as the gauge is still on full. Discovered it doesn’t like to start well after a heat soak though. Starts fine if restarted immediately after shutting it off but between 15 minutes to 45 minutes in a heat soak it has prolonged cranking before it will start. After it sits for about an hour it fires right up. I suspect a fuel tank vent issue….I had a similar issue on the K10 as well. Anxious to see if that annoyance persists as the fuel level goes down.

So...sounds like you need a long-distance towing trip to get some real fuel economy numbers.

 

[Big Ray]

Fuel boiling easier due to lower atmospheric pressure up there...?

 

[Larry]

So...sounds like you need a long-distance towing trip to get some real fuel economy numbers.

For sure! In May I plan to drag my in-laws little tent trailer to Flagstaff for the Overland Expo. Should be a good test run for the ole Bear. That is about a 1600 mile round trip

 

[Kay86K5]

Well, the towing verdict is in…. Hwy 50 is pretty hilly between Pueblo West and Canon City (both cities are around 5100 ft. elevation) and there was a strong headwind to buck the entire way but it ran down the road 65-70 MPH without much of an effort nor a need to downshift out of 5th gear (65 MPH speed limit). I wouldn’t go so far to say that K5 on a trailer wasn’t noticeable as that load would be noticeable with any tow rig especially on a windyass day like today.

It’s way too soon to say how the fuel economy was but we’ll know what this tank delivered in a few weeks as the gauge is still on full. Discovered it doesn’t like to start well after a heat soak though. Starts fine if restarted immediately after shutting it off but between 15 minutes to 45 minutes in a heat soak it has prolonged cranking before it will start. After it sits for about an hour it fires right up. I suspect a fuel tank vent issue….I had a similar issue on the K10 as well. Anxious to see if that annoyance persists as the fuel level goes down.

That's what I like to hear. I was assuming that 8.1/nv4500 in that burb was gonna pull that thing just fine. And I have been on that road between Pueblo West and Canon City, if you can keep it in 5th on those....that is pretty good if you ask me!!

On the hard starts when warm....do you have a fuel line that is close to exhaust? Maybe it gets it hot enough that even the prime isn't getting enough to the fuel rail. Just something to think about I guess

Edit: After looking at your issue again, I think my "solution" isn't correct cause if that was the case it would show the same problem when trying to start it up right after you shut it off....so maybe the vent could be correct. Let us know what you find out

 

[campfire]

That's what I like to hear. I was assuming that 8.1/nv4500 in that burb was gonna pull that thing just fine. And I have been on that road between Pueblo West and Canon City, if you can keep it in 5th on those....that is pretty good if you ask me!!

I agree. I've taken that road twice in the last 2 summers. I remember downshifting fairly often. Though my memory might be skewed by the higher passes further West.

 

[Larry]

Yeah, there are some pretty good hills going West towards Canon City. There is a long grade once you get past Hwy 115 where I used to have to shift down into 4th with the old TBI 5.7L to pull the long grade even without a trailer. That gives you a better idea how much more grunt the 8.1L provides. Pulling a K5 on a trailer up the same grade didn’t even require shifting out of 5th

Oh, and stopping power is no problem either and I have 13" DRUM brakes in the rear along with hydroboost! It stops with just as strong of confidence as my 2001 HD truck

 

[Kay86K5]

Oh, and stopping power is no problem either and I have 13" DRUM brakes in the rear along with hydroboost! It stops with just as strong of confidence as my 2001 HD truck

That is really good to know too. I was wondering if I was going to need to upgrade the rear of mine to disc's, but I didn't really want to. But hearing that the factory hydroboost with drums in the rear stop that well...I will just leave them be (obviously fresh'n them up though). Thanks for all the info Larry!!

Oh, and FYI...I will probably be going to over to Alex's house tomorrow to check out his Tahoe....maybe I'll get a look at your old Raylar cam

 

[Larry]

That is really good to know too. I was wondering if I was going to need to upgrade the rear of mine to disc's, but I didn't really want to. But hearing that the factory hydroboost with drums in the rear stop that well...I will just leave them be (obviously fresh'n them up though). Thanks for all the info Larry!!

Oh, and FYI...I will probably be going to over to Alex's house tomorrow to check out his Tahoe....maybe I'll get a look at your old Raylar cam

Yeah, I am not one of those guys that will jump through my very own asshole to install a rear disc conversion kit on a big heavy 4x4…..or cross over steering.... or Jeep steering i-shafts….blah, blah.. I’m not into any of those forum trends. Perfectly content with drums. Personally, I feel the only good method to obtain rear disks would be to install a complete GM HD truck rear axle that was originally engineered for disks. I’m pretty sure Alex agrees with my petpeeves and that guy is a true engineer

Tell him hi for me

 

[POORBOYK5]

Oh, and stopping power is no problem either and I have 13" DRUM brakes in the rear along with hydroboost! It stops with just as strong of confidence as my 2001 HD truck

did this have factory hydroboost or did you source this from something else? I'll prob answer my question looking back through this thread..

Do you welcome visitors?? Me and the lady get down your way about once a month. We try to take a decent day trip somewhere in the state with whatever old beater we have running at the time. I'd love to see your fleet sometime!

 

[blazinzuk]

I never went to discs because of stopping power. My big drums stopped better than my discs. I did it because of mud and sand. Mud and sand can get into the drums and it greatly reduces the serviceable life and decreases stopping ability. Discs clean out alot bettet

 

[Larry]

I never went to discs because of stopping power. My big drums stopped better than my discs. I did it because of mud and sand. Mud and sand can get into the drums and it greatly reduces the serviceable life and decreases stopping ability. Discs clean out alot bettet

That I agree with if you're mud racing or just in the mud A LOT