Project “Polar Bear”: 1989 V2500 Suburban

[huntsonora]

:drool:

 

[Larry]

Only word that comes to mind is "awesome!". Can not wait until I am able to do mine this summer. It will first be with the sm465 and np205, but will soon follow with the nv4500 swap. Thanks Larry for all the great information and pictures and your time to post it all up for us.

Thanks! 465 still works well. I ran a 465 behind the 8.1L in the K10 for the first two years. Lack of overdrive was a gas killer though

Larry,
Do you do your own relearn and reset on the fuel trim? I'd love to be able to do that stuff, but I'd have to improve my computer skills considerably I'm sure.
Your install is clean and factory appearing, it should make the old burb zip right along.
My first drive in an 8.1 was an eye opener compared to a 454. Much zippier, so I can't imagine the RayLar cam making it run even stronger. Did you have to change your valve springs to accommodate the cam? Do the 8.1's run the bee hive valve springs?
It is odd how LS engines peak torque rpm's are so high, yet the cruise RPMs rarely exceed 2500.
The newer engines torque band is way too high as I see it.
To recap, my recollection is your running 35" tires, 4.11 gears and NV4500 trans with a .73 5th gear.
My guess is around 1900 to 2200 rpm at 70mph, sound about right?
Thanks for posting up, I am a big Suburban guy, so I love reading about your modifications.

Ah, it is not as tech nerdy as it sounds. Those two functions can be done with a poke of a button on the Tech II scan tool

Although it took some creativity with the Tech II as the 8.1L was never offered with a mechanical throttle body so I had to lie to the Tech II telling it the engine was an L29 7.4L to reset the IAC then lie to the tool to tell it the engine was a LQ4 6.0L to reset the fuel trims. For some reason it wouldn't let me do both resets by using an L29 and LQ4. Had to use each for each function

Nah, did not change valve springs. That is the beauty of the RayLar 202 cam as it does not require stiffer springs or swapping on adjustable valve train. This particular cam works with the stock valve train unlike the throwaway Comp Cam for the 8.1L. The springs themselves look like any other BBC spring.

You're right, Gen III LS engine peak torque (and HP) is at a stupid high RPM but the 8.1L is not an LS engine. All of its peak numbers are very low. Peak torque on stock 8.1L is at 3200 RPM while making 355 lb. ft. of that torque at 800 RPM! Peak HP is at 4200 RPM. LS engines need to spin well over 5000 to get any snot out of them, which is why I like the 8.1L so much…it has more of a personality of a diesel (low end grunt) without the weight and other BS associated with diesels. With the RayLar 202 cam in the Burb I would suspect the peak HP and Torque are much higher than 3200 now though. I've spun the Burb up to 4500 yesterday and it still wanted to pull more. It honks well! I don't think in 7 years I've ever spun the 8.1L in the K10 past 4,000 RPM. The stock 8.1L pretty much runs out of steam at 4,300 RPM.

You're close….the K10 and Burb both run 315 tires (~35) with 4:56 gears and the .73 OD. Cruise RPM's at 70 is around 2100 – 2200 RPMs.

Well done Larry. Well done.

:drool:

Thanks guys

 

[justcuz]

Thanks for the reply.
What rocker ratio is the 8.1?
Does it have aluminum heads?
I had a buddy years ago that had a 468 with a Sig Erson RV cam, that acted like a diesel. It would pull like crazy up to about 3500 or 4000 rpm and then fall right on its face!
That being said, with a cab over camper, trailer and a 6000 lb race truck it would run about 90 mph across the desert. :Wow1:
I would never consider doing anything that risky today, but 35 years ago our behavior was different.
We were young and dumb and there was way less traffic.
I know you are running the Dana 44 out of the old pickup, but if I was to run a Ford high pinion 44 and 241 down the drivers side could I run the stock Chevy push/pull steering using Chevy stuff knuckle out? I know I would lose the Ford dual piston front brakes, but I have not seen that they are any better than the 3/4 ton Chevy stuff.
I'm looking to get rid of a turbo 350/203 combo and replace it with a 700/241.
Since the drivers drop 241 are much easier to find I was thinking of that with the Ford HP Dana 44.
Not going with much lift so cross steer is out, plus I want to avoid a track bar. Keeping it simple.

 

[Larry]

Thanks for the reply.
What rocker ratio is the 8.1?
Does it have aluminum heads?
I had a buddy years ago that had a 468 with a Sig Erson RV cam, that acted like a diesel. It would pull like crazy up to about 3500 or 4000 rpm and then fall right on its face!
That being said, with a cab over camper, trailer and a 6000 lb race truck it would run about 90 mph across the desert. :Wow1:
I would never consider doing anything that risky today, but 35 years ago our behavior was different.
We were young and dumb and there was way less traffic.
I know you are running the Dana 44 out of the old pickup, but if I was to run a Ford high pinion 44 and 241 down the drivers side could I run the stock Chevy push/pull steering using Chevy stuff knuckle out? I know I would lose the Ford dual piston front brakes, but I have not seen that they are any better than the 3/4 ton Chevy stuff.
I'm looking to get rid of a turbo 350/203 combo and replace it with a 700/241.
Since the drivers drop 241 are much easier to find I was thinking of that with the Ford HP Dana 44.
Not going with much lift so cross steer is out, plus I want to avoid a track bar. Keeping it simple.

I believe the 8.1L rocker ratio is 1.5 like all the older BBC.

Yeah, we all tend to take fewer chances as we get older that is for sure. I don’t know enough about those Ford D44’s to know for sure but it seems like you might be able to bolt on Chevy knuckles, spindles and hubs to make it work. I still think finding a passenger’s side drop 241 would be an easier proposition. Heck, the passengers drop GM round pattern 205 would even be easier to find than messing with a front axle hodge podge. I agree, if I had a TH350/203 I would be anxious to get rid of it too. Oh, wait…I already did.

When I first got my K10 back in 1996 it originally had a TH350/203. Good riddance!

 

[hidesertwheelin]

Thanks for the reply.
What rocker ratio is the 8.1?
Does it have aluminum heads?
I had a buddy years ago that had a 468 with a Sig Erson RV cam, that acted like a diesel. It would pull like crazy up to about 3500 or 4000 rpm and then fall right on its face!
That being said, with a cab over camper, trailer and a 6000 lb race truck it would run about 90 mph across the desert. :Wow1:
I would never consider doing anything that risky today, but 35 years ago our behavior was different.
We were young and dumb and there was way less traffic.
I know you are running the Dana 44 out of the old pickup, but if I was to run a Ford high pinion 44 and 241 down the drivers side could I run the stock Chevy push/pull steering using Chevy stuff knuckle out? I know I would lose the Ford dual piston front brakes, but I have not seen that they are any better than the 3/4 ton Chevy stuff.
I'm looking to get rid of a turbo 350/203 combo and replace it with a 700/241.
Since the drivers drop 241 are much easier to find I was thinking of that with the Ford HP Dana 44.
Not going with much lift so cross steer is out, plus I want to avoid a track bar. Keeping it simple.

I saw 2 NP241's passenger drops at the Pick-A-Part in Hesperia a few weeks ago.

 

[justcuz]

I saw 2 NP241's passenger drops at the Pick-A-Part in Hesperia a few weeks ago.

Is that the one off of 395?
That's where I saw the Ford HP Dana 44's

 

[justcuz]

I believe the 8.1L rocker ratio is 1.5 like all the older BBC.

Yeah, we all tend to take fewer chances as we get older that is for sure. I don't know enough about those Ford D44's to know for sure but it seems like you might be able to bolt on Chevy knuckles, spindles and hubs to make it work. I still think finding a passenger's side drop 241 would be an easier proposition. Heck, the passengers drop GM round pattern 205 would even be easier to find than messing with a front axle hodge podge. I agree, if I had a TH350/203 I would be anxious to get rid of it too. Oh, wait…I already did.

When I first got my K10 back in 1996 it originally had a TH350/203. Good riddance!

Larry,
As I mentioned I don't have much lift, so with the Ford HP 44 and the driver drop 241 which is clocked higher I feel the front driveline would be slightly more protected from ramp over and rocky road (like Lippencot Trail) driving off road.
Just a random design idea from a retired guys mind.

 

[justcuz]

Has the weather been nice enough to take it on a shakedown run?
I am kind of interested in your impression of the new cam actually and see how you feel about the low range torque delivery with that cam. I know you said it had some real pop while driving down the road, it will be nice to see if it gives up much bottom end power and if the new found down the road power translates into better mileage (if you can discipline yourself enough to not romp on it!).
Do you plan on stopping at the Expo in Flagstaff this year?

 

[Todd McLaughlin]

Those things look awesome nose to nose Larry, What tire and rim packages are your running and are those warn hubs?

 

[Larry]

Has the weather been nice enough to take it on a shakedown run?
I am kind of interested in your impression of the new cam actually and see how you feel about the low range torque delivery with that cam. I know you said it had some real pop while driving down the road, it will be nice to see if it gives up much bottom end power and if the new found down the road power translates into better mileage (if you can discipline yourself enough to not romp on it!).
Do you plan on stopping at the Expo in Flagstaff this year?

Meh, the weather has been decent enough I just haven’t had time to mess with it. As mentioned in post 450 I probably won’t have time to mess with it much until late May or June. Between work travel lately, family vacation we just returned from this afternoon then more work travel coming up it will be a while. I actually have an appointment the first week of June for it to have a live dyno tune performed to straighten out the tuning to compensate for the cam. It runs decent now but pretty choppy in open loop and pretty rich in both closed and open loop.

Nah, we’re not doing the OX this year but we are starting our 10 day annual desert trip that same weekend.

Those things look awesome nose to nose Larry, What tire and rim packages are your running and are those warn hubs?

Thanks! Nose to nose does make for an interesting photo. The wheels are Level 8 brand Strike 8 wheels. Also known as Moab STR wheels through Desert Rat Off-Road Centers. The Burb has Fierce Attitude tires while the K10 just got a fresh set of Goodyear Duratracs as previously mentioned. Both are 315/75R16’s load range E. They both also have Superwinch hubs. I love those ¼ turn hubs! They cost a fraction of the price of WARN hubs and I haven't seen a Superwinch hub break yet while I have had several WARN Premium and Mile Marker hubs break.

 

[Todd McLaughlin]

Thanks Larry, Good to hear about the Superwinch hubs, I was about to buy the WARN Premiums for my Suburban. Good luck with the Dyno tune I'm sure you are going to get it dialed right in.

 

[justcuz]

My sister and her husband will be visiting from Tennessee, so I'm out too. Where is your desert trip this year?

 

[whoareu2200]

Let me just start by saying you cuz of u i want an 8.1 swap. I found a Kodiak parts truck but the motor runs on propane. Can i swap fuel rail and injectors and pcm ? or what do i have to do to make it run?


your work is impressive any help would be great. Your build is awsome

 

[Larry]

Let me just start by saying you cuz of u i want an 8.1 swap. I found a Kodiak parts truck but the motor runs on propane. Can i swap fuel rail and injectors and pcm ? or what do i have to do to make it run?


your work is impressive any help would be great. Your build is awsome

LOL, welcome. Well on the fuel rail.....Yes, no, maybe…. Depending on the propane system you might be able to just remove the propane fuel rail and add a gasoline fuel rail and injectors but some systems the upfitter drilled holes in the intake next to the gasoline fuel injectors and just left the gasoline injectors in place. How the they installed the propane system depends if it was a vapor or liquid system. If that is what you have you may need a different intake. Most of the used propane 8.1L engines came from Schwan Foods trucks and have a boat load of miles on them or stationary well pumps/gen sets with thousands of hours on them. On the other hand, the nice thing about using a propane unit as a donor is the fact they are super clean on the inside. Yes, you will need ECM work done, which you would need done anyway. There are lots of good tuners around that could map the ECM to suit your needs. Tuning an 8.1L ECM is no different than any run of the mill LS engine.

Here are two useful resources for people interested in 8.1L swaps. This one is a useful thread I put together on CK5 in an effort to slow down PM’s on this subject and there is also a group on Facebook called the “8.1 Info Swap Classifieds” dedicated to 8.1L swappers. Lots of good info there as well. Several of the guys on there also started with propane engines from well pumps or Schwan’s trucks.

 

[whoareu2200]

Larry thanks for the info and directing us the right way. The truck has 80k 1k for motor and trans. I think its a start good considering the brackets are the right ones. I'll read up on the post thanks for your time and sharing knowledge.