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I'm formulating a plan to slap a GM 8.1 into the honcho.

What progammers do people typically use to program these? I"m not looking for 'how' to program them, but rather what hardware/software is the best to use? I realize the cheapest solution is to pay someone to do it, but that's not my style.

thanks!

Couldn't you just use the ECU that they come with? Although I suppose 8.1's only came in front of automatic transmissions. Is there a bell housing that will work with the 8.1L?

Well I've been toying around with the idea of the 8.1 swap for a while and read a lot about it (some time ago). IIRC, there are some secruity features that need to be disabled, along with a few other things. I honestly havn't looked into the tuning aspect that much, I've always messed with the older TBI stuff.

Hoping somone will chime in on some personal experience.

But with regards to the actual engine swap itself, I think these engines use the same bellhousing as the old school small block/big blocks. I'm already running an NV4500 with an AA bellhousing adpating it to an AMC 360. So I'm thinking that I could simply get a junkyard SBC bellhousing and bolt that to the MV4500, correct? I can fab the engine mounts and new radiator mount. The honcho's 360 is getting very, very tired. Oh and I'm thinking of doing UA 2015, so I'll need something reliable.

found this one on ebay. http://www.ebay.com/itm/8-1-LITER-VORTE ... 58&vxp=mtr

Yeah quick search shows it is the same as the old engines. So should be easy to adapt.

My uncle had an '04 Silverado 2500 with an 8.1. It had good power, but I don't think it ever got double digit fuel economy.


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The 8.1 uses the 4L80e in some application and the Allison in others. My '02 GMC 2500hd has the Allison behind it, which has done great.
I run an Edge tuner on my truck and get 10-12mpg in town and 13-16mpg on the highway empty. This is maintaining 60mph. At 65 to 70mph I get closer to 12mpg. When I had my 20ft dovetail (2,000lbs empty), and keeping it at 60 to 65mph I would get about 14mpg. When loaded mine averages 10mpg.
This summer I took a trip to Colorado pulling a 12ft trailer with about 2500lbs of gear with 1 atv in the bed and averaged 12mpg on the highway.
The 8.1L uses a ton of oil. Mine has 65,000 miles on it and it will use about a quart in 1500 to 2000 miles. You dont see it burning it, this is just how they are.
The 8.1L also has issues with exhaust leaks. The common area is the mating surface of the manifold to the head. They warp in a short amount of time. The only cure I have found is switching to headers.
If you really want to wake one up put a good set of headers on it, a tuner and good free flowing exhaust and the beast comes alive.
There was an 8.1L on craigslist here (Tulsa, Ok) and I thought seriously about buying it for my GW, but opted for the 5.3 for simplicity and fuel mileage.
The 8.1 is a torque monster and I think it would be a great swap, and would still get better mileage than the old 360s.
Hope this helps.

I spent a good hour or so looking at that seller's various motors. The one thing I noticed was that they all had A LOT of rust on them. Once block was even flagged for excessive rust. The seller being in New Hamshire is probably the reason. Are there any closer to home? Or from CA or AZ perhaps?

Those 5.3's look tempting, but I have no $$ as usual.

The 8.1L engine is kind of rare. The 6.0L was the most common gas engine used.
One thing you will want to do is change the crank position sensor out. The stock 8.1L CPS starts acting up between 50k and 75k miles. Mine did it at 58k. You will be driving down the road and its like you shut the key off and turn it back on.

Blake wrote:
What progammers do people typically use to program these? I"m not looking for 'how' to program them, but rather what hardware/software is the best to use?

I don't have personal experience with the 8.1 but I use EFI Live FlashScan V2 for my 6.0. EFI Live will program the 8.1 as well as a lot of others including the Cummins. I have gone to http://www.tunefiledepot.com/ and downloaded a 8.1 tune to see what the tables look like but never tuned one.

I had HP Tuners years ago. The reason I went with EFI Live was due to the fact it supported the Dodge Cummins as well as GM. Both programs are user friendly IMO.

XJChad wrote: The 8.1L uses a ton of oil. Mine has 65,000 miles on it and it will use about a quart in 1500 to 2000 miles. You dont see it burning it, this is just how they are.

The intake gaskets are normally the cause of this. I belive there's a TSB for that.

As Lobie said, EFI Live or HP Tuners should do what you want and more.

Well Blake, since you live in Longmont, an enhanced emissions area, you need to look at the emissions, if you want to drive the Honcho on the road. You need ALL the emissions equipment that came on the engine. That includes all four O2 sensors, all the cats that it had, and the worst is the EVAP system. That includes all the sensors and equipment required for the ECU to do the EVAP system leak check. After you do that, you have to take it and have an emissions inspection done where they check to make sure you have everything and all emission monitors are present and the ECU says they are complete.

The trans is the easy part. Just send the ECU to LT1swap.com and he will disable the transmission controls. Then you have to find a flywheel.

Well I've kinda discounted the 8.1 swap for a couple of reasons. I don't think I can keep it running cool and they are kinda rare (as in I've never seen one at the junkyard).

I'm running Collectors plates, so no emissions.

Blake wrote:Well I've kinda discounted the 8.1 swap for a couple of reasons. I don't think I can keep it running cool and they are kinda rare (as in I've never seen one at the junkyard).

I'm running Collectors plates, so no emissions.

Well you can always look for a 6.0, they are pretty common and typically have in the ~360hp range.

Blake wrote:Well I've kinda discounted the 8.1 swap for a couple of reasons. I don't think I can keep it running cool and they are kinda rare (as in I've never seen one at the junkyard).

I'm running Collectors plates, so no emissions.

As of July last year, vehicles 1976 and newer with collectors plates have to get emission tested to renew the plates. Also, one can now only get collectors plates for vehicles 1977 and older. No more 25 years old business. The only benefit now is that you only have to test every five years and you only pay the road and bridge fee once. You can thank Morse from the 'Springs for this.

yes, but as of November of 2013 I renewed my 5 year collectors plates on my '78 and according to the DMV, I will retain my 'grandfathered in' status and continue to not do emissions past then. Regarless, my cab is in horrible shape and I'm pretty sure the frame is tweaked pretty good. I probably won't renew the honcho in 5 years. I'll build another one that's older than 1975 that hasn't been 'wheeled like mine has.

The point is that I've been reading up a lot on the vortech injection stuff and as stated in the first post, I won't be shipping my ECM to some guy to program. I'll pony up the $$$ to buy my own hardware.

Interesting, I have to emission my 80 next year and it has collector plates. Then again, the DMV has never been a fountain of knowledge.

http://aircarecolorado.com/consumer-inf ... or-plates/

I think this explains it under Misc info.

http://www.colorado.gov/cs/Satellite/Re ... collectorv

Manimal70 wrote:http://67-72chevytrucks.com/vboard/show ... t=8.1+swap

Sounds like another person who doesn't understand the difference between gross hp and SAE net hp. On a engine dyno, the 8.1 will do 400+hp and 500 lb-ft of torque, GROSS, but that is not how it is measured. You are not going to get 50 hp from a tune. Horse Power TV, when it was called that, built a 5.7 Hemi, with an after-market engine controller, put it on a dyno, and claimed it made 40 more horses than the stock rating. They either didn't know, or left out, they were comparing apples to oranges.

Larry works for GM, I think he knows what he is talking about.

On a stock engine, it's hard to get much better than the factory calibration. NA engines anyway. With forced induction the gains are more.

It's all BS without numbers to back it up.

Besides, emissions equipment doesn't take away performance. At WOT and close to it, the PCM is in open loop, so it is ignoring the O2 sensors, EGR is closed, and the PCM is using lookup tables. He is also comparing the feel of a 4000 lb Blazer to a 7000 lb truck.

csuengr wrote:On a stock engine, it's hard to get much better than the factory calibration. NA engines anyway. With forced induction the gains are more.

It's all BS without numbers to back it up.

Besides, emissions equipment doesn't take away performance. At WOT and close to it, the PCM is in open loop, so it is ignoring the O2 sensors, EGR is closed, and the PCM is using lookup tables. He is also comparing the feel of a 4000 lb Blazer to a 7000 lb truck.

I have to disagree with this. Factory engines are almost always tuned for emissions and economy. If you are willing to do away with meeting those, you can certainly get more power out of them with a tune. Some emissions equipment does not take away performance, but the tune certainly can.

There are plenty of dyno tests that show tunes can help. It all depends on the engine and application.