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Testing on Super Bowl Sunday

Blackfoot Tucker

Well-known member
GOLD Site Supporter
Scott and I like to test snowcats in “real world conditions”, which for us means at higher elevations and in deep snow. That last part, the “deep snow”, can be problematic as we are at Mother Nature’s mercy, and sometimes she’s downright stingy in the snow department.

The western US has a network of what are called SNOTEL sites (SNOTEL = snow telemetry). The sites transmit data and that's reported daily. The measurement used is called “Snow Water Equivalent” and that is the depth of the water (in inches) if the snow was in liquid form. We all know sometimes snow is “dry”, meaning very low moisture content, and other times it’s wet. Well, snow water equivalent adjusts for the snow’s moisture content. Utah is having a pretty good winter. The SNOTEL sites where we will be testing are at roughly 114% of normal snowfall, and with a snow water equivalent of 14-15”.

Though we’ve gone to the Uinta Mountains before with only one machine for testing, we prefer to take two - just in case, and fortunately both CHUGSzilla and the 1544 are ready for testing. Another benefit is you can do head-to-head testing in identical conditions, and that’s much better than just subjective seat-of-the-pants feel. Two machines, great conditions, we’ll see just how well they perform. Expectations are high.

- The 1544 has seemed to be on the cusp of being a pretty darn nice machine - cosmetics excepted. For us, the downfall has been the engine. It has never started particularly well and while power-wise it’s okay, but not great, the biggest limitation has been the carburetor. We are itching to see if the Edelbrock ProFlo 4 fuel injection system is the key that unlocks the handcuffs imposed by the carburetor.

- CHUGSzilla will finally see snow after a multi-year hiatus and a ridiculous amount of work making modifications and improvements. The GM LS engine should make the machine a great performer, but sometimes what looks great on paper doesn’t pan out in the steep and deep. While the machine has been fully assembled with the front six-way blade, we’ll leave the blade at the shop.

We’ve used three different locations:

- Cedar Hollow is the least crowded. But the big downside is you can’t get to the better areas without using trails whose brush has grown in appreciably. That translates into Rocky Mountain pinstripes… scratches in the paint from branches. It wouldn’t be right to hand the machine over to The Infamous WBJ1 with the paint covered in scratches.

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- Mirror Lake Highway gets us to the highest elevation and the deepest snow, but it’s 14 mile slog along the road to get to the testing grounds.

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- Soapstone has big testing areas closer in, though we expect it would be the most crowded. There is a fair amount of snowmobile traffic on the trails, and the last time we were there some clown was going way too fast on his sled and almost met the 1544 up close and personal. It would not have been pretty.

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So… stay tuned and we’ll report the results.
 
In my first post I said “Expectations are high”….

Well, to cut to the chase I can accurately say “Expectations were not met”. On the plus side: the weather was perfect, and we had no trailer tire issues. But other than that, lot’s of disappointment.

CHUGSzilla loaded and ready to go. (Note the new spare tire on the trailer. After California Mountain Madness last year and the trailer tire blowout on the way home, the trailer now has all new load range H tires.)

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Both machines have started well at Scott’s shop. CHUGSzilla has started so quickly I’ve wondered if the engine makes even two revolutions before it’s running. And the 1544 after getting the Edelbrock ProFlo 4 has started easily, too. But when we got to the parking lot to unload, it was like Dr. Jekyll and Mr, Hyde. CHUGSzilla didn’t want to start, then it didn’t want to run. And this is before we even got it off the trailer! We looked at the sediment bowl under the fuel filter and it had a chocolate milk look to it (water and crud in the fuel). We drained that twice and it ran much better (a new filter has been ordered).

The 1544 was like “Well, if CHUGSzilla is going to be a PITA, watch me. I bet I can be a bigger PITA”. And it was! We had to use starting fluid to get it started, and starting the engine was problematic all day long. We have some work to do to get the fuel injection system dialed in, because it isn’t close to being acceptable.

After unloading at the trailhead.

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While at the trailhead there was a fellow loading all kinds of stuff on his snowmobile and he had a toboggan, also heavily loaded that he was going to tow. In conversation with Scott I called him "Cider Tom Jr.", as we think he was going winter camping... but doing so in style - the way Cider Tom does it.

Way back when we were building Thundercat I called Griffin Thermal Products for their radiator recommendation. They suggested one of their universal combos and boasted "It will cool 550 horsepower”. Yeah, well the 8.1 Vortec in Thundercat was factory rated at 340 horsepower, and it didn’t cut it. Of course Griffin Thermal Products took no responsibility for their failed recommendation! That’s like the IRS. You call with a question, and if they give you a wrong answer… too bad for you - you can pay interest and penalties. Griffin copies the IRS's pathetic “customer service”.

But big block Chevys are notorious for having cooling issues, and the L94 engine in CHUGSzilla is aluminum, and aluminum transfers heat better, so we thought there was a good chance it would work In CHUGSzilla. Remember my other line about “...things looking good on paper but not panning out in the steep and deep”? Exhibit one is the Griffin Thermal Products radiator that doesn’t cool CHUGSzilla’s L94 engine, either. It would be one thing if it only overheated when working really hard in deep powder, but just running up the groomed trail it got too hot.

Another issue are the fourth gear shift points in the Allison AT545. They need to be adjusted, and that means in the valve body. The linkage on the six-way valve for the blade is a rattling son of a gun. Very obnoxious, and not sure how that can be resolved. The transmission temperature gauge is not working properly, and we have some work to do on the windshield wipers. (We had left the wiper arms and blades off until Saturday as UV exposure would damage the rubber on the blades and the machine wasn’t ready for use.) Yesterday was the first time they had been used.

We had decided to go up Mirror Lake Highway (the 14 mile slog I mentioned) but turned around after about five miles. With Chugszilla’s overheating issue, we could go about a mile or maybe two before we’d have to stop and let it cool. After already identifying a bunch of issues to address, it didn’t seem worthwhile to continue.

On the way back we found a couple of small meadows to play in just a bit. I will say CHUGSzilla has some serious power. To quote Scott, “It has power out the a**”. He has such a way with words… though he got his point across.

Now It’s back to work….
 
DAVENET,

Thanks for the suggestion!

We had that completely disassembled once before, and I suppose we could again and add nylon washer shims during reassembly (time permitting before SV 2024). When I described it as "obnoxious"... I wasn't kidding.
 
I took two videos when we stopped to play in the small meadow. I sent them to The Infamous WBJ1, and he put at least one on Facebook (with my permission). It seems appropriate that forum members can watch them, if they would like.

Videos were taken at an elevation of about 8,400'.

Video 1:

Video 2:

I don't monitor my youtube "channel" so if you have comments or questions, this would be the place if you would like a reply.
 
Loved those videos. What's the plan on the radiator/under cooling issue?
When we had this issue with Thundercat, we followed several suggestions Griffin Thermal Products provided, but they were a complete waste of time. Just starting that engine at Scott’s shop and letting it idle, it would come up to temperature and one electric fan would come on. Then the temperature would keep climbing and the second fan would come on, and stay on… and the whole time the engine was at idle. The radiator had the capability to cool the engine…at idle.

My recollection is the programmed computer temperatures for the electric fans are fan one on temp is 187º, and off is 180º. Fan two on is 207º, and off is 200º. How much horsepower was the engine making at idle? I don’t know the answer, but I think it’s completely accurate to say it wasn’t close to 550.

What solved the problem was a new radiator and fan setup from Ron Davis Racing. Their radiators are spectacularly built in terms of quality. They are totally functional, but the craftsmanship is so exceptional it borders on artistry. Not cheap, but they are gorgeous... and most importantly they work!
 
How much horsepower would be in my 1975 Tucker with the original 318 engine?
Our elevation is about 4,000 ft and I have an automatic transmission cooler in front of the rad. In heavy pulling in second gear the engine and automatic will get hot.
I’ve modified the grill to get more air and still waiting to test the changes. No snow.
 
How much horsepower would be in my 1975 Tucker with the original 318 engine?
Our elevation is about 4,000 ft and I have an automatic transmission cooler in front of the rad. In heavy pulling in second gear the engine and automatic will get hot.
I’ve modified the grill to get more air and still waiting to test the changes. No snow.
YDPC,

That’s a good question. In this sales flyer Chrysler says 187 Gross horsepower at 4,000 RPM.

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Gross horsepower is how US auto manufacturer’s rated horsepower up until about 1971-1972. Then they went to net horsepower, which is less. Typically, SAE net horsepower is roughly about 75-80% of the gross number. Using that rough percentage, 187 gross would equal about 145 net, so I don’t know how Chrysler gets 175, which they claim in this flyer.

But that’s also at sea level. The rule of thumb is a normally aspirated engine loses about 3% for every 1,000 foot gain in elevation.
 
Using the 145 HP at sea level I would be seeing 128 HP around here, and 113 HP at 8,000 ft. Probably not much to worry about shift points for the transmission when the only time it would hit 3rd gear is going downhill.
At least the EFI carburetor and electronic distributor will make sure I get the 113 HP. Ha!!
By the way, I have never had a start issue in any conditions since I installed the EFI.
 
After the testing debacle we got back to work right away. Like the 1544 and CHUGSzilla, Thundercat is getting all new track belting and we had decided to make new grouser backing plates similar to the ones we made for CHUGSzilla. We were in the process of painting them when we went testing, so we needed to finish painting those before getting back to CHUGSzilla. But we thought the 1544 problems should be easier to address, so we started there.

As part of the fuel injection installation procedure you have to decide which available baseline tune is right for your engine. Edelbrock provides a selection matrix, and you look for what’s closest. You choose the engine displacement, and because of the Hughes Engines’ cam profile - we chose “mild” instead of stock. You have to set the fuel pressure regulator at either 58 PSI or 43 PSI. We had somewhat arbitrarily chosen 58 PSI, so those were the original matrix parameters.

But after our experience testing we thought the engine was getting too much fuel, and we decided to go back to ground zero. After some discussion we decided to reset the fuel pressure regulator to 43 PSI and try a tune for a stock engine. Then you upload that to the Edelbrock computer, and start the engine. It ran much better. Much! We are, to quote an overused phrase, “cautiously optimistic” the engine will run much better than on Super Bowl Sunday!

The computer system has basically three running profiles: idle, cruise and acceleration. Using a tablet or phone (Unfortunately only Android. What’s with that Edelbrock?) you can monitor the engine’s operating parameters such as RPM, air-fuel ratios, ignition timing, short term and long term fuel trims, and more. The computer also goes through a self learning process, and at the shop it could really only learn the idle mode. Next time we test, it will have the cruise and acceleration learning opportunities.

Then it was on to the hideous green machine, aka: CHUGSzilla. And to answer the question, No, the color hasn’t grown on me. I still hate it!

We started on the list of items to address by slightly tweaking the track alignment. Then, it was on to the wipers. In a previous post from several years ago, I had mentioned we had performed our “wiper mod” which relocates the wiper blade shafts to position the swept area of the wiper arcs more optimally for both the driver and passenger.

Tan tape arc: Stock Tucker
Blue tape arc: After wiper mod

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Part of the modification is relocating the linkage to different existing holes on the wiper shaft arms. We had neglected to do that, so it was relatively simple to make that change Both of these adjustments were done with the snowcat still on the trailer and Scott, true to form, was complaining… a lot, about his body position while working under the dash. Here’s a pic of him on his back in the process of relocating the wiper linkage. I tried, but failed, to come up with any sympathy….

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(Note: I read him a draft of this post and he said he would post a rebuttal. (Stand by for revisionist history!) He was whining because while he was on his back I went to the wood shop to grab some AN washers for the wiper arms. He hates AN washers for no good reason, and anything related to AN washers is pretty-much guaranteed to provoke a negative comment from him, in one form or another.)

We also checked the transmission temperature gauge, and the integrity of the wire from the sender to the gauge. Both are functioning properly. Next time we test I’ll bring a handheld IR gun and see what the transmission fluid temperature is, and if the fluid temperature really is as low as the gauge says. I have hard time believing that as Thundercat has the same transmission and we have to monitor the transmission fluid temp so we don’t damage the transmission. How can CHUGSzilla’s transmission be running that much cooler?

We spent some time digging through the Allison AT545 manuals available online to see about changing the 4-3 downshift RPM. We didn’t find the answer in the book so I called the local Allison dealer to pick their AT545 specialist’s brain. Wayne is a really good guy, and I’ve reached out to him before. He is kind and generous about sharing his extensive knowledge. My understanding is Allison no longer supports the AT545 transmission, so having a resource like Wayne is really great. The valve body has springs inside and there are spring tension collars with seven detents. By changing the spring pressure you can change the shift points. Each step changes the shift RPM by about 50 RPM. But the upshift and downshift RPM can not be adjusted independently. It’s both, or none. At this point we don’t know which position the adjusting collar is in, but our plan is to back off the spring tension by two or three steps for the fourth gear shift points. That should lower the shift RPMs by roughly 100-150.

After discussing the cooling problems with The Infamous WBJ1 it was decided to ditch the ineffective Griffin Thermal Products radiator and go with the Ron Davis Racing setup. I am 99% sure that will solve the cooling issues. Unfortunately, and like so many other things in the Joe Biden economy, the 2024 price is just over 50% higher than when I bought the one for Thundercat. The Infamous WBJ1 will be squealing when I tell him the cost. The radiator comes with "Ron Davis Racing" in big blue letters painted on the front of the radiator and I special ordered one without the blue paint... which is a week delay.
 
As we only brought the 1544 out on 2/25/2024 for additional testing, I posted the update on the 1544 IRAN thread:

 
Addressing CHUGSzilla's other issues are detailed on this thread:

 
Update provided in new thread:

 
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