Feb. 28, 2002
This story actually began two years ago during a camping trip to Clear Creek hot springs. It was in the late fall and we were camped in tents in the snow - and then it rained. If it weren't for the hot springs it would have been an absolutely miserable time. It was that misery that sowed the seed of an idea in Ryeguy's (aka Robert Bryce) head. He decided to build a 4x4 big enough to sleep in so he wouldn't ever again have to suffer in a soggy tent. But being true to his nature, this 4x4 would also have to be immensely capable off-road.
He decided on a Chevy Blazer as the basis for his vehicle since they were plentiful, cheap, roomy, and big enough to run 44" tires which Ryeguy decided was a requirement for his ultimate camping rig. Somewhere along the line I innocently suggested that Unimog axles would be a good and relatively-easy-to-implement alternative to the expensive and finicky Gamma Goat axles that he was considering.
Now fast forward to this month when I had the opportunity to get behind the wheel of what was spawned by that fateful weekend...
"HULK" (1983 Chevrolet Blazer) SpecificationsBone stock except for the following:
The first thing you notice about Hulk is it's size. I mean, this is a BIG truck. Anything sitting on 44" tires, is huge and Hulk seems even more so because it rides on the relatively short wheelbase of the Chevy Blazer. The second thing you notice is the enormous amounts of ground clearance (19 inches under the differentials which is the absolute lowest point of the vehicle).
Once all that sinks in and you start having a close look at Hulk's underpinnings, you notice that Ryeguy has built a very tall truck without using the typical methods. For starters, Hulk is equipped with very modest (for full-size trucks) 4" BDS lift springs in the front and stock Ford F150 springs in the rear. Combined with a rear shackle flip and a front shackle reversal, he ends up with a suspension that uses relatively flat springs that provide a good ride and a flexy suspension. The suspension isn't super flexy like a rock buggy but that's a good thing when you have a vehicle that requires you to swing your foot up to a 42 inch height in order to get in. Rancho RS9012 shocks add to the vehicle's stability and allow him to tailor the shocking damping for the street or trail. (This is probably the easiest vehicle to kneel under and adjust the shocks!) Of course, that's not enough lift to clear the massive Dick Cepek Fun Country tires. Generous amounts of fender trimming were also required but the Bushwacker flares did a good job of making the enlarged openings look good. A 3" body lift was added to clear the engine due to the added height of the Edelbrock intake and propane mixer. The high output Chrysler V-twin air compressor also made a body lift a requirement. The side benefit was that it made routing of the shifter linkages, exhaust and vent lines a lot easier.
Now, in a regular 4x4, these modifications would still not be enough to run 44" tires. But since Ryeguy is using Mercedes Unimog 404 portal hub axles, he gets an additional 5.5 inches of clearance. The end result is massive ground clearance, massive tires, using a suspension with a modest arch which can still provide a good on- and off-road ride. And no ridiculous lift blocks, either!
It's no surprise that the Unimog axles are the features that draw the most attention. Many people have day-dreamed about fitting them to a non-Unimog chassis but to actually turn that in to a reality requires overcoming two very large hurdles. The first is the fact that the Unimog suspension is rather unusual: it uses a single track bar and a very long torque tube to locate the axle. This tube bolts directly to the differential and it also contains the driveshaft which is essentially a VERY long pinion gear shaft running from the differential up to the transfer case output. Unusual? You bet! The second odd bit is that the 404's combination of differential gear ratio and portal hub gear ratio yields an overall axle gear reduction of 7.56:1. This is far too low for a street-going vehicle and there are no gears you can swap in to reduce this ratio.
This kind of technical challenge is too great for most rock monkeys but then again, Ryeguy is not your average monkey. He's an orangutan of the highest order, as is his wrenching partner, Chris Borton. Together, they came up with solutions that made 'Mog axles a viable solution for a daily-driver 4x4.
The torque tubes were dealt with by cutting them down and modifying them to become a seal/bearing retainer. The pinion shafts were cut down to accept a yoke close to the differential, like a regular differential pinion yoke layout. It sounds easy doesn't it? Kind of like me telling you that you can carve a watch from a block of wood simply by cutting off everything that doesn't look like a watch. Yeah, I think you get my point.
The gear ratio problem was addressed in typical Ryeguy fashion. You have to remember that with his previous 4x4, he wanted lower gears so he designed and built his own reduction gear box using guts from a 241 transfer case. The 'Mog gear problem was addressed with similar directness. He decided to add an NP203 transfer case in front of the NP205 he was planning on using. "But wait! That would give him an even lower gear ratio!" Yes, you're right...but not if you install the transfer case BACKWARDS! In essence, he gave Hulk a very heavy-duty over-drive that halved the overall gear ratio. Of course, you can't just bolt a 203 to a 205, especially if you're going to run the 203 backwards. Fortunately, Ryeguy had a lot of help in the form of OTT Industries. These guys have a long and storied history of devising all manner of Frankenstein drivetrain combinations and they succeeded yet again with Ryeguy's reversed NP203 concept. It required some internal modifications to the NP203 and most of the work centered on reverse mounting it to the TH400. As a precaution, temperature sending units were added to the 203 and 205 just in case they overheated due to an oiling problem.
With these two hurdles behind them, the dream of a Unimog-axled Blazer became a very tangible reality. To power the beast, a Cadillac 472 big block was built. It was treated to some modest performance enhancements and had its compression upped so it could maximize its performance on propane. Why propane? Because it's cheaper to run than gasoline, it's widely available (at least here in Canada), and the motor will be able to run at any angle. It also pollutes less which is a good thing. This environmentally friendly engine puts out a respectable 350 horsepower and 500 ft-lbs of torque. The engine was chosen because it's a torque bomb. All the power is generated low in the rpm range. It can handle up to 4500rpm, but there really is no point in turning it faster than 3500rpm. That's why the torque numbers are high and the hp figures are relatively low.
For fine control on the rocks and deep snow, Hulk was given a TH400 automatic transmission and massaged with a Trans Go Stage 2 shift kit, installed and tuned by Wayne "Fozzy" Foster. (Ryeguy says: "I was quite amused when he followed the instructions for some items, then set them aside and did his own thing for others.") From there, the torque is sent to the reverse-mounted NP203 reduction box and then the NP205 transfer case with custom twin-stick shifters. The NP205 also received a cable-operated caliper and custom fabricated rotor to act as a driveshaft parking brake.
As you might imagine, the portal hubs have the potential for creating a lot of axle wrap. To control it, Ryeguy used a pair of track bars on each axle. F150 radius arm brackets are used as frame mounts for the track bars.
If you're familiar with Unimog axles, you are by now probably wondering about Hulk's steering linkage. For starters, the stock steering arms were turned around so the tie rod mounted in front of the axle. This was a required modification in order to provide room to mount the anti-wrap bars. A custom steering arm was then fabricated to mount on top of the passenger-side knuckle. This would allow for a near-horizontal drag link angle and elimination of bump steer. For maximum safety and adherences to vehicle modification laws, they used existing bolt holes which became available when the 'Mog's drum brakes were removed. Removed? Yup, to make way for disc brakes at all four corners. This was another bit of custom design and fabrication that ate up countless days and nights.
Now that you're familiar with Hulk, let me tell you about my experience with it. I've had the opportunity to ride in and drive a fair number of 4x4s. I can tell you that, hands down, Hulk is by far the most annoying vehicle to climb into. Even worse is getting out because even though you know it's a long way down, it always feels further when you do step out and land with a jolt. Riding in Hulk is pretty much the same as riding in any other truck, like a Kenworth, Freightliner, what have you. You suddenly realize how many male pedestrians have bald spots when you're riding in Hulk. It draws attention and slack-jawed stares from all who see it. They may hate it, they may love it, but they can't stop staring at it. Hulk is not the vehicle of choice if you're headed to your local adult video store.
Off-road, the first place I had the opportunity to drive it was on the washboard covered Butler Main logging road near Sooke. I was surprised to notice that it actually felt and drove like a regular Blazer. Judging the location of the tires relative to the road was easy and the steering was quite precise. The washboard surface was smoothed out by the fat contact patch of the Fun Country 44's so we actually had a better ride than the "normal" 4x4s that were in our group. When we finally reached the snow, we aired the tires down to 5.5 psi and shifted into 4WD and engaged the lockers. Despite it's titanic size, Hulk actually floats on the snow. Lighter vehicles like a CJ7 and Toyota pickup were digging in while the massive Blazer crawled along on its 44" tires which, when aired down, turned it into the equivalent of a tracked vehicle. Steering became more vague since the tires' sidewalls flexed so much but it was still easy to guide the Blazer along the trail, packing down the snow to let the other trucks follow. The trick to driving in the snow was to stay in the absolute lowest gear and crawl. I could actually feel the front tires begin to climb onto the fresh snow and then sink a few inches as it packed it down, forming a surface hard enough to support our weight. To get an impression of how soft the snow was, I got out of the Blazer and stepped into the fresh, unpacked snow...and promptly sank up to my crotch. You'd basically need snow shoes to follow this truck on foot.
Now that you know how well it performs on snow, you're probably wondering how it performs on the rocks, right? Well, that's a little hard to tell right now because most of the trails on Vancouver Island where Hulk resides are covered in snow. It flexes ok but not spectacularly but on the other hand, it's 44" tires and lockers will give it amazing traction and its relatively long wheelbase and track width will give it stability. It's propane-fired engine, auto tranny, and low gears will allow it to crawl at low speeds at any angle with full control. So, on paper, it should work great as long as it can fit through the trail. But rather than sit here and speculate, we'll give you, the reader, the chance to put Hulk to the real test. If you want to see Hulk go head-to-head against some of the world's toughest trucks, buy the current issue of Fourwheeler magazine and vote for contestant number 7. Go ahead and do it now, I'll wait.
Great, thanks for voting.
Interested in 'Mogging your 4x4? Check out Ryeguy's website: www.exaxt.ca. With EXAXT, you too can 'Mogify your ride!
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