Project Money Pit
I have been running my
present Suzuki for almost three years now and have learned a lot about what
works and what doesn't. I was getting ready to tube the back end when it
came to me, maybe I want to start a new one, something built from the ground up
with rock crawling in mind. The basic idea is to slowly build one up on
the side, keeping my present trail rig useable so I don't feel the need to rush the
project vehicle along. My design goals are much the
same as when I started my original Zuk:
1. Keep it light.
2. Rockcrawling abilities are the #1
3. Keep it street legal (although it
will be trailered).
Here is the general plan:
Chassis: Samurai frame, front Shackle reverse
with YJ springs, rear coil with 4 bar link. Wheelbase to be extended to
95-98" depending on final drive train. I plan to cut the factory
frame and tub off behind the passenger compartment and replace it with a tube
structure. The front end will be similar to what I have now for clearance.
I'd also like to find a way to raise the rocker panels up to just below the door
Axles: At the end of the project I will
swap my existing Toyota truck axles to the project rig. I plan on
shaving the front axle for more ground clearance. In order to setup the
rear coil links I will need to locate a bare rear axle housing.
Drive train: I would like to try an
automatic transmission and I definitely want dual transfer cases for a wider
selection of gear ratios. Ideally with an automatic transmission I think
something around 100:1 would be great, with a manual I would double that.
The hard part will be making sure I have enough gearing options so I am not
too low for the easy parts of the trail but still geared high enough in high in
case I have to run some freeway to get to or from a trail.
Misc: As time permits I would like to
make a custom dash and run some sort of hydraulic assist steering. I plan
on using a fuel cell and would like to setup the back end so tools and
spare parts are securely stowed and easily reached. I have a feeling this
may be the toughest thing to get right and may require a little
experimentation. I also want to run with a full-size spare, or at least
have the provisions to mount one for remote runs.
Tires: At this point I am aiming for 36
x 12.50 TSL's but that may change depending on what the wheelbase ends up
So with the plan in place I am starting to
look at drivetrain options since this will determine how long my wheelbase will
have to be. After a little digging I have found there are a ton of
different motor/gearing options which is going to make it hard to decide which way to
go. My rig will primarily be a rockcrawler so I am looking for a wide
range of gearing ratios between 200:1 and 90:1. If you run sand, mud,
logging roads or a little of everything, you may benefit from more ratios from
150:1 down to 50:1, basically having a gear for every situation. Here's a breakdown:
Stock 1.3l - The Suzuki small block
(literally). Horsepower is right around 64 in a carbureted version, torque
is around 45-50 ft-lb? (I couldn't verify this spec). The only available option for a
dual case setup was a second 4:1 transfer case w/adapters made by Klune. Unfortunately
they pulled that kit off the market, no word on when it will be
back. The Klune replaced the intermediate driveshaft and allowed you to
run a stock transfer case behind it. Although you can't put an automatic
behind a 1.3l, the Klune and a 4:1 gearset would have provided some very good
gear ratios. I used the RPM gearing spreadsheet located at Off-Road.com
for all the following calculations. I used my existing 5.29 ring and
pinion ratios since I will be using the same axles. Note you could put a
GRS II or 6:1 behind the Klune for even deeper gears, but I felt the options
with a 4:1 gave a better range and the 4:1's are half what a 6:1 gearset runs.
(321:1, 171:1 and 125:1 are deep enough yet spread apart enough to give you some
cool options). The only downside was the price, when the Klune was
available it ran roughly $2400.
Klune, 4:1 with Stock 5 Speed
Some people have been experimenting with
mating two stock Samurai transfer case together. I was not able to find
any real world feedback other than they dump oil out on side hills due to having
to clock the first transfer case. You also have to deal with the added
complexity of having two more connections in the drivetrain (some sort of driveshaft/coupling
between the transmission and 1st t-case, then another between the two
t-cases). Lastly the Samurai transfer case is actually geared 1.4:1 in
high range as a sort of displacement compensator. Stacking stock cases
makes your high range even deeper and can really hinder your top speed on the
freeway. Here's what your gear ratios look like with a 6:1 and a stock
transfer case. I ran the numbers with 37" tires, so your rpms go up
as your tire size goes down. Costs are estimates, don't take into account
core or installation charges, and you'll have to add money for making new
mounting crossmembers and getting new driveshafts if needed (rear may have to
get shorter, front longer). I think $100 for the couplings needed is
light, but if you can do it yourself you can probably do it for that.
Lastly look at the high range, your top speed will realistically be around
6:1, Stock Case
with Stock 5 Speed
1.6l - These motors are commonly
found in a Sidekick or Tracker. Two versions exist, an 8 valve and a 16
valve. The 8v is good for about 80 horses, the 16v about 100.
Couldn't find torque numbers on the 16v, the 8 makes about 94ft-lb at 3300
rpm. This is a nice jump over the stock 1.3l and the engine is pretty much
bolt in to the Samurai frame. With the appropriate harness and ECM I could
add the fuel injection, a nice bonus and a 3spd automatic transmission is available.
Doing some web surfing I discovered several companies that make adapters that
bolt to the 1.6l's bellhousing which opens up a lot of dual case gearing
options. The first one I looked at is running the stock Sidekick 5 spd
transmission, transfer case and buying an adapter to mount a Toyota transfer
case to the back of the Sidekick transfer case. The adapter also requires
you to send in the Sidekick transfer case to remove the front drive portion of
the case, basically it becomes a hi/low box. I would install a 4.7:1
gearset in the Toyota case and leave the other one stock (although a 4:1 is
available is you want to go lower). This setup falls a little short of my
overall gearing goal but it's simple, no extra couplings since all the cases are
attached to each other and relatively cost effective (assuming you can find a
parts car for the drivetrain for a couple hundred).
Stock Sidekick T-case, Toyota 4.7 T-Case with 5
Another thing to pay attention to in the
above numbers is the high range, the Sidekick t-case is 1:1 in high so you are
only factoring your ring and pinions in while on the road. OK, so if
that's not low enough? You can add another 4:1 to the sidekick case but
right now they are expensive ($890). Also, in my searching I noticed that Marlin (they
make Toyota crawler boxes) does not recommend putting a 4:1 reduction box in
front of a 21 spline Toyota transfer case (the most common ones). If you
need deeper gears they recommend upgrading to a beefier 23 spline transfer
case. After I discovered this I really don't think dual Samurai cases will
hold up since they have even smaller components than the Toyota transfer cases.
So how about the automatic? The
first gear is much lower than the first gear in the 5sp transmission. The
torque converter will make up for this and many people consider the torque
converter equal to another 2:1 reduction. For my charts I did not make
this assumption. One reason not to go too low of gearing with the
automatic is it will have a tendency to want to creep forward in some
situations, the lower your gears the worse is can get possibly to the point of
overpowering your brakes.
Stock Sidekick T-case, Toyota 4.7 T-Case with
Another interesting option for the 1.6 is
to use two Toyota t-cases via a divorce mount adapter. This combo results
in lower gearing but adds some complexity with the need for an extra coupling
and adapter. Just for reference the same setup below except with an
automatic transmission results in a 136:1 lo gear.
Stock T-case, Toyota 4.7 T-Case with 5 Speed
22R - With all this talk of Toyota
transfer cases why not just drop the Toyota drivetrain in? The motors are
a 2.2l four banger, the carbureted 22R making 103hp @ 4800 rpm and 133 ft-lb of torque
@ 2800 rpm. The EFI 22R-E is even better with 116hp @4800 rpm and 140ft-lb
of torque @ 2800rp. In a light rock buggy that's a lot of useable torque.
Another bonus is the gear ratios in the 5spd, they are a little lower than the
Sidekick ratios which will help on the street and on the trail in first.
Also, if you can find a 5 speed from a turbo truck, you can have a 4.30:1 1st
gear! For this swap to work I think I'll need more room up front, but
since I'll be cutting the fenders off that shouldn't pose a problem.
Stock T-case, Toyota 4.7 T-Case with 5 Speed
For an all around machine this option
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