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 EPIC BIG BORE .18 POWERPLANT |
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With
all the talk about big block this and big block that, we thought it
would be nice to take a look at another powerful, yet more cost effective
solution for breathing new life into your truck.
PACKAGING
- EPIC does a fantastic job packaging the Big Bore engine. Not only does
it come securely wrapped in foam inside a cardboard box to protect it
from shipping damage, it comes with its own nylon carrying case adorned
with the EPIC motorsports logo. Sweet! Any RC enthusiast can find a use
for this great little carrying case. 
QUALITY
/ FIT & FINISH - By simply giving the engine a visual
examination, it is easy to see the quality EPIC has poured into it.
The engine case, head and other included components are nicely manufactured
and make you feel great about the money you just invested in it (just
wait until you run it - then you will be thinking "why did I wait
so long to get this engine?"). 
Note the picture to the left: Take a look at the
difference between the EPIC (left side of picture) and a standard
Traxxas .15 small block (right side of the picture)! When EPIC says
"Big Bore", they mean it. The top green line aligns with
the top edge of the bore of each engine. Notice the bottom green
line and the obvious difference in bore size (16.4mm bore size on the EPIC).
This difference can be felt when pull starting the BB.
The
one way bearing (reference picture to the right) is of considerable size
as well and never once gave us any slip problems. Of course time will
tell how long it lasts and how resistant it is to slipping. If it is of
the same quality as the rest of the engine, it should last a very long time.
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INSTALLATION
- EPIC recommends sealing the carb with red high temperature
sealant before operation so we heeded their instructions and did that
before starting the install. This is a good idea with any new engine or
anytime you remove the carb from your engine as it prevents troublesome
air leaks. Installing the EPIC 18 Big Bore requires cutting the threaded crank shaft to make it fit. We installed the engine in an "old style", original T-Maxx with "tons" of aluminum on it (chassis, bulkheads, shock towers, skids, chassis braces, etc). It is a heavy truck and the extra power provided by the BB will be welcome. Obviously, installation may be different in your RC vehicle however the basics should remain the same. PIPES, HEADERS AND FILTERS OH MY! For the most part, we simply used the parts from the engine we removed (OS CV15 small block) to make the EPIC feel at home in its new chassis.
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| BREAKING THE EPIC .18!! UMMMM...WE MEAN BREAKING IT IN! |
    
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BREAK-IN
- The instructions give suggested needle settings for the basher and for the racer. One item we did not find on the break-in instructions is when we should start leaning the engine out. We contacted EPIC and they told us to start making needle adjustments (leaning it out) at about the 4 tank mark. The break-in instructions could be a bit more detailed however the parts breakdown is excellent. EPIC's break-in procedures require running the engine and burning a 1/2 tank of fuel, then letting it cool (with the piston at BDC - Bottom Dead Center - at the bottom of the stroke). Getting the engine hot and letting it cool is called heat cycling. It allows the piston sleeve to expand and contract during break-in. We ran about 1.1 quarts of fuel through the engine during the break-in procedure. The picture to the left shows the high-speed needle (light blue circle), the idle hex screw (green circle) and the low-speed needle (red circle). The idle screw placement is smart and easy to get to. Both needles turned smoothly and worked properly. As recommended by the instructions, we utilized Trinity Monster Fuel 20%. Engine temps were taken using a MIP on-board temp gauge. GEARING WE USED - The test truck was equipped with an 18 tooth Racers Edge clutch bell, a 70 tooth Kimbrough spur gear and standard issue Traxxas slipper pegs (all 12) and plates. The clutch used was a standard two-shoe Traxxas clutch. It is apparent that upgrading to a 3 shoe aluminum clutch would be beneficial with this engine (and many other engines for that matter). In our opinion, a standard 2-shoe clutch is just not strong enough for power of this magnitude. We could see a significant amount of clutch debris building up on the chassis after running a quart through the engine. And the engine was mainly run at slow speeds during the first 1/2 quart. Here's some test data we collected during the break-in procedure:
Additional notes: We have a full gallon of fuel through it now (December 4th, 2003) and the engine has continued to get stronger with every tank. The videos you see below are at the 9th and 10th tanks. They do not do the engine justice. |
| WHAT
WE HAVE BEEN WAITING FOR! LET"S SEE WHAT IT CAN DO! |
 screaming down the road (1MB)more pavement burning (727kb) still running a little rich....at the 10th tank.  This baby will idle all day long (900kb) We got tired of waiting for it to die!  |
PERFORMANCE
- OK! Break-in is done and it is time to start tuning for power.
Watching this truck FLY is a real treat. And when we say "FLY",
we mean "FLY". We can't wait to put it up against some other
trucks in our fleet. The power is smooth throughout the powerband with no indications of flat spots or sluggishness. Overall power is also very strong with the engine hitting maximum RPM very quickly. We have no trouble believing the 1.8HP output claimed by EPIC. As a comparison, we felt it was noticeably more powerful than the Traxxas 2.5. Looking at the specs, the EPIC has about 28% more HP than the TRX 2.5. This is a serious increase in power. In high-traction situations (heavy, moist dirt), the truck would pull the front end off the ground without much trouble. In most situations, the shear HP and torque of the engine would break the tires loose (pavement, concrete, grass, dirt, etc). We left the stock T-Maxx treads on the truck during our testing. Bolting on a set of special treads would have helped the truck hook up better in some of these instances. (Hey! This is a engine review not a tire tread review!) We made some adjustments to our controller to try to keep the front of the truck on the ground. Remember this is a heavy truck that is LOADED with aluminum goodies. Sticking this engine in a "stock" (lighter weight) truck would certainly deliver sickening amounts of wheelie's. As you will hear in the videos, the shift point needed to be adjusted. It was shifting out of first in about the first 10-15 feet. We adjusted it after shooting the video clips shown on the left. According to our gearing calculations, the truck should be running at about 38 MPH top speed. We didn't get too crazy filming video as you will be seeing more of this engine in many BYT videos to come. Take note of the "clicking" sound you can hear in the some of the videos....time for new differential gears! FUEL CONSUMPTION - The EPIC Big Bore is a thirsty engine and gobbled up a tank of fuel every 7-10 minutes, depending on how hard we were beating it. Our OS CV15 and TRX 2.5 will run about 10-13 minutes on a tank of fuel but they are not nearly as powerful or fun to drive as the EPIC. This is a small price to pay for big performance. Here's some data on the conditions we were running in during the end of break-in / tuning the engine for top performance:
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| MAY I HAVE THE ENVELOPE PLEASE..... |
 banging around (453kb) Listen for the "clicking" sound coming from the diff's! OUCH!!! Time for new differential gears :)  beating around (699kb) look for the nice smoke trail.... |
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