This article was originally published in RC Driver’s November 2015 issue.
Nitro off-road 1/8 buggy racing is still a strong competition segment in the hobby and with so many advances has become a battle of equipment along with skill. The battle of equipment certainly means more cost and to some its difficult to pay out to stay on top, so when choosing equipment you have to choose wisely and within your budget. Luckily with REX, a division of Novarossi, back in full swing you too can own that championship-winning high quality, Italian-made engine at a reasonable cost. We took a look at the new REX- USA.com website and came across the Revenge .21 and its price tag wow’d us. It even included a pipe with purchase (limited time offer). Could this be the affordable engine racers are looking for to compete with? Remember its Novarossi based so we’re eager to try it.
COOLING HEAD & COMBUSTION CHAMBER
The large round purple anodized head grabs your attention with the REX Novarossi Revenge .21 logos etched on the top. The REX head is lightened with drilled holes through cooling fins from the bottom. Relief cuts on the sides of the head in an alternating pattern give the head a cool look while exposing bare aluminum for cooling. An aluminum combustion chamber is perfectly milled to mate up with the turbo style glow plug. The head comes with two shims from the factory and can be tuned depending on your fuel type.
The cast aluminum case features cooling fins around the upper portion of the case and ribs at the bottom of the housing. Inside, precision-machined transfer ports eﬃ ciently ﬂ ow fuel to the sleeve ports. After a look inside it appears these ports are well aligned and even the exhaust port is nicely chamfered. At the top of the case you’ll notice the alignment pin to help line up the sleeve in the case. On the side of the case you’ll notice the REX 21 logo etched into the nameplate area.
The crank has milled turbo cuts to improve fuel mixture and ﬂ ow to the ports. Inside the crank’s deep cut port, Novarossi rounds the inner crank port for eﬃ cient fuel flow, sorry no silicone ramp here. On the front end a sealed bearing with 5mm i.d. supports the crank and a standard bearing is used in the rear.
The first thing you’ll notice on the Brass/ Chrome sleeve, besides the etched “R” for Rossi logo, are the precision cut transfer ports, three in total. Letting the spent gasses escape is a single large exhaust port. All the ports with their ramped shape and positions allow the fuel mixture to ﬂ ow at maximum performance.
PISTON AND ROD
A silicone based aluminum piston with a drop skirt on the exhaust side features dual oil grooves to provide a seal during combustion. The rod is double bushed with oiling holes and is narrow edged to reduce windage when cutting through the ﬂ owing fuel.
At the front of the case is a composite body with aluminum core 2-needle slide carb. Fine threaded needles allow minute adjustments for maximum performance. REX includes sever composite carb inserts with varying venturi openings to tune air ﬂow.
We tested the REX Revenge .21 in a Mugen MBX7R owned by my racing buddy Paul Quartuccio, a northeast Mugen rep., who was interested in the performance of the new REX mills. The engine was fitted with the included free 50003-026 Black Tuned Pipe from REX USA; which is a limited time oﬀ er so act now if you like what you’re reading. We used 30% Byron Gen II Race fuel for break-in and testing. After a few laps to get the engine tuned, I started to lay in the throttle to get a feel for the engine. On the bottom end, the Revenge feels like it has plenty of rip, the buggy pulled hard coming out of the corners. The midrange feel was nice and smooth and there was no sign of hesitation from the fuel ramping up into the engine which can cause a lag feel in some engines. Then on the high-end of the throttle range, the Revenge made good power. With the Black Pipe I was expecting performance to be held back, but the sound and feel of the pipe was good on the mid-sized track. With some practice under the belt, I ran the Revenge engine and Black Pipe combo to get a feel for fuel mileage which netted about seven minutes of run time on a full tank. Overall we were extremely impressed with the performance the combo put out and at a price tag of just over two hundred bucks, the performance you get is a real steal. But just for fun we swapped out the pipe for a Novarossi 9901 and this let the engine breathe better. The engine was a bit snappier and really got on the pipe on the straights with a noticeable bump in power. The fuel mileage, too, improved from seven minutes to around seven minutes and thirty seconds. The REX Revenge is a great overall engine.
PART NUMBER: REVENGE 21 OFF
PRICE: $219.99 (Limited Time)
DISPLACEMENT: 3.5 cc
SLEEVE: 3 ports
REAR BALL BEARING: Steel
FRONT BALL BEARING: Steel
CARBURETOR: 9 mm
GLOWPLUG: Turbo (C6TGC)
REX is back and to clear up the confusion from some, yes it is made in the same factories from the same machines and assembled by the same workers as the world famous Novarossi engines. On a Novarossi factory tour, I saw with my own eyes REX engine parts sitting next to Novarossi parts. Are there diﬀ erences between the two, or TOP for that matter, which is also made in the same factory? Yes, but these tweaked differences are from proven formulas that Novarossi has developed over the years. The results are multiple lines of strong, quality, competition grade engines that even the super affordable REX Revenge .21 engine we tested here falls within. The Revenge had great power, good throttle curve and fuel mileage that is on par with other engines we saw running on the track during our testing. If you’re looking for a new competition grade engine and want that Italian quality and power at an amazing deal you need to check out the REX line.
REX-USA, rex-usa.com 205-306-4526