131 Merch Turbo
Lord won't you buy me a Mercedes Benz
My friends all have Softails, I must make ammends. My motor is bigger than your motor. My belt is wider than your belt. My 11" rear rim is meaner than your rim. Well, when you're a big man you better get a big bike and big horsepower...There's no point in thinking small when you've got a clean slate and big ideas. Order a frame from Germany. Contact Merch for a 131 cubic inch motor. Order a bunch of billet stuff from Performance Machine. Get the biggest belt drive you can find from Hitech. Get a forged aluminum / titanium transmission from the Soviet Union (since disappeared). Then call RB Racing and tell them to put a Pro Street turbo on this unassembled Fort Knox pile of parts.
350 Horsepower Takes Planning
The whole Harley Davidson aftermarket deal is all over the place with everyone determined to build a better version of an antiquated 1908 air pump on steroids. We told the customer there was no point in getting an assembled motor because we'd just have to throw some of the stuff away. We are partial to S&S Cycle equipment because we are heavy into our ORCA program and have worked with S&S and their parts in the past on Bonneville projects. The Merch cylinder head follows the traditional "bathtub" hemispherical combustion chamber with a minimal squish band. We have cc'ed the Merch chamber and one of our S&S Cycle Special Application "SA" heads than we use in our 113" and 124" ORCA motors. The SA chamber is 75% of the volume of the Merch chamber, or the Merch chamber is 32% larger depending on your point of view. The SA head employs larger valves on both the intake and exhaust. Inlet and exhaust ports are much smaller on the Merch yielding higher Mach Index values at lower rpms. The Merch is a street motor set up for grunt and 5000 rpm and the ORCA motor is designed to push a lot of air out to 7000 rpm, with Mach Index values reaching optimum speeds @ 6400 rpm.
Heat Equals Power
All that heat comes out the exhaust ports...Merch on the left, S&S Cycle "SA" on the right. The 113" 9.9:1 ORCA turbo piston on the left has .5cc's in the valve pockets whereas the Merch has 16cc's in the dished piston they provided. The ORCA piston centers the burn around the spark plug and the exhaust valve in an asymetrical shaped pocket whereas the Merch employs a 3.5" circular chamber with a narrow circular squish band on the 4.250" bore. Everyone has a different approach and they probably all work. One thing that doesn't work well however, is the dome thickness on the Merch which measures a scant .200"...Under 350 hp it is marginal in so far as thickness goes.
The ORCA turbo pistons weigh 420 grams and have a .250" dome thickness which is a minimum for turbos. The Merch piston weighs in at 516 grams. Add in the Merch rings (42.1g), pin(110g) and clips(9.4g) and the total piston assembly comes to 677.5 grams. The Merch piston pictured above yielded a Static Compression Ratio of 8.49:1 with no head gasket (Merch doesn't use one). The Merch has a bore of 4.250" and a stroke of 4.625", .040" piston to head clearance and the above noted cc measurements. You have to take into account the Dynamic Compression Ratio when planning this stuff...Don't try to run 9.9:1 unless you have an ORCA motor, otherwise keep the static compression ratio 8.0 to 8.5:1.
Yo Mama is so wide she.....
Put a garage door in the bedroom. Fats where it's at and a 10.5" rear rim sucks up the 250 tire and begs for more. This rim is waiting for a 280 or 300 tire.
Forkless in California
Up on a Blanchard ground steel plate awaiting the 21" front rim from Germany. Once the rim arrives the customer can decide on the front fork assembly. Swingarm pivots on spherical ball bearings captured in the frame. That's a new one for us.
Turbo Plumbing Started
Non standard frames mean custom fabrication. Oil tank had to be cut for a larger starter motor. Tabs had to be added for RSR Ecu mounting. Extra mount fabbed for transmission support. You have to gather up all the stuff because the aftermarket never heard of "concurrent engineering". Wooden blocks temporarily hold frame at 5.5" off the surface plate. Long way to go.
We'll be showing you the wheels, the tires and the gear that it takes to make a 131" Turbo Merch come to life. Things like a custom 350 hp intercooler, water injection, RSR Closed Loop Fuel Injection, big brakes, and an on-board air shifter to keep things interesting. A big man has to think big and in the big leagues he has to play for keeps.