TTS Performance are prolific designers and manufacturers of supercharger conversions for cars and motorcycles with over 100 different conversions designed over the last 17 years using the Rotrex superchargers. As a Harley enthusiast the new Milwaukee Eight engined bikes had to be supercharged! So I bought a new FXBR 107 cu.in. In Oct. 2017. We had many design ideas and manufactured several prototypes before settling on our final design:
The Inferno Supercharger conversion.
Why Inferno? We intended to market worldwide and there is already a TTS company in the USA involved with Harley Davidson's. We didn't want any confusion.
Why Rotrex? We are the UK's distributor for Rotrex superchargers and have been for 17 years. These superb units are unique, in that they run a roller epicyclic gearbox that allow them to rev to extraordinary speeds and they are virtually silent. Their speed means they make boost from very low engine revs. Their patented planet drive means they use very little energy especially on light throttle and cruising situations. They are also extremely compact and can fit on motorcycles in places others can't.
What Power? Harley have their Screamin' Eagle arm with 4 stages of power upgrade, many very reputable Performance Shops also have great power upgrades. All at reasonable prices. So we had to offer something special. The answer was to bring something to the table that no one else has! Power that exceeded other forms of tuning without opening the engine and being extremely easy to fit in a very short time. Additionally it would enhance the power of what other tuners were already selling. If a performance cam made a 20 Hp increase in an NA engine it was going to make close to double that when supercharged! Obviously higher compression is not required, but a thin spacer under the barrels means aftermarket forged Pistons are still usable.
What torque? Careful matching of the right Rotrex unit gives good bottom end gains, great midrange and awesome top end, no lag and instant throttle response at any revs.
Cooling! The Rotrex units are extremely efficient but compressed air always heats up. With a lot of research and testing we have a unique intercooler that cools exceptionally well. Having end tanks that are finned in the same way as the core gives additional cooling. It also looks great on the bike.
Looks! Harley have made a fantastically good looking engine. We did not want to detract from this, we wanted to enhance it. Our plenum chamber looks great and mirrors the fins on the engine barrels. There is no add on after thought of a blow off valve hanging off a pipe or welded to the plenum. The blow off valve is integrated into the back of the plenum, never to be seen! Additionally its protected from road dirt, rain etc. This is yet another unique feature of our conversion.
Supercharger placement! This is again a Unique design. Our supercharger is mounted inboard of the drive train, not adjacent as seen on other Harley's. This not only keeps the weight more central but allowed us to make an extremely simple, easily maintained, quickly installed drive train. We have Patients Pending on some of these features. We looked at fitting the supercharger over the clutch, this worked well but restricted the air filter and supercharger sizes, so with a little bit of juggling we came up with the current position.
Drive train! We use a duplex sprocket mounted midway between the crank sprocket and clutch, the conversion comes with a longer primary chain, of higher quality than the Regina OE one. The extra length gives all the tooth contact we need to drive the supercharger. The sprocket shaft drives through two substantial, quality sealed bearings to the supercharger drive pulley. A High quality tooth belt links the drive pulley to the supercharger pulley. As the tooth belt stretches very little the belt tension is taken up by simply moving the supercharger mounting plate fore and aft on slots. No tensioner pulleys required! Another big plus of this arrangement is that the cranks compensator system also damps the supercharger drive, giving the belt and supercharger an easier life. If the supercharger was driven directly from a crank pulley loads on both the crank and the supercharger would be much more severe.
Air filtration! The air filter is a quality paper element/wire mesh unit that can be removed and refitted in a few minutes (one clamp). It's forward position captures cold air with no engine heat issues. A curved guard can be fitted when riding in poor weather conditions.
Supercharger oil! The Rotrex unit uses its own traction oil in its own separate circuit. It requires an oil tank, oil lines and filter. Additionally an oil cooler can be required. Space is a premium on a motorcycle. The Rotrex oil tank is cumbersome. So we built the oil tank into the Inferno chain case in the spare space above the clutch, it holds more fluid thank the Rotrex tank and oil cooler combined. As the supercharger is out in the open, and also the finned oil filter we have found that with the extra oil capacity the fluid stays at an acceptable temperature without the need for any additional cooling. If in future certain climates cause a temperature concern a cooler will be available. The fluid temperature is monitored by the gauge at the top of the tank.
Power options! The core supercharger we use for these conversions is the Rotrex C30-74.
All the conversions are fundamentally the same, just a change in pulley ratios.
A stock 107 Softail with slip on exhaust the Inferno supercharger and a 1:1 pulley ratio will give around 140hp/140ft.lb of torque. The supercharger is running to 80% its max speed with a 5900rev limit.
A stock 107 Softail with slip on exhaust the Inferno supercharger and a 1:1 pulley ratio, a drop in cam like the RS468 will give around 180hp/160ft.lb of torque. The supercharger is running to 80% its max speed with a 5900rev limit.
A stock 107 Softail with 2/1 exhaust (say D & D) the Inferno supercharger and a 1:1.143 pulley ratio, plus cam will give around 185hp/165ft.lb of torque. The supercharger is running to 100% its max speed with a 6400 rev limit.
Going to 114 or 117 cu.in will fatten up the torque curve and take it to around 200hp/175 ft.lb
Dropping the rev limit to 5800rpm and re gearing the supercharger to 1:1.286 will give a very fat torque curve of over 200 ft.lb and still give around 200 whp.
These are just examples of what can be achieved. Performance shops with more experience I’m sure will only build on these figures. On the higher performance stages I would strongly recommend Forged pistons, welded crank pin, Cometic gaskets etc.
I’m opening up a whole alternative to making power out of this platform.
At the moment kits are designed for the Softail range. But not the mid Peg bikes. The front fender on some models may need modifying or replacing to give clearance to the intercooler. FXDR and FXBR etc it’s a straight fit. We are just about ready to test the Touring version on my Ultra Ltd.
Oh and I nearly forgot to say if the power achieved is not enough we can go to the C30-94 supercharger and with the right engine mods I’m sure we could see over 300whp
Progress with the Touring M8 Inferno supercharger Intercooler and radiator
We're now pushing on with the Touring version. The case is much slimmer. We're looking at fitting an intercooler under the left crash bars and radiator under the right, fitting a new slim line fan and re routing the plumbing. We may fabricate some shields to sweeten the job up, but for sure the leg shields had to go.
Hopefully you can downsize those intercoolers as you make progress. Those are massive, like another set of saddlebags altogether. Nicely done on the softail versions.
Hopefully you can downsize those intercoolers as you make progress. Those are massive, like another set of saddlebags altogether. Nicely done on the softail versions.
There's no point in making small intercoolers, they have to be a decent size to cool and flow properly, we don't want it to reduce power, we want more and with reliability.
At this time everything is CNC'd out of billet which is an expensive exercise, but the quality is top notch, the kits are intercooled and come with injectors to match. You only need your preferred engine management control. The price will be $6300.00 USD including Air freight to the USA other countries may differ slightly. We are offering an introductory offer to the first 5 US customers. Please email sales@tts-performance.co.uk with your interest. Dealer enquiries welcome
04-08-2019 | 10:12 AM
The tts performance inferno supercharger.
