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My supercharged K8 project...

131638 Views 192 Replies 85 Participants Last post by  D.Man

The bike pictured above is my bone stock K8. A friend gave me a fantastic deal on this bike last year, and it has just under 2000 miles on the clock. I love this bike for the same reasons everyone does -- incredibly smooth, extremely capable and controllable, great power, and fantastic ergonomics for a supersport machine. The local Dynojet 250i says it puts down 152whp (SAE corrected), which is actually more power than a full-exhaust, PCIII-tuned '04 ZX-10R produced on the same dyno.

Now, normally the next step would be to add an exhaust, change the gearing around, or add some braided lines, and while I'll eventually get to those mods, I have something different in mind right now...

It's a Rotrex C15-60 supercharger, right off the plane from Denmark. This little unit can support over 230whp, and that's the number I'll be shooting for with my little project here. Also, the impeller wheel used to be cast, but these new wheels are apparently machined out of billet.

Before you ask, yes, I am a power junkie. There's just no going back once you've ridden a boosted literbike...

You can see how small it actually is compared to the bike. Somehow, some way, it will fit in there...

After staring at this sight for a couple of days, I realized the only place to put this thing is in-between the engine and the radiator, just below the frame. I'd love to stick it up higher, but the frame would get in the way of the belt (which is a dealbreaker) and the radiator fan would also have to be relocated. Placing it lower eliminates these problems, but makes it much harder to hide the drive behind the fairings and also places the inlet of the Rotrex very close to the header. I also do not want cornering clearance to be compromised at all, so it will be in as far (and up as high) as possible.

If anyone is wondering how I plan on driving this thing, take a look at the picture above. The M10 bolt currently fastened into the end of the crank will be removed and a machined adapter will take its place (this adapter has to locate perfectly off the crankshaft for this to work). A pulley will sit on top of this adapter and then drive the supercharger via an 8mm synchronous belt. The supercharger bracket will either take the place of the stock cast cover or locate off of it -- I'm not exactly sure yet which way to go.

There's a lot of work left to be done, but I'm looking forward to it. I plan on tuning the ECU directly and, of course, it will run on pump gas. In the meantime, wish me luck, and stay tuned...
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I apologize for the lack of updates lately; I've been going through some major changes in my personal life and could not find the time to post everything. However, I have time tonight, so I will bring you all up to date...

Here's the completed exhaust...

That's an O2 bung for the wideband datalogger. Not pictured here are the tabs that were later welded onto the top that mount the muffler in the same spot as the stock cat. The 4-way split inlet is a snug fit onto the header and, once clamped, everything seals up rather nicely. I played with the finish of the stainless and decided to leave it brushed for that no-nonsense works look.

Everything prepped and ready to bolt onto the bike. That's kevlar-lined thermal shielding and it reflects an extreme amount of heat. I actually had to buy a special pair of scissors just to cut the stuff.

Mounted on the bike. So far, so good...

Crank pulley mounted and belt installed.

Intake tubing in place, BOV mounted, and airbox firmly secured onto the throttle body. The Rotrex canister will go in the empty space on the right. The BOV vacuum reference is sourced from one of the big ISC lines on the front of the TB, since all the other ports are restricted and would not operate the BOV properly.

Here's how the inlet tube and filter is set up. The filter gets fresh, cool air directly from the ram air port, and the filter clears both the steering and the bodywork once mounted. Thermal barrier abounds everywhere, so despite the incoming air running directly behind the header, it should stay relatively cool across that short distance.

The radiator has been spaced out up top and the inlet hose has been spliced with an extension elbow to work around the supercharger.

Priming the Rotrex oiling system. There is a custom curved oil cooler mounted at the top of the radiator to help cool the traction fluid -- Rotrex superchargers do not like it when the fluid gets hotter than 180ºF, so the cooler ensures that does not happen. You can also make out how the exhaust fits on the bike with the O2 sensor mounted up.

The Rotrex oil canister mounted up. Thankfully there is plenty of room under the tank to clear these components.

Now, at this point you might be wondering if it all worked out...

...and that is a story for another day (when I can get some time to edit video)...
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Bloody brilliant :)
Have you checked inlet temps yet to see if there is much rise ??
With the bolt together plenum you have now it would be relatively easy to redesign to include a heat exchanger core clamped within the halves
Wowsers. Still subscribed and :drool ing
This whole build was amazing. Beautiful work. Can't imagine it being done any more perfectly...honest.

What a great project and good to see such nice workmanship. I am looking forward to the ride review.
You sir do some mighty fine work! That plenum is tits. Can't wait for some vid.
OMG,,,,,, My K6 want's a setup like this......... damn some mighty fine work there SIR.... +1
Looking good!
right clean job this is fantastic project and fantastic work too!!!keep walking and Im waiting for that video and the dyno chart's too!
Thanks guys. Since I only plan on running 9-10psi peak, I'm not worried about an intercooler. The time and expense that goes into designing an air-to-water system just wouldn't be worth it. If I feel I need extra protection, I'll add a water/meth-injection setup or run better gas. I don't do top speed runs, so this engine should handle my style of riding and 9-10psi just fine.
speechless.... ive seen quite a few people attempt projects of similar magnatude and faily horrificly.... you my friend.. NAILED IT!!!!!
Great job! Please let us know when the kit is available! would love to fit one!
Is the stock header with the SET going to get trashed? I would have to think with a motor breathing as heavily as this you wouldn't want to stick with the stock headers.
The stock header should be fine for all intents and purposes. I've left the SET valve in there, but have it fully open. Since the Rotrex doesn't provide tons of power down low, the smaller tubes of the stock header will certainly help keep a snappy feel with the higher velocity of the exhaust gases. Besides, the stocker is not too shabby when it comes to power. Take a look at this dyno chart -- the green line is a full Leo Vince system, and the red line is the stock header with slip-ons. There's only a 5hp difference up top. The purple line is with MR9 race gas, btw.

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I'm kind of sad the build is over. Guess I'll just have to look over the pics you've put up for us time and time again. Beautiful job, absolutely gorgeous machining.
Thanks guys. Since I only plan on running 9-10psi peak, I'm not worried about an intercooler. The time and expense that goes into designing an air-to-water system just wouldn't be worth it. If I feel I need extra protection, I'll add a water/meth-injection setup or run better gas. I don't do top speed runs, so this engine should handle my style of riding and 9-10psi just fine.
you are the man Toro
I talked to AA performance last week , the build ain't over yet ! I'm sure Toro will tell everyone about it soon
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