Three-way Suzuki Hayabusa exhaust test – what gives the most power?

Hayabusa with SC Project 4-into-1 system

Our long term Hayabusa gets a run on Big CC’s dyno with the SC Project full system fitted

We’ve tried out a few exhaust systems on our long-term Suzuki Hayabusa test bike, so we thought we’d do a bit of a summary of how they performed. We used the Dynojet dynamometer at Big CC Racing in Wokingham to get a base run on the bike, and then tested the peak power after fitting a set of GPR end cans, an SC Project 4-into-1 full system, and a Yoshimura TRC stainless 4-into-1 full system. We also had a K&N race air filter and a Dynojet Power Commander V fitted to the bike with the pipes, and a quick remap done with each pipe once fitted.

 

Standard pipes

Hayabusa in stock trim

STOCK EXHAUST

It’s important to get a baseline for any comparisons, so once the Hayabusa was run in properly, we took her to Big CC for a stock run. The dyno there is quite a ‘mean’ one – which is to say it generally reads a little low compared with other dynos. But since we’re interested in comparisons, that’s not a problem really. So – peak power at Big CC on our bike was 167bhp, and peak torque was 94.8 ft-lbs. Now we could go and play with some other pipes!

 

GPR CANS

GPR end cans tested

GPR end cans on Hayabusa

Our first test was on a pair of GPR end cans. These Furore cans are made of stainless and aluminium, and they weigh just 2.7kg each – compared with the stock cans at 7.1kg each, erk! So we saved almost nine kilos in about ten minutes just by unbolting the old cans.

But what about power? Well, the peak power was up a tad, at 3.5bhp more, but the big news was in the midrange – a hefty boost to power and torque around 7k. But a picture tells a thousand words, so here’s the dyno curve:

GPR vs stock

Dyno curve of GPR end cans vs stock

Nine kilos saved, a tad extra peak power, and a heap more midrange – we call that a win here at SuperBike Towers…

 

SC PROJECT FULL SYSTEM

Hayabusa with SC Project 4-into-1 system

SC Project full system

Next up was our first full system, from the guys at SC Project in Italy. You’ve probably seen their pipes on the MotoGP grid, where they’ve made a big impact in Moto2, MotoGP and Moto3, supporting riders like Scott Redding, Stefan Bradl and Nicky Hayden. So they know what’s what in exhausts. And that shows in the full system they sent us. Beautiful welds, a sweet carbon end can, and super light weight – just over 7kg in total – compare that with nearly 21kg for the full standard exhaust system of headers and twin cans. A couple of hours labour saw the SC system on, saving us 14kg in mass!

The SC system is actually for a Gen.1 Busa, so the rear downpipe bracket didn’t line up, and the can strap covered the SC logo. But the headers fitted the motor fine, so we went ahead and tested her. And what a result – 13bhp more peak power, and a barely-credible 27bhp gain in the midrange:

SC Project system - 13bhp more peak power!

SC Project Hayabusa full system vs standard

On the downside – the SC system is very loud, and you’ll end up in trouble with the neighbours if you’re an early riser – and it may struggle at quiet trackdays. There is a supplied dB killer, but this also kills the power, knocking 20bhp off when fitted…

 

YOSHIMURA TRC FULL SYSTEM

Yoshi TRC system

Yoshimura TRC 4-1 system

Finally, we tried out a Yoshimura America full system. Yosh and Suzuki go together like vodka and Red Bull, so we expected great things. And the Yosh sure looked pretty when we got her out of the box! Gorgeous, deep-polished stainless headers, and a sweet carbon end can. Like the SC system, it was far lighter than stock, tipping the scales at 7kg-ish, similar to the SC pipe. This system is designed for the Gen 2 Busa though, so it fitted perfectly all round.

On the dyno, the Yosh did almost as well as the SC, with a 9.2bhp peak power increase, and 20-odd bhp more in the midrange. The Yoshi pipe is far quieter than the SC system though, and even without its optional dB killer, is much more livable-with.

Yoshi TRC vs stock

Yoshimura TRC system vs standard Hayabusa

 

SO…

Stock vs GPR vs SC vs Yosh
Finally, here’s a graph showing all three exhaust vs stock (SC is light blue, Yoshi is green, GPR is dark blue and stock is red)…

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