Milltek Sport releases ‘Toyobaru’ performance exhaust system
Milltek has designed and manufactured a new exhaust system for all three variants of the anticipated ‘Toyobaru’ – a vehicle the company describes as “one of the most hotly-anticipated tuner cars of the last decade”. The Toyota GT86, Subaru BRZ and Scion FR-S – the three versions of the tuning car – is to be offered gains in power “throughout the rev range”, according to Milltek. The exhaust manufacturer’s engineers worked alongside leading Subaru tuner Litchfield to create a design that enhanced the normally aspirated flat-four engine.
From the factory the Toyobaru’s exhaust has a system diameter of 53.8mm, a measurement the Milltek engineers increased by 15 per cent after careful testing, finishing at 63.5mm. This should have the effect of reducing back pressure and improving performance, according to Milltek. Mass was also a consideration from the outset, with the design team seeking to trim excess weight from the original equipment set-up – despite the desire to run a larger diameter bore throughout. Two systems will be available upon launch; a secondary cat-back design that is 4.75kg (23 per cent) lighter than stock, and a primary cat-back design that saves more than 8kg (27 per cent) over the standard part.
On a car that is about refinement and light weight, these figures are encouraging, but Milltek is equally keen to stress the tangible power gains achieved with its systems too. Under independent evaluation the Milltek Sport secondary cat-back system delivered increases of 7.2hp (4 per cent) and 4Nm (2 per cent). With the primary cat-back system, the car was able to produce an increase of 11.9hp (6.6 per cent) and 16Nm (7.7 per cent).
Milltek also aimed for an aesthetic improvement: two 4.5” GT115 single-skin tailpipes follow the lines of the rear diffuser, offering a new finishing touch that Milltek says juxtaposes “a more aggressive demeanour with an ‘OEM+’ attitude”.
Enthusiasts and tuners can choose from a wide range of options when ordering their system. The OEM exhaust system features two catalysts, one primary cat, located in the manifold and, one secondary cat, located just after the over-pipe. The car will pass emissions tests as long as the primary catalyst is left in place, so Milltek is offering options that cater for both this and the secondary catalyst to be included or deleted. Resonated and non-resonated centre section options can also be chosen – as can up-rated ‘over-pipes’ and secondary de-cat ‘straight through’ sections. The ‘over-pipe’ is a small replaceable pipe which fits after the manifold, routing the exhaust over the top of the front subframe.
This modular system has been carefully designed to allow owners either to tailor precisely their system to produce the exact power and noise levels that they require, or to allow them to upgrade over time to spread the cost of development. In ‘resonated’ guise the system keeps the exhaust noise – which Milltek describes as a “superbly sonorous soundtrack” – outside the car. If ‘non-resonated’, the sound becomes part of the in-cabin driving experience. Milltek’s OEM experience has allowed it to produce a system that removes the cabin drone that can often be found with lesser systems, the company claims.
In a similar sense to the Y-Pipe on the Nissan GT-R, replacing the BRZ’s over-pipe with the Milltek Sport Over-Pipe is a simple modification, since the OEM part features numerous crushes, dimples and changes in pipe radius. The Milltek Over-Pipe features smooth-radius mandrel bends, optimal pipe routing and is manufactured from a larger-bore pipe – 63.5mm versus the OEM’s 53.8mm, though the Milltek part is also 33 per cent lighter. The Milltek Sport Over-Pipe has been engineered to fit both left and right-hand drive vehicles and is fully interchangeable with the OEM exhaust system and the Milltek Sport system.
The Milltek Sport BRZ/GT86/FR-S system is being exclusively released by Litchfield Imports throughout Europe and Mann Engineering in North America.