SILVERSTONE PERFORMANCE MR2
Graham Bell samples SP’s turbocharged Toyota
Silverstone Performance / Toyota MR2
The third generation MR2 has won many plaudits for its handling poise, which has a lot to do with Toyota’s engineers endowing it with a long wheelbase relative to its compact size and keeping its weight below 1,000kg.
Inevitably, with such highly regarded cornering capabilities some people felt the car was let down by its straight line performance and deserved more power. That obviously included some people at Toyota, because in 2004 the company announced its new TTE tuning division, an offshoot of Toyota Motorsport in Germany, and the first car it produced was a turbocharged MR2.
Road testers loved the straight line performance but felt the little roadster’s body maybe wasn’t quite stiff enough to make the most of it, so TTE took it away and stiffened it up. All well and good for German petrolheads, but sadly Toyota UK had no interest in offering TTE upgrades here - though that didn’t stop a few keen MR2 owners taking their cars over to Germany to get them converted.
Enter respected TVR fettler Silverstone Performance, which saw a gap in the market and set about filling it by becoming UK distributor for TTE, which it's done in conjunction with Champ Cars in Bicester. However, not satisfied with merely offering UK Toyota owners TTE gear, SP is also using its own tuning talents to come up with additional parts to further enhance the MR2’s performance.
Which brings us to the metallic grey example featured here.
This currently uses the standard TTE turbo installation, which unlike some aftermarket turbo fitments looks neat enough to be an original factory fit. In addition to the actual turbo and plumbing, TTE’s kit also comes with a high flow panel air filter and an engine management chip that changes fuelling, boost and cooling fan cut-in points to help deal with the extra heat.
On its own, this boosts the 1,800cc four pot’s power from 138bhp to 180bhp and boosts torque from 125lb-ft to 188lb-ft, though the car tested here does better than that thanks to an SP tweak -- which we’ll come to in a minute.
First though we’ll deal with the other big TTE upgrade, which is the framework it's installed to stiffen the MR2’s body. This is bolted in place under the floor so as to effectively link the lower suspension mounting points on all four corners and, according to Phil James (PHer BossCerbera) who’s working in conjunction with SP, it makes a noticeable difference.
As indeed do SP’s own bits.
For example, the twin outlet exhaust – which unlike most such exhausts is no heavier than the original – has been dyno-developed and boosts the turbo engine’s output to 197bhp and 210 lb-ft. This is mated to a ‘de-cat’ downpipe, though it still incorporates a ‘pre-cat’ to satisfy MOT emissions tests.
All the other SP bits fitted to the car are designed to improve the handling, the most noticeable of these being the larger wheels and tyres.
Phil James says that with standard tyres, the extra power of the turbo engine tended to make the MR2 oversteer, so SP upped the rubber to 245/35 x 17 on the rear with 205/40 x 17 on the front, all courtesy of Toyo. As for the wheels they’re fitted to, these are SP’s own and are designed to keep unsprung weight down to standard MR2 levels.
Keeping these pressed to the tarmac are Eibach springs to SP’s specifications, which include a 30mm drop, though surprisingly the dampers are standard MR2.
Finally there’s a front strut brace which, unlike others on the market, has been designed so that you can both access the brake fluid reservoir and remove the spare wheel well cover - even if it does require removal of the latter’s hinges so that it slides out rather than lifts up.
SP’s final handling tweak is something most people simply wouldn’t bother with, and that’s to make a few subtle adjustments to the suspension geometry to better suit the bigger wheels.
Sadly I haven’t tested a standard Mk3 MR2 so have no personal basis for making comparisons, but SP says its car feels pretty much like the standard model to drive, only faster.
One exception to this is the clutch. That’s because as well as being the company’s demonstrator, this car is also SP’s development mule, and with plans for higher power in mind it’s been fitted with a rather vicious cera-metallic clutch that’s better suited to the track than the road.
Normally for cars to this spec, SP would fit a milder uprated clutch that’s easier to live with in everyday traffic. As it is, you have to give the engine a few more revs than normal and carefully ease the clutch in to avoid stalling.
Once on the move you find the SP exhaust produces a nice note at low revs – not that loud, but with a sporty burble (in a four-pot way).
You also find that the engine pulls quite happily – albeit rather sedately – from these low revs even in the upper gears, though things perk up noticeably around 3,000rpm when you enter the peak torque zone. This continues to around 5,000rpm by which time you’re entering the max power zone which takes you to the 7,000rpm red line.
The upshot is that you can make quite rapid progress without having to constantly rev the engine’s nuts off, which is great for relaxed cross country touring. However, when you’re really going for it the slick gearchange and close ratio six speed box make it easy to keep the engine in the max power zone, with changing up at the end of the zone putting you right back at the start of it for the next gear.
Full-on acceleration feels respectable rather than staggering and, while SP has no measured figures, a power to weight ratio equivalent to a Boxster S (plus a torque to weight ratio that betters the Porker’s) would suggest 0-60 in under six seconds is possible.
Where this car really shines is along winding country roads where its enhanced acceleration combines with its light weight and enhanced handling to produce a highly amusing toy.
SP’s spring and tyre combination seems ideally suited to British B roads (certainly the ones around Bicester anyway) providing a very settled ride, and when used in conjunction with the TTE chassis brace the result is a very taut handling machine.
Make a rapid right hand turn at a roundabout and you can really feel the nimble little roadster dig in as it changes direction, while the traction conferred by the mid-engine layout and bigger back tyres enables rapid corner exits without undue fear of sudden power oversteer.
Although I didn’t risk exploring the car’s limits on my short drive, it certainly feels quite neutral in reasonably quick use, while if you do reach its limits you’ll discover mild understeer on turn in that can be turned into oversteer using the throttle. And unlike some mid-engine machines there’s no nasty snap transition but a nicely controllable progressive one – as Phil James demonstrated by casually correcting a sideways car with only one hand on the wheel.
One aspect of the car that SP so far hasn’t uprated is the brakes. Bigger brakes are planned to cope with future power hikes, but SP feels the standard brakes are perfectly adequate for road use with this level of power. They certainly had no problem coping with a brisk run along a narrow, twisty country road where oncoming traffic and constant blind bends required repeated firm applications.
But is it worth it?
In terms of outright dynamics, the SP MR2 is neither as hard-edged or as fast as a VX220 turbo, but it does come with Toyota’s renowned rock-solid build quality and a Toyota-backed guarantee for the turbo conversion. It also provides Boxster S performance with much cheaper servicing and insurance costs.
The TTE turbo kit (including chassis brace) costs £3,995, the springs are £302, wheels and tyres £1,080, front strut brace £250, suspension set-up £58.75, twin outlet exhaust £502 and ‘de-cat’ downpipe £302. All above prices include VAT and fitting and are ‘per item’ – go for a job lot and you’ll get reductions. So if you’ve got a Mk3 MR2 you could turn it into a real Boxster baiter for around £6k.
Now you’ll doubtless have noticed ‘more power’ has been mentioned a couple of times, and SP has already developed an induction kit that boosts power by a further 13bhp. However, they reckon they’ll be able to get even more by combining it with an ECU remapped to enable the engine to fully exploit the improved breathing, so guess what’s next on the ‘to do’ list?
For more information on progress with that – or any other aspect of the SP MR2 – contact either Silverstone Performance or Champ Cars.
© Copyright Graham Bell 2006