Car manufacturers are not stupid. I've noticed that the new Subaru MY01 WRX (for one) is a lot more tinker-proof than previous models - and why not? From a manufacturer's point of view, it's in their best interests to make it difficult to modify. The spin-offs will be less warranty issues and a public image of reliability.
The MY01 is a good illustration of how some car manufacturers are 'wising up' and making things tough for aftermarket tuners. While putting together a recent step-by-step power-up story on the MY01, it became obvious that the days of assured top-end gains from exhaust and intake bolt-ons are indeed slipping by. We've had it easy up 'til now.
But it concerns me that some people overlook this massive change and are still judging products by their stand-alone bolt-on power improvement.
In the MY01 WRX story (that I put together), the APS hi-po exhaust that was being installed looked very, very good. After doing many stories on exhaust systems I've learnt what to look out for - gentle radius bends, a direct pipe path, constant internal diameters on the bends, straight-through mufflers with low-drag perforations, high-flow cat and, of course, a large pipe diameter. The APS system had it all - and I'd bet my left nad that it would out-flow the factory system by a country mile. Unfortunately, however, the engine management in our build-up MY01 snubbed its nose at the new system and hammered the peak horsepower figure line-ball with the standard level. So whose fault is that? It sure as hell isn't the exhaust system's!
If you want to get everything - or, in some cases, anything - out of an exhaust upgrade, it's likely you'll now need to make management changes.
That's why it frustrates me to see people making a point out of the fact this particular exhaust system - on its own - yielded no increase in peak power. Furthermore, people drew comparisons between this and other exhaust systems that have been tested on different days, on a different dyno and on a different car. Arrrhhhh! Sure, one particular vehicle may find a bit more power with a new system, but that will depend on many specifics of the vehicle. Things to take into account include the air/fuel ratio, boost pressure and ignition timing.
I suggest that if you want to get a picture of how well an exhaust system flows, why not simply measure back-pressure rather than the resulting power output? Looking back, I'm annoyed that I didn't measure the 'before' and 'after' backpressure for the story. At least that would have emphasised the improved gas flow and taken a million other factors out of the final power equation.
In addition to making it hard to get gains out of the exhaust, Subaru has also made the air intake harder to poke around with: the top of the airbox and the airflow meter is now moulded into one piece. This may partly be a cost cutting exercise, but - more likely - it's intended to stop people from bolting pod-style aftermarket filters straight onto the 'meter. I'm punting that Subaru doesn't want any more owners to fit a pod filter that (quite possibly) lets more crap into the engine, sucks under-bonnet heat and may lead to damage the airflow meter hotwire (due to somebody over-oiling the aftermarket element).
So don't get snarly with Subaru for making it hard to fit a pod - they're only trying to protect their (and your) car!
Indeed, the MY01 power-up story was sure to be an eye-opener for many Rex owners. I can understand that some readers don't like to hear that they now need engine management changes to accompany their simple bolt-ons - but in many cars, it's now the truth.
Times have changed.
Following my list of performance cars that could sprint from 0-100 km/h in less than 8.3 seconds ("Michael's Speed Zone"), I've received a couple of emails to remind me of cars that weren't included.
Firstly, there's a hot little Alfa Romeo that many people would never have heard of (let alone remember). The Alfa 75 3.0 'Potenziata'. The what, I hear you ask? Don't worry, I had no idea either!
Unfortunately - despite doing a fair bit of poking around - I haven't been able to find much info regarding the car, but I can tell you that the Potenziata name did not come from Alfa. It's just somebody's label that stuck. The rear-wheel-drive 75 sedan was first released with a four-cylinder and then a 3.0-litre V6 in 1988. However, from May 1990-onward, it copped the same donk as fitted to the big 164 saloon; this became known as the Pontenziata. The Ponteziata is said to generate around 139kW (depending on your trusted info source), puts torque through a rear LSD and weighs approximately 1180kg. It's a package that's apparently good for 7-ish second jaunts to 100 kays. Pretty good for a car I'd never heard of before! On the other hand, though, the Potenziata appears to be a bit of a lead-tipped arrow. The weight of the V6 apparently induced some measure of understeer.
An interesting car nonetheless.
I also received an email reminding me of the performance (and potential) of older V12 Jaguars. Sure, some of them are getting on a bit these days but - again - they're an interesting eye-opener. The 1985 XJ-S (in 224W UK-spec) could crack 100 km/h in an impressive 7.2 seconds; the Aussie model (with around 200kW) should also be a pretty quick machine. And I'm told that they're easy to enhance as well - just remove the factory mechanical fan (gives 5-10kW), remove the first set of silencers (10-15kW) and install fat cold air ducting (15-20kW). Note that those figures have simply been passed on to me - we haven't proved them as gospel. Over and above this you can achieve almost any power output you like - depending on your budget. Of course, the Jag isn't a harsh sort of car either. I'm told that, "You will not lose your teeth when you drive it to work and back everyday - and the ladies are much more impressed by a gentleman than a hoon!"
Oh, and it seems that a couple of the magazine performance figures might be a little shady. With the Series 6 RX-7 quoted as good for 6.8-seconds to 100, we've since heard that in real life they're much closer to cracking the high-5s. Maybe the second turbo on the magazine test car wasn't working... And note that power is said to rise to 194kW from late '96 as well.
Just thought you might be interested.
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