How to make 280bhp in Two Different Ways and Which is Better.

Yes, yes, yes. This is one of the topics that I mentioned that I am going to write about and finally, it has been transferred from the incredibly complex and very car savvy mind of mine to this article.

Recently, 2 chaps are in their (early) 30s and the first person bought a 2003 Subaru Impreza WRX STi and the other a 2005 Nissan 350Z Fairlady. Both are grey imports and cost basically somewhat close to the RM150,000.00 figure (one slightly higher and one slightly lower). Now these two fellows are good friends of mine, thus they let me wring out their rides a little for me to make a comparo of things.

I basically noticed that firstly, and very obviously, one is a 4 door rally special and the other a 2 door all out sports coupe. Now the only similarity about these two ride is that they make on the average 280bhp from each of their powerplants. The Impreza has around 280bhp and approximately 400nm of torque. The Fairlady makes around 287bhp and 371nm of torque. As you can see, pretty close in power but both made in different ways. The Fairlady I tested is the base automatic model, hence it did not come with Brembo brakes and weighs close to the weight of the Impreza (1450kg) by weighing in at around 40-50kgs heavier.

One Saturday evening around Petaling Jaya I did a semi hot-lap or two in the STi. Now it has been awhile since I sat and drove in one of these ultimate Imprezas but familiarity allowed me to really chuck the car around a bit. So there was I, with the owner in the passenger seat, slotting the 6 speed manual transmission into 1st and then accelerating. However, the feeling was not something I can describle as being sublime.

Now the reason for this feeling of disappointment was that I just remembered the Impreza WRX STi tends to be very old school in its power delivery i.e 'slightly' laggy.

It was 1st gear,

1000rpm,

1250rpm,

1500rpm......wait

....take a look at the watch.......2000rpm

...wait summore......2250rpm

...still waiting...2750rpm

...la la la la...be bop aloo laa...3000rpm

....and at 3500rpm KABOOM! .....6,250rpm and engage 2nd gear......

All hell breaks loose and suddenly from feeling slightly slower than even a tuned Subaru Impreza 1.6 at low rpm (mine actually), it hammers nearly all of its 280bhp at once (and feels nothing like a 1.6 and would leave it for dead many, many times over). The only thing that actually holds the driver, and car on the road is the All Wheel Drive system, with its trick Driver Controlled Centre Differential (DCCD) and mechanical diffs front and rear.

If this car were one of those really old school turbo cars like the Mazda 323 familia Turbo or some older rear wheel drive turbo like the Lancer Turbo of the early 80s. we'd see lots of rich college kids which their father bought them STi leaving the road, heading for the nearest tree, hedge, drain or even sign posts with the need to hug one of those cars lovingly. This manic power delivery still exists in an 03 Impreza STi, even with variable valve timing and a twin scroll turbo that supposedly spools faster than most normal turbos.

The Impreza WRX STi is still one of the most interesting cars around. This is due to the flat four thrum (no other car sounds like a Subaru) and its quirky styling. However, in STi form, it will be devastating IF you drive it on track where you'd never use revs lower than 3000rpm. However, on the road, with its peaky power delivery, you're better off with an Impreza WRX as its smaller turbine spools up so much faster and it being so much more linear. In rush hour traffic, you need insteanteanous thrust, which the STi does not give you.

It is meant for a windy, with fast sweepers kind of B road, the Sepang circuit rather than the cut and thrust of KL traffic. Even on some really windy B roads like say, going up Genting, the initial lag may bog the car down on extremely tight corners unless you are really gunning for it like crazy and letting it on boil all of the time. However, if you drive like that around Genting all of the time, you'd find yourse;f doing an E.T. Instead of having a BMX floating over a forrest with the moon as your backdrop, you'd have the Impreza STi flying into some ravine with the moon in the background. If an experienced driver in a stock Impreza WRX chasing an STi driven by a novice up Genting, the WRX will leave the STi for dead due to the lag (and even if its 50bhp or so lesser, it is also around 50kg lighter than the STi).

Overall it is a stonking car, but it needs work or around RM3,000.00 to at least re-map the ECU and a change to lightweight pulleys to get over the initial inertia or lag. After such work is done, it will feel more like its rival, the Lancer Evolution, which basically pulls right from 2000rpm onwards. I know this as I have driven a stock Evolution VII a few years back. I suppose that is the price you pay for having more character than the Evo.

On the other hand, driving 287bhp was never easier. I tried the Nissan Fairlady 350z the next day and the 3.5liter V6 pulls effortlessly from nought. Speed piles up effortlessly and before you know it you're hitting 150km/h and it still feels relentless (and will do this right up to the 187km/h limiter or around 250km/h de-limited). The steering uncorrupted by power as the rear wheels are the ones handling all the power feels pointly, direct and sublime. I left the traction control on as I decided after 5 minutes behind the wheel that with the way the car feels (it's overall setup), extremely quick steering and rear wheel drive it was so easy to bring the tail into play and as we were driving around areas with lots of concrete kerbs it was safer to let electronics wring the chassis in if were were accidently brutal with it. However, I also noticed that the chassis balance was still superb, allowing us to drive at speeds much higher than we would have in an STi without having to concentrate too much. At first glance you think that the 350z is a large car. It isn't, you sit low and it somehow envelopes itself round you and you feel at one with it. It does feel nippy cutting itself through the mid afternoon LDP traffic.

The 3.5liter V6 makes a decent 287bhp and has a very distinctive V6 burble unlike other V6 engines that you can find around here. You won't find the noise it makes if you bought an old 2001 Nissan Cefiro 3.0 as it is induction as well at manifold tuning that brings out the sound. The engine also builds on the well known fact that there's no substitute for cubic inches or size of the engine for making power. What Nissan did here was build a V6 that had enough grunt to pull a 1500kg car to around 250km/h and do 0-100km/h in around 5.5-6secs. While the Impreza STi uses a 2.0 liter 4 cylinder engine, forced induction was the way to go in making 280bhp (and maybe more). Somehow, get the gearing right and the slight lack of torque isn't all noticeable compared to the STi.

And in order to get a lot of grunt from a smaller engine compromises had to be made.

The main compromise is that you cannot run a high compression ratio. The STi runs about 9.0:1 while the 350z makes do with an 11:1 compression ratio. This is because with forced induction, static compression ratios have to be low as at full boost, this may vary to around 14:1 due to the air being compressed at speed by the turbine. If you run a high compression engine here, it will surely destroy itself (however new technology has enabled direct injection and this allows high compression turbo engines like the Audi A4 1.8TFSi I tested earlier). Higher compression normally aspirated engines have more tactile feel when it comes to power delivery. It is very adjustable and has more finesse.

A low compression engine usually lacks the will at low rpms and tends to be sluggish and lazy. these engines need the turbo to give it a nice shove. But, again I state, it lacks finesse. With the 350z the car feels so balanced on the throttle and you can use this throttle adjustability to drive the car, hence making it a hoot to drive (or drift if you're a really skillful bugger). The Impreza STi, you're actually holding on for dear life as half throttle and full throttle feels the same. There's not much finese there, as everything goes when the boost comes in. It is lucky that the Impreza STi's chassis is pretty sophisticated to ease thing up.

So what the Impreza STi really needs is a step by step power delivery. Doing 140bhp to 280bhp in a single bound isn't nice to drive most of the time. It is thrilling, the turbo rush and all, but it needs more graduation, maybe 125bhp, 200bhp and then 280bhp at 3,500rpm. Maybe the newer STis are like that, but I do know that if you tweak the STi, it will be a fantastic car with more progression and an extra 30bhp or so. That step is just RM3,000.00 away for my friend.

As stated, the Nissan piles on power effortlessly, with finesse. It still has excitement as the engine is still cammy in nature where after a certain rpm the engine note hardens and there is a step up in power. But as it's normally aspirated, it feels balanced. It feels exciting in another way i.e the relentless acceleration instead of explosive, one off acceleration. Both cars would reach 245km/h quickly, the Nissan would gain from the initial acceleration but by 3,500rpm, when the engine of the Impreza STi wakes up, the advantage would be erased till around 220km/h and then the naturally aspirated power of a large 3.5liter would come back strongly. It is sledgehammer technology against a precision tool. Both deliver pretty much the same end result, but the way it is delivered in either one is as different as night and day.

If road tax weren't an issue, RM4,000.00 a year road tax for the 350z versus the approximately RM374.00 for the Impreza STi, the 280bhp made in the normally aspirated way is the way to go. However, if you didn't have to choose, take one of each as you get an apple and an orange. It'll make you a very happy man indeed.

When in doubt. Buy Both.