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Michael's Speed Zone

5th March 2001

By Michael Knowling

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It's easy to fall into a false belief that the only decent AWD turbocar on the second-hand market is the Subaru WRX. Certainly, the number of times you hear people ranting over the super Subie is incredible. The reason? Well, the WRX is the proven performance king - isn't it?

Let's take a closer look...

Flicking back though early-to-mid 1990s road tests you'll see sizeable spread of performance numbers - not only for the WRX, but all the AWD turbos. For example, the 148kW Mitsubishi Galant VR4 saw 0 - 100 km/h numbers in 7.2 - 7.6 seconds, the 153kW Toyota Celica was consistent at 8.3 - 8.4 seconds and Subaru's own 147kW Liberty RS placed itself between 6.7 and low 7 seconds.

The next generation of AWD turbos had a similar spread of times. The then newly introduced 141kW Lancer GSR did the 0 - 100 thing in 7.7 - 8.4 seconds, and the 155kW MY94 WRX ranged between 6.9 and 7.4 seconds. Its quarter mile time hovered around 14.9 and 15.4 seconds.

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Part of the reason for this variation comes down to the conditions for each road test. Unlike others, Wheels magazine run their performance times with 2 people on-board, and - as always - there are varying atmospheric conditions, fuel octane and heat-soak issues. That's in addition to the all-important launch technique...

Okay - getting back to it - it appears Subaru's Liberty RS and MY94 WRX do share the slightest outright acceleration lead over the other mainstream AWD guns. Their overall acceleration performance, however, is another story.

Just take a look at these graphs to compare their third, fourth and fifth gear acceleration splits...

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You may notice some definite trends in these graphs.

In third gear, there's generally up to half a second 'scatter' between each vehicle - except for the 'alive' Lancer GSR, which is notably quickest below 70 km/h, but slower than the rest of 'em once road speed passes 100 km/h. The MY94 Rex holds a firm grip on the ace card once it boosts its way past around 90 km/h.

In fourth gear, the little Lancer really starts pulling away in those low speed splits. Its Mitsi VR4 brother then catches up fast and then eases away from the pack. By comparison, the RS, GT4 and MY94 all make ground on the Lancer as speed rises, but none are ultimately as quick as the VR4. Even the MY94 is j-u-s-t pipped in the high-speed split.

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Fifth gear really sorts the responsive zippers out from the laggy luggers. Between 40 and 90 km/h (combining the 40 - 70 and 60 - 90 km/h split) the MY94 is up to 93 percent slower than that GSR! How's that for a caning?! Again, it's the VR4 that picks up the lead from the Lancer GSR (at around 100 km/h) and clings to it. We would expect the MY94 WRX to really hit back in the high-speed split, but - unfortunately - that performance time is not available.

So what's the story with the WRX's dismal down-low performance and the Liberty RS's overall 'also-ran' in-gear showing? These cars have the quickest outright performance, remember.

Well, let's take both cars one at a time.

To be honest, I don't know why the Liberty RS was always dragging along at the back of the in-gear increments. The 'super-Liberty' is slightly lighter than the VR4, has a higher static compression ratio (8.0:1 versus 7.8:1), a similarly sized turbocharger and both vehicles share a DOHC, 16-valve head layout. The only possible excuses I can think of are its much shorter crankshaft stroke and the less-than-ideal location of the turbo - a long way from the exhaust ports.

I get the impression the Mitsubishi engine is simply a more efficient design than the Subaru's.

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Using essentially the same (but slightly more powerful) EJ20 engine is the MY94 WRX. Its lack of low rpm torque is further aggravated by an overly large turbo and - from what I've heard - wilder camshaft specs. The only reason the MY94 doesn't trail the RS in the lower speed splits is its weight advantage - it's some 110kg lighter.

You realise how much the MY94 WRX cherishes revs when you compare its factory torque figures to the RS - 270Nm at 4800 rpm versus 260Nm at more accessible 3600 rpm. Certainly, the MY94 typifies a small engine-large turbo combination; fast once it's revving with a decent stomach full of boost, but not much good anywhere else.

Put into Context...

I should point out that many of the aftermarket big turbo conversions we've seen on WRXs totally destroy low rpm torque and response. Many of these conversions would make the standard MY94 feel responsive and nippy... Bear that in mind if you're looking to take your street-driven WRX to the next level of power.

The driving performance of Subaru's WRX took a turn for the better when the ever-popular MY97 update was released.

With the EJ20's output again lifted slightly - to 160kW - the 1997 update saw different cams, a slightly larger intercooler and - more importantly in this discussion - a much smaller turbocharger. A smaller turbo than the original RS Liberty, in fact.

This backward step in turbo size was primarily responsible for the dramatic change in driving behaviour.

The post-'97 Rex felt much more alive in everyday conditions than the MY94. Boost response was sharpened massively, and - as a result - good torque arrived sooner in the rev range. Take a look at these same in-gear splits to realise how the WRX's performance improved...

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As you can see, the MY97 WRX beats the MY94 in every one of the above in-gear splits. In some cases the margin is a hair, but there's up to around 20 percent in it in others.

The change in factory torque figures tells the story - the MY94 had to spin to 4800 rpm for 270Nm, while the MY97 made 290Nm at only 4000 rpm. As you might imagine, the two cars drive quite differently in everyday circumstances - even though their 0 - 100 km/h and quarter mile performance are very similar.

To bring things back into perspective, however, it's worth remembering that the Galant VR4 remains stronger down low than the MY97 WRX, but - due to its 12kW shortcoming and additional weight - it's marginally down in outright acceleration.

And that brings me to the next bit of misinformation in the AWD turbo scene. For some reason, many road tests and reviews of the Galant VR4 list it at 1170kg. That struck me as awfully light considering the equally-sized, equally-equipped Liberty RS weighed 1355kg. In actual fact, Japanese press release documents reveal the VR4 weighs 1470kg - I'm not sure where that 1170kg figure came from!

On the opposite side of the weight coin is the Toyota Celica GT4. This is one strange car, because - on paper - it looks like a flyer. In practice, however, it's the slowest of the aforementioned AWD turbo bunch. Many people put the GT4's slowpoke performance down to its supposedly heavy weight - but that's rubbish. Weighing 1390kg, it's considerably lighter than the Galant VR4 - but, then, maybe that's where the problem lay.

I guess the GT4's 1390kg would seem a lot when you think a Galant VR4 weighs a mere 1170kg...

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