Archive for September 29th, 2007

Toyota phased out it’s iconic Celica in 2006.

The memory lives on though. Although many people did not have a good impression of the last mass produced Celica (the T230 1.8 VVT-i engine. YUCK!), there is one Celica a true boy racer will remember with tears in his eyes: The Celica GT4 S185.

To call this vehicle a sports couple is actually an understatement. The Celica GT4 ST185 was originally designed and produced to compete in the World Rally Championship and give european auto manufacturers a run for their money.

It went on to bag the WRC Driver’s Championship in 1992, and WRC Manufacturer’s and Driver’s Championships in 1993 and 1994. Not bad for a normal ’sports coupe’.

So what’s under the hood of this baby?

Well…it gets a little technical here. The Toyota 1998cc 3S-GTE engine is built in-line, 4-cylinder and utilizes a CT26 or CT20B Dual Entry turbocharger.

The Dual Over Head Cam (DOHC) 16 valve cylinder head is designed by Yamaha.

The pent-roof combustion chambers are complemented by a cross flow intake and exhaust layout. Spark plugs are located in the middle of the combustion chambers.

The engine churns out 204 Bhp@6000 rev/min, 275 NM@3200rev/min.

To all the drifting nuts out there (which should be 60% of my reader demographics), the GT4 has an all wheel drive system(AWD). It is fitted with a Central viscous coupler, Torsen rear differential. The Epicyclical center differential with 50-50 % F/R distribution.

HUH?? What was that?

Ok layman terms…

A Viscous Coupling works very similarly to a Limited Slip Differential (LSD).

A viscous coupler can be seen as a tube containing a pressurized viscous fluid in which discs are rotating. Half of the discs are attached to the incoming axle and the other half to the outgoing one to the tube’s walls.

The discs are pierced and the viscous fluid completely surrounds them. Minor speed differences are allowed between discs. Increased slip (i.e. rotational speed difference between discs) leads to a rapid increase in the viscosity of the fluid which, in turn, locks up the coupling.

During normal driving conditions, both sets of plates and the liquid ‘connecting’ them within the coupling are all rotating at the same speed. However; If one set of wheels loses traction, its set of plates will rotate faster than the other set.

In this case, the liquid within the viscous coupling transfers torque from the faster spinning plates to the slower spinning plates, ie torque is transferred to the set of wheels with more traction.

The fastest recorded speed of the GT4 S185 is 230Km/h, with a pickup of 7.9S in the 0-100Km/h test.

Before the WRXs and the EVOs came about, Toyota was already trashing the competition with the GT4 S185. Unfortunately, Toyota pulled out of the WRC to focus on F1…and ever since it stopped producing AWD/RWD cars…

Well you get the picture. The last celica didn’t sell well probably because it was a Front Wheel Drive and remember this:

The main plus point of RWD vehicles is with some of the mechanical parts removed from the front and installed at the rear, vehicle balance and handling are much improved.

Using the rear tires for acceleration traction takes the load off the front, so drivers accelerating out of a corner have much more lateral grip.

Looking at the kind of family vehicles Toyota produces now, I mourn the departure of a Toyota classic,  a rare one blessed with technology ahead of its time.