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Under this supercharged rat Cortina is a work of art and a triumph of clever and original thinking… all topped off with forced-induced Zetec power.

supercharged rat cortina

We usually turn up for photoshoots to find the car’s owner titivating the engine bay, fiddling with carpets or generally making sure every window rubber’s perfect, the glass is smear-free and each alloy’s pristine. Not Steve Tonge though, who proudly tells us that in six year’s of ownership he’s not even cleaned his Pre-Aeroflow Cortina once. Well, he did polish out the mug rings on half the boot about a year ago…

Polishing is not what this car is all about though; in fact it couldn’t be further from the point — the point is far more ingenious and subtly hidden than a simple shiny surface.

supercharged rat cortina

The old saying is to never judge a book by its cover and, although this is a wretched cliché, it couldn’t hit the nail more firmly on the head if it was a lump hammer guided by Eric Bristow. The bodywork’s not beautiful, in fact it’s far from it, but pop the bonnet and with the sight of an ST170 Zetec and Mercedes supercharger things start to make a whole lot more sense. Oh, and then you’ve got to crawl around in the mud to have a look under the rear end, because there’s a fully independent suspension set-up and it’s a work of art…

supercharged rat cortina

Doing Time

We love the ratty, patina-laden appearance of Steve’s 1964 Deluxe as you’d never guess what was lurking on the underside, save for the tell-tale supercharger whine and subtle badge on the rear panel. The fact is he’s taken five years over the build and roughly 1000 hours on the rear end on its own. So why all the extra effort? “It’s the car I’ve always wanted to build,” he smiles. “I’ve always wanted to have a Mk1 Cortina with independent suspension and all that. I thought if Ford could do it for Jim Clark, then so could I! It’s all been done in a single garage too — it’s amazing what you can do with a grinder, vice and pillar drill.”

It’s only with the car up on a ramp that you can really appreciate the work that’s gone into removing the live axle rear end, and Steve’s managed to make the whole lot work without simply chopping out the existing floor. We wouldn’t say it looks stock, but it is pretty
damn good. 

supercharged rat cortina

In Steve’s words, it’s very similar to what you’d find if you peered under the back of a Toyota MR2. A Sierra diff is used with specially-made driveshafts, and the diff itself is held in place with a cradle that bolts to a frame that Steve’s made up and welded in place, with strengthening plates on the existing chassis rails. Using Fiesta front hubs, custom Rose-jointed arms to control toe-in/camber, Skoda anti-roll bar, front coil-overs from a Mk2 Escort (in extended turrets that are both braced and tied into the roll cage), and what are essentially link bars mounted to the existing mounting point for the old leafsprings, Steve’s created something that works perfectly in unison. 

Sounds complicated, but when you see it all in place it makes perfect sense — credit for 1000 hours Steve spent designing and perfecting the setup. “I enjoyed doing it and never lost my rag with it,” he says. “I’d work on the car for three hours, three or four nights a week after work. You wouldn’t believe how much time I’ve spent lying on my back under it, working out how to solve problems.”

Change Of Focus

And the big question, was it worth it? After riding through town and blasting through the back roads the answer is an emphatic ‘yes’. In Steve’s own words, it rides like a new car, completely settled and stable at speed on uneven roads and sharp bends and badly patched surfaces; the kind of place even the best set-up and extensively-linked live-axle car falters. Properly impressive, and seriously rapid too.

supercharged rat cortina

Oh yes, it’s interesting at the front as well. Originally built up using a silver top Zetec, Steve soon realised the potential of the ST170 lump, especially with a Mercedes M62 supercharger bolted to the side. And guess what: the install’s a work of genius too.

There’s a standard ST bottom end, with a CNC head by Ric Wood (a close friend, who Steve’s been going racing around the globe with for years) and long duration cams, to maximise the supercharger’s boost. Alfa Romeo inlet and injectors have been modified to fit the Ford head, the plenum has been home-made out of two headlight bowls (really!) and a piece of rolled sheet steel, he’s used a Ford Ranger 36 mm throttle body, Corsair V4 radiator, Ford Transit intercooler and a air temperature sensor from a Bentley Turbo. As you can probably tell, Steve likes to utilise what he can find lying around the garage at work!

It’s a tight squeeze, but nothing looks out of place or forced and, amazingly, the engine bay hasn’t had to be chopped to pieces either. Steve’s used his own engine mounts, and the supercharger mounts via a plate off the crossmember and the pulley’s gone over the top of the original bottom pulley — it’s extremely tight down there, but since it’s been in and running it’s proven to be an incredibly reliable source of power. 

Peak power of 220 bhp doesn’t sound huge, but it’s the delivery and 200 lb.ft of torque that makes this car quick. Power delivery is difficult to describe, with the best comparison we can think of being a modern, big-engined and powerful turbo diesel cruiser. Not in terms of overall pull, but the way there’s power from nothing, literally. The hybrid powerplant’s making huge torque from 1600 rpm and is linear throughout the rev range, meaning it’s pulling like a train right up to 7000 rpm and beyond. Not that it needs to though, which is the most impressive part. You can be cruising along at 3000 rpm, then plant the throttle in any gear and you’re off, instantly, with no lag or waiting to come on cam. This makes it very easy to drive fast, as we discovered…

Boxing Clever

Steve’s opted for a Borg Warner T5 ’box, which is much stronger than the usual Type-9 but not known as being the quickest or slickest change. Not that it matters when power is always available and gearchanges aren’t actually that important. With some custom mounts and careful persuasion of the tunnel he’s even avoided having to chop the insides up, bar that stunning top section — who’d want to cover that with carpet?

“I’ve built what I wanted to build, and always promised myself I wouldn’t skimp. It was done originally to go round the Nürburgring — holidays and work allowing. Driving it is like chalk and cheese compared to a live-axle Cortina: it’s really flat and neutral, only oversteering when you want it and provoke it,” he says with a smile.

As you can imagine this hasn’t been a cheap build, but Steve’s ingenuity, skills in a single garage and willingness to use, modify and fabricate what’s at his disposal means it’s been completed on a fraction of what you’d expect — less than some spend on an engine.

Obviously, all the work at the rear end would be wasted if it still steered on the box and throttle, so Steve’s converted to rack-and-pinion using Mk2 Escort bits, coil-overs and eccentric top mounts — although you wouldn’t know as he’s cut the strut tops, inched them back and welded them up seamlessly. 

Low Rider

The front suspension’s tied into the cage (a Safety Devices cage was a starting point, and has been added to extensively), as are those extended rear turrets, with coil-overs meaning the car can run seriously low. So low in fact there’s a separate tunnel cut into the rear floor for the exhaust silencer to run through, and the tail pipe exits the rear panel. The fuel tank doesn’t pose a problem, as there’s an alloy Escort tank sat in the boot with the filler relocated as the original well was removed for the rear end setup to fit in. 

This neat approach adds to the sleeper feel as, bar the ‘Supercharged’ badge, there are few external clues as to what lies beneath — it’s all tucked up above the line of the sills. That’s what we love about this car though, and we’ve not even had the chance to mention the home-made bias pedal box, rear disc conversion, the fact a five-speed Capri propshaft bolted straight up, the various repairs to the shell or that Steve regularly drives the Cortina all over the country. Just have a damn good look at a show, and don’t be afraid to roll around in the dirt.

So it’s not shiny. If that bothers you then turn to the person nearest you and make a joke about their mum, because you deserve a firm slap. 

Words and Photos Jon Hill

supercharged rat cortina

This feature on Steve Tonge’s supercharged rat Cortina first appeared in the January 2010 issue

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