The best part about owning a car like this is driving it on the street,” says Julian Di Matta of his Silver Fox-styled ’69 Capri. “You can run down the freeway at 120km/h, give it just a bit and she’ll bag it up! You get out of the car and your body is shaking.”

First published in the January 2007 issue of Street Machine

If you’re thinking that there’s no way this baby sees road time, we forgive your scepticism. Especially if you’ve had the misfortune of receiving attention from your local constabulary for legal mods on your own streeter.

Julian makes no claims to legality. He’s simply at the outlaw end of the street machining; choose your time, take your chances and don’t act like an idiot. If you get caught, cop it on the chin.

Which is exactly the plan when Julian ties the knot with his lovely fiancée Carmel next year. “It’s a ritual with the boys when they get married: normal cars for the girls, tough street cars for us.” Accompanying the Capri on the big day will be his cousin Tony Di Matta’s blown SHY66 Mustang, featured in SM back in Dec ’02.

There is a reason the Di Matta Fords are especially well-suited to street driving – both run electronic fuel injection.

“Driveability was the whole point of the exercise. It had to run on pump fuel and I had to be able to get in it, turn the key and drive away,” says Julian. “It would have been cheaper and easier to run mechanical injection and methanol, and we would have made a lot more power too, but that wasn’t what I was after.”

Long before the current 430ci blown motor went in, Julian was running the car with a tough aspirated 351W, a sweet trim job, wheel tubs and cool Silver Fox duco (SM, Feb ’03). It ran 10.20s and saw plenty of street duty, as documented in Rumble In The Jungle (SM, Oct ’02).

After enjoying the car for a few years and taking home a bunch of accolades – including a SMOTY nomination and Top Engineered in Tough Street at Summernats 15 – Julian was at a crossroads.

“On one hand, I wanted to find and restore an XY GT. That would be awesome,” he says. “On the other hand, I wanted to build a monster. I actually found a GT for $17K at one stage and turned it down, damn it!”

The monster idea won out instead so Julian approached Paul Sant of Pro Flo Performance fame with the aim of turning his dreams into reality.

“I asked Paul if we could make maybe 800hp with a blown small-block Ford on pump fuel. He said it was no problem – and we ended up with more than that.”

Paul is no stranger to building stupidly powerful race engines; Tristan Ocker’s 362ci, 7.55sec MINCER Capri is just one example. He’s also built a few milder blown engines that run EFI for streetability, like his brother Anthony’s stunning 1957 Chev. Paul can deliver either end of the scale but Julian was asking for something different — outrageous power on pump fuel, with the style and impact of a traditional 8/71 supercharger.

“What hurts this type of combination is inlet temperatures,” says Paul. “Making big power on pump fuel is never easy — look at the money guys are spending to win Horsepower Heroes. The difference between those guys and the Capri is that there’s no intercooler to reduce the inlet temps. You can take it out to the track and give it three hard runs but the fourth run is going to be marginal.”

With those goalposts in mind, the boys went for a Dart block, filled with a 4in Crankshaft Rebuilders forged steel crank and 8.5:1 CP pistons, displacing 430ci. It’s topped off with a set of Edelbrock Victor heads. Paul put about a week of work into porting and assembling those suckers, with flow figures in the region of 720hp. The cam is a lumpy Camtech item, meaning that while Julian can start the car without a support crew, it sounds just as wild as any Doorslammer.

Cubes and cams will only get you so far; the next piece of the equation was a Mick’s Metalcraft sheet-metal intake manifold topped by the Mooneyham 8/71 pump and an Enderle Birdcatcher hat. Squirting PULP into the top of the blower are eight of your everyday Commodore injectors. Another eight 75lb items pump straight into the intake runners.

Sparks are provided by a Crane Fireball coil and a custom-made distributor, while fuel is kept up to the engine by a duo of SX and Bosch The whole shebang is controlled by an Autronic SM2 computer tuned by Adam at Just Engine Management. Initial tuning on the engine dyno bagged 855hp, though Paul guesstimates that with subsequent mods the engine is now making in excess of 900hp.

Those mods include a Snowman water/methanol injection system. While the cluey Autronic computer would be more than capable of running the spray, the Snowman kit came with nozzles, pump and its own computer, so it seemed easier to set it up as its maker intended.

The Autronic also has datalogging, meaning Julian can keep an eye on exhaust gas and water temperatures, fuel pressure and boost.

“The upshot is that unless we really wind back the power or switch to race fuel, we are always going to be careful with this motor,” says Julian.

“At events like Powercruise, the first two or three Powerskids of the day are fine but once you’ve been at it for a while and the ambient temperature is getting up, you’re in danger of something going bang.”

Winding back the power isn’t an option, so he’s just going to have to try to be careful.

Julian handled the installation of the new motor himself; judicious use of KY Jelly left the engine bay sheet-metal untouched.

A pair of bars extend from the rollcage to the strut towers and then to the front chassis rails to add strength to the spindly Capri front end. With plenty of braided line and polish, the engine bay is as neat as you like – one of the reasons it’s taken out Promoter’s Choice two years running at the Sydney Powercruise.

He’s keeping the Capri on a tight leash until after his wedding, when he plans to run her down the quarter. And after that?

“I’ll just enjoy driving the car. There isn’t really any further I can go with modifying this – it’s as good as it gets. The next car I’ll build will be the resto.”

MISTY-FY ME

Detonation kills engines. One of the major causes of detonation is increasing cylinder pressure and temperature to a point where the charge pre-ignites before the piston reaches top dead centre.

You can drop cylinder pressure, which will lose horsepower, or lower the intake temperature to prevent detonation. Or you can run better fuel.

Julian wanted to run PULP so the octane of the fuel was a constant and they had to look at other options. Lowering the boost (and horsepower) wasn’t on so they fitted water injection to cool the intake.

Water injection is just an application of simple physics. To turn a liquid into a gas we have to add heat. So to turn the water into vapour, we use the heat from the intake. Now here’s the trick – in using that heat to convert water from a liquid to a gas, we draw heat away from the intake charge. Put another way, we make the intake charge cooler. Neat, eh?

But you can’t just pour water into the cylinders because if enough liquid gets in, you get hydraulic lock and we hit some more high-school physics; you can’t compress a liquid. Bang! Your motor will destroy itself. Plus there’s the law of diminishing returns; the more heat you pull from the fuel charge, the less heat there is to convert more water into vapour. And the more water you add, the less room there is for the fuel/air mix.

While water is the best way to control detonation, tests have shown that a 50/50 mix of water and methanol will make the most horsepower before you get detonation.

Water injection isn’t all sunshine and roses. If your engine is set up to use it, make sure the water tank is full. If it runs dry when your foot is flat to the boards, look out! Oh, and don’t mount the water tank above carb level, unlike the guy who added water injection to his Ford Bronco with the tank high on the firewall. He came out the next day to fire it up. It kicked once and went bang. Water had leaked into the engine overnight and filled a couple of cylinders; that bang cost about half of his conrods. – Scott Taylor

JULIAN DI MATTA
1969 FORD CAPRI GT