Interview with Domenic Rigoli

Who is Domenic Rigoli and what is his background?

"My dad was a general mechanic and about 12 years ago he started playing around racing a little 850 Fiat with a Lancia rally engine in it. Back then I was young and I watched him closely and picked a lot of things up. Then I did a TAFE mechanic course and started playing around with Fiats myself, but that didn't last too long because there aren't too many good Fiats left on the road. That was when I bought my first Subaru and started playing around with that - and it's all progressed from there."

What has been some of TRP's recent highpoints?

"Well, we did have the WRX quarter mile record but for the last year and a half we haven't done a real lot. After we did the white car we went on to build an Impreza 2-door, but there was a move, a marriage, this and that. The tubbed 2-door I really want to get going again - we just bought the gearbox to put in and get it running. We'll start off running that car with a flat-four and then we'll probably convert it to a six - I've got all the bits here, it's just a matter of putting it together."

You've built countless high performance Subaru fours - which MY engines are the best platform?

"In strength they're all pretty much the same, but the late-models and STis tend to spin bearings a lot. The '94 - '96 is probably the fastest motor with the least modifications but the '97 - '98 has better heads for if you want really big power - they came with solid lifters, which don't pump up at high revs. The '99 - '00 cars are slower; they've probably got more pollution gear and maybe the cams are different, but everything else looks the same.

"The local WRX engines are all open deck blocks, but we've found the import Liberty engines have a closed deck. I have found both open and closed deck blocks in import WRX engines - the STis all used a closed deck block, though. But really, for a 2.0-litre, you can usually get away with just an open deck block. A closed deck is stronger but we've used open deck blocks in cars running big boost with no problems.

"I also know the import Liberty turbo engines have more compression than the local ones, but they've also got sh*& heads - a kind of rocker arm arrangement. Subaru in Australia recalled most of those set-ups for modification or updating when they were released here.

"Looking at the heads there's not much difference. The intake manifold bolt up is different across some models and maybe the ports are a little bit different but, basically, they're much the same. And, as I said, the earlier ones had hydraulic lifters while the later ones use solids."

How many different camshaft variations have been seen in our local WRXs?

"Oh, they're all different [laughs] .

"They're the same from '94 - '96, but '97 - '98 are different and '99 - '00 are different again. I guess 2001 to current ones are different still. I notice on the earlier models they arrange the cams to open one inlet valve slightly before the other. The '99 - 00 heads are slightly different to the earlier ones - you can't mix and match those. I remember when we were in Queensland we put the same turbo, computer, intercooler and everything on a '98 and a '99 and there would be about 20 horsepower difference on the same boost; I'd say it all comes back to the camshafts.

"The 2.5-litre atmo flat-four has a lot more lift than the turbo cams and sometimes we mix and match those on our big power turbo engines. Across the range, I couldn't tell you exactly the difference. I would suppose the earlier ones have a bigger cam to compensate for the hydraulic lifter."

What do you suggest is a good engine and turbo combo for a street-driven WRX with a standard gearbox?

"On a 2.0-litre anything bigger than about a VF22 or VF23 will dull its response. When you go to something like a T3/T4 you lose a lot down low but you make sh^% loads at the top-end. No matter what you do with a 2.0-litre with anything bigger than a VF22 you won't have much response. On the other hand, a few of the set-ups we've been doing for a guy in the 'States have used a 2.5-litre engine with a T3/T4 and they respond almost like a 2.0-litre with a VF22 on it."

What are your views on top-mount versus front-mount intercoolers?

"If anything, temperatures and power is just more consistent with a front-mount - it doesn't get the heat soak of the top-mount. In overall horsepower, though, you're not going to get much difference. We've done a lot of models - some of them make the same power with a front-mount, some make a bit more and some make a bit less. You'll find with a front-mount, though, you can run it on the dyno seven times and you'll get the same readings - with a top-mount, you'll cook the core and figures go all over the place."

Is a bar-and-plate intercooler core essential or is much of this hype just rubbish?

"It is rubbish. My white car had a you-beaut bar-and-plate core and Dave's Liberty RS at the time had just a tube-and-fin core - and that car actually made more power on the same boost. I wouldn't say it was all because of the intercooler, but - you know - it's no limitation."

Is it inevitable you'll break WRX gearboxes with basic intake, exhaust and boost mods along with an aftermarket clutch?

"Not really - driving style makes a big difference. I've seen people that hammer the car so hard the gearbox breaks in a week. The clutch makes a big difference too. A lot of people go for a brass button clutch, which is rubbish in these cars - you're guaranteed to break the gearbox. We use an organic clutch face and get a stronger pressure plate made. The later-model ones from Subaru are pretty good now, though - you can do a few mods and it all seems to last no problems."

So should owners of WRXs avoid fast gear changes and hard launches?

"Not so much fast changes, but the way you release the clutch. If you snap the clutch out, that can quite easily break the gearbox - the torque output from the engine won't break it on its own. So, yeah, as soon as you start banging gears chances are you'll break the 'box.

If you ride the clutch a bit when you're launching the 'box lasts much longer. You've got to get used to the technique, though - I can drive an 11-second car with the standard gearbox and drive it so it won't have any problems. The later-model 'boxes from '99s-onward have a stronger casing and they do seem to last longer overall."

Have you had a look at the 6-speed in the current STi?

"I've never seen one. I know a guy, though, whose blown three engines and four clutches in a current model - obviously he gives the car a beating, but I don't think he's had any problems with its gearbox. I hear the gears in them are about 1 ½ times the size of the standard ones."

For the street driver sick of replacing standard WRX gearboxes, is there a more practical option than a dog box?

"The guy we use now does synchro sets for WRXs - an upgrade synchro gearbox. We've put about seven of those in cars in the 'States, which all run stroker engines and big turbos. They don't race them - they're streetcars - but they still make a bit of power. Sure, they could break the gearbox if they wanted but, again, they just need to treat it good. It is certainly stronger than a standard 'box - the gears are bigger and made from better material - but it drives just the same."

Once a powerful WRX has been fitted with a good clutch and a dog box that enables hard launches, is there anything else that can go wrong?

"You need to do the axles and CVs when you start pushing 10-second passes - when you've done everything else they're the last thing you change. The front-wheel-drive Liberty shafts are stronger than the front WRX shafts, but you really need to make something from scratch for the rear."

And what tyres do you use on your fastest Rex drag cars?

"We used to run Falken Azenis but in America they use BF Goodrich drag radials - and they're very good. I watched a Toyota Supra run a 9.0 with those tyres, which are still classified as street radials. My brother - Sam - launched one of our cars over there and it'd bog down and run a 10.5. I told him to launch it harder and he told me he was already ripping the sh^% out of it. That was when we decided to hit the nitrous and then let go of the clutch... He did and the car shredded first gear off the dog box and blew a front and back CV joint. No other street tyre would grip that hard."

Were any of your quick Rexes partially stripped to save weight?

"Not really; my white car at one stage was running no seats but I put everything back in it. When we were running it had full interior, a fuel cell instead of the original fuel tank and a few bits and pieces taken out here or there. My new car, though - the 2-door - is fully stripped; I think you either need to do a lot or don't bother. The thing is, though, if you take a lot of weight out - depending on where - you can lose traction."

Do you think that variable fuel quality from the bowsers is responsible for some performance engine failures?

"Definitely - it detonates them and you break a piston. I think it's usually piston four on Subarus - the one at the back on the passenger side - that goes. In the later-models, they actually made the injector in number four slightly bigger; we've flowed the injectors and that's how they come from the factory."

It's amazing the amount of performance we're seeing from WRXs with standard heads - is there much room left for improvement in terms of flow?

"In the last six months we've started doing the heads. I think we got a fair way with the standard heads on my car and on Jamie's - the guy that used to work for me - but now the cars we're doing with headwork we aren't pushing the same boost and the power is still there. I'd say it is better. The last engine we ported also had a set of cams in it - and that sounded tough!"

Is the standard cast iron exhaust manifold any good?

"Yeah, we still use the standard ones. At one stage we had extractors made to mount the turbo in front of the engine - and that made the most power we've ever got out of one of those engines. That was a big job, though - we had to move the radiator and everything else and it also sounded a lot different. The next set-up I want to try is an engine with headwork and extractors."

When you fit aftermarket engine management to a Rex, what sort of ignition timing do you aim for?

"On pump fuel we set it to about 18 - 19 degrees of timing at full boost and, with C16 fuel, anywhere up to 30 degrees. It revs cleaner when we go up with the top-end timing.

"I don't usually push these motors past 18 - 20 psi on pump fuel. Depending on what's been done to it, an engine like that might be making 280 - 340 horsepower at the wheels. An engine that makes 340hp on pump fuel can usually make 500hp pretty comfortably on C16 - that's with up to about 38 psi versus 20 psi."

Contact:

Tony Rigoli Performance
+61 2 9726 6662

Share this Article: 

Digg this story

Seed Newsvine

Post to Reddit

Save on del.icio.us

Email