Hey there people, firstly my apologies if this has already been discussed, but i did a search and couldnt find what i was looking for.
I have $20k to spend on my 350Z, and was tossing up between SC and TC.
Which would you chose if you had the choice?
which one will deliver the more significant power/performance gains?
Which one is more reliable?
Can you give me some links to Aus based companies that deal with these type of upgrades. I know of APS dealing with turbo, but what about company's that deal with SC's?
Is $20K your total budget? And, if so, have you done anything else?
I don't know if I'd double the factory power output without doing some handling mods, but you may have already done so. At the very least a better set of tyres and aftermarket swaybars, and I'd go a set of coilovers if I could swing it.
But, if we're talking pure powertrain, I'd go an APS Twin Turbo kit for $16K and use the change for a set of high flow cats, and larger plenum (with replacement strut brace to clear the plenum). If I had money left, I'd also add a cam upgrade to bring out the turbos.
Turbochargers are always more efficient than a supercharger. While turbo'ing isn't a "free" power gain (which everyone talks about regarding parasitic loss compared to a supercharger, there's still parasitic loss from a turbo setup) its a lot more efficient than a supercharger. If people don't think that a turbo causes its own parasitic loss, try sticking a great dirty restriction on a NA car that
isn't powering an air compressor on the induction side, and see how it runs afterwards.
I also feel centrifugal superchargers (the most common kit for the Z) to be technically inelegant. It combines the downsides to turbocharging with the downsides of "blower" type (i.e. a Roots style supercharger like on the old V6 Commodores) supercharging, and then adds its own downsides.
Not only do you have to build RPM to make boost, like on a turbo, but you get the greater parasitic loss of a supercharger. So it will be doughy low in the rev range, like a turbo. On top of that, you either then have to get your supercharger to make peak boost at redline to avoid detonation (which means your SC makes hardly any boost in the lower rev range) or you gear it to make boost low in the rev range and then bypass all the extra boost that you don't want. Unlike a turbo where the wastegate opens when you reach peak boost to free up your exhaust (and help reduce the parasitic loss from the exhaust restriction), your supercharger keeps causing its parasitic loss in a linear fashion even though its not providing any more boost.
So why even release a supercharger kit, especially a centrifugal one? You use superchargers because they're less invasive, and a centrifugal one because its compact (the only Roots kit I've seen, from Stillen, makes requires you raise the bonnet and replace your strut brace). The power delivery is a relatively linear to smooth exponential curve, and there's no boost "ramp on" when you come back on-throttle. This makes it a lot more drivable, although having been in ZTRACK's car the APS TT setup is hardly a lag monster.
Which one is more reliable? For $20K, you'd have a budget to ensure they both will be. But since the turbocharging route requires so many more parts over more parts of the engine, assuming both kits were built to the same quality the SC would technically be more reliable (on a "number of points of failure" perspective).
There's varying opinions about stress on the engine itself, and how since SCs deliver power smoothly as revs rise, unlike turbos which ramps up onto boost relatively suddenly at higher RPM which causes shock on the system, that its a more reliable option. That is definitely true in the past, but these days most turbo setups are comparatively low boost and spool up gently and smoothly so the differences are less marked.
You know about APS for turbo setups; the only Aussie-based supercharger outfit would be
CAPA, who have a love affair with centrifugal supercharger kits. If you're going the SC route I'd recommend the Stillen kit instead. It uses the better of the two available supercharger setups. If you're sold on the compactness of a centrifugal setup, get the HKS. Its more expensive than CAPA's, but its a very complete kit and well within your budget.
For either of the SC setups I would combine with high flow cats and an APS True Dual 2.5" exhaust, and a set of extractors if I could afford them.