Added costs of turbo/blower

Posted on August 28th, 2005 in Opinion by Julian Edgar

When Japanese import engines and gearboxes first started flooding into wreckers, I can remember writing cautionary tales spelling-out the fact that while the engines were incredibly cheap, by the time you got one installed in a car and had provided engine management, engine mounts, radiator modifications and sometimes a new tailshaft, the price may well had gone up three or even four times. These days, with many engines available with uncut looms and the factory ECU, you could probably reasonably budget on a doubling the in-car price.

And a similar price multiplication also occurs for individual engine parts.

Over the last few months I have fitted firstly a Japanese-import supercharger, and then latterly a Japanese-import turbo. Both were installed on a car that is normally naturally aspirated. And rather like the old days of buying cheap engines, I’ve found that the main cost of both the supercharger and turbo conversions hasn’t been the initial cost of the blower or turbo, but instead all that is required to accompany it.

The little supercharger cost me $250 from a wrecker, while the turbo was even cheaper. (All dollars are Australian.) Hell, that’s good value! In both cases, the devices were in excellent condition and compared with buying new, represented savings of hundreds and hundreds of dollars. In fact, you could get very excited walking out of the wrecker with one of these in hand….

But you really need to budget at least another $1000 to get either a supercharger or turbo into a car and working. And that’s doing as much work as possible in your own garage at home…

Unique turbo matching…

Posted on August 14th, 2005 in Opinion by Julian Edgar

The matching of a turbo to a particular application is something about which the ignorant knowledgably proclaim – and about which the experts are very cautious and tentative indeed.  In short, matching the compressor to the required airflow is difficult (what with the variations in air density caused by temperature changes and boost, and with the variation in engine air consumption caused by throttle position, variable valve timing and different engine speeds), and sizing a turbine to suit both the compressor and available exhaust gas flows is something that can send you around in over-decreasing circles of frustrated indecision.

So when confronting a unique turbo situation, one of the best ways is to take the lead from OE manufacturers. In short, they’ve done the hundreds of hours on the engine dyno and road (chassis dynos are rarely used in new car R&D labs, except for emissions testing) that result in a turbo that has minimal lag, flows enough air, has low exhaust backpressure, and is durable in the application. If you’re dealing with modified road car engines developing sane power levels, the role models are the single and twin turbo production engines of the world. Sure, you can run a different turbo arrangement (for example, one huge turbo instead of two smaller ones), but usually that will involve a drawback that a car manufacturer wasn’t prepared to embrace. (Terrible lag from the single turbo versus the twin – especially sequential – turbos, for example.)

All these thoughts have been running through my mind. You see, today Michael Knowling and I were prowling the wreckers of Adelaide looking for a turbo to suit my Toyota Prius. Adelaide is the cheapest city in Australia that I’ve found for bits, and furthermore, the available range is second to none. And the Prius? As regular readers will know, the small supercharger that I had fitted to the hybrid petrol/electric car worked superbly in every respect – except for noise. If you wanted a small police siren hard at work under the bonnet, it was good. But if you wanted a quiet, effortless power – well, it wasn’t. So despite the massive amount of work that fitting the supercharger had involved, it was time to move to the other forced aspiration option. A turbo.