Hi geewizztoo, and thanks for the greetings. I got the Spiralmax's from an American site:
http://www.spiralmax.com/
Good service and very fast delivery from California. Though it seems a lot of money for a bit of stainless. It is a long term thing and savings are gained with time. The idea is basically to twist the incoming air, and with the exhaust tube the outgoing exhaust gasses. I have found that fitting one pre-, and one post-turbo that the lag is reduced and the Turbo seems to be "on the boil" sooner. I fitted one in the soft rubber part of the intake next to the fuel primer bulb, and a smaller one in the soft rubber hose just before the intercooler. Fitting is simple for the intake twisters..it will tke you longer to undo the hose clamps than it will take to fit. The exhaust tubes need to be rivetted in (i have already lost one through NOT rivetting it in) and the shape of the pipe doesn't help either, so will take a little bit longer, but it is still easy to do.
Now before you say "what good is that", have a look at your own car, at the air intake pipe that enters the filter box. Can you see that bit of pipe about 6-8cm long that bulges slightly as it passes behind the radiator, just after the bend???? Well if you undo the hose clamps and have a look you will see that it is an "air twister". A factory fitted one. So there must be some merit in the idea of spiralling the incoming air pre-turbo...at least Peugeot engineers think so.
The exhaust tube does the same in reverse. It lowers back pressure in the exhaust and helps the motor to breath better. This seems to work quite well, and my Pug is still running the stock exhaust that was on the car from new...270,000k's and 12 years later!!! I fitted mine tight up near the bend in the tailpiece and rivetted it in. I think it is a 50 or 55cm insert type. It gives the exhaust a bit of a heavy whoosh sound under fast acceleration too.
Anyway, back to Biodiesel I have read in other b.d. forums that some vehicles need a couple of degrees adjustment on the injector pump to cope with the different burning characteristics of biodiesel. Have you heard anything yourself?