john banks said:I think the TD06 20G is too big for a 1.8 litre road car engine. IMHO, you want the upper half of your RPM range to be fat even in a low gear. TD05H 20G on a 2.5 litre engine is nice for road use, I made mistakes by going bigger than this. The difference between them is the turbine wheel (there is an 06 and 06H by the way) but this has a massive impact on spool up, and of course power as well. You may find a TD05H 20G has compressor surge if you pull in the boost too hard as it does on the 2.0 Scooby engines with a big bore inlet if you try to run silly boost before 4000-4500 RPM, but not the 2.5, can run full boost before 3000 RPM.
john banks said:I think the TD06 20G is too big for a 1.8 litre road car engine. IMHO, you want the upper half of your RPM range to be fat even in a low gear. TD05H 20G on a 2.5 litre engine is nice for road use, I made mistakes by going bigger than this. The difference between them is the turbine wheel (there is an 06 and 06H by the way) but this has a massive impact on spool up, and of course power as well. You may find a TD05H 20G has compressor surge if you pull in the boost too hard as it does on the 2.0 Scooby engines with a big bore inlet if you try to run silly boost before 4000-4500 RPM, but not the 2.5, can run full boost before 3000 RPM.
john banks said:Nice plot Bill. You could so easily ruin that by going to a bigger turbo IMHO. Can you datalog to produce a histogram of how much time you spend at various RPM intervals on your chosen circuit then match that to the dyno plot?