By hearsay the Blouch TD05 18g is a bit of a disappointment and one should go for a 20g instead. Though of course, though many people say this, no one has explained why to my satisfaction. I'm going to guess that whilst it has the same turbine and compressor wheels as the 20g, the turbine cover being a bit smaller chokes it.

According to PSR, on a 2L the 18g should reach full boost at about 3500, the 20g at about 3700, and the Dom 1.5 at about 4000 when all have the 7cm hot side and use 98ron.

In saying that, I have my doubt about the rpm; perhaps it's a very best case scenario. Most EJ207 Dom 1.5 graphs I have seen seem to hit peak boost at about 4500-4600 and I've seen 20g graphs that are the same. Also, confusingly enough, the 20g 8cm has made about 260awkw on pump, and I've seen Dom 1.5 8cm's make less on E85 with almost the same mods (which frankly I find very disappointing). Can't say what boost they were running, as I believe the TD05's are much better at 20+psi, and the 1.5 at 22-24+psi. I'm led to believe that 18 ish psi is pretty much a waste of potential on these turbos, and one would get better results all round with something like a VF34 p20.

All this is quite confusing, and seems to say to me is that there is a lot of variation in tuning and supporting mods (probably more in regards to the tuners skills and how much the owner wants to push it), and it appears to be quite difficult to judge.

I've spent quite a bit of time sifting through various opinions and results (some reliable, and some blatantly spurious) regarding these turbos, as I'm intending to get one myself next year. My desires are primarily max possible torque and peak boost by 4k rpm in 3rd, and about 230awkw. At the moment it seems like the TD05 20g 7cm will be the closest to my goals, but I have as yet to properly examine some EJ207 Dom 1.5 speed density flex fuel tunes that push the car right to it's edge.