Any thoughts on the below are very welcomed:

I keep thinking about various turbo choices for the car.

It's basically a track day car, with a 2.1 with new age UK WRX heads (non-avcs). It's currently being run in with a td06-20g (yes, a 06), and I can feel already that it's going to be nice when it's "on song", but it will also realistically be too laggy for track work (If it was a road car, I'd leave it as I think it'd be a "fun" setup).

Now, the question is, where do I go?

I already have a genuine td05-16g sat on the shelf, which I'm going to be rebuilding (and making front entry etc...), but the question really is, how good will that be on a 2.1? Mid-range will be improved, even over the old td05-20g I ran, but I'm a little bit worried that even though it will be easier to drive, it will not be as fast around a reasonably twisty track as e.g. my old td05-20g would have been.

Here's my old bug with a td05-16g (mapped on crap fuel on purpose):


You can see that the power tails off after about 6000 RPM, and with a 2.1, I'd expect the tail off to start at about 5500 (at a guess).

I could also build a hybrid when it's all apart... I'm thinking of either getting myself a billet 16g wheel (which would make the turbo near as damnit an sc36 (Which I also had on a 2.1, which for track work would have been great, now in hindsight, as there was very little lag). I could also cannibalise the td06-20g and steal its compressor wheel and cover, though that seems a shame as it's a blouch 20g unit...

 

Argh, searching for threads about sc36's on 2.1s I came across my own post from the past: https://www.scoobynet.com/general-te...l#post10568286

What a moron - why did I get rid of that?

 

Here's my 2.1 with no avcs with an Andy Forrest 18g.

 

That is a nice graph!

It seems like your turbo makes 200hp at the same time (3000rpm), as my old sc36 did, and then makes more power throughout (with peak power for the sc36 coming in later than peak for the 18g).

I think the car was mapped to be as smooth in the delivery as possible, but that's still a bit shocking to me


Would you mind describing the other mods you have (in particular headers and exhaust)?

 

It's actually making 200bhp @ 3500rpm, 200 @ 3000rpm is the torque.....headers and up-pipe are RCM but I have a set of holy headers to go on which will hopefully improve spool even more.Exhaust is 3" hks.

 

Ah, sorry, yes 3500 rpm, which is the same as the sc36.

Comparing the torque graphs as well, it looks like the sc36 was down about 60ftlb at 4500 rpm, which surely isn't possible "normally", so I'm going to assume that the sc36 was mapped to have constant torque rather than max power everywhere (the sc36 map has about 300-320 between 3600 rpm and 6000 rpm with no "hump")

 

I also have RCM headers at the moment, but I'm thinking of going back to ported OEM and maybe a Harvey up-pipe.

 

I think the 18g is more on par with the sc38...I have a Harvey up pipe which I will try on the rcm's before I fit the killer b's.....I'll be looking to go 450 plus with my set up soon,hopefully it won't lose too much drivability.