Another turbo

Yet another turbo swap for Helga, this time a fancy ball bearing Pulsar GTX2860R

I suspected the Chinese T3 turbo I’d fitted was burning oil, so it didn’t take much to convince me to try a modern ball bearing unit to see how much better they spool. For a while I considered a genuine Garrett GT2860RS but instead took a punt on a Pulsar GTX2860R. This is a copy of the GT2860RS but with an upgraded billet compressor wheel, at about 2/3 the price of the Garrett.

Unfortunately I’ve been a bit slack taking photos lately so you’ll have to look at a stock photo

Fitting it wasn’t super easy, mostly because the new turbo uses a T25/T28 flange which is smaller than T3. I bought a Mamba adapter which has the effect of spacing the turbo about 25mm forward in the bay. This meant all the pipework I’d made so far needed tweaking.

I think I improved the downpipe quite a bit this time. Rather than shooting straight down and back I added some more bends to better sweep between the gearbox and driveshaft tunnel.

From above…
…And below

After that I wrapped it again to try to keep the heat away from the rest of the bay. S0, how different is it? Initially, absolutely crazy. The actuator my turbo was supplied with opened at 20+ psi so I had mega boost, enough that the clutch had no chance of holding. It didn’t just slip a bit, by 3.5k revs it would let go completely and the engine instantly hit the rev limiter.

The cure was a Mamba adjustable actuator. This is a really nice thing, supplied with a bunch of springs from something like 7 psi to 25 psi. I went with the softest because on a car with a separate boost controller, the actuator pressure wants to be set quite low because the controller can only block air from the actuator, not supply extra (obviously).

The car still really needs properly tuning in T5 suite to properly take advantage of the modifications, but keeping an eye on the AFR gauge it’s not running dangerously far out in either direction. It’s proving really hard to find someone to tune the car properly, two remote T5 tuners have let me down now. The last one seemed to know less than I do (which is very little). A complete waste of money. Anyway, before I can do that I need to sort a clutch that holds the power. For now I’ve reduced the boost to just about the point it can more or less handle.