| My race car had a little problem at its last race meeting – I don’t think turbos are supposed to do this You tube of turbo problem Engine Specs, Stock block, stock crank, CP pistons, Carillo Rods, Tomei Gasket, GT28RS turbos 0.64A/R, custom cams, ported heads, upgraded valves, BDE VTC, MS Manifolds, custom 2.5” intercooler piping, large dual pass front mount intercooler. 
Running Av Gas (Aviation Fuel 100 octane). So decided to replace the turbos (GT2860RS) with the new Gen II GTX2860 also with 0.64 A/R. They were supposed to have a 0.82 A/R but there was some miscommunication somewhere between CZP and JWT and my mechanic had already fitted the dual port wastegates and made the other mods we needed to fit before I noticed. Being in New Zealand – sending back to the USA was not really practical. Hopefully CZP/JWT will sort out something. Anyway – great opportunity to do a comparison where the turbos are the only change and I mean only, we had just dynoed with a new exhaust just before the track day when one turbo exploded in a cloud of smoke. We did have to re tune slightly and as we had been struggling to get boost with the dual port wastegate actuators on the GTs, but did not have the same problem with the mid range on the GTXs. However at the top end both turbos were still boost limited, just the GTX's were running a bit more. The 0.82 A/R would have made more top end but I am actually glad I did not get them as they would have been laggier I bet. So yes the boost and tune changed but that was all. 
Video here dyno video Had to play around with the boost, as on the GT28RS we were maxing out the boost/boost controllers. The new turbos were happy to make 26psi but at that level getting a bit of detonation (running Av Gas) so had to back it off. Part of my problem might be the dual port wastegate actuators as they are only 8psi but we a running a 4-port boost controlled and putting boost to help keep it closed. Might be better with a higher base spring but they are not changeable. 
Just a tiny bit more lag than the old turbos but made more power/boost easily. We reckon with C16 race gas could easily run 25-26psi and make over 500rwkw. Heres the boost. 
So definitely an advantage with the new design of the Gen II GTXs, better boost control and more power (30kw/40hp)with only the tinnest bit more lag. We did a run with no boost/wastegate only 8psi and got 300rwkw (400rwhp) and did a low boost setting at 15.5psi and got 394rwkw (528rwhp).
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GT280RS vs GTX28 Gen 2 (long) - 
