Recommended Boost Setting
Turbo Mini Forums

Hello Chaps,

I've recently completed my 1293cc Turbo and final stage was to rolling road tune it. The tune identified that the turbo a Garrett T3 was only developing 2 PSI or 0.6 bar and engine 85 BHP. The actuator and turbo are being rebuilt and new turbo seals installed. My question is what recommendations do you have for PSI settings. The car will not be raced just fast road and the engine is pretty well sorted, reground black face, reground and balanced crank, Kent 500 cam, new cam bearings, reconditioned metro head, new main bearings, con rods and thrust washers, new valves and valve guides etc. I would like the engine to be reliable but hoped to achieve about 120 BHP. I would like to set the boost to between 6 and 8 PSI has anyone got a similar story to tell or recommendations? Many thanks.

what pistons, and compression ratio? and I assume youve got an intercooler on there? any head porting?

generally about 10-12 psi should get you there, but it depends engine to engine ( and on the rolling road)

absolute priority is setup of fueling and ignition advance, too many people just whack the boost up and it ends up lean and too advanced and then wonder why the engines fucked due to detonation.

Hello Joe, pistons are standard plus 0.20 making 1293cc, yes intercooler is from an RS turbo I believe. I'm not sure of compression but cylinders have all been checked for pressure loss and all seems good. The carb is being fully serviced so hopefully the fuelling will be set right on the rolling road. I get a bit of over-run at the moment when the engine is shut down so I guess she is a bit rich? Thanks for your advice.

I ran 10psi on Metro turbo pistons on a regular basis, with intercooler and up to 15psi for short bursts.
John and Andy ran 20+psi on standard pistons on "The Upside Down Skip" of hallowed memory.