Originally Posted by johnfelstead
OK, did some more work on the mapping yesterday and also found why we lost power with increased boost.
The OEM dump valve wasn't sealing fully it appears, which would have been feeding hot air back into the turbo inlet. So we fitted a Forge recirculating dump valve and did another mapping session on the road.
It instantly picked up 0.25BAR and sharpened up the response even more, so after mapping the car and spending a bit of time fine tuning the cruise AFR's etc. now the pressure of time had gone for the sprints i was doing we have achieved the following.
Power of 473 BHP, Torque of 540 FtLb !
Power and Torque
Power and Boost
The engine knocked a bit of timing out at the top end on the rollers, it doesn't on the road. This is a road mapped car, there is no attempt to optimise the engine for the rollers. It looks like on the road it's producing 490 BHP
WOW! This is quite the setup you have and glad you figured out the Topend issue.
Do you happen to have any Dyno plots on Pauls MY03 Spec C, with this turbo for comparison to yours?