SDI and tuning in the same breath?! If that's even a 'thing'... Just thought I'd update all you non turbo, diesel tuning people out there.
Over the last few months I've been running DLSA150P544 injector nozzles. Same economy on a run, but accelaration torque is way better. Who says you need a turbo? All good, and car 'almost' keeps up with a stock lupo GTi! No access to rolling road at the mo, so no idea what power gain if any. Definitely more torque though. I also adjusted the injection pump quantity adjuster to make it idle at 0.2mg when warm. So a bit more fuelling top end, like 5mg. In theory about 15-20% more fuel. More fuel = more power in a diesel.
But.
Yesterday my car failed its MOT on emissions. D'oh. Smoke reading when blipped to between 6-7.5. Limit is 0.7 on the plate.
Oh.
Took it on a quick 20 mile blast to clean anything out, along with some purge in the tank (i don't think the stuff works). Retest. No change.
Back to the workshop and had a dig around for some original P745 injectors (0.190mm holes). Chucked em in. Back to tester who was now laughing... Scraped through with an average (after a few tries) of 0.66 smoke. Pass.
Moral of the story- you can have more grunt from an SDI, but it's not gonna be legal...