Bought a VT calais 5L... ran like crap when I bought it, but i did the mandatory maintenance as soon as i could. rotor button, dissy cap, leads, plugs, high flow filter, cleaned the tb and AFM, full service, adjusted the tb cable slack, timing in diagnostic mode is normal It seems to be very unresponsive down low and at light throttle applications. but... when you bury the throttle its got plenty of go. had a twin 2.5 into 3 inch system on it that created an even worse illusion of drone, yet not going anywhere. that was rusted out anyway.... so i replaced it with a stainless twin 2.25 full system. now it sounds quiet and nice but still lags. Also it sits on 15L/ 100 av, town driving and ive now had it 3 weeks. is there something im missing? or are they like that? Mind you, this is my first IRS commodore.... could i just be gettng thrown off by the initial crack of the throttle making the car squat?
Get a tune from Foamy, Dr Bob or the like and advance the timing a few degrees (consult with them first), I would also recommend changing the bottom half to a stock LSx airbox with two hole mod / MCAI or something I have done this myself and the difference was noticable. What diff gears is the thing running, might be geared a little low, a common modification to the VT 5ltr is swapping out the diff gears to give it a little more blast off. If all that fails you might be bleeding cylinder presure somewhere, how old is the engine?
If it get any tuning it will be a realtime tune. Its done 190k and was original apart from springs and catback Might throw some gears at it at some stage.
