As the thread suggest I am getting smoke (I beleive its either silver or white) when I come off throttle when on full boost. The car was purchased from 300zx.co.uk member "3horses" the performance upgrades as far as I know are as follows: - powerflow exhaust, de cat, twin blitz induction kits, manual boost control valve is fitted I beleive its running 0.8 bar but do not have an aftermarket guage to verify this. It has had a recent oil and filter change with the chosen oil spec being 20w / 50 semi synthetic. Also within the last 2 months a new rear main crank seal has been fitted, as have new PCV valves and both rubber pipes. An aftermarket oil pressure guage is fitted and is reading what I would consider normal - rich when cold and around 50psi when driving normally once warmed up. Since I noticed the smoke as described when coming off throttle (this was yesterday) I have started the car this morning and watched the smoke coming out the exhuast on start up which is silver as it should be but I after a few minutes I thought I noticed a blue tinge to it but before I could establish 100% that it was more blue than silver the car had reached temperature and resultantly the smoke stopped coming out. Having thought about it since I can not say for sure that there was any blue in it I think I may just be being paranoid. Basically any advice would be appreciated becuase I know that blue smoke can indicate turbo problems and Id like your thoughts on this and also the smoke when coming off throttle. Cheers.

This can be quite common with turbo cars, mine certainly does it a little. It's probably a little oil and perhaps some unburnt fuel, especially as you have no cats. I wouldn't worry too much unless it's bad, or gets significantly worse quickly.

Is it possible that, due to the improvement in the spooling of the turbos gained from the breathing modifications and slight boost increase, that I do actually need to fit a pair of blow off valves and is it in a sense dumping through the exhaust system? I had an MR2 turbo previous to purchasing the zed (I know many of you wouldnt class this as a car in the same class) and I dont recall it happening with that car. My brother, who has an NA but is better mechanically than myself, doesnt see it as a problem and it is he who thinks that fitting the blow off valves will stop it.