Hi all.I know I've asked a similar question, but the deeper I dig the more questions arise. Breifly the turbo on my std 96 1.8t blew with the aid of some oil feed problems. Engine flushed through and new oil pump fitted now ready for replacement turbo. I intended to chip the car b4 the turbo blew, but my thinking on this has changed a little. With a std chip, around 190/200bhp on the k03, the turbo is I beleive producing somewhere in the region of 17/22 psi, and is maxed out so working Hard. As I'm replacing the turbo,I'm finding it hard to resist fitting the larger k04. Now I'm not looking to really go above the 190/200 bhp mark, to preserve as many mechanicals as poss. I've read on lots of posts that fitting the k04 requires specialised mapping larger air flow sensor, injectors and so on to get the max from it. But if I run the k04 with the boost set lower say 12/14 psi with a std k03 chip, would the k04 still be moving the same volume of air as a 20psi k03 and therefore produce the same sort of BHP without the strain on the turbo. The maths may need a tweek but is this theory practical.. Cheers to anyone in the Know.

 

Just find a used ko3s from an 01+ for about $150 and call it a day. It uses the same size wheels, but a more efficent compress wheel design. It is only rated 5hp less than the ko4 which has a larger turbine wheel (1-2mm). And no need for a different remap and larger injectors. Run it to 20psi and enjoy.