zx td tuning????

zxman10 · Post by **zxman10** » 17 Oct 2010, 23:36

HI all
I have heard that the turbo and bosh pump that is fitted in the zx/306 can be easyly tuned to give power outputs of around 120bhp.
Has anyone had any 1st hand experiance of this and is it safe to do?
I did speak to an ex-citroen mechanic who told me not to do it as it would blow the headgasket. Is this correct?

Chlorate · Post by **Chlorate** » 18 Oct 2010, 00:08

Depends on how old your engine is really. It is quite easy, mostly achieved by meddling with the boost compensator (the "UFO" on top of the pump) and a little bit of adjustment with the maximum fuel delivery screw.
But it can be a little bit dodgy since these cars are getting on a bit and you may find out which parts are more worn than which.
Personally I've been tempted, but as yet haven't had a go at it. A good thing to do first is fit a boost gauge and possibly a bleed valve (if your turbo is the Garret T2 type) and have a muck around with that.
Not so sure if that'd blow the head gasket, I know these engines have a tendancy to chew through them reliably, but that's mainly down to neglecting the coolant.

-Alex

zxman10 · Post by **zxman10** » 18 Oct 2010, 00:21

Well she's an old lady (K reg).
Also she's covered some 187k miles, was treated to a new head gasket at 155k.
The heigh miles do worry a little although I often see them on autotrader with well over 300k miles.
Must admit I do drive her a little hard at times but she never makes a fus about it.
I do find it quite a quick car for its age considering it's a diesel but against some of the new 130-150bhp diesels it's out performed.

Chlorate · Post by **Chlorate** » 18 Oct 2010, 00:26

Yeah, mine has turned over 150k and had a new head gasket and cylinder head last year. They're a fun little car nonetheless though.
I find it does give a lot of modern cars a run for their money, considering they've only got 92BHP out of the factory

That being said, I'm still tempted to have a little play. They are rather resilient engines. But then again it's my daily driver and I can't really afford to replace it if it goes boom..

-Alex

evilally · Post by **evilally** » 18 Oct 2010, 00:50

I've tweaked my 405 using the max fuel screw and waste gate adjustments, it now runs 18psi (standard is 13psi). That's as much as I'd give it without a front mount intercooler. Run for over a year now and no problems, but it does have a new headgasket and is serviced every 3,000. I'm going to revisit this at some point and look at adjustments to the on boost compensator.

A boost gauge is a must, make adjustments in small increments and go for a test drive in between. I also got someone to follow me in another car behind with a hands free kit. That way, we could test off boost and on boost smoke levels to make sure it was acceptable (it still easily passes the MOT emissions). My dad's 1.8 16v 120bhp 406 had a hard time keeping up

MikeT · Post by **MikeT** » 18 Oct 2010, 07:41

It is possible to get those sort of power outputs from these engines but it will, obviously, put parts under more strain. Do you know which engine you have (DHY or DHX) and turbo (KKK or GT)?

I see you're not too far from me and if you're ever down this way, I'd be happy to offer any help I can.