Xantia TD Tuning

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vanny
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Post by vanny »

The DervDoctor is a guy called Gav (possibly with a couple of others i think). He's located near Derby, so basically he is the Midlands equivalent of Allards. He comes to me very highly recommended! Deffinately has an impresive portfolio, getting anything upto around 120BHP from a totally standard 92 BHP 1.9TD. Generaly they tend to tune up to 113Bhp, and thats with minimal loss to economy and the loss seems to only be when propely hammering it on motorways etc at 90+mph, i think it will also drop the top speed a little, but i've never had the balls to puch mine hard enough to find out the top speed so im not worried about loosing a little there.
A tuning service (which is pretty much a whole day affair) is £120, and when you look at the sort of costs of single runs on rolling roads and the amount some people insist on paying for much less gains (piper high lift cams for maybe 5bhp more on a diesel at a cost of £250 to £300 as a rough example) i think its well worth the money! He does mainly Pug 306's but is quite happy to do Cit diesels as well.
I think the only way he is different to Allards is by way of historic reputation (allards has been around for many many decades!), but he has a good reputation in the Pug Diesel world!
http://www.thedervdoctor.co.uk/
vanny
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Post by vanny »

As an added note to the previous message;
Allard charge £185 for the same service as DervDoctor. Gav did recomend that a GOOD head gasket is needed before tuning the power, im not too worried about mine, but if your worried about yours then it might be worth emailing him as im sure he could do both.
Got to admit, i've seen some of the knowledge he has and does seem to know his stuff!
Its great that diesels are finally starting to get talked about online. There arent really any single sources for really good diesel info :(
James.UK
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Post by James.UK »

hmm, Not at all sure I see the point to all this super-tuning diesels.. [:I] .. Adding power to an engine sounds fine, but what about all the associated components? how long will they stand up to the extra strain?
Personaly I think you are better off buying a car that was built for the job, not sure turning a workhorse into a racehorse is either necessary or desireable really? If you want power and speed, why not just buy an old series 3, 4.2 jag or something? [:o)]
I bought my ZX solely BECAUSE its a nice comfy, reliable, economic diesel.. And I love it just the way it is.. [^]
Not sure I want icky wicky's in my fuel though? [:(!]. And my dad has an old cabin cruiser thats prob never had its fuel tanks (3 of them) cleaned out in its long life... Access to the tanks wont be a prob though. Boats made of wood, and I have a chain saw! [}:)] [}:)]
James..
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davek-uk
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Post by davek-uk »

I could do with a bit of help here! I started to have a go at tuning and I have fallen at the first hurdle... DOH!
My Xantia has a Bosch AS3 pump and although I adjusted the boost compensator (which has helped avoid the judders at low rpm), I couldn't find the max fuel screw. Where it should be (on the older pumps I assume) I have a plastic plate covering an electrical plug. Does this mean the max fuel is controlled by the ECU and I cannot adjust it or was the screw moved?
Has anyone tweaked their late Mk1 Xantia with the same setup?
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Post by DarkendViper »

I think the Max Fuel Screw is to the right of the electrical connections. Mine was under a cover that I had to prise off. I've left it off to make adjustments easier.
Not played about with tnuing it much yet as i've got an air leak into the fuel supply. Fuel drains back into tank so want to sort that first.
Please keep us informed as how you get on.
Ste
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davek-uk
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Post by davek-uk »

Thanks for that info, I took the cover off but due to not removing the pipes to the intercooler I couldn't see too well. So far all I have done is screw in the boost compensator one turn. There does not appear to be any increase in smoke during hard acceleration.
That one change has made a fair difference in the pickup at low revs (where the engine was slightly juddery) and throughout the turbo range. I cannot wait for more!
I'm new to the Xantia and haven't had a TD before - should I experience a 'kick' from the turbo? Before any changes the pickup from anything under 2000 revs was slow. I can notice when the turbo starts to deliver some boost but it is not dramatic; nothing like my old SAAB... I do have a bit of a whistle and wonder if I have an air leak in a pipe somewhere.
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Post by Dave Burns »

Max fuel screw is out of reach under the immobiliser tamperproof shield, pump has to be removed from engine to get this shield off because its held on with shear head bolts, some also have a pin punched in aswell and these types then have to be ground off.
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Post by davek-uk »

Despite the poor weather I have taken step two in my tuning saga - adjusting the turbo wastegate.
I have been running with just one adjustment for a few weeks now (the boost fuelling) and am pleased with the extra response and better low revs running - this adjustment alone is well worthwhile.
So, in my usual no holds barred style, I have screwed in the actuator rod end to shorten the rod all the way (10 turns). Am I about to blow my engine? Have I gone the right way?
My early thoughts are that it hasn't provided the performance increase I was expecting. It certainly is a little easier to hold 2k revs up a hill (which is useful) but no dramatic difference considering how much adjustment was made. I had to really heave on the rod to re-attach it to the wastegate so the pressure needed to open it must be phenomenal now.
I still have a whistle from the turbo so I may have an air leak that would render this latest change useless – I will have to investigate. I haven’t followed up Dave Burns’ comment on the location of the max fuel screw. Max fuelling is probably paramount to the situation…
A last series of questions (something I should have taken more notice of when I was under the car working): Is the end if the wastegate actuator rod in a diaphragm assembly? Is it this that is connected to the inlet manifold and sucked to open the wastegate? Does this vacuum pipe also split to operate the boost fuelling of the diesel pump? – Just some thoughts – I’m not really sure how this all works.
Jon

Post by Jon »

Davek-uk
If the turbo is a Garrett then popular opinion is that one complete turn in on the actuator rod is about 1PSi. As standard they are 12 ish PSi and I believe that around 18 is considered "safe".
Have a look at this very helpful website, good text and pictures on this subject:
http://homepage.ntlworld.com/ken.waters1/306_tuning.htm
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davek-uk
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Post by davek-uk »

Thanks Jon, I have read the link and others.
It would appear I have a Garrett and a Bosch AS3 pump. I think I'll back it off a bit and have a look at the vacuum piping at the same time.
Does anyone know how the wastegate is opened and how the pump boost fuelling is supplied. I'm assuming it is all just connected to the inlet manifold (or intercooler piping) fairly directly - but I may be totally wrong!
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Post by ActivaV6uk »

On the old systems the boost pipe came off the back of the intercooler to the fuel pump which then added more/less fuel as needed. the waste gate is opened by the actuator you have already worked on the rod actually goes to the handle which opens the gate.
Andy
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Post by stevieboy1 »

Hi All
Been reading this thread, I have a couple of questions.
Where do you put the pressure gauge, is it before the bleed valve or after it?[?] What does the bleed valve do?[?] If its to frig the wastegate into staying closed longer, how do you know what pressure you are running at when you have finished messing with the fueling, don't want to go to high and really stress the head gasket[:0]. Or is the bleed valve a replacement for the wastegate and therefore more of a pressure release valve which keeps the boost on at maximum for longer?[:D]
Thanks in advance
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Post by Kowalski »

Xantias with turbos have a light on the dash to tell you when there is too much boost being applied (i.e. a stuck wastegate), I'm not sure whether this is petrols or diesels. I don't suppose anybody has managed to get theirs to come on.
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Post by xantiaBFY »

Hi Kowalski,
Is this light fitted to all Xantia turbo cars. This is something new to me.
thanks.
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Post by RichG »

My Xantia has the Bosch AS3 VP20 fuel pump. This is partially ECU controlled. 2 of the bolts that hold the top on the boost compensation chamber top (squarish thing on top of pump) also hold the Load level Sensor which sits on the pump control lever (see Haynes BOL page 4B.20 picture 22.25). The book of lies says that this must not be touched on pain of a visit to the dealers.
If I am very careful and mark everything would I be able to get it back in the same position? I assume that it has some sort of splines to locate it to the lever. Has anybody had a Load level Sensor off and back again successfully?
Richard
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