Citroen XM Forum

Hi mario

That must be like a new car, I'm so jealous.

Your search for more power is very interesting, please report the developments on here.

The XUD11 is boosted at 0.8 bar from factory. I have installed a mechanical gauge, confirming this. 0.8 bar is about 2/3 on the car's gauge, so the start of the red line would be about 1.1-1.2 bar roughly?

I'm looking to play with the fuel's boost-compensation, more than with the main fuel screw (don't want the smoke, and don't want the permanent increase in consumption). Compensation is regulated by a small conical slider valve. Pretty much the "chip" of the 80s-90s for TD cars, there were aftermarket cones with more "agressive" profiles etcetc -all new to me. Depending on the car, you may just be able to simply rotate the existing cone to get to a more "aggressive" angle. Or one can start searching varieties of cones, to find one that will do it. I don't know how the Xm 2.1td is in that respect, not had a look yet. Playing with the spring preload is another area to adjust. I've not done anything myself yet, but I'm thinking a higher max boost + a firming up of the spring, + a more agressive angle at the cone, should do a good result. I know there's a limit to this path, but I think it'll be sufficient to my needs.

The 2.1td, from all I've read, will easily go to 130hp, and apparently the factory turbo sets the limit to 150hp.

Probably you knew all that -I missed that era, so it's all new and exciting to me. Keep us posted!

George

Hi George

Just adjusting LDA did not make any big diferance, specialy whan i just put the cone to half of maksimum set up. But smoke was there with full throtle. So i turn it all the way 90deg. on the maks, and adjust max fuel screw for a 3 turns.

My pump is alrady litle in advance, so the exact turns will be probobly diferent on other car.

Also i removed pvc washer under cone, it just block the full movment of cone, and i unscrev the torax on top of LDA. This screw is for also for adjasting the fuel with no boost, or people call it smoke screw.

I think some moderate power it can be gained with no smoke, but if you want noticable differance, it is imposible. More fuel=more power, but also more Black smoke... even if you just play with LDA.

May be if you put more forced air in the engine, then you can burn some of this smoke. So there i made mistake, i shuld turn accutator arm to the max, and force the turbo to stay closed more. Then my manual boost control may work... Probobly il tray that. Then more air will reduce smoke, but i do not think it will go away even with a biger turbo...

You said good that cone is a 90is way for chip tuning. Princip is the same, you ad more fuel. I think the aftermarket more agressive cone can be used with aftermarket turbo. Specialy if you do not want balck cloud whan you get to full boost...

My setup now do not make smoke on half throtle, may be litle more, but nothing serius. On full it is Black cloud...

Tomorow il make 200km, so i will test litle more. I have rear camera that can be turned on while driveing, so i will chek the smoke...

Hi Mario

Oh, so you have already been there -sorry, didn't realise that "LDA" stands for what I called "boost compensator". Thanks for all the info, very useful.

So there are 3 things to adjust on this device:

-the torx screw ("smoke" screw)
-the cone, and,
-the spring preload.

Hmmm, question: how did you achieve boost to the red line if you have not tightened the actuator arm on the turbo to make the wastegate open at a higher boost? You say you achieved it "with more fuel" -I must be missing something in the theory.

The tactic I was thinking of following is to up the max boost progressively while upping the fuel each time, until I get to a point that is satisfactory to me. E.g. I'd add 0.1 bar increments, test, etc.

Enjoy the 200km drive!

cheers
George

Always found Eastern Europeans to be handy with the spanners - and not afraid to get stuck into anything. I've worked with loads of Poles who could turn their hand to anything but the most amazing were two Hungarians who could mend just about anything with a knife and fork. Very few tools and not a Haynes manual in sight, but that didn't stop them.

Very nice list of motors for a petrol head. How will a diesel XM cope with the Croatian winter?

The standard boost is 0.9 Bar and gets the needle to the "b" of Turbo, so I think just to the red line is about 1 bar.

You need to adjust the wastegate preload to get more boost and reduce the black smoke. It's on my list of things to do.

A white Series 1 with no sunroof...heaven.

George, im a rough on thermodynamics, but what i Know, more fuel will make more heat. Heat will expand and make more pressure.... But if i turned my accutator to the max i will not have leek of boost. I was assuming that i will do this with manual boost controler, i had same problem with T16. Stupid, i did not learn anything from T16, and that all factory accutators leek if left without adjustment....

Now i Know what is next move.... screw the turbo accutator all the way... (it culd be so easy whna engine was out)
As Dieselman said, it will give more air thru the rpm, and boost will be more constant.... Result is less smoke, and litle more mid range rpm power...

Eddie, 50 years with only blacksmith tehnologie, make people very handy with nothing .... Our standard is that smothing is always missing. In most cases you do not have tools, or parts, (manual is almost always missing)... many times you are mising everything....

I worked for Peugeot in Australia, i was in heaven.....

About winter.... in Croatian mountuns it can be cold -25 for fu weeks in winter... In area where i live, we do not have harsh winter. Fu days it can go -10 -15C but not for long, and last winter only -10... With winter tires and good engine, there is no problem.... I also installed new WAX thermoelement and new heat plugs.... So i have no fear