Adjusting turbo boost, 200tdi

Hi,
Im thinking of adjusting the wastegate on my Turbo by shortening the wastegate shaft to gain more boost ie, let the compressor spin faster...

Im not a decent mechanic or engine expert, so i need to know whether this will be pointless without adjusting the fuelling as well, as it obviously doesnt have an ECU to compensate.

Can anyone shed some light?

Cheers.

you can tweek the fuel pump on the 200tdi. I did it to mine many moons ago and it perked up a little. I cant rememebr the details of how i did it though, and i dont want to post up wrong info!! Sure theres someone on here who knows...

SMiFFAD said:

you can tweek the fuel pump on the 200tdi. I did it to mine many moons ago and it perked up a little. I cant rememebr the details of how i did it though, and i dont want to post up wrong info!! Sure theres someone on here who knows...

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Seek and ye shall find Here is How to Increase Your TDi Performance - almost for free ! Comments please !!!

Cheers dude, but its a shame theres no actual link to 'Diagram 1, 2, and 3'.

If you read through the article and the subsequent comments, there are some more links later on to the same diagrams on a different site.

Even without the diagrams the instructions aren't hard to follow - just make sure you have a bloody good look at EVERYTHING before you start and if it says 'make alignment marks' then make alignment marksor you'll never get it back to where it is now.

Anyone care to take a guess at how long it would take to adjust the fuel pump? looks quite a complex job for a novice...

Always a good idea to have manifold pressure gauge fitted, just in case it lets loose and blows your engine up.

At 2 BAR pressure most engines will be heading for trouble, as the effective compression ratio will be way too high.

CharlesY

You want to do all three tweaks or just increase the fueling a bit at max boost?

CharlesY said:

Always a good idea to have manifold pressure gauge fitted, just in case it lets loose and blows your engine up.

At 2 BAR pressure most engines will be heading for trouble, as the effective compression ratio will be way too high.

CharlesY

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Blimey CharlseY! 2 BAR on a Tdi !? Leave it at 1 BAR and tweak the pump unless you're looking for a 'short term' competition engine

Gonna say, youd have to be mad to let it run that (if its even possible).
Im only after a little more power/torque, i like to spend my money on other things besides diesel!

What I was trying to say is that tweaking the turbo up is fine, but without a gauge you are doing it "blind", and in some circumstances the thing could let rip and hit 2 BAR.

Few Landy motors would last long at that sort of boost.

A little over 1 BAR is plenty.

CharlesY

Im fine with the turbo, i know what im doing to an extent with it, i work as a research technician at Cummins Turbo techs. Ill try a couple of turns at a time and see how it goes.
Having nothing to do with real engines im not brilliant with them mechanically!

Will i be OK just adjusting the boost for now (will it be noticable?), and then doing the fuel pump when ive sought some more advice?

All you need to do is adjust the fuelling at max boost using the 'starwheel' tweak - if you're careful about how you go about things and take yer time you can be all done and dusted in under an hour.

If you're slapdash and don't care if it blow up on you and you can't put it back you could do it in about 5 minutes.

Whichever way you go about it, it will still cost you more in diesel - more power out has to equal more fuel in which means less in the tank

Cheers,

Sure, but as he's in the business, he could easily get a gauge and fit it to the manifold, rather than at the turbo.
That alone will mean more real boost after the intercooler, AT THE ENGINE, where it matters.

Just adding more boost (i.e. more air) will make the engine more efficient on the SAME or less fuel. The problem is in most turbo engines the injection pump senses more boost and hoicks in more fuel!

This will ultimately be OK as the fuel limiting setting will prevent over-fuelling even if the boost goes way up.

But, fit the boost gauge so you do NOT end up hitting mega-boosts of 2 BAR!

CharlesY

TomE said:

Im fine with the turbo, i know what im doing to an extent with it, i work as a research technician at Cummins Turbo techs. Ill try a couple of turns at a time and see how it goes.
Having nothing to do with real engines im not brilliant with them mechanically!

Will i be OK just adjusting the boost for now (will it be noticable?), and then doing the fuel pump when ive sought some more advice?

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It' a diesel - if it doesn't puff a little black soot when the engine is working hard you're not going to notice any performance gains by adjusting the boost - any gain you'd get from the extra pressure in the cylinder will be overshadowed by the extra heat the turbo will generate and as all the fuel was being effectively combusted before you upped the boost the net result is err.. nothing.

If it's got a clean exhaust at max boost - wind the starwheel in a quarter of a turn at a time until it starts to make a black sooty smoke at full throttle and max boost - then wind it back until the smoke almost dissappears and see if you like the increase.

This is the point at which a boost modification will make the biggest difference.

In any event - messing with either the fueling or the boost can seriously damage yer engine - so make sure you're completely happy with the way it' running and that it's been well serviced before you start - the end results are on your own head mate - I ain't taking any responsibility for it

FWIW - altering the fueling is probably safer, provided you're methodical about it and don't go mad straight away, than modiying the boost if you're a novice.

Cheers,

Disagree.
Easy first step for a bit of economy and maybe a tad more ooomph ...
Fit a gauge and lift the boost pressure, but not more than 20 psi / 1.3 BAR.

CharlesY

I only want to adjust the turbo if i can help it... One of the reasons being that the t-piece coming out of the comp cover for the wastegate actuator also has a pipe leading to the fuel pump. Im guessing this is for a mechanical pressure sensor so that more fuel can be added as the turbo pressure goes up.
Which leads me to think that to an extent i wont have to touch the fuel, as i think someone said earlier.
Am i right?

You go for Gold, TomE.

Another useful trick is to take the pressure pipe OFF the turbo shell itself. They only fit them there because it's close to the waste-gate doo-dah, and handy. Block the pressure-pipe outlet, or remove it and fit a plug to the hole.

Far better to fit a take-off nipple on the back end of the inlet manifold itself, and run a pipe back to the wastegate and pump, thus measuring pressure in the inlet manifold, rather than at the turbo, with all the pipes and intercooler in between. This dodge alone will probably make a difference that you will notice, and should cut down the black exhaust puff when you deck it.

The idea is that we don't care what air-pressure the turbo shoves out - what we want to know is what air-pressure the engine is getting IN.

The two are a long way from being the same.

CharlesY

Righto, cheers guys, ill let you know how it goes!

So ive shortened the wastegate shaft by 4 turns, its has actually made a noticable difference to acceleration and hill climbing! Not by a lot, but its there!
I might pop down to the local Halfrauds a buy a boost gauge when i can be arsed.