E300TD turbo boost tweaking, possible?
 

Hello, is is possible to play with the Turbo to get the boost earlier? I advanve the pump and the car react better but I love to get the turbo kicking in faster, any way possible ?
Thank you.
Olivier

Boost controller is the cheapest and easiest thing to decrease turbo lag, but not by much.

Since this car has a vacuum actuated wastegate, it's going to be challenging to raise the boost level mechanically.

A switch to a VGT would be an excellent choice to increase the responsiveness on this car.

Hiya,
Do you mean that if I was able to block the waste gate, the boost will be there earlier and I'll get more performances?
What would happen if I took the vaccum pipe out of the waste gate? What is the waste gate for anyway?
Thank you.
Olivier

I don't believe there's anything you can do with the stock turbo to induce the boost to come on earlier in the RPM cycle. The only mod I'm aware of would be to find a way to produce a higher amount of boost by delaying when the wastegate begins to open. As has been mentioned, this wastegate is vacuum operated. The valve is normally open and requires a vacuum signal for the gate to shut completely, and thus allow boost to build. The gate begins to open up when the vacuum signal is gradually reduced as the engine computer senses that maximum boost is approaching.

Thank you, I look at it tommorrow a little closer, if I take the vaccum out, would that mean that the waste gate would be all close, or all open?
A wee confuse on this.
How about changing the spring on the valve for a stronger one, to delay the opening ( this if the gate is opening to let the pressure out), or the oposite , a stronger spring if the gate need to be shut for longer?
Thank you.
Olivier

If you're looking for more boost at high RPMs, adjusting the wastegate can do this (although efficiency of the turbo might decrease plus heat). However, the wastegate does not affect how soon the boost builds, as the wastegate will be (should be) closed until boost approaches the wastegate-opening limit (.95bar?).

To build boost faster without changing the turbo or any other mechanical swaps, reducing exhaust flow resistance/backpressure and improving intake flow will create minimal (if any) improvement. Fueling the engine sooner (adjust ALDA) and even slight overfueling will help however as the fuel introduced sooner is heat to the turbo sooner, and expanding/hot air is what makes the turbo spin. Power at the cost of BSFE.

You can't really adjust the vacuum actuator (if you remove vacuum, the wastegate will always be open --> no boost ever). The best you can do is replace that unit for a pressure actuated version and then add on a boost controller, which will allow you to custom set your wastegate opening pressures. Having said that, I wouldn't evem bother with the tiny stock turbo MB installed on these; they have a rather narrow efficiency range, so adjusting it will probably just be counterproductive.

Thank you all. Interesting about the wastgate as I didn't know when it open or close. Its always open then untill the pressure build up, then shut at a certain pressure and this give the turbo boost.
Auspumpen, the turbo look tiny indeed, and I have to say that I am jealous of Evan's new size, this look like a proper turbo :)
Olivier

Wastegate tweaking.
 

If I understood properly, this is not only the RPM that make the boost, but the speed of the gas going out, creating the pressure that will shut the wastegate, is that correct? Then if you want to booster, you need to floor it a wee bit, is that correct?
Today following this tread, I decided to have a look at the wastegate, after removing the engine mount shield, I could understand what was going on there, and found out that you could tweak the bar that commend the wastegate and mve it forward for the valve to shut earlier as its already advance.
I did move it forward about 5mm, and it work a bit, might be the placebo but on first gear, starting, I can feel the boost and the wheels have a little more tendency to spin... Not to sure on third at about 2000 RPM, as it still as a wee lag when you gently press the accelerator ( my first question above?) but if you floor it a little more, the boost is there.
Olivier

Normally the wastegate is closed. It starts out closed before you start the car, remains closed as you drive the car, only opens if the boost gets higher than the designed limit.

Changing the length of the actuating rod will change the pressure where the wastegate opens, but as this is a safety valve of sorts to protect the engine and turbocharger, you should not adjust this unless you know what you are doing / what the new opening pressure is.

Since the wastegate is closed on acceleration until the boost exceeds the (.95bar?) limit, and that usually shouldn't happen until high in the RPM range at full-throttle, you can now understand how wastegate adjustment will not effect off-the-line performance unless you are dumping the clutch at high-rpm.

If the wastegate is defective/stuck open, this is a different issue and probably not cureable by mis-adjusting the wastegate linkage.

Humm, would that be then that my wastegat was not acting properly and by moving it manually few times I put it back in place and that what I did as nothing to do with a little gain on first?
Now I am wondering, if the wastegate is close and only open when the pressure exceed the norm, what I actually did by moving the rod was that the wastegate would open earlier, therefore loss of gain? I am correct?

If it opens earlier, you have reduced the peak boost available and therefore some peak power.

I need to reverse this then :) To my understanding it was the other way around.
Thank you.
Olivier

Back to reverse the other way around. Now another question, I didn't really try it but it seems a wee moresluggish, I put the screws back the other way about 5mm, will it be a tipping point where you actually open the valve pushing it the other way around or will it shut completly at the end?
Cheers.
Olivier

OK, here's an update from my observations this afternoon:

The angle of the wastegate in the relaxed condition is similar to the one shown in the picture. Actually, the wastegate arm is angled slightly more toward the outlet clamp. (Longer adjustment position on the rod).

As for the operation of the vacuum wastegate, prior to starting, the actuator is relaxed and the wastegate is open. After starting, the wastegate closes and remains closed unless the ECU senses an overboost condition at which time, it vents the vacuum on the control circuit and allows the wastegate to open.

Exhaust pressure also aids in opening the wastegate rather than closing it tighter.

Hope this rambling explanation helps.

Thank you Evan,
I'll see whats happening today with it. I was wondering if I could find a spring that fit the lengh of the rod to slightly make it harder to open the wastegate, this would create more pressure? No?
Olivier
The important question I forgot to ask, if the arm pass a certain angle toward the clamp, would that open the valve the other way like a swinging door or the valve will sit and shut tight the more the arm is put toward the clamp?
Thank you.
Olivier

In this case, the wastegate has a spring that's trying to open it all the time, unlike a pressure type where the spring is trying to close it all the time. You would need a tension type spring working in opposition to the existing built-in spring in order to make the wastegate close tighter.

On a side note, I have read somewhere here that shortening the rod (adjusting the nuts) to bring the control arm into a more parallel position with the exhaust clamp can help increase or stabilize boost.

Finally, to answer your last question, the control arm moves AWAY from the clamp to close. The valve inside the housing stops against the casting to seal like a regular household door rather than swinging through.

You can see it in this picture:

http://tinypic.com/jr2tjb.jpg

Thank you Evan,
This is what I did yesterday, I move it a wee more paralel and I thought it was better, then put it back the other way around 5mm pass the original as I thought what I did was wrong. Defenitly the car was more sluggish this morning. I need to put it back again on the paralel side then.
Its not a too bad job to do, the worse is removing the engine mount heat shield, especially with a hot engine. Ouach!
Olivier

It look like its a fine tweaking. I put it back a little further from where I did it the first time and the car seems better but not like the first time, need to go under again the put it back another mm or so...
Tomorrow will tell :)

Finally, got it.
I put it back like the first time, about 5mm ot the width of a nut away from the clamp, as Evan says, paralel.
The car is more responsive on first and feel better.
Don't know why it work as it should be the opposite, but it does to me anyway.
Thank you all.
All the best.
Olivier

Oliver,

Are you sure by perfoming this tweak that the max. turbo pressure is not exceeded, since at a certain moment max. pressure is reached and wastegate needs to be open ? Issume by adjusting this nut you determine the opening of the wastegate.

Cheers,
Ingmar

To tell you the truth I have no clue. All I know is that it worked for me. What I think is that the valve might be slightly open ( as you screw the nuts away from the clamp) but there is still plenty of pressure to boost but it take longer for the electronic to realise or reach the max pressure so the boost might stay longer? But again, I need to be honest, I haven't got a clue.
Next I might look for a spring, that will fit on the rod, this will certainly increase the pressure as the valve will be slightly delayed to open fully.
How's your car?

Car runs fine on the home-brewed WVO, last weekend I had a problem...lost the turbo-power, drove home the last 15 km felt less than a 200D:rolleyes:. Appeared to be the main filter that had lasted for 13.000 km that was the cause, after changing the filter I got back my rocket :) Not too bad I reackon, my 207 stopped after 2000 Km when changing the fuel.


Before the winter I at least want to check the strainer in the tank, and probably the fuel line change it from 10 to 12 mm, also the heat exchanger will be fitted under the bonnet.

Together with this conversion I willl also change some of the old "gardena-style" fuel lines together with putting in some helicoils for the intake manifold bolds. In the past I think someone torgued them too much:mad:. Might as well change the glow-plugs as well, just preventative.

But first coming friday I willl change my condensor to get the airco working again. Visited a indy/forum member 2 weeks ago and discovered that this was the cause for the malfunctioning.

Cheers,

Ingmar