Obtaining More Boost From The Turbocharger
If you are trying to squeeze a bit more out of your 200 tdi motor, you might consider increasing the boost pressure from the turbo. The more air and fuel you can get into the engine, the more power you can get out.
On the 200 motor, the default boost pressue is around 0.7bar. The turbo fitted is
capable of producing around 1.2bar boost, but this is right on the limit, both for
the turbo and engine. A sensible goal is around 0.9 -
The first job is to check everything is in good order. Check that all the hoses are in good order, no leaks from the intercooler and that the waste gate actuator is working. The actuator can be tested by disconnecting it's air line and applying air pressure using a bicycle pump. With just moderate pressure the the actuator should move the linkage.
Next, you will need to fit a boost pressure gauge, they are about £10 from a good
accessory shop. Plumb it into the blanking plug in the plenum chamber, I drilled
and tapped the plug and fitted the hose barb supplied in the kit. Once fitted, take
it out for a run to see what boost you have. Maximum boost is at 2500 -
To adjust the boost pressure, remove the small clip holding the actuator link to the waste gate. Loosen the locknut, and shorten the link by screwing it further up the rod. Refit everything and take it for another run, and note the boost pressure. Repeat if nessacery.
I found I needed to shorten the actuator rod by about 6mm in order to get enough adjustment. You will need a pair of pliers to pull against the spring in the actuator to remove / attach the link to the waste gate pin.
Once the boost pressure is set, it is worth while looking at performing the pump adjustments on the previous page. The off boost adjustment and turning the diaphragm through 90° give the best results along with more boost pressure, the truck will then be quicker off the mark and have better acceleration. For further gains, fitting a bigger intercooler will really help.
Adjusting the boost pressure on a 300 tdi is unadvisable, as they already run at around 1bar. However, that said it is still worthwhile fitting a boost gauge, and the pump adjustments and intercooler can still be done for more power!
