Thread: Turbo boost

Originally Posted by laney

Hi all I am putting a performance intercooler in my TD5 Discovery will a larger intercooler drop boost pressure I have a D2A intercooler at the moment and a Bruce Davis tune stage 2. If I boost pressure on the turbo do I have to bypass the waste gate modulator I'm not after more power would be nice but just reliable. I am going to change the turbo core has anyone used the Pommy made cores or is it better to get a new turbo same as the stock one thanks all for your comments.

The larger intercooler won't drop boost levels, but depending on how much larger it is in volumetric capacity, you may notice slightly more lag.

The cores from the U.K. Seem to be of good quality, definitely better than fitting a second-hand turbo, which is often just as much money.

You won't get much noticeable performance increase though.

Thanks Shack if I increase boost after doing the intercooler (Allisport) do I need to bypass the modulator for the turbo and will increased boost stop the lag car is a manual Thanks.

Originally Posted by laney

Thanks Shack if I increase boost after doing the intercooler (Allisport) do I need to bypass the modulator for the turbo and will increased boost stop the lag car is a manual Thanks.

The modulator and wastegate actuator on a standard TD5 don't do/ can't do anything to reduce lag. Lag is a product of a small displacement engine and no VGT, although a VGT won't completely get rid of it either.

In fact they don't really do anything until boost is ~ 1 bar. After that they can be used to sustain boost levels when normally the wastegate would start opening.

There's no point in bypassing them, in fact it will reduce performance as the wastegate will start dumping exhaust gas.