The V8 Owners Forum -

CastleMGBV8 wrote:Stevie,

All you are doing by inserting a short piece of brake pipe into the boost hose is reducing the internal bore and therefore the wastegate will read a lower pressure. It may sound crude but it is very effective, and I know several people who have done it and it costs nothing.

Kevin.

I am with Stevie here the way your describing it will not increase boost, all you could possibly be doing is causing a lag at the wastegate and that's extremely doubtful.. Its simple physics, there is no flow so you cant restrict anything just as Stevie said.. The only way what your describing could possibly work is if you made a T on the boost pipe and used the restrictor on the vent part I.E a fixed bleed valve.

Marki,

I am nowhere near qualified to challenge the law of physics all I can say is, it's been done and does work, in one instance we did it on a Renault 5 Turbo and the increased boost blew the top off of the cheap plastic topped intercooler! The car was incredibly fast.

Kevin.

CastleMGBV8 wrote:Stevie,

All you are doing by inserting a short piece of brake pipe into the boost hose is reducing the internal bore and therefore the wastegate will read a lower pressure. It may sound crude but it is very effective, and I know several people who have done it and it costs nothing.

Kevin.

Again, in a dead ended system such as this, inserting a restriction will make no difference whatsoever.

The only thing that can make a difference, is an air leak.


It doesnt matter if you blow thru a garden hose, or a straw into a dead end. Its still a sealed system, so pressure remains the same. One will just fill faster than the other. So at best, you may introduce a boost spike if the restriction was very big, but that is an even worse approach that a dinosaur bleed valve ( which in all fairness, can work very well in some setups )

Until you start bleeding off air, you have no chance of proper boost control or raising.

I have this which is a simple pressure regulator, you put it between your manifold pressure and the feed to your wastegate and then just dial your boost.


Never needed to use it personally, as just winding my wastegate rods has been fine so far.

Yeah that's the sort of thing Eliot, would you mind telling me where you got that from? (Only reason I ask, they seem to be wanting upwards of 20-30 quid for a similar thing on ebay!)

cheers

CastleMGBV8 wrote:Stevie,

All you are doing by inserting a short piece of brake pipe into the boost hose is reducing the internal bore and therefore the wastegate will read a lower pressure. It may sound crude but it is very effective, and I know several people who have done it and it costs nothing.

Kevin.

i own and run a nissan 300zx twin turbo..the standed boost is 9 psi...ime now running 16-17 psi by inserting 2 mig welding tips (1mm inside diameter) inside the wastegate actuator lines which slows down the boost signal to the actuators btw ime a long standing owner,and committee member of a zx club before ya all start screaming "you dont know what your talking about"

All a restriction can do, is cause a spike.

I assume the factory boost control system is still in place on the Nissan ?? ie, a solenoid to bleed air off.