Hi there, I got a few question bout WG. Recently I've juz replace my turbine housing/center housing/backside if I m not mistaken, from VR4 to Evo3 housing but I m still using the same VR4 compressor/front housing n fin. Bcuz my old VR4 housing got a big and long crack @ the actuator flap which causing a leak.
Rite now, the Evo3 actuator gate and flap have been welded together by the old owner which mean I got no choice but to use a ext WG. I m totally noob in WG stuffs, but I do know how it works... @ certain pressure it will open up and release the excess pressure to prevent overboost. But I m kinda confuse wit the size, I dunno wat size to get for my emgine setup. I've read bout the "Turbo size+Boost pressure=WG size" la... But I m not too sure bout it. Since my last setup wuz a disaster, so I m planning to stick wit 1bar of boost only. My question is:
1~Wat size suitable for my setup???
2~Is a Wastegate adjustable or is there such thing?
3~Any specific place to mount my WG since I m still on oem VR4 cast iron manifold
My engine setup is:
1.6T
TD05H VR4
Exhaust (juz incase) 2" piping, straight bullet 2", Straight Flow muffler 2.5" in and 5" out.
Evrything else is stock as how it is...
Thanks
Well, it works the same way like ur internal wastegate. At low boost, the wastegate releases more exhaust gasses, at high boost, the exhaust gas is used to turn the turbine remaining less exhaust to exit through the wastegate.
However, due to the price difference of 38mm and 44/45mm wastegate, most of the ppl will get a 38mm. They'll work fine.
The best place to mount ur wastegate is where the stock internal flap is. Get the flap removed buy a customize flange with 2 holes. 1 hole foe turbine exducer and 1 hole for wastegate. Extend the hole for wastegat. With a 1 1/2" schedule 10 pipe and mount ur wastegate there. Remember to port the hole on the turbine housing to 38mm to suit ur wastegate. If u doesn't like the noise of the wastegate, u may vent to wastegate outlet back into the downpipe.
An alternative location would be removing the flap on ur manifold outlet and mount the wastegate at the centre of the hole with the wastegate inlet pipe on top of the manifold. Please make sure the fabricator knock off all the welding flux and left overs COMPLETELY. If not handle propey, it may comes out later and damage ur turbine fin later.
I have mine mounted between runner 1 n 2. But I bored a 38mm hole, shape the manifod flat at the place where I mount my wastegate, then weld the wastegate flange on the flat surface. My welding is only at the top of the manifold.
Hope it helps.