Holset hx35 KA-T overboosting???

[zenki850]

alrighty, i have a holset hx35 on my ka24de-t with a tial 38mm external wastegate. im using a small green spring wich should be 7.5psi. i have my vacuum hose coming from the turbo housing to the bottom of the W/G and the top port is empty im just trying to fun W/G pressure for now to get it tuned on low boost. BUT everytime we do a pull it makes 16psi of boost.......... any ideas would be awesome if anyone has had this problem with their holset or any other turbo. Thanks zilvians

[GroundPerformance]

Do you have a TS type turbo manifold? Post some pics of your setup..

[zenki850]

no im using the jgs cast log manifold the flange on the manifold is just one big hole not divided

http://i248.photobucket.com/albums/gg194/b16sauce/motorbuild006-1.jpghttp://i248.photobucket.com/albums/gg194/b16sauce/motorbuild004-1.jpg

[repda916]

isnt that turbo twin scroll? i thought you have to use a twin scroll manifold

[zenki850]

Yes the turbo is twinscroll. ive seen log manifold used before but im not 100% sure if you HAVE to have a T/S manifold. if anyone can shed some light on this that would be awesome. Thanks

[[email protected]]

maybe youre using a 1 bar spring. (14.7psi)

[zenki850]

i have a small green spring in the WG now and on tial's website it says that that one is 7.5psi

[jholman]

Once on an RB25 with a wastegate mounted real similar to that the boost was somehow bypassing the wastegate....like it need to be angled more or it just wasn't big enough

But that was a 62/62 on a RB25....just saying

[a7olyte]

Sounds like you have a failing diaphragm. Either the diaphragm is leaking or it's not seated correctly. Since your wastegate pressure port is easily accessible, you can test it. Get a air compressor regulated at 7-9 psi and pump it into the wastegate pressure port and see if the wastegate opens.