10 replies to this topic

[taylor98v70xcharris]

I just got the new ipd heavy duty compression bypass valve but realized I'm still running stock boost pressure. Do I need to increase boost pressure before I install either 1 of the 2 springs and diaphragm?

[Martijn_B]

No you do not need to increase, read the manual as it advises the correct colored spring with your pressure :-)

[taylor98v70xcharris]

Ive got the xc modle with the low pressure turbo, at full throttle im only getting 5psi. Is that really how "low pressure" the turbo is?

[RZT5]

the upgraded compressor bypass valve spring will only make a difference if you're running close to 15 psi. otherwise it is not needed and will make no difference at all.

I think the LPT motor in the XC is supposed to run about 5 or 6 psi.

[850wagonT5]

taylor98v70xcharris, on 05 January 2012 - 02:25 AM, said:

Ive got the xc modle with the low pressure turbo, at full throttle im only getting 5psi. Is that really how "low pressure" the turbo is?

That's proper boost for your car. You don't need the HD CBV. And FWIW, I melted a hole in the IPD HD CBV with a 17psi tune on the 15G. =X

[Big Will]

The XC should boost about 8 PSI stock.

[RobTarD]

Unless you're noticing a problem with your stock CBV, the IPD valve isn't worth the trouble. I'm running 1 bar on a stock 15G and haven't had any issues whatsoever.

[Hippicus Rebuildacus]

Not to knock their product but unless your is straight tore up... I wouldn't replace it. I have seen more threads & images on here about blown apart "HD CBV" than stock ones taking a shit. Even in the event mine blows apart after 165k original miles... I will be replacing with a stock unit. The stock unit is rubber where as the IPD one seems to be reinforced fabric-esk material (only judging from images) and new supple rubber seems more flexable than a fabric type material. In theory something fiber reinforced IS stronger but not when it sees a ton of movement because eventually sooner than later the fibers get hard & crack then turn into little pins that eventually perforate the CBV causing it to tear or tare... idk i cant fucking spell

[RZT5]

Ash Filler, on 08 January 2012 - 06:21 PM, said:

Not to knock their product but unless your is straight tore up... I wouldn't replace it. I have seen more threads & images on here about blown apart "HD CBV" than stock ones taking a shit. Even in the event mine blows apart after 165k original miles... I will be replacing with a stock unit. The stock unit is rubber where as the IPD one seems to be reinforced fabric-esk material (only judging from images) and new supple rubber seems more flexable than a fabric type material. In theory something fiber reinforced IS stronger but not when it sees a ton of movement because eventually sooner than later the fibers get hard & crack then turn into little pins that eventually perforate the CBV causing it to tear or tare... idk i cant fucking spell

I agree with this. However, I would use the stock one in conjunction with one of the IPD springs if you are running higher than stock boost.

Just in case someone doesn't know, the reason the stock springs cannot hold higher boost is that there is a substantial pressure drop across the intercooler. Enough that the manifold pressure is not high enough to counteract the pressure at the compressor outlet. This causes the CBV to open when it shouldn't and is why you need a stronger spring to keep the CBV closed at higher boost levels where the intercooler is less efficient flow wise and has a higher pressure drop.

Edited by RZT5, 09 January 2012 - 10:25 AM.