External (Diaphragm) Wastegates

[Chainfire]

Hey all,

I recently purchased a 'turbosmart' wastegate from a fellow forum member (whom for now, I will not name). Prior to purchasing the gate, the guy swore to me that it was a genuine product. I did some background research on him, and also had him send me a few pictures. All seemed okay, and the price was low enough for me to accept the risk.

Well, it didn't pay off in the end, and now i'm stuck with what i'm pretty sure is a fake turbosmart wastegate, and feeling like an idiot for thinking I could get such a bargain (cost me $200 in the end).

Anyway, after pulling this thing apart and inspecting every peice I found that for a fake, it isn't built that bad... definitely has some flaws, but overall, it's not terrible.

The problem/question I have is, is it normal for these type of wastegates to leak? (even if the smallest amount). After pressure testing the one I have (Compressed air to top and bottom chambers, whilst gate is sitting in a tub of water) - I found that when pressure is applied to the bottom chamber, air would escape through the valve shaft (bubbles coming out from the exhaust bypass chamber) and the smallest amount would come out of the top chambers port (obviously getting past the diaphragm a little bit).

When pressure was applied to the top port/chamber of the gate, a small amount of bubbles would come out of the bottom chambers port, and also a very small amount from the valve shaft again.

So in summary, I found that the following 2 things are true;

- Diaphragm does not provide a perfect seal between top and bottom chambers.

- Valve shaft does not seal properly, and allows pressure to escape from bottom chamber.

*Note: - No visible cracks/holes were found in the diaphragm.

- It is a 50mm V-flange 'Furbosmart Pro Gate'

Is this at all normal, or acceptable for an External Diaphragm wastegate? Can anyone see it causing big issues? The valve opens pretty quickly when pressure is applied to the bottom chamber (and I only tested using very low pressure) It seems to function okay, although It hasn't been tested on a car yet. I'm just wondering if these minor leaks are going to cause me major headaches, or if it is relatively normal. Might also be worth mentioning, I'm running a MAP & IAT Sensor setup, and will be using a HKS EVC 2 Boost controller.

The obvious recommendation from most people I can already forsee, is going to be that I should just go and buy a genuine product, and solve all my problems that way. That is fair enough, and I agree... But at the moment, I just don't have the spare $700 - $800 to fork out for a wastegate, so am trying to determine if this one might be okay (even if only for temporary use).

Any advice/input is appreciated. Cheers.

[TiTAN]

you will find the bottom chamber will leak around the valve stem on virtually all external wastegates, once its heated up/been used a bit (carbon buildup) the shaft would become tight and restrict/stop movement of the valve.

[hypergear]

Yes its suppose to leak a alittle out from the buttom. As that cools the piston operating the valve. And it must have some clearance for heat expansion, or they will jam.

[Chainfire]

Thanks for the responses so far guys, very helpful! Has helped to confirm some suspicians my friend and I had already had.

Does anyone have any information regarding the diaphragm? Is it fairly normal to have a slight (very slight) leak between each side of the diaphragm, or is there meant to be a complete seal between both chambers in an external gate?