wastegates

[renxun]

currently using an original trust 50mm. whats the difference over much more expensive like turbosmart racegate and those cheaper china knock offs. lets not put durability into consideration. i would like to know about the performance.

after all a wastegate is just to expell exhaust when set boost is achieved (my opinion) how does a better gate perform? and i do understand about the general idea on how a wastegate works. does differant gate affect the nearer it is to open on the set boost? so that full boost can be built faster?

[Draven]

cheap knockoffs use cheap parts, which means higher risk of failure - example, wastegate spring fails, gate stuck open, then engine/turbo fails

[BigWorm]

Valve travel is another thing claimed to be far superior in expensive wastegates- A cheap 50mm gate with only a couple mm of travel won't flow as good as a awesomo brand 50mm gate with heaps of valve travel.

But it's durability that seems to be the biggest concern. I've heard that there's a few cheap ones out there that have the same diaphragm pattern as the pricey ones, so you can replace the crappy diaphragm for a good quarity one & end up with a half decent gate for cheap.

[Stefan]

From what I have heard and read, a wastegate isn't somethign you want to skimp on. Cheap ebay knockoffs = spikes.


Slightly off topic but relevant:

Is there any/harm benefit to running an internal wastegate AND internal wastegate? Seems to me the potential for spiking is much decreased...

[renxun]

im not sure ... im more concern about boost building.... whether a gate will hold it shut long enough to open nearest to my set point. or it could also be opening a little bit when its near the set level and fully open when it reach set boost thus making full boost building much slower.

or only electronic boost control are capable to determine that?

[big_zop]

cheap knockoffs use cheap parts, which means higher risk of failure - example, wastegate spring fails, gate stuck open, then engine/turbo fails

If the gate is stuck open wouldnt there be next to no boost as opposed to if it was stuck shut - then there will be problems as you suggest?

Is there any/harm benefit to running an internal wastegate AND internal wastegate? Seems to me the potential for spiking is much decreased...

Hope you mean internal and external as ive never seen a turbo with two internal gates! It wont be too hard to do but the most common way i have seen it done is to actually weld the internal gate shut and rely on a properly sized external gate. With two (and at different points in the exhaust stream) there may be the chance that the two will be fighting each other, reducing response.

im not sure ... im more concern about boost building.... whether a gate will hold it shut long enough to open nearest to my set point. or it could also be opening a little bit when its near the set level and fully open when it reach set boost thus making full boost building much slower.

or only electronic boost control are capable to determine that?

The basic principal of a wastegate is to open when a exhaust gases generate enough force to move the valve that is held shut by a spring. This also uses a reference signal from a positive pressure point to give a certain 'boost' level. Engineering formulas for springs would dictate that no matter who makes it, as long as they are made the same that you will get the same performance - yes this is assuming alot but i have yet to see a manufacturer claim their weastegate design is better that another because of this reason.

Differences in performance (relating to response, spiking, control) would all seem to be based upon the controller, whether that be what the stock spring generates, or some form of artificial increase (mechanical or electronic). I hve yet to see back to back testing for this apart from a generic mechanical vs electronic boost controller - in which the electronic was shown to be superior in every sense (and obviously jounralistically enhanced as they only used dyno plots of the boost curve for their judgements). If i find it ill post it up for you.