UK952

I think if you mount the Tial in the correct orientation it will still be pushed open by exhaust pressure rather than held closed. Being dual port with a suitable controller you can give it a signal to remain closed against the exhaust pressure, and I believe it has a bigger diaphragm relative to valve size which will also help. In single port mode it can still be forced open.

Tony

dmoffitt

i have been extremely happy / satisfifed / impressed with my lindsey dual-port, the fitment was stock-simple.

that said, i think if i had to do it over again - i would get the TIAL - but IF and ONLY IF you have a boost gauge not the stock one, and either some GOOD overboost protection in your software, a boost-level warning light (like the Greddy Warning Meter - what i got - a boost gauge with a user-defined value to light a big bright red LED if you hit/exceed a ceratain boost threshold). The TIAL scares me a bit in the sense that it will NOT open, period, unless your boost controller gets it a signal, that's great to hold the best, but, well, as i said if you don't have adequate warning of a malfunction such as loosing a vac. line, well, it could get pricey to burn holes in valves/pistons

although only having held a TIAL for a few mins at one point, well, i could be wrong - tony might be right, it probably has a lot to do with mounting, and i do think i remember someone saying you could swap / adjust / preload springs?

UK952

With the Tial the input is underneath and the valve lifts off its seat allowing the exhaust to exit through the side port.
With the standard wastegate the input is on the side and the valve opens downwards to let the gas out that way.
I think there were some Tials installed backwards (same orientation as standard) resulting in massive overboost.
Tony

tconn

So let me get this correct.
The tial is a dual port wastegate?
If you loose vacum to it there is a good chance of detonating the engine because the
valve won't open under pressure?
I thought the reason for the spring was to hold the valve shut until the limit of the spring was met??

Dark Lightning

TiAL = dual port, one pushing the gate open and one pushing it closed (for use with an EBC.)

The spring is in place to provide a base pressure the valve opens at. If there is NO vacuum line helping push on the spring at wide open throttle, the wastegate will open when the EXHAUST pressure overcomes the spring's pressure on the valve. This may or may not be what you want; it all depends on the exhaust design, turbo setup, spring pressure, yada yada.

Bear in mind that a 1 bar spring will not necessarily give you 1 bar boost pressure; typically, you see a little less boost than your wastegate spring pressure. For instance: I ran a 21.75 psi (1.5 bar) spring in a 38mm TiAL and with no boost controller at all the boost gauge registered a maximum of 18 psi (1.2 bar) at wide open throttle. This is due to the exhaust pressure working together with the vacuum line to overcome the spring & open the valve.

UK952

Its a boost signal that opens the wastegate not vacuum, the wastegate valve in both designs will open under pressure (but maybe not soon enough dependant on the spring) provided your tial is fitted the right way round.

If your running in dual port mode and you boost controller failed it may fail holding the wastegate closed this is unlikely but if it did you would overboost which could be fatal for your engine if you missed it.

Tony

dmoffitt

thx for the clarification.

Jake951

I have a 38mm Tial with a 1.1 bar (16 psi) spring and I see similar behavior. With the WG installed in the car in single-port mode and the control line connected directly from the banjo bolt to the WG side port (no boost controller inline), the car boosts to a maximum of 14 psi. In other words, I see a 2 psi differential between the rated spring rate (16 psi) and the unregulated boost pressure (14 psi). If I disconnect the control line completely, then it will absolutely overboost like crazy. It is NOT a fail-safe condition.

I also bench-tested the Tial with a controlled pressure source. I found it takes 17 psi of pressure (just 1 psi more than the 16 psi spring rating) applied to the side port to first crack the WG open.

Keep in mind there is a pressure drop between the banjo bolt (where the control 'signal' comes from) and the intake manifold where the boost pressure is actually measured. I think this accounts for the car boosting to 14 psi maximum with banjo bolt pressure applied directly to the WG. There is probably 17 psi or more at the banjo bolt at that point.