seattle951

I am replacing my aftermarket dual port wastegate with a 38mm Tial unit. Tial makes a number of units ranging in size from 38mm to 46mm.

I was looking over another post on another board that claimed a smaller wastegate would spool faster. Looking at the Tial schematics, I can't see why.

However, I would guess that a larger unit would create less backpressure after the desired boost level is reached. Therefore, there should be no downside to going large (except for higher cost).

Did I miss something?

Spool rate is more important to me than peek HP. The car currently makes 320 RWHP at 16 PSI boost. My guess is that at 320 HP, the larger unit is not needed and the 38mm will be just fine. Maybe at 600 HP things would be different and there would be a benefit to the larger unit. Comments?

spoolin51

I went with 44mm to get the best of both worlds.

gt37vgt

ok some wastgates with large valves and not massive cans on the back lack the proper mechanical advantage to hold back exhaust back pressure this has caused the misconception that a big wasegate valve will be laggy . so if you changed only the lower valve part of the wast gate you could have trouble .
I would go for a minimum for 44 isn't the factory one 46?? in wich case you realy want 50 or more

Tom M'Guinn

I have the 46mm Tial on my 3L, working great with a Profec B controller. With an electronic controller, I reasoned the larger vavle would allow allow for crisper control with less spiking, etc. I presviously used a smaller Deltagate, and I must say that worked fine too with the same controller. The 46mm is a slightly tighter fit under the car, but it does fit fine when installed carefully.

seattle951

Before purchasing the 38mm, I talked to a couple of vendors. They all steered me away from the 46mm saying that there was no value add for a street car. In their opinion, the 38mm Tial would exceed my needs.

After doing more research on this and other boards, I ended up with more questions and started this discussion.

Any other opinions?

Rogue_Ant

It depends on how restrictive your turbine side is. The tighter the turbine, the larger the wastegate is needed.


-Rogue

jasonlp

40mm synapse?

VOoDOoGTX

where should i buy one from?

jasonlp

Dsitributer
Halfway down the page
http://www.speedforceracing.com/prod...wastegates.php


or

Manufacturer
http://www.synapseengineering.com/


Same difference though

Spidey944

I think pauertuning has them all.

seattle951

Doesn't the "38mm" refer to valve that vents the exhaust away from the turbo?

If so,

What is the relationship to tubine size and performance?

Shouldn't there be no impact on turbo spool at all?

Wouldn't the value of larger unit be to protect against over boost?

Wouldn't the value of larger unit be to reduce exhaust back pressure after the turbo was at max boost?

pete95zhn

If the turbine and compressor are matched to the engine and intented boost pressure to be used, you could basically run without a WG...

No, if the WG keeps closed during the boost build-up.

Yes.

Yes.

George D

That's what I'm using. It works very well and has no diaphram. Piston driven, and works flawlessly. Go to http://www.synapseengineering.com/.

George

jasonlp

+1

95ONE

38 should be fine. 44 has a valve that can handle leaded. 38 can be upgraded to handle it also.