40mm or 45mm Wastegate opinion.
 

I currently am getting ready to install my t04e turbo on my 90 TII. I am not sure which wastegate will be needed I know bigger is always better but would a 40mm wastegate be enough. Here is what I have for mods and what I am planning on.

SR Full divided cast manifold (Ordered)
720cc Primaries
1600cc Secondaries
Fuel Rail
Tial Wastegate 40mm or 45mm
Tial BOV (Ordered)
Walbro Fuel Pump
NPR FMIC
T04E Turbo (Stats written down somewhere with the turbo)
Haltech (Ordering Next week)
Radiator (Next week)

I just dont really want to spend the extra few hundred on the larger wastegate if its not needed with my setup. Any suggestions are greatly appreciated.

first thing is to figure out which ones will bolt to the manifold... they both might not. but I don't know. bigger is aways better though.

and you have Soooooooo much fuel!!! dam. that's good for like 800hp LOL.

Until I get a replacement engine i'll be running at like 60% fuel capacity of the injectors but oh well.....at least I wont have a problem keeping it a bit rich to save my setup. I only want around 400hp when I am done....even after I get a full engine from pineapple.

-Morbius

40mm is really too small.&nbsp I would recommend the 45mm at least (I recommend 46mm Tials for 400+hp turbos).



-Ted

Ted as always a great help. I changed the order to a 46mm on your suggestion today. Next question is what kind of spring rate will I be looking for. It comes with a 0.8 Bar spring but there are all kinds of other spring rates available. Any suggestions in that department?

Thanks
-Morbius

I'd go with a .7 bar spring.

Why the .7 spring? Anyone have a good diagram explaining the entire turbo system works together. If you produce extra boost because the wastegate isn't opening soon enough wouldnt you just be pushing the extra boost out the BOV? I am new to this full turbo upgrade and expect to blow up at least one engine (hopefully not more).

-Morbius

Doesn't the BOV only work on decel or a shift? The wastegate would only open on acceleration when boost pressure overcomes the spring tension right?

Well if the BOV only works on decelleration then I guess I will have to play around with the springs. I would like to get 14psi max out of my turbo for right now. Be my guess alot of exhaust will be going through the wastegate but oh well. What is the best way to vent the wastegate since putting it back into the exhaust loses HP?

-Morbius

Wastegate spring rate is about how much MINIMUM boost you're trying to run?&nbsp Typically, it's 7psi (0.5bar) or 10psi (0.7bar)...



-Ted

Anything below .8 bar is a good choice, if you have a boost controller, that way if the boost controller fails you can revert back to low boost, you can always raise boost from a low point with a boost controller, but you can't drop it from a high point..
In reguards to the wastegate sizes, it depends on what manafacture you chose, the Tial wastegates outflow larger wastegates from other manafacturers, the deltagate and what are not comparable to any tial gate, or really even the Hks or sard gates. A 40mm should be tons big, with the right manifold and proper wastegate exhaust piping, having a really huge wastegate is a bandaid for poor manifold piping and design..Max

Ok I got it now...I ordered the 45mm Tial Wastegate but the springs are special order so I will order a 0.7 bar spring. The wastegate ended up being $450 and I dunno how much yet for the spring. Oh well getting that much closer.... Thanks for all the help guys. I will eventually learn enough from this forum to finish my project. I really do wish there was a good rotary shop within an hours drive from my place here in WV.

Thanks
-Morbius