OK, long story short im asking for a friend of mine. His cars making 400rw kw, it currently has a Greddy 45mm wastegate but has a problem holding boost. Its spiking 20, coming back down to 17 and then going back up (The last bit indicates poor flow) and still makes 400kw Its not a normal problem- the diaphram and spring is out of a turbosmart gate as the greddy stuff was too expensive to buy ($600 for spring and diaphram) So, the tuner has a 44mm tial in stock and ready to go, but he doesnt do many RB30 bottom end tunes and we are not sure if its going to be big enough. Since its a cut and weld job, I really want to know if a 44mm tial is big enough for you guys (who actually run 400 rwkw, 530 hp ATW)

as far as i know, the more boost u plan on running the smaller the wastegate u need, think about it, if ur running more boost, u want less gasses to leave the manifold, hence not needing a huge gate to vent them!, maybe just stick with a 38 mm gate!

Quote: Originally Posted by SII_Turbo as far as i know, the more boost u plan on running the smaller the wastegate u need, think about it, if ur running more boost, u want less gasses to leave the manifold, hence not needing a huge gate to vent them!, maybe just stick with a 38 mm gate! yeh that is true but look at all the cars running around that sort of power figure there gates are bigger then a 38mm gate.

i'd go with a 80mm gate mate

44mm tials are pretty small,from memory they measure about 40mm across the inlet. the turbosmart 48 is a much safer bet,but the turbosmart 50mm will be perfect with its huge valve lift. the tial 60mm has massive diameter but bugger all valve lift. having said all that i would be more inclined to point the finger at a poorly setup wastegate pipe than undersized wastegate.

go 48mm turbosmart

a 45mm gate working properly is fine mate..most of the big hp vl turbos run 40-50mm gates, and 400rwkw isnt as bigger power as it once was.

What size exhaust housing? Quote: Originally Posted by SII_Turbo as far as i know, the more boost u plan on running the smaller the wastegate u need, think about it, if ur running more boost, u want less gasses to leave the manifold, hence not needing a huge gate to vent them!, maybe just stick with a 38 mm gate! But once you run more boost, you need to let more exhaust gas to escape to control it.

I use 2x38mm Tial gates on the 1FZ (6cyl 4500cc GT42). Boost line is perfectly flat. (538rwkw) You could buy two from the USA and you'll get them for under $600 total. Just an idea anyway. Sean

48mm turbosmart progate, i never had issues when making 400 - 450rwkw with that gate,

Id say a 38mm turbosmart wastegate should be excellent for it. But then again you got people using 48mm so pretty much your choice dude.

Unless you have a pretty poor exhaust manifold design or a restrictive exhaust, don't even think about running a 38mm gate. I can't believe people would even suggest it, you talking about a 20+g driveline and you want to save $200 by using a smaller gate?? The answer as to which gate you should use is absolutely the biggest one you can afford or are happy to pay for. Personally, back to back on the same overboosting engine, a Tial 44mm gate, a turbosmart 48mm gate, and a turbosmart 50mm gate all held the exact same boost and crepped to the exact same boost. While I appreciate that a bigger valve with more lift should flow more air and keep boost lower, I simply haven't seen any evidence that any of the 3 are better than the other. Out of interest, its wasn't the wastegate outelt, as with the gate removed altogether, it held 3-4 psi, not 30. For bang/buck, you can't go past the Tial 44mm, there are many reputable sellers now selling them at a good price, they come in 4-5 colours, and I have at least 50 customers making 400rwkw or more with them. 6BOOST

yep tial 44mm would have to be the best bang for ya buck on the market and look sooooo pretty

Totally dependant on the setup, boost being run etc. See below link, good info for you. http://www.skylinesaustralia.com/for...pic=43638&st=0 (http://www.skylinesaustralia.com/forums/index.php?showtopic=43638&st=0) cheers