Can anyone give some thoughts on if this is a worth while mod. I'm thinking of welding the internal wastegate shut on my rebuilt T3 and welding on an external one with a screamer. This should flow heaps better but i'd like to hear from people who've already done this and see some pics if they have any. cheers

hrmm tough one, apprently the stock manifold is good for big power when like power ported or what ever it is, seen afew with wastegates in em with no probs, but welding the t3 gate shut and using an external i wouldnt have a clue about that one

yep i have a standard manifold with an external gate on it mani has also been powerported last car it was on made 250rwkw with a t04b at 18psi i doubt that was the limit of the manifold i thought the standard mani was good for 10's or so with the right mods and about welding your internal gate shut. i dont know either i can get a pic of it this arvo if you like

i have a power ported stock manifold, with a 42mm external wastegate with screamer pipe, made around 270rwkw on 20 pound, never had any prooblems,

From my interpretation its better to get it on as much an angle as possible... Manifold was ported aswell-the outside was weld filled then inside ground out.

im in the process of pissing off the internal gate on the standard t3 atm. but im not using the standard manifold... i have the gate and manifold ready to go on. the reason behind putting the external gate on the standard turbo is because the standard internal gate cant hold boost very well at all. you always hear that it boosts to 12psi and through the rev range it dies off to about 9psi. the external gate stops this, it will hold 12psi the whole way. another way to stop it is to use a t4 actuator... but the screamer sounds better and will already be on there for if you choose to upgrade the turbo later on. Some original photos have not been recovered yet.

I made up a plate and blanked off the stock wastegate hole and just cut one for the compressor wheel. Made up a full 3" custom dump pipe in a jig so it was identical to the stock cast one. I'm using a Tial 38mm gate on the stock manifold. I can try and take some close up pics tomorrow night.

Yeh pics would be great. I'm not that worried on the level of power the manifold will get me as I'm only ever going to have standard engine management. I more or less want to see pics of ones and there placement on the maifold etc and feedback from guys who have done this. That turbosmart one looks sweet. I can understand why you'd want it on an angle like that, so the gas flow isn't as interupted to flow through the wastegate as apposed to the flow to the turbo. Next question I suppose is will a 38mm wastegate do the trick if I'm only chasing 200 - 220 kw.

just get one of the ones off ebay tim like the one I got there are more benifits to having an external gate on your manifold as apposed to standard flap. You will gain top end power through being able to hold a more steady boost pressure but you will also be able to make more power by having less back pressure high in the range. This effectively allowing the engine to breath better on the exhaust side this should allow you to push the turbo right you to its maximum efficency and you will be able to make it run to the point were the turbo isn't able to feed the engine with enough air to make any more power. I reckon that you would make some decent gains from doing an external gate up grade tim you can pick up lots of cheap ones on the net if you were interested don't worry about welding up the flap hole just wire the flap shut.

Big power doesn't equal big wastegstes. Read this: http://www.skylinesaustralia.com/for...howtopic=43638 (http://www.skylinesaustralia.com/forums/index.php?showtopic=43638) Some original photos have not been recovered yet.

So the size of the wastegate needed depends on the efficiency range the turbo will be running in. So a standard T3 on a standard manifold running 14 psi is very close to flat out so a 38mm will flow enough. But if I had a GT42 running 14 psi I would need a much larger diameter wastegate to get rid of the excess flow. Run 30 psi with the same turbo and I would be looking at using a smaller diameter wastgate as more flow would be going through the turbo to create more boost, hence less required through the wastegate. Interesting....................................... ....

With more boost you can get away with a smaller gate as more of the exhaust gas is going through the turbo. A 45mm would be big enough for a GT42. Anyway here aa couple of pics of my Tial 38mm mounted on a stock manifold. Some original photos have not been recovered yet.

Looks good man. What set up do you have. Standard T3 etc?? and what boost are you running? Boost tap or electronic boost controller. Do you have a whole engine bay pic. cheers

Big highflowed T3/T4 running 15psi. Standard internal gate was way too small for it. Put the external gate on and havent looked back. Running an E-Boost which works really well.

Sweet. Any 1/4 times??

PSI086 , what mods / power do you have ?? your set up sounds similar to mine...

242rwkw - 12.12@115.5mph in a manual on 15psi

very very similar to mine, altho im a 3 speed... what would 240rwkw go in a 3 speed / lsd / semi slicks?

His being manual yours being auto, you wouldnt make 240rwkw with the same mods...As an example, mine made 243rwkw manual, did Auto conversion and made 205rwkw....ran a 12.07@115.07mph. Gives you an idea as to how much dyno figures will vary.... Internally gated Hiflo aswell.

Have to be close to that or better with a high stally etc, as long as you have the same diff gears.