Hi guys,

There seem to be a few qualified and apprentice boiler makers and such floating around in here so i figure someone would know someone who can cut a hole into my stock manifold and weld on a bit of steam pipe properly so it won't crack up once it see's the track.

I have ongoing boost control issues with the internal gate 3071 and just can't be stuffed (and cant really afford) to redo all the piping again as well as shell out for a decent steam pipe manifold and gate.

cheers

Dave

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relitively easy.. biggest problem will be if you dont preheat and cool down the manifold properly before and after welding

would be better off making an adaptor between manifold and turbo that can have a pipe coming off it to utilise an ext gate.

nah your not then comes issues with lines dump pipes rubbing and cooler pipe not fitting..

makin your manifold external is very easy i have done dozens including the one on my 25. never ever crack even when glowing red the steampipe doesnt even change colour (still black)

if your not a very good welder i dnt reccomend tryin it yourself though hees one of the ones i made

If you don't mind butchering your turbo exhaust housing, although I assume you'll weld up the internal wastegate anyway, you can have the ext wastegate pipe come off the housing just behind the flange. You can improve things if you have it exiting in the same general direction so the exhaust gas doesn't have to change direction too much giving better flow. Whatever you do make sure you have the wastegate bleeding exhaust gas after all the collectors have merged or your boost control will crap. Welding cast iron isn't a drama, but yeh you should take care with prep not to crack it.

no you can have the gate on one cylinder if you like doesnt matter as all its doin is gettign rid of extra pressure.. the pressure is the same everywere so it doesnt matter at all.. i have done it many different ways all workin extremly well. boost control all depends on the qaulity of your wastegate..

and as for butchering up your exhaust housing as you out it.. all you need to do is tack the flap so it doesnt more, can always grind it of later if you wish.

to be honest you could put the gate in the total oppesite direction to flow and i will garentee it will still flow much better than any aftermarket manifold other than 6 boost ect.

Yeah once the pressure is all up she'll flow but don't we want the most efficient flow to get the best result? If you get the opportunity to increase the efficiency why not take it? And i have to disagree about attaching your wastegate out to just one runner, to me it's obviously half arsed (imagine the horribly uneven back pressure to each cylinder on exhaust stroke too) and i do know of quite a few guys i've seen do it and have a really average result with major boost control issues. Would you put a sudden 180 degree turn around in your exhaust? No? because it introduces back pressure and bad flow, why should the manifold be any different? I don't see the point of cutting corners just to have to do it all again to get a decent result. go look at a few rally, indy, and turbo'd formula 1 cars, they know what they're doin.

dude im not sayin at all thats its a good idea to run a gate of one cylinder by any means.. all im sayin is that of you had to do it, it doesnt make much difference..

f1 are you serious how can you compare any sort of mod to a stock manifold to the likes of what formula 1 are doin.. they have copious amounts of money and wouldnt even think about stock items..

all i was tryin to say is that china = fail.. a good properly welded stock mani will do a better job and flow much better thasn most aftermarket..yes we would make evrythin flow as much as you can but iven if you dnt its not like it costs the world.

A mate did this to his rb30 manifold, only used a 32mm external gate and it worked perfectly, not more over boost or boost creep, came onto boost harder since the gate was not opening before he reached full boost like internal gates do and from the stories i have heard from the china manifolds i would go this option before using a manifold made of tin, unless of course your aiming for 300+rwkw but your not going to be using a china manifold then either.

heres the one i made for my 25.. come onto boost straight away and hold a perfect flat 1bar!!!!

gate has to be after all the collectors have merged. at least at the back of the manifold. a billet spacer with a 90* attachment for w/g b/n manifold and turbo will do. If you have casting capabilities tried to reduce the 90* bend into a smaller angle/smoother transition

ill put monay on it that if i had this flow tested it would flow better than any china item on the market... and is a milliontimes cheaper and stronger..

And it doesnt look half bad either! Nice job

How much would this cost to get done? Interested.

not to bad pending your in perth lol.. its alot harder to do it with out the car as you dnt know clearances ect, however i could do the gate same as mine and you can get screamer made local, aslong as i can get ahold of your gate flange ect wont be a problem and it will be much cheaper than any china manifold!!!

also just incase your worried about it holding power back heres a graph and pic of my car now that its done. 362rwhp

NIce job, however there is no way it will flow better and be heaps cheaper than the china manifolds, you can get high mount china manifolds for under $200 from ebay, and plenty have made far more than 300rwkw with them which is the well known brick wall for the factory manifold.(on pump fuel)