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it may or may not be similar to what i have, exceopt i doubt the AVO wont will cater for the full 60 mm wheel. I have a cropped 3071R with a GCG cast rear housing (OP6 copy) which meets up to rb25 dump and manifold. it is a 0.71 AR. i just dynoed it the other day with cams in it no and made 290 rwkw on 1.2 bar.

personally i think 0.63 is too small for a 25

Well thats the thing, my turbo IS the 60mm wheel (-5023 on the garret serial number) and this housing is apparently made for it.

I think the 0.63 housing on the 3071 will give a good mid-range: I'm aiming for about 260ish, and given that the 0.86 housing makes 270-280 without a problem, it should go alright. Guess we'l have to see when one of us gets these things going =)

Anyway i might take my chances with this AVO housing. It fits the turbo and is exactly the same ratio, so i can't see why it wont work just as well as the garret item in terms of flow. Can always interchange it down the track anyway. :D

I can , Garrett have designed the housing and turbine as a matching set and they even give you a turbine flow map for them . I wonder what sort of response AVO would give you if you asked for the map of the GT30 turbine and their housing , I think you can assume that it doesn't exist .

If the price difference is not significant I don't see any positives in using a "bitzer" turbine housing - aside from the Hitachi dump pipe flange which is nothing to write home about .

Also changing from a "Hitachi" type housing to a proper GT30 one means the turbo moves and that means alterations to all the plumbing , I think it makes more sense to base the conversion on a Garrett housing . That way you could make housing A/R alterations and know it will all fit back in .

In fact if you really want to future proof it have a look at the spacers used to fit a GT3582R IW in the bay , most wouldn't fit these to an RB25 but hey if you inherited a fortune and had an RB30 under it you know it all goes in .

I think you really only want to be doing this one off stuff once because the time and money involved in moving turbos around is not insignificant .

Edited by discopotato03

pics of my piping install for anyone who's interested. BOV flange/return yet to be added. I'll do that once i get it running and rego sorted out.

DSC00372.jpg

dump pipe merge

DSC00373.jpg

gcg flange with the IW outlet enlarged. still to be tidied once i get the pipes welded on properly

DSC00374.jpg

DSC00375.jpg

DSC00376.jpg

trial fit

DSC00377.jpg

lucky no air con anymore

Edited by BHDave

Hi all , if I was trying to develop a dump pipe for those Garrett GT30/35 IW turbine housings I'd take a leaf out of HKS's book .

If you look at how they did their Pro S IW gates vent pipe its not to difficult though probably time consuming . They basically cut a section of pipe in half and seam weld it on the outside of the turbine outlets tube . It would not be very difficult to "form" it into the shape of the back of the IW turbine housing .

I don't know who's making the flange plate for them in those pics but I would want it to be the same shape (outline) as the gates outlet area - not just another slightly smaller hole . From a manufacturing point of view merely hole sawing the two holes is simple enough - read cheap to do . Whats needed is a template taken from the housings outlet flange and possibly laser cut versions made .

Cheers A .

It was originally a 1 1/4 inch hole roughly centered over the wastegate flapper. I have enlarged it (roughly at this stage) to the outer edge of the turbine housing casting or the inner edge of the 2 inch pipe, which ever is closer. I will then die grind to smooth the inlet where the hole doesn't extend to the outer edges of the turbine housing.

The flange i have was all lazer/plasma cut. There is no way it has been drilled. I think it's more targeted to the omgsik split dump crowd to be honest. If i'd just stuck a 1.25 pipe on it i think boost creep would be inevitable as the wastegate flap does a good job of blocking the hole on initial opening. By enlarging it to the side i have hopefully overcome this problem.

if I was trying to develop a dump pipe for those Garrett GT30/35 IW turbine housings I'd take a leaf out of HKS's book .

If you look at how they did their Pro S IW gates vent pipe its not to difficult though probably time consuming . They basically cut a section of pipe in half and seam weld it on the outside of the turbine outlets tube . It would not be very difficult to "form" it into the shape of the back of the IW turbine housing .

Check the photos:

post-19642-1205058956_thumb.jpg

post-19642-1205058987_thumb.jpg

Having just made these items and (almost) ready to install, I can tell you that it is time consuming, and it is difficult. There is a lot of judgement, time, and fabrication skill that goes into making one of these items.

When you look at the Pro S design, there was little room for HKS to go other than with the dump pipe design they use.

I've looked at the Garrett casting, and agree with comments from Cubes in a thread somewhere that a bell mouth design would work well with it. The main aim should be to let the vent act as a vent, not as a restriction. Pipe size and placement would play a big part in that, as Dave has alluded to. BTW Dave, I think your result looks quite neat. Interested to hear how it pans out. :D

Hi all , if I was trying to develop a dump pipe for those Garrett GT30/35 IW turbine housings I'd take a leaf out of HKS's book .

If you look at how they did their Pro S IW gates vent pipe its not to difficult though probably time consuming . They basically cut a section of pipe in half and seam weld it on the outside of the turbine outlets tube . It would not be very difficult to "form" it into the shape of the back of the IW turbine housing .

I don't know who's making the flange plate for them in those pics but I would want it to be the same shape (outline) as the gates outlet area - not just another slightly smaller hole . From a manufacturing point of view merely hole sawing the two holes is simple enough - read cheap to do . Whats needed is a template taken from the housings outlet flange and possibly laser cut versions made .

Cheers A .

Personally, I would take a leaf out of CES's book rather than HKS. I've seen back to back dyno tests of a CES twin dump vs HKS merge dump on a 2871R on a SR20 and the CES lost nothing at any stage and gain more hp from 5500 onwards. CES make GT35 twin dumps for the falcon XR 6's so see if you can locate some pic's and note the way they have done it and apply similar principles.

In the main you should concentrate on reducing turbulence caused by the wastegate gases and CES does this by keeping the wastegate gases separate for as long as possible by merging them back into the main pipe at a shallow angle as it goes under the vehicle.

Edited by juggernaut1

room is allways an issue

but this is my design using 316 mandrel bent stainless

once it was all tig welded i ground out the waste gate pipe to suit the shape of the xr6 dump gasket and then

decked it flat in the mill and it done.

no possible restriction near the flapper, and i joined it as far as practible down the main pipe.

post-24852-1205105537_thumb.jpg

post-24852-1205105609_thumb.jpg

Dangerman4 that flange is more along the lines of what I was thinking only instead of having a figure 8 shape where the pipes touch I'd make the bypass tube the same shape as the housing side - D shaped if you know what I mean .

You could achieve this by cutting the gates tube and adding fillets to form this D shaped section or just cut and grind a big tube and weld it to the outside of the dump tube so they have a common wall .

Part of the advantage is that its closer to the same temperature on both sides so less thermal stress and expansion/contraction cracking issues .

I'm not really sure how you go about feeding the bypassed gas back into the system and not affect the main gas stream .

One silly idea may be to merge it with the front of the Cat's reverse funnel because it opens up gradually to expose the front of the core/matrix . Its a fair length to go and rapid temp rise as the gate opens could cause expansion and cracking problems without some sort of soft spot .

Thoughts ? Cheers A .

Thats some nice work, wish i had the time and effort to do that myself... oh well someone else can do it for me when my turbo gets here.

As a side note, maybe we should merge this thread into that other 3071R thread that was going on a month or so ago...

Dangerman4 that flange is more along the lines of what I was thinking only instead of having a figure 8 shape where the pipes touch I'd make the bypass tube the same shape as the housing side - D shaped if you know what I mean .

You could achieve this by cutting the gates tube and adding fillets to form this D shaped section or just cut and grind a big tube and weld it to the outside of the dump tube so they have a common wall .

Part of the advantage is that its closer to the same temperature on both sides so less thermal stress and expansion/contraction cracking issues .

I'm not really sure how you go about feeding the bypassed gas back into the system and not affect the main gas stream .

One silly idea may be to merge it with the front of the Cat's reverse funnel because it opens up gradually to expose the front of the core/matrix . Its a fair length to go and rapid temp rise as the gate opens could cause expansion and cracking problems without some sort of soft spot .

Thoughts ? Cheers A .

Hey Disco

as i mentioned in my above post, i welded up the gaps from both sides with my tig then placed the xr6 gasket over the flange and traced out any exposed metal.

this was then ground out to leave a purfect D shape and then the flange was decked flat.

i just forgot to take a pic of the finished product so i cant show you.

In my rush to get the thing installed i didn't think to take photos of the finished dump.

I ground out to the extents of the 2 inch pipe where possible and then shaped the flange to match the back of the housing so it's kind of a D shaped bell mouth.

As the car ran out of rego and is just silly loud now (thanks to the more open gt30 turbine over the old t3) i had to baby it down to the mechanic for a pink slip without really pushing it. It did make .5 bar by 2500 just on the actuator which is promising, i tried a couple of the old presets on the ebc and got about 1 bar out of it on the way home, though i think i need more gain. It was very linear. Oh, and hektik flutterz even with stock air box thanks to no bov....

At this stage it's looking good. hopefully tune next week.....

Ok, My dump is rubbish.

When the wastegate opens it's blocking the outlet so i get a big 4-6psi bump in boost as it comes on.

When it comes back down it's stable at the top end, but unfortunately as i add boost, the hump gets bigger so i couldn't really test the limits. We did an initial run at 16psi (with a 22psi hump) and it spat out a lazy 260rwkw uncorrected in shoot 6. Couldn't really play with the gain to bring it on quicker, but did a quick test with the wastegate held shut and saw high 20psi under 3k before i could get off the throttle!

took some timing out so it would be safe for a track outing, hump got bigger! egt's increased and span the turbo up more......

Personally, I would take a leaf out of CES's book rather than HKS. I've seen back to back dyno tests of a CES twin dump vs HKS merge dump on a 2871R on a SR20 and the CES lost nothing at any stage and gain more hp from 5500 onwards. CES make GT35 twin dumps for the falcon XR 6's so see if you can locate some pic's and note the way they have done it and apply similar principles.

In the main you should concentrate on reducing turbulence caused by the wastegate gases and CES does this by keeping the wastegate gases separate for as long as possible by merging them back into the main pipe at a shallow angle as it goes under the vehicle.

I would avoid using CES if it was me. There was a large contigent of satisfied 200sx's using them and they worked well until they got really hot on the track... Then nearly all of them cracked severly. Ironically now none of them use them and went to HKS dumps.

I would avoid using CES if it was me. There was a large contigent of satisfied 200sx's using them and they worked well until they got really hot on the track... Then nearly all of them cracked severly. Ironically now none of them use them and went to HKS dumps.

Really - I have one and give my 200sx a belting for 30 mins at a time at Barbagello for 4 sessions each time I go and no probs. I know some removed the tranny support becuase it needs to be ground out to fit the CES which would cause it to crack as it is supporting the front half of the exhaust system. The only thing thats cracking are my discs.

Ok, My dump is rubbish.

When the wastegate opens it's blocking the outlet so i get a big 4-6psi bump in boost as it comes on.

When it comes back down it's stable at the top end, but unfortunately as i add boost, the hump gets bigger so i couldn't really test the limits. We did an initial run at 16psi (with a 22psi hump) and it spat out a lazy 260rwkw uncorrected in shoot 6. Couldn't really play with the gain to bring it on quicker, but did a quick test with the wastegate held shut and saw high 20psi under 3k before i could get off the throttle!

took some timing out so it would be safe for a track outing, hump got bigger! egt's increased and span the turbo up more......

20 psi before 3K?!?! i hate you hahaha

fix the dump up and it sounds like it will be awesome!

Ok, My dump is rubbish.

When the wastegate opens it's blocking the outlet so i get a big 4-6psi bump in boost as it comes on.

When it comes back down it's stable at the top end, but unfortunately as i add boost, the hump gets bigger so i couldn't really test the limits. We did an initial run at 16psi (with a 22psi hump) and it spat out a lazy 260rwkw uncorrected in shoot 6. Couldn't really play with the gain to bring it on quicker, but did a quick test with the wastegate held shut and saw high 20psi under 3k before i could get off the throttle!

took some timing out so it would be safe for a track outing, hump got bigger! egt's increased and span the turbo up more......

I had similar problem with profec b 2, i had the set gain too high, dropped it down a couple of psi and it worked fine! also seemed better leaving the gain on 10%

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