Reinforcing Stainless Manifold To Stop Cracks

[Bennis]

Hey guys,

I forgot my old account name and email with it so I made a new one.

Long story short, I am currently selling my GQ Patrol and am about to buy another skyline.

Most likely an R33 GTS-T and will be going with the fairly common route of unopened rb25 / gt3076r based build.

Now, I have lieing around one of those cheap stainless steel china manifolds and I will be using it in the build. I know it would be wiser to go with a nice steampipe manifold from 6boost/ ETM etc etc but I have one, its free and currently in perfect condition.

I am aware these crack easily but have heard rumour that if you brace and support the manifolds to take alot of the weight off them it can help with preventing this.

I was wondering if anyone who has braced / reinforced a stainless manifold could post up how they did it with pics or similar. It would be great.

I was thinking of just bracing the individual runners themselves as well as bracing the entire manifold to the engine bay or similar to help take the weight off it.

Any info or experiences would be great.

YES I DID SEARCH BTW

Cheers

[ARTZ]

Hey guys,

I was thinking of just bracing the individual runners themselves as well as bracing the entire manifold to the engine bay or similar to help take the weight off it.

and what happens when the engine moves?

[Bennis]

Good point, I didnt think of that at all.

Still after examples though... I was thinking of bracing the collector area to the head flange. Could also brace the comp / turbine housing to the engine somewhere too?

[ARTZ]

lol....i think a brace from the turbo flange on the manifold to the head flange on the manifold can work wonders mate,,,both are solid lumps of steel so joining them kinda makes sense..just make sure nothing is in the way of your turbo lines and your laughing ..

[r33_racer]

Precisely what ARTZ said. Weld a rod or two from the head flange to the turbo flange and it will help keep the stress off the exhaust runners in between.

Also try and support the dump pipe somewhere so the first half of the exhaust isn't hanging from the turbo, that will also help.

[Bennis]

Great idea, I could add an extra hangar to the dump pipe.

I was also thinking of adding a flex piece to the dump pipe, do they cause any restrictions in flow? I would be aiming around the 300rwkw area with the 0.82 GT3076R and supporting mods (fmic, injectors, etc etc).

Also, the mainfold has a wastegate pipe for a 38mm gate. The pipe is not on an ideal angle and I dont want to run a 38mm gate. I am going to get an external wastegate welded onto the turbine housing. If I simply cut the wastegate pipe as short as possible and cap it off will this small pipe create any negative effects on flow in the manifold?

Here is a pic showing where I would cut and weld shut the pipe on the manifold (not my manifold but exact same type).

[r33_racer]

I use the flex pieces all the time. They work well and provide a nice amount of 'give' for the exhaust system, however I put it right at the bottom of the dump pipe where it connects to the rest of the exhaust system.

If possible use the next size up for your dump pipe if it is still to be fabricated, especially if you are going to plumb the waste gate back into it somewhere. So use a 3.5" dump pipe with a 3" system from there back.

You can cut it off close to where it merges with the other pipes, however leave a little bit out, perhaps 3/4" worth and tig a cap over it. Or you could just bolt a cover plate onto the flange, that will work fine too. It wont really make any noticeable difference. With the welding of the support rods, make sure you use stainless and make sure it is tig welded on. If it is mild steel and mig'd it will more then likely crack off and potentially cause more stress risers.

[brenton21]

You can try a brace but i reckon its just the cheap, thin stainless they use that can't handle the repeated heat cycles.

[KiwiRS4T]

What is your power goal? Just use the stock manifold up to about 300kw

[Dobz]

Just cap off the flange and do as r33_racer said, use a flexible bellow for the exhaust. The reason so many of those manifolds crack quickly is because they're solid mounted to the exhaust which acts like a big lever on the manifold.

Don't try and weld bracing on it, it an just make things worse.