46 replies to this topic

[turbotrana]

Main benefit of stainless steel is that it keeps the heat in the manifold much better than mild steel. It is generally well know that stainless aids spool time.

I've seen the jap/chinese manifolds with goldy coloured welds. I can weld stainless quite well but would love to know how the jap/chinese get those goldy coloured welds.

[makka]

the $2.50 bends, are they 90 deg. bends? what dia?

[Bart]

i dont have prices of 321 as i dont use it.
2" pipe is way too big.
steampipe bends are about $2.50 each and the pipe is about $100/6.5m

im in wollongong mate.

2" too big?
The internal port diameter is 48mm. Thats pretty close to 2" isnt it? Or am i missing something here? Its a Nissan V8 by the way.

[Bart]

I made a stupid mistake, ID is 46mm 1.8"
https://cache.gmh-torana.com.au/i50.photobucket.com/albums/f312/toranacar/DSC00438.jpg[/img]]My Webpage://https://cache.gmh-torana.com.au/i50.photobucket.com/albums/f...img]]My Webpage://https://cache.gmh-torana.com.au/i50.photobucket.com/albums/f...img]]My Webpage

[turbotrana]

Thats a very nice looking weld. Will try with the gas lense and a bit more gas. I thought it had something to do with that. But I need to use a long narrow cup to weld alot of the manifold so I end up not using the gas lense much. I also dont bother gas back purging as it cost too much extra work and gas. This does not help with colour also. I end up just grinding any sugar out and dont always try to get full penetration with 2.77mm SS

Although a nice cosmetic look is important, for me if it is a sound weld, then that is all that matters. When the heat gets in the manifold it changes colour anyway.

Regards

[Bart]

Agreed, very nice.
With the size of tube i would need, 2" would be ok yeah?

[Bart]

is that exhaust gasket the shape of the port bart?
what is the capacity of the engine?

Yep it sure is, the wire ring under it is something i made up to work out the diameter of the port, I bent up the shape of the port with that wire then bent it round and mesured the diameter and got 46mm. 48mm if wall is 2mm
Obviously I would have to shape the primaries oval like the ports.
Forgot to mention capacity, its 4.1lts, can be stroked to 6ltrs, thought id mention that to make things more complicated lol

Edited by Bart, 07 October 2006 - 01:48 PM.

[Bart]

700-800 depending how much i spend on it, but at first to get it all together and running for rego and engineer etc i would be happy with 400-500hp.
So the idea is approx 700hp eventually
Just an idea, instead of flaring out the primaries maybe I should buy cones?? and weld them to the primaries, as cones can make a nice gradual step down.

Edited by Bart, 07 October 2006 - 05:02 PM.

[Bart]

no worries mate, should i use step down cones for the join of the primaries to head flange?
I still have to ring Gair about the 321 SS if thats too far out of reach ill go Liverpool exhaust steam pipe otherwise if you werent so far id buy the stuff off you.

[Bart]

i would make reducers from straight pipe.
cut it down the middle and add a triangle piece.
perfect reducer;)

sounds like a goer
Thanks mate

[Bart]

thanks mate

[turbotrana]

My suggestion is to use 316 stainlesssteel which is from my sources 2 to 2.5 more expensive than mild steel.
Stainless steel comes in sched 10 thickness (about 2.77) as opposed to mild steel that only comes in sched 40 thickness (about 3.something). Just use mild steel flanges as this has benefits of not expanding as much as stainless.

I prefer to have the manifold tubing at least the same size as the port or slighly bigger for the primaries in performance applications. Those exhaust ports look pretty big.

(32nb)1 1/4" with inside daimeter of approx 36mm is too small IMO for this large size port.You would need to go the next size up with 1 1/2" which in stainless would give a I/D of around 43mm in stainless sched 10

I then use a press and a big flat bar on the insides of the pipe to get the oval shape of the port. If its still slightly too small you can use a die grinder to take a bit out of the walls of the thick pipe to match port.

There are so many considerations and more than one way to skin a cat. Remember all this pipe work has to make its way into a turbine. I've spent many hours just pondering the best possible way to make a turbo manifold.

[Bart]

Goair quoted $160 for a 90deg mandrel bend, 47mmID 321 SS, 1.3mm wall
A bit too pricey, the steam pipe is looking more inviting
The guy i spoke to seems quite helpfull and even suggested other suppliers, nice bloke.

Edited by Bart, 10 October 2006 - 08:22 PM.