Turbo header - Pipe vs Tube

[spoolin70]

Hi all

Anybody have any experience of making your own turbo header/manifold ?

I 'think' I've found a route around the engine plate and rear cage/bars that will make all pipework pretty close to equal length and twin scroll. Question is, what should it be made from ? 99% seem to be made from mandrel bends but cast/steam pipe is thicker wall (better heat retention for turbo) but heavier and harder to cut/angle. Mandrel bends are cheaper and more readily available.

I'm torn between 1 3/4 inch mandrel bend tube - 1.5mm wall VS 1.5" sch10 pipe - 2.7mm wall. 

Any thoughts or opinions welcome

Thanks
Darren

[Garrick Clark]

What I realised when I did my header was is the turbo needs to be bolted directly to the 4 into 1 collector, if you bolt a pipe to the collector to position the turbo higher or to the left/right the spool up is slower.

[PPRMicke]

If you use twin entry, you need two WGs to get smoother pressure control

The thing to keep in mind is to try to have the same pipe diameter as the exhaust port    (if you do not have a good control system can help start up the pressure faster)
Because it will build pressure faster and more responsive
I always count on the 3 pulses in the tube to avoid a lot of back pressure
/// Micke

[spoolin70]

Thanks for the replies

Garrick - Did you make your own header ? if so, out of what material. 304 steel is the most popular but not best for longevity. My turbo is twin scroll and pipes will merge at the collector.

Micke - I have 2 Tial wastegates ready to use. Also intend to use a controller and not just rely on spring pressure. Used this on my last engine (ecu controlled) and use a standalone system on my 'other' car (not vw).

The exhaust port on my heads are 36mm dia. T304 SCH10 pipe has an id of 42mm. Close but this is hardly ever used.

I have found some mandrel bends in 1 3/4" with 2mm wall but they are 316 steel. only 90deg available and a little more expensive. 321 steel would be great but the price goes up and availability down.

[spoolin70]

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[PPRMicke]

38 mm super
we in sweden use thin-walled pipes (1.5mm)
If using stainless steel, consider the expansion For stainless steel, the loin increases by 1 mm pear 1m at 100 g c

What is it for heads jpm ??
How much hp?
/// Micke

[Garrick Clark]

Mine is a 38mm stainless. 1 piece modified turbo Thomas. No slip joints. I tig welded them up. Big 3 bolt at the merge.

[Chip]

https://www.aceraceparts.com/collections/weld-fittings-weld-els/schedule-5

These are what I'll be using to do my next couple of headers. Not crazy thick, but nice tight bends available, also the 321 is better than 304 for exhaust use. Not the cheapest avenue but should be really nice when done.

[spoolin70]

Garrick - is that 38mm inside diameter ? Also did you back purge while tig welding ?

Micke - thankyou for the information on expansion. Yes, JPM heads MS250. I am hoping to see around 600hp from the engine but this is just a figure in mind at the moment. I know of a similar engine that made around 580hp from memory using MS230 so 600 should be achievable.

Chip - thankyou for the link. I should mention I'm in the uk so really need a supplier here. 321 is indeed more suited but harder to obtain.
Would you be using sch10 ? Mario from dubshop used sch5 I believe.

I while back I got this header from vw Speedshop. It's an over the gearbox type but would never fit due to my engine plate so I was happy to cut it up and use the parts for measuring.
It's 41mm outside , 38.6mm inside with 1.2mm wall.

To me that's a little thin on the wall size plus 41mm is 1 5/8" which isn't easily available. So that's why I was thinking  using 1 3/4" with 1.5mm wall.

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[PPRMicke]

Garrick - is that 38mm inside diameter ? Also did you back purge while tig welding ?

Micke - thankyou for the information on expansion. Yes, JPM heads MS250. I am hoping to see around 600hp from the engine but this is just a figure in mind at the moment. I know of a similar engine that made around 580hp from memory using MS230 so 600 should be achievable.

Chip - thankyou for the link. I should mention I'm in the uk so really need a supplier here. 321 is indeed more suited but harder to obtain.
Would you be using sch10 ? Mario from dubshop used sch5 I believe.

I while back I got this header from vw Speedshop. It's an over the gearbox type but would never fit due to my engine plate so I was happy to cut it up and use the parts for measuring.
It's 41mm outside , 38.6mm inside with 1.2mm wal

To me that's a little thin on the wall size plus 41mm is 1 5/8" which isn't easily available. So that's why I was thinking  using 1 3/4" with 1.5mm wall.

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With the right cam, it should be easy to get 500whp at 1 bar 1.3-1.4, so it should leave more than 600 Hp
Make sure you have good EFI and easily powered injectors (more than 8 ohms)
/// Micke

[Garrick Clark]

Some of it was back purged. The welds aren't snotty. There like crescent moons and don't obstruct flow inside the tube. I'll go measure inside diameter in morning.

[Chip]

Garrick - is that 38mm inside diameter ? Also did you back purge while tig welding ?

Micke - thankyou for the information on expansion. Yes, JPM heads MS250. I am hoping to see around 600hp from the engine but this is just a figure in mind at the moment. I know of a similar engine that made around 580hp from memory using MS230 so 600 should be achievable.

Chip - thankyou for the link. I should mention I'm in the uk so really need a supplier here. 321 is indeed more suited but harder to obtain.
Would you be using sch10 ? Mario from dubshop used sch5 I believe.
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I'm doing sch5 too.

[Garrick Clark]

Measured mine not guessed it.
40mm I. D
1.3/4mm wall.
Bit more than I thought.
I was quite hard to do it as a 1 piece thing as I used the engine as a Jig, like you do but the welds would shrink the overall size making it difficult to remove. Resulting in having to cut some  welds, clean  them back up and go again. Eventually I got it to fit with out making it difficult to remove

[Erlend / bug66]

I went for 45mm OD / 42mm ID (1,5mm wall), 304 stainless.

500+ up engine, and yes, probably a bit big, but suitable to reuse for later 

[spoolin70]

More great info - thanks guys 

Garrick - thank you for taking the time to measure yours. So its roughly 1 5/8" pipe. I do worry a little about expansion and movement so ill try and incorporate some joints.

Chip - sch5 in 1 1/2" is about 1.7mm wall. Would sch10 at 2.7mm not be better or is the weight an issue ?

Micke - JPM cam too  I dont have the injectors yet but Bosch make 1650cc at 4bar now which is what i will probably use (1450cc at 3bar)

Erland - The size you mention in 304 seems to be most available here. I'm thinking of using that size for the first version and if there is a strength issue later, perhaps getting it remade in 321.

Thanks all
Darren