Twin scroll with single 38mm wastegate?

[pl0x]

Finally building my twin scroll set up. 2.0L with some head work.

In theory it's going to be bp/bl headers with up pipe adapter to T3 t/s (with a single waste gate from here), gtx3071 0.82 t/s rear, high boost of 2ish bar.

 

Will a single 38mm wastegate be enough? currently have a semi new 38mm tial so I'd like to use it if i could.

I've read most people advise 44mm, but want to know if anyone has had creep with a 38mm

[Dairusire]

Curious, what sort of power range are you looking at? 

 

Also, yes a 38mm tial will work for a single wastegate as long as it's divided properly. 

 

The biggest downside to the single gate style is the divider up to the gate. When you beat on your car and get that hot, it'll probably get weak and probably break. 

I say this because @Furze and I have had no end of issues with the single wastegate on his car. Twice the divider has broken off and jammed the gate open. 

 

If you've also got headwork going into your build I assume you're shooting for more than 350kw. To which I'd say get off the BL/BP headers and get STi headers. You'll run into a wall from 350kw onwards which @SAS will confirm. 

 

So, on that note, bugget allowing, go twin gates and STi headers / up-pipe. It'll make your life easier and if you go to a bigger turbo / cams etc that'll likely and easily outflow the BL/BP headers and single gate setup, you won't need to do it all over again.

[pl0x]

I'll be happy if it finally cracks the elusive 300wkw (for this engine). Head work was done when I got the engine.

I've already got the headers, I've gone through 2 sets of a/m headers, so when a bl/bp header/sump combo popped up I grabbed it.

 

Interesting, I hadn't heard of any dividers issues before. Space and plumbing would be the biggest pain with twin gates.

[Furze]

58 minutes ago, Dairusire said:

Curious, what sort of power range are you looking at? 

 

Also, yes a 38mm tial will work for a single wastegate as long as it's divided properly. 

 

The biggest downside to the single gate style is the divider up to the gate. When you beat on your car and get that hot, it'll probably get weak and probably break. 

I say this because @Furze and I have had no end of issues with the single wastegate on his car. Twice the divider has broken off and jammed the gate open. 

 

If you've also got headwork going into your build I assume you're shooting for more than 350kw. To which I'd say get off the BL/BP headers and get STi headers. You'll run into a wall from 350kw onwards which @SAS will confirm. 

 

So, on that note, bugget allowing, go twin gates and STi headers / up-pipe. It'll make your life easier and if you go to a bigger turbo / cams etc that'll likely and easily outflow the BL/BP headers and single gate setup, you won't need to do it all over again.

 

This has happened to me twice now..  going twin gate in the near future

 

[pl0x]

Nice, I'm interested to see it once it's all built. I didn't really want to go twin gates due to space but will consider it.

 

Side note - I just had a read through your build, what turbine housing ar are you running?

[gotasuby]

We had the same issue with the divider breaking off once. It did last a while though. 

[Dairusire]

Nice, I'm interested to see it once it's all built. I didn't really want to go twin gates due to space but will consider it.
 
Side note - I just had a read through your build, what turbine housing ar are you running?

I think its a 10cm or a 12cm.@evowrx

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[Andy_Mac]

I thought the Murch 35/2 ones were more like 14cm

[Dairusire]

I thought the Murch 35/2 ones were more like 14cm

It may well be? I don't remember though.

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[pl0x]

Oh yea, Holset turbine housings don't do a/r.

Edited March 9, 2018 by pl0x

[Jono24]

Pretty sure the smallest hx35 twin scroll housing is 12cm, they make an hy35 single scroll housing which is 9cm.