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Split Dump Pipe Issue

*daz*

By *daz*,
in Engines & Forced Induction

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*daz* Apprentice

*daz*

Posted
Posted (edited)

I installed a split dump pipe on my r32 gtst today (rb20det

When I took it for a drive I noticed it takes longer to come in with full boost

then the original dump pipe did (around 5000rpm)and it seems really laggy. I haven't done one of the top bolts from the dump to turbo

up tightly because it was stripped when I went to do it up so it no doubt it is leaking, but

I just wanted to know if this is normal with the split dump pipe?

Also the amount of psi has increased from 10psi to about 15psi.

Does anyone know if this is normal?

Edited by *daz*
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GTSBoy Grand Master

GTSBoy

Posted
Posted

You usually pick up 2 or 3 psi. 5 is unusual.

What sort of split dump? The shorties that just replace the original dump or one that has the wastegate pipe drop the full length of the downpipe and join the main pipe down at floor level? The reason I ask is that I have heard people complain that the shorties don't seem to work any better than the standard dump, but when I put a long split dump on I saw an improvment in both spool and power over the standard dump.

Does the dump have a divider that goes into the outlet section of the turbo exit flange to separate the wastegate exit from the turbine exit?

Does the wastegate flap still swing freely?

*daz* Apprentice

*daz*

Posted
  • Author
Posted

It's one of the short ones that just replace the original dump...

The split dump has a divider that goes into the outlet of the turbo.

I'm not too sure if the wastegate flap still swings freely. What's the best way

to check this?

MrStabby Grand Master

MrStabby

Posted
Posted

It's one of the short ones that just replace the original dump...

The split dump has a divider that goes into the outlet of the turbo.

I'm not too sure if the wastegate flap still swings freely. What's the best way

to check this?

A pre-turbine exhaust leak will cause lag. If the wastegate has fouled on the dump and being held open by it that will cause a lot of lag.

Re: wastegate, try disconnecting the actuator rod and turn the flapper arm with your hand. If you aren't sure of the position the arm should be at fully closed, you might need to take a photo and post it here for someone to take a look.

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