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Discussion Starter #1
I just ordered a JT 3" down pipe form PFS i am asuming this just bolts on to my standard exhaust till i get the rest of the 3" system.

Is there any thing i should know before trying to change this ?
 

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Also - no need to add the rest of the 3" system until you get to about 250~300bhp. I think you need to move the battery to fit in the 3" downpipe. Either to the LHS of the engine bay or to the boot.
 

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Discussion Starter #4
I have moved the battery to the LHS.

Does it HAVE to have a reducer? Coz i am gonna get the rest of the system any way. (at some point) i don't wanna waste money and time on a reducer if i don't have to.
 

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Discussion Starter #6
What sort of BHP do you think i will be runnig when im done ruffle. I got a 9k fmic, K&N cone, APC mods, striped out the EGR system and the whole 3" system. On a 87 T16
 

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I think the answer to that question depends on the answer to this one: how much boost are you running? You can get a lot of HP very easisly on a turbo car - all the other stuff just helps run stable boost so you can mantain the performance.

If that's the full list then I'd say you'll be pushing something around the 200 mark. Maybe a bit less.

Hard to say though.
 

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downpipe

Have you removed the section off the turbo yet?

I was wondering how difficult it was to get the elbow bit off as i've tried striping a few old turbos and always have loads of trouble getting the elbow off.

Any tricks for removing it?
 

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Discussion Starter #10
I should be on 1 bar.

I havn't tried taking the elbow off as the replacement part hasn't arrived yet
:D
 

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Hey!

I believe the original system is 2.25".

Ejenner: Are you sure 3" downpipe without restrictive elbow + original system (no cat) can handle 250-300 hp??

I have a heavily modded 900c (filter, fmic, intake, head, injectors etc) with the mitsu TE05-12b turbo and a forge wastegate actuator.

Problem is the wastegate leaks pressure at high rpm - because of backpressure i Think?

I have two different springs for the actuator. the wealker one holds base boost at 0.5 bar but max boost at 6000 rpm is only 0.8 bar. With the stronger spring, boost is 1 bar at 6000 rpm but base boost way too high (0.8 bar)even at lowest possible level and the boostpressure at mid rpm gets very high.

So it appears that max boost at 6000rpm depends on the strength of the spring - It doesn´t matter how i adjust the APC.
Can this be caused by the exhaust system being too restrictive?

Has anyone experienced similar problem?? Will 3" all the way reduce backpressure so the wastegate can hold itself closed with a spring that can be adjusted so base boost is around 0.5 bar.

:confused:

SG
 

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Discussion Starter #12
A simple yes/no answer please

Is the 3" downpipe able to connect to the standard exhaust system without a reducer temporarily (few months maybe)

 

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hej sg min ven , look to the dark side :cheesy: if you want stable boost conditions with a few mods get an mbc , i sent kaas my old one ,iive got a dawes device nowthat i use with no problems
 

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Discussion Starter #16 (Edited)
I think i could live with the blow for a few months hopefully weeks ;)

How much are reducers anyone know any links?
 

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"Problem is the wastegate leaks pressure at high rpm - because of backpressure i Think?" - yes it is backpressure but it's backpressure upstream of the turbo and the size of the exhaust downstream of the turbo will have no influence whatsoever. Get a better flowing turbo or stronger actuator spring.
 

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trackside said:
"Problem is the wastegate leaks pressure at high rpm - because of backpressure i Think?" - yes it is backpressure but it's backpressure upstream of the turbo and the size of the exhaust downstream of the turbo will have no influence whatsoever. Get a better flowing turbo or stronger actuator spring.
Its actually the pressure differential across the wastegate which causes it to blow open, and this is made worse by fitting a free flow downpipe and removing the restriction of the elbow.
 
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