That is the question

Some people have told me my ERST need to have some back pressure to keep the oil seals in the turbo ok, others have told me that it doesn't as the gases need to flow out as quickly as possible.

I'd be grateful if someone could confirm this as I hatching a cunning plan.

It isn't running a standard set up, so I am wondering if this would make any difference?

K&N Filter (with cold air feed)
Full 2.5" stainless with one backbox and 3" tail
Turbosystems 195 chip
running 14psi

Cheers for the help guys

 

THERE ARE NO SEALS,as such, if std turbo, so one myth gone.
A certain amount of backressure is indeed beneficial to oil control past the turbo shaft, but you can have the turbo rebuilt with 360 and STEP GAP SEAL which will ALMOST totally control the oil loss, through the turbo.
Losing backpressure can allow it to develop more power, and a lot more noise!!
tabetha

 

errrrrrrrr........i think you'll find there is!

Standard T3's have the dynamic ring seal.

Phil79 as tabetha is saying though, on a standard T3 they have just a standard dynamic ring seal, which basically like a piston ring, has a tiny tiny gap in the seal, and it relies on simple physics to contain the oil within the turbo, so in this case the back pressure in the exhaust exceeding the oil pressure within the turbo core.

If you start fitting large diameter exhaust systems you majorly reduce back pressure and its common for the oil enter the exhaust, so a step gap seal is what you'll want in your turbo to control this, which basically means there is no straight gap in the sealing ring

 

So if I was to make a pressure-less system with a 2.5" bore on a standard T3 then the turbo would, invariably, shit its guts on me?

 

Don't think you'll have a problem there, ive got a 2.5" bore on mine with a standard turbo, seems fine

A standard exhaust could well be 2.5" but dont quote me

 

mongoose do a 3inch bore with single straight through box . 2.5 is standard bore size iirc

 

Correct. And they do benefit from a little pressure as they are a differential pressure seal. That said, the T2 doesnt suffer too much. Unlike the T2, they start smoking almost the moment you fit a big bore. Garbage little things. ROLFOL.

 

An old trick was to drill tiny holes in the ring to let pressure in to help stop oil flow.
tabetha

 

Just run that one by us again

 

OK, so we took the backbox out of the system last night (well, Geoff @ CSG did, I stood and watched )

Sounds mean as you like now, proper growly, but looks like it lost around a pound of boost. So, as you do, I gave the death valve a twist to sort that out, but now it seems to have a bit of a flat spot.

If I accelerate in 3rd, it loads up as usual from 2800......... then at 4000 its like being hit in the back by another car Really comes on song, screams away and off I pop down the road. Strange.

Can MFi have flatspots pulled out with a decent set up by a tuner, or is that only EFi?

 

Just out of interest why have you removed the back box

 

yer your just running a straight through long pipe?

 

was just wondering the same,and also why are you playing about with a bleed vavle when it comes across like you havnt a scooby do what you are doing?

sounds like a recipie for disaster

 

Erm, why don't I have a clue what I am doing?

I seemed to have lost a pound or two of boost, so I wound the valve out a little until I can get a new actuator. Surely the bleed valve does the same job as pre-tension on the actuator?

I do have a gauage and I don't let it go above 1 bar, which is safe as it's set to run 18psi.

And I took the backbox off because the weld around it had split and thought that, if a pressureless system wouldn't cause any harm, then I would just replace it with a piece of straight pipe.