Turbos, wastegates and Dump valves.

[Timbo_Mint]

I've lost Turbo boost (0.2 where I was getting 0.7bar). I'm told that the waste gates are stiff and the bearings may have gone but the only way to be sure is to take off the turbos and look.

Q1. Can they be referbished and is it worth it?

Q2. Is it worth fitting Dump valves (Noblemods £155)?

Q3. What make of Turbo is fited to the 2.5 - 51 plate?

[D_G]

I always get my turbos refurbed, I'll get the number tomorrow of the place I use if your interested.

Your problem could be either a sticking or broken wastegate or a siezed turbo. You can see both the wastegate and exhaust turbine if you take the downpipes off, probably worth doing this before taking them off altogether.



HTH



Dave

[mgbond]

D_G said:

I always get my turbos refurbed, I'll get the number tomorrow of the place I use if your interested.
Your problem could be either a sticking or broken wastegate or a siezed turbo. You can see both the wastegate and exhaust turbine if you take the downpipes off, probably worth doing this before taking them off altogether.

HTH

Dave

Hi Dave, Interesting post this. Whats the cost to refurb them T25s think and what else should be done i.e. I'm sure I herd about ugraded bearings and something about 360?

Cheers

Bondy

[D_G]

The people I use can do a straight refurb or upgrade to ball bearing for fast spool up etc. They did some standard Supra ones for me (BB upgrade) and the customer loved them (and the're more durable to boot).

Not sure what other upgrades they can do for the T25 but can ask the question if interested. I know turbine profile etc has a huge effect on the spool up and power delivery so I need to speak to them for advice.



Dave

[mgbond]

D_G said:

The people I use can do a straight refurb or upgrade to ball bearing for fast spool up etc. They did some standard Supra ones for me (BB upgrade) and the customer loved them (and the're more durable to boot).
Not sure what other upgrades they can do for the T25 but can ask the question if interested. I know turbine profile etc has a huge effect on the spool up and power delivery so I need to speak to them for advice.

Dave

Cheers Dave, don't go investigating unless you are for yourself as I'm interested for maybe next year.

Bondy

[D_G]

I'm not looking either (unless the unfortunate happens) but I'll ask next time I ring them.



Dave

[ajg31]

Ball bearing is not for spoolup speed, IIRC, it is just to allow more boost/load to go through the unit (why people upgrade to 360 deg bearings i suppose).

Just dont get caught out by the refurb charges if they say your unit is scrap (scrap core and housing) as this would make the cost as much as a brand new unit.

Could always uprate the wasegates to 0.8 ones while your refurbing, but thats a very crude way of raising power.

I have just get one refurbed, but it cost 389 quid... Ouch... Was caught with my pants down there. Think 200-250 for bearing and seals is about right.

Edited by ajg31 on Tuesday 22 May 22:37

[D_G]

Ball bearing turbo has much less friction loss so does spool slightly better, but are much more durable as you say. If you can find a fully rebuilt guaranteed unit for £200 please let me know as I'll start using them! £400 inc VAT for a fully rebuilt standard turbo isn't bad so don't feel so hard done by.



Cheers



Dave

[obes]

I got mine refurbed at Turbo Technics when I had the engine out. £440+VAT for the pair. That was for new bearings, seals and wastegates reset. Befores and after...











IMHO it is worth fitting a dump valve. They prevent the turbo stalling when upshifting due to back pressure. This takes stress off the bearings and gets the turbo spooling quickly again