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What is the advantage of fitting a restricted oil feed banjo to the turbo ?
Garrett T250-04 - oil feed
- Thread starter miktdish
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What is the advantage of fitting a restricted oil feed banjo to the turbo ?
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This is a surprise ... does no-one have any insight ?
tottot
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Who say's there is any advantage ? and what is it supposed to be ?
tottot
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Plenty of stuff on line about this. Looks to me it is something to consider on high revving high performance engines which spend a lot of time at the top end of their power range.
For Every day vehicles that can spend much of their time at low revs could end up starving the turbo of oil at times.
My thoughts anyway.
For Every day vehicles that can spend much of their time at low revs could end up starving the turbo of oil at times.
My thoughts anyway.
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I didn't know you could get them.
I know you can get in-line pressure regulators to go in the oil feed pipe.
Scooby22
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I could understand a restriction to keep oil from draining quickly after stopping to aid cooling and lubrication on rundown but not a restriction to feed oil in.
tottot
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As the revs increase oil pressure will increase up to the point the limiting valve opens. With high performance engines this can be quite high and may force oil past turbo seals so a smaller hole in the banjo limits the flow. Also forcing more oil into a turbo bearing than what is needed uses up some of the engine power. Only important for those looking for every last bit of power as in racing engines
A more sophisticated [ and costly ] method is a system that controls the flow of oil to the turbo dependant on pressure and rpm.
A more sophisticated [ and costly ] method is a system that controls the flow of oil to the turbo dependant on pressure and rpm.
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With the Fokker moving slower than i'd like (mainly due to working on the drive under a gazebo) my mate said I could use his tin shed to change the suspenders. Thats another story .. I drove it up the hill and the turbo screamed most of the way.
So I took it off and was dismantling it looking for non rusty parts to put it back togetrher with and came across 'restricted banjo bolts'.
Having read up/UTubed them I couldn't find anything specific to Garrett (T250-04) turbo's in 300tdi's, so thought I ask the fountain of knowlege that lies in here ...
The turbo is deffo knacked, the CHRA wobbled about so i've contacted Turbo-rebuilds near Blackpool and it's off to them tomorrow.
I also noticed that the pipe from the intercooler was a bit oily (not hugely) and (in the pic above) you can see that inlets 1 and 2 are slightly oilled, as compared to 3 & 4.
Back to the restriction ...
I was wondering it the increased velocity of the oil (coming through the narrowed nozzel) would help although I guess the flow would be reduced ?
So I took it off and was dismantling it looking for non rusty parts to put it back togetrher with and came across 'restricted banjo bolts'.
Having read up/UTubed them I couldn't find anything specific to Garrett (T250-04) turbo's in 300tdi's, so thought I ask the fountain of knowlege that lies in here ...
The turbo is deffo knacked, the CHRA wobbled about so i've contacted Turbo-rebuilds near Blackpool and it's off to them tomorrow.
I also noticed that the pipe from the intercooler was a bit oily (not hugely) and (in the pic above) you can see that inlets 1 and 2 are slightly oilled, as compared to 3 & 4.
Back to the restriction ...
I was wondering it the increased velocity of the oil (coming through the narrowed nozzel) would help although I guess the flow would be reduced ?
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They might have had the same issue I currently have with too much oil coming through the turbo seals and in to the induction system. Mine's burning quite a bit.
You can get new CHRA's from Fourby for £99 https://fourby.co.uk/300TDi-Turbo-Core-CHRA-T250
You can have a lot of oil going through the intercooler, but when you take it apart it just looks very slightly oily. The air is going through at such a fearsome rate that the oil is blasted through and you are only left with a fine residue when you switch the engine off.
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Cheers @Al2O3 I did speak with Fourby's and decided to go with https://www.turborebuild.co.uk/ as they will rebuild it for me with new seals etc and set it up for 17psi uplift. It comes back ready to be bolted straight in.
I also chose the slightly more expensive 'enhanced' core as i've got the supersized Alisport intercooler and have tweaked the fueling slightly.
I'm still open to advice on the oil restrictor .....
I also chose the slightly more expensive 'enhanced' core as i've got the supersized Alisport intercooler and have tweaked the fueling slightly.
I'm still open to advice on the oil restrictor .....
tottot
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Double check the banjo you have is the right one for your engine and not just something that has just ended up there with the wrong size hole.
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As tottot said it could well have accidentally been used if someone lost the original. Failing that, I can't see any other reason to restrict the oil flow other than to stop excess oil going through the seals in to the induction system and getting burned.
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tottot
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Recon you need to talk to a turbo guy.
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Reckon no-one on here knows ...
The original has 2 x 5mm inlets and bored with a 6.1mm outlet. At circa 2Bar (30psi) the flow rate is ~1.5ltr/min @ 5mm around 0.5ltr/min, below that and the flow is next to schweet fanny adams.
At 3 bar/45psi the flow is ~3ltr/min - none of that seems excessive and kinda points towards staying with the original ......
The original has 2 x 5mm inlets and bored with a 6.1mm outlet. At circa 2Bar (30psi) the flow rate is ~1.5ltr/min @ 5mm around 0.5ltr/min, below that and the flow is next to schweet fanny adams.
At 3 bar/45psi the flow is ~3ltr/min - none of that seems excessive and kinda points towards staying with the original ......
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I've read that the inlet flow rate and pressure isn't an issue so long at the return pipe is big enough and with no restrictions. I'm not entirely conviced that's true. I've got a spare CHRA and I tried blowing through it a few weeks ago. Inflated my cheeks and there was quite a resistance as I blew through it. The oil ways around the CHRA spindle etc are quite fine. I'm wondering that even with a clear, well fitted return pipe there may still be problems with too great an inlet oil flow and pressure. I shouldn't need to but I'm considering putting on a pressure regulator to restrict the pressure to 40psi. Whoever had yours may have had a badly fitted return pipe without realising and went for the restriction in the banjo bolt as a solution?
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Yeah, there must be a reason these things exist and that they are available for the Garrett T250-04 (as fitted to 300tdi's) ...
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Turbo rebuilder says "in this application, use the original" ... so I will.
