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M35 Banjo Restrictor

scotty nm35
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scotty nm35 Grand Master

scotty nm35

Posted
Posted

I have moved the discussion off the Dyno results thread.

We have been recommended to drill out our turbo oil restrictors to 3mm once going to a bushed core highflow, I only found this out after Aaron's failure. I have been running the stock 1.2ish mm restrictor with my old turbo for well over a year and the shaft play is fine so I doubted the info but every turbo swap I have done now has included the drilling of this banjo to 3mm.

I dont think the BB cores require it but Aarons core failed almost straight away. I can only assume the reason his stock turbo and then his BB highflow failed was from gunk blocked in the hole. (it was very mucky inside the banjo when I drilled it out.)

I am still running the stock restrictor in mine as I have gone back to the stock turbo temporarily. My restrictor was clean inside but I recently flushed it and I have always changed my oil before 5k. Perhaps it is slack servicing while in Japan that causes the block to dirty up?

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https://www.sau.com.au/forums/topic/358131-m35-banjo-restrictor/
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Commsman Veteran

Commsman

Posted
Posted

Great info, thanks Scott.

Like you say, it may just be that the stock turbo can handle more boost if they get the proper supply of oil. I'll be checking for any gunk in mine ASAP.

scotty nm35 Grand Master

scotty nm35

Posted
  • Author
Posted

Its only a theory, and it will definitely shorten it life still. I say to anyone buying an M35 to keep some cash aside for what will eventually happen.

If I can save one person's turbo though, by explaining this oil issue, i'm a happy man. :)

Sunkist Grand Master

Sunkist

Posted
Posted

it will shorten the life, i ran my stocky at 20 psi and it took just under 6 months to blow up.

but who knows whether it was being starved, i'de say the BB core was, it make a loud whining noise from the word go.

but the stock turbo's power was very impressive!

Sage222 Rising Star

Sage222

Posted
Posted (edited)

you ran 20psi for 6 months with a factory turbo?? and other mods to help support it?

hmm.. maybe ill add a couple more psi! :)

how hard is it to drill out the restrictor? would you recommend it for a standard turbo setup?

Edited by Sage222
scotty nm35 Grand Master

scotty nm35

Posted
  • Author
Posted

lol, wait till I have worked out the Garrett install just in case. >_<

The stock turbo shouldn't need any more flow, would it hurt? Im not sure, I dont think it would damage anything, if there is too much flow it may get past the seals and burn in the dump. Its not too hard to get the banjo bolt out, and easy to drill in my lathe but it can be a pain to line the banjo back up to get it all back together and if the bolt isnt straight it will munch the thread. (cast alloy sump)

The stock setup will run out of injector fairly early, if you plan to bump it up, get some way of adjusting the mixture and timing. (Emanage) You will make a much greater gain then.

Sunkist Grand Master

Sunkist

Posted
Posted

you ran 20psi for 6 months with a factory turbo?? and other mods to help support it?

hmm.. maybe ill add a couple more psi! :)

how hard is it to drill out the restrictor? would you recommend it for a standard turbo setup?

yeh as scott said. it probably isnt advisable, i was just a young p plater then and all i wanted was boost and a loud PSSHHH sound.. ive grown up now..

lol

i didnt realise i wouldve maxed my injectors duty cycle, and probably considered myself lucky i didnt break things(more than the turbo)

i probably wouldnt drill out the restrictor, incase you need to go back for whatever reason, or drill it out to much..

im happy with my set up now, i just want to run lower boost now, but cant with the wastegate size being a tad bit too small - didnt realize 1-2mm of wastegate, would make such a difference.

Jetwreck Grand Master

Jetwreck

Posted
Posted (edited)

yeh as scott said. it probably isnt advisable, i was just a young p plater then and all i wanted was boost and a loud PSSHHH sound.. ive grown up now..

lol rofl.gifrofl.gifrofl.gifrofl.gif

i didnt realise i wouldve maxed my injectors duty cycle, and probably considered myself lucky i didnt break things(more than the turbo)

i probably wouldnt drill out the restrictor, incase you need to go back for whatever reason, or drill it out to much..

im happy with my set up now, i just want to run lower boost now, but cant with the wastegate size being a tad bit too small - didnt realize 1-2mm of wastegate, would make such a difference.

I'm surprised your turbo builder didn't think of that since his not just a machinist! :P on a more serious note...I'm surprised your turbo builder didn't think of that

P.S. You might want to add "running E85" in your signature! :P

Edited by Jetwreck
  • 4 weeks later...
whiteaxis Explorer

whiteaxis

Posted
Posted

I'd really like to check out the banjo restrictor as the whining has been getting louder from my turbo (the whining has been getting louder from the passenger seat since the new exhaust aswell but that's a different story......)

I've read that the restrictor is on the block but where is it exactly? Should I approach it from the top or from underneath?

Hopefully checking this and doing a flush will extend the life of my turbo a little.

Sunkist Grand Master

Sunkist

Posted
Posted

I'd really like to check out the banjo restrictor as the whining has been getting louder from my turbo (the whining has been getting louder from the passenger seat since the new exhaust aswell but that's a different story......)

I've read that the restrictor is on the block but where is it exactly? Should I approach it from the top or from underneath?

Hopefully checking this and doing a flush will extend the life of my turbo a little.

theres two bolts. one to the turbo, and one on the engine sump or block.. find the line on the turbo and trail this to the block.

the banjo on the block has the restrictor and will need to be checked.

im thinking it was the cause of mine blowing up the 2nd time. If you can save it, thats a plus.

scotty nm35 Grand Master

scotty nm35

Posted
  • Author
Posted

Once its whining the bearings are shagged so its only a matter of time before the rear wheel contacts the housing and smashes itself to pieces unfortunately. You may get a few more months out of it, perhaps a lot more if you drive conservatively. (Yeh right. :))

  • 7 months later...
FHF Enthusiast

FHF

Posted
Posted

I'm getting myself prepared to drill a bigger hole 1.5 - 2mm and I just wanted to find out the correct procedure for this...

Would it be ok to use a table vice and a cordless drill ?

It would be appreciated if someone could give me detailed information in how to drill this hole.....

thanks in advance...

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