Jump to content
SAU Community

M35 Banjo Bolt Drilling For Highflows

scotty nm35
 Share

Recommended Posts

scotty nm35 Grand Master

scotty nm35

Posted
Posted

I have always suggested to drill out the banjo bolt in the block (that supplies the turbo with oil) to around 2.5mm once a highflow bush core turbo is installed. After the recent failure of a highflow due to oil starvation I did a flow test of the line at idle and found there wasn't enough oil flowing, even with the line/banjo disconnected. Suspecting a blockage in the block feed I checked another car and surprisingly found the same thing, the oil was only dribbling out. I checked on my spare engine and found in the sump another oil feed line, with two more 1mm restricted banjo bolts that feed oil to the external line. So it seems there are actually 3 x 1mm restricted banjo bolts as stock. Nissan definitely thought the oil pressure was way too high for the standard ball bearing turbo...

It also explains why the oil feed is so commonly blocked. On this car I have opened up the two sump banjo bolts to 2.5mm and approximately tripled the oil flow to the turbo, hopefully enough to supply the bush core with surplus. It was a bit wet today to take pictures but I will organise some next week, it's not a difficult job other than taking the pan off.

I am not suggesting everyone should rush out and drill these two extra banjo bolts out as I have, but Hypergear and I have agreed I should do this mod to all further turbo installs, to make sure not only the holes aren't blocked, and won't easily block again, but that there is sufficient oil flow to his turbos. I am also thinking about running braided lines and a filter inside the sump to replace the hard line, as it's easier to get to than the block mounted line, and would make sure no further blockages would occur. Not sure if it's warranted yet.

scotty nm35 Grand Master

scotty nm35

Posted
  • Author
Posted

Yep, Stao ships his turbo's out with a new banjo to suit the smaller thread in the CHRA. No idea why he doesn't simply tap it out, surely it's easier than cutting a banjo on the lathe... Anyway, what you did is fine Chris, just pointless if there are still two more restrictors. I would definitely suggest drilling them next service. ;)

scotty nm35 Grand Master

scotty nm35

Posted
  • Author
Posted

No worries guys.

I have had a few questions on this, one being can there be drawbacks. I personally don't think it will affect oil pressure to the engine, as only a small amount still flows to the turbos, even after drilling the banjos. I would definitely like to check the difference in oil pressure between my engine and this one but I have no gauge at the moment, and it is quite hard to read pressure without the adapter plate under the oil filter. I will check it at a later date.

Another question was, why aren't other turbo's blowing up. I believe there is JUST enough oil flow to keep the turbo's spinning, any partial blockage may be enough to do damage imo. Drilling the banjos out will give the turbo some leeway with oil requirements.

Here is the oil line we are discussing...

post-63525-0-89135900-1375444037_thumb.jpg

post-63525-0-28664500-1375444051_thumb.jpg

gleeson Community Regular

gleeson

Posted
Posted (edited)

No worries guys.

I have had a few questions on this, one being can there be drawbacks. I personally don't think it will affect oil pressure to the engine, as only a small amount still flows to the turbos, even after drilling the banjos. I would definitely like to check the difference in oil pressure between my engine and this one but I have no gauge at the moment, and it is quite hard to read pressure without the adapter plate under the oil filter. I will check it at a later date.

Another question was, why aren't other turbo's blowing up. I believe there is JUST enough oil flow to keep the turbo's spinning, any partial blockage may be enough to do damage imo. Drilling the banjos out will give the turbo some leeway with oil requirements.

Here is the oil line we are discussing...

Edited by gleeson

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • Black_CSR
      Wheel Sizes & Offsets For Skylines

      By Black_CSR · Posted

      Yeh I think i'll message an old contact i had for ages that manages his own tyre shop now.. n tell him what i want n work with him before ordering..  Got this 17x9 +30 Driftteks on 245/45/17 PSR Drag Radials on the rear.. They fit well - for your reference in future - Rear guards  have been lipped in & minimal to non flaring of the rear Gaurds.  
    • Kinkstaah
      Wheel Sizes & Offsets For Skylines

      By Kinkstaah · Posted

      If only it were that easy! I also needed to remove seats, shocks, brake calipers, send my car through a fence, and use measuring and ended up guessing because I didn't remove seats, shocks and brake calipers. It can be hard sometimes Can be a little more complex than 'just measure' if you want to truly measure the entire wheel through all of it's suspension travel. But if you aren't going for every last mm then yeah, you can check the space you currently have and guesstimate.
    • GTSBoy
      Wheel Sizes & Offsets For Skylines

      By GTSBoy · Posted

      If you own a car, and it has wheels on it, and you know the offset of those wheels, and you have a measuring device, you have everything you need to work out if other wheels will fit.
    • Black_CSR
      Wheel Sizes & Offsets For Skylines

      By Black_CSR · Posted

      Will this fit? but they are staggered set - RAYS 57DR SEMI GLOSS BLACK 18x8.5 +37 | 18x9.5 +38 5-114.3 STAGGERED SET   or If no go could just get a set 4's wheels of 18x8.5 +37 5-114.3 - would i run 8.5's 235s up front n 245's at the back if I do?   Thanks.        
    • MBS206
      MAJOR FUEL ISSUES 25det neo r32

      By MBS206 · Posted

      Put a clamp on your return line. I have a feeling it's sucking air, and introducing bubbles to your fuel. With a lot of fuel, less problematic. I'd honestly be redoing all the lines in the tank and clamps on everything.   Also, you've given two different answers to the same question: Asked if being followed by the police you could get down to use the whole tank, you said yes you could, so long as you keep off boost. However, you then followed this up that free revving, it would also cause the issues. I'm doubting free revving is enough to make any noticeable boost on what is likely a decent sized turbo.   So now I have to ask, can you actually drive it lightly and use all the fuel, or does it break up even free revving? Also, have you put a fuel pressure gauge on it? Can you hear the pump change noise at all when you're having this issue?
×
×
  • Create New...