Jump to content
SAU Community

Bottom End Stuffs

Anonimo

By Anonimo,
in Engines & Forced Induction

 Share

Recommended Posts

Anonimo Rookie

Anonimo

Posted
Posted

Crank stuff

Ive noticed that std rb30 cranks are cross drilled. I guess like most production cranks. The common knowledge is that at higher rpms oil has a hard time getting to the big end journal when it has to fight centrifugal forces acting against it. As a result its usually the big ends that go first normally due to insufficient oil supply...which commonly happens in the higher rpm range.

Has anyone come up with any mods (crank or otherwise) to overcome this, whether its a critical issue or not? Or perhaps even thought about it? I am aware that it helps by running higher oil pressure to overcome said forces, but high oil pressure also robs horsepower, creates excess friction and heat to both the oil and bearings. Obviously if a billet crank was being made soley for performance applications it would be a straight-line or straight shoot.

Block stuff

I know there are a few block mods to do to most rb30 bottom ends to allow them to handle more power for racing/performance situations.. Like drilling out the main feeds to 7mm and the bearing shells to suit. Some even goto the length of grooving the block(not caps/girdle) so you can run gtr bearings with the multiple oil holes on the top shell.

Has anyone thought about or tried perhaps 360 degree grooves. So both block and cap have oil flow around the bearing? You would have to mod the bearing with oil holes so you could take advantage of this, but i would think it would allow for a constant oil feed to the mains/big end.

Obviously with all these extra passages for oil to flow pressure would drop and you would need to either up the pressure or get a higher flowing pump to provide enough extra oil for these extra areas.

Anybody have any thoughts/ideas/tip or tricks?

Link to comment
https://www.sau.com.au/forums/topic/269253-bottom-end-stuffs/
Share on other sites
psi Experienced

psi

Posted
Posted

The humble old RB30 is a very durable device. Just look at how many are still driving around on the roads..

What sort of punnishment are you thinking that you are going to apply to your engine?

In standard form, with standard oil pump, they are prone to some oil issues at hi revs only.

But from what I have found, the problem lies totally in the oil pump itself.

The pump does not like and cannot handle prolonged hi revs. We have had cracked pump housings and such, but never had any oil issues anywhere else with the stock RB30 configuration.

Unless your building a monster engine to do insane revs, it seems to as if your trying to fix an issue that does not yet exist for this engine.

in this part of the forum, look up 'RIPS', he has done some very crazy things with the RB30.

If anybody has struck such issues, it would be him! and he would know how to fix them!

Anonimo Rookie

Anonimo

Posted
  • Author
Posted

This is all in reference to high end pure race motors...not road cars. Drag, Drift and circuit cars only. Not including peoples road cars that see track work either.

Yeh ive seen the RIPS stuff and followed some of his/their work. Very good stuff. I agree with you bubba. He seems like he holds quite a few secrets close to his chest! But with good reason. It would be nice to know if there are some things he does that he hasnt eluded to publicly. Especially when you get up in the high horsepower and big rpm areas!

Everyone i know who races hybrids have to keep revs low and always seem to have bottom end issues. Often seen in engines pushing 600hp+ and see anything over 7500rpm.

spannerx Contributor

spannerx

Posted
Posted

The cranck my be standard but im sure it will be all about the clearences, stud size, clamping torques, oil gallery enlargments including bearing shells, i wonder how much nascar engine spec is applied to a meir nissan 6 ?

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

    • GTSBoy
      Unknown sound similar to BOV on positive boost with partial throttle RB26

      By GTSBoy · Posted

      No. Turbo shuffle and surge/flutter are not the same thing. Specifically, on a GTR, turbo shuffle has a definite meaning. On a GTR, the twin turbos are assumed to be the same thing and to operate the same way, exactly. In reality, they do not. Their exhaust sides are fed and exhaust a little differently, to each other. Their inlet sides are fed and exhausted a little differently, to each other. Consequently, when they are "working" they are often at slightly different points on the compressor map compared to each other. What this means, particularly when coming on boost, is that one of them will spool up and start producing extra flow compared to the other, which will put back pressure on that other compressor, which will push the operating point on that other compressor up (vertically). This will generally result in it bumping up against the surge line on the map, but even if it doesn't, it upsets the compressor and you get this surging shuffle back and forth between them That is "turbo shuffle" on a GTR. It is related to other flutter effects heard on other turbo systems, but it is a particular feature of the somewhat crappy outlet piping arrangement on RB26s. There are plenty of mods that have been attempted with varying levels of success. People have ground out and/or welded more material into the twin turbo pipe to try to prevent it. Extending the divider inside it works, removing material doesn't. There are aftermarket replacement twin turbo pipes available, and these exist pretty mush purely because of this shuffle problem.
    • Duncan
      Leaking Rear Subframe Bushing?

      By Duncan · Posted

      You can temporarily* use lock collars to keep it in place until you can do the bushes, back the nuts off, slide them in, snug back up. *temporarily is often for ever
    • nouveau_poor
      Unknown sound similar to BOV on positive boost with partial throttle RB26

      By nouveau_poor · Posted

      Thanks for the quick reply. To be clear, when you say turbo shuffle do you mean turbo flutter "stustustu" or referring to something else? I had thought they were the same thing. When I wrote the post my intention was to say it wasn't a flutter/compression surge sound. My understanding was that a flutter sound would be occurring when throttle is released, whereas I can keep the throttle in the same position for this noise
    • GTSBoy
      Unknown sound similar to BOV on positive boost with partial throttle RB26

      By GTSBoy · Posted

      Yeah it does.
    • nouveau_poor
      Unknown sound similar to BOV on positive boost with partial throttle RB26

      By nouveau_poor · Posted

      Hi everyone, I've been wrestling with this for a while now and have been trying to find out the cause. For context, the turbos used are Garrett 2860 -5s, the BOV is a BNR32 HKS SSQV IV kit, the car is currently tuned to ~470 whp on 17.5 psi. The car drives normally, pulls well when it doesn't happen, and I can replicate it fairly easily. It does not sound like turbo shuffle or flutter. The engine has only a thousand or so miles and has had this behavior since it was completed. After my engine was built for my R32 GTR, I noticed that the car now sometimes makes an air discharge sound on what appears to be positive boost pressure that sounds really similar to a BOV. I had thought that it was a BOV issue but even when replacing it with a brand new unit, the sound persisted. It seems like it's coming from the passenger side but I may be mistaken. The closest scenario I could find was this post here https://www.gtr.co.uk/threads/maybe-a-boost-leak-opinions.147955/https://www.gtr.co.uk/threads/maybe-a-boost-leak-opinions.147955/ started by @yakshii and it sounds very similar. As in, at partial throttle once I reach positive boost I begin to hear the same psh psh psh psh psh sound like air is leaking somewhere when I keep the throttle in the same position. It most commonly happens in 4th gear at around 3-3.5k RPM and 5th gear around 2.5-3k RPM, which seems to coincide with normal positive boost thresholds. It might be similar to what @Austrian GTR mentioned about his own HKS SSQV. Notable difference would be that when he applies more throttle when it happens, it stops. In my scenario if I apply more throttle during this repeated psh psh psh sound, the cadence of the sound gets faster and louder rather than stopping. If I lift off slightly and apply throttle again, it will normally stop and pull without issue. I've checked all rubber couplers to ensure that they are tight, but have not gotten the opportunity to properly do a pressurized boost leak test. If anyone has had similar experiences or thoughts on what might be the cause, I'd be very keen to hear them. I also have a video of it happening from inside the cabin, if that would make it easier to understand: https://youtu.be/2zqZXcx8jbA
×
×
  • Create New...