Jump to content
SAU Community

Rb26 Rod Strength Settled!

Cateans05

By Cateans05,
in Engines & Forced Induction

 Share

Recommended Posts

  • Replies 87
  • Created
  • Last Reply

Top Posters In This Topic

Popular Days

Top Posters In This Topic

Popular Days

Popular Posts

GTSBoy
GTSBoy

This spot reserved so I can come back and say I told you so when the thread turns into a hopeless shitfight.

GTRPSI
GTRPSI

Mercury ran 850hp at all 4 (630Kw) in their R34 GTR on 43 PSI with a stock bottom end from what i remember. They too wanted to find the limit and were expecting failure. Finding the limit is sort of

whatsisname
whatsisname

A piece of string is always twice as long as it is from one end to the middle, unless it's a one-ended piece of string.

Posted Images

QUP29 Community Regular

QUP29

Posted
Posted

Build engine with standard rods and aftermarket Pistons if that's what you want to do. But be sure to abuse it (and video it) and post back with results(and videos) :)

+1 on video

can't wait to see the photo of this carnage, don't do a half ask job too. i want to see a massive hole in the block :)

Stixbnr32 Rising Star

Stixbnr32

Posted
Posted

I know of a car that ran about 400kw with standard rods for 10 years before they failed. When they failed the ripped in half. But it lasted a long time. I went with brand new rods on my build (nitto's) because they were cheap enough while the engine was apart.

Blackkers Experienced

Blackkers

Posted
Posted

+1 on video

can't wait to see the photo of this carnage, don't do a half ask job too. i want to see a massive hole in the block :)

What do you seriously think would cause that to happen with 450kw and prepped standard rods?

GTSBoy Grand Master

GTSBoy

Posted
Posted

What do you seriously think would cause that to happen with 450kw and prepped standard rods?

Age. It will eventually get any reciprocating part. Prepping standard rods buys you a certain amount of extra strength, and depending on how much effort is put into looking for cracks and so on, a certain amount of confidence that they are in good condition and not harbouring any cracks. But new cracks can form at any time once they've been up and down enough times.

The other killer is of course, rod bolts and the usual risks of being assembled incorrectly.

scotty nm35 Grand Master

scotty nm35

Posted
Posted

I have seen a few built blocks split their bore at not much more than 450kw, personally I would be keeping it as close to stock sized pistons as possible so as not to weaken the bore.

It's not pretty snapping or bending rods, I have been engulfed in the oil fueled fireball whilst standing beside the dyno, I would hate to see the carnage if it happened on the road at full noise for the sake of a relatively cheap set of rods, especially as you have the engine apart...

Why bother at all, just see what you can get out of the stock internals.

scotty nm35 Grand Master

scotty nm35

Posted
Posted

It was a late model 1UZ, light rods known to be undersized for the 1200nm of torque it was putting out. Ethanol was the culprit, along with the GT35 I fitted to it.

The RB26 block split was due to cylinder pressure I imagine, as was the Cossie Sierra race block that did the same thing. Tuning past that imaginary point where pressure beats steel. :P

  • Like 1
scotty nm35 Grand Master

scotty nm35

Posted
Posted

Ethanol produces more torque compared to petrol for similar power, especially when you lean on the boost past where the power stops rising. It is also nearly impossible to find the point where cylinder pressure rises exponentially due to it's anti detonation qualities. At some point some part will let go, where that is who knows, it comes down to your tuner at the end of the day.

If the 1UZ was on petrol, due to being high comp we would have had to stop boosting well before the point the rod went, with less timing. Revs were kept pretty much stock as I remember.

XRATED Veteran

XRATED

Posted
Posted

Just throw a stock rod under a 100lt press and record the pressure it starts to bend at, then do the same for an h beam/forged rod.

Bam...

Stock rod strength question answered!

15deg axial load, I'm going to say..... 3t

J.

Cateans05 Collaborator

Cateans05

Posted
  • Author
Posted

Just throw a stock rod under a 100lt press and record the pressure it starts to bend at, then do the same for an h beam/forged rod.

Bam...

Stock rod strength question answered!

15deg axial load, I'm going to say..... 3t

J.

Thats actually quite genius! anyone willing to donate a H beam? lol i got heaaap of spare rods

Guest
This topic is now closed to further replies.
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • GTSBoy
      Boost cut after swap(RB25DET NEO) R34

      By GTSBoy · Posted

      Yes. You will need to get the original boost sensor and wire it in. That is.... if you plan to use a stock ECU - even a Nistuned ECU. The Nissan ECU will not operate correctly without it connected. And yes, it will do annoying stuff like you are experiencing. You will almost certainly be better off with some aftermarket ECU, than trying to hunt down rare sensors.
    • Kapr
      Boost cut after swap(RB25DET NEO) R34

      By Kapr · Posted

      Ok so ABS/TCS is "not" the problem. Yeah i know now about the ABS with Nistune(i told that to the Nistune guy) but iam not 100% why or why i dont have ABS. ABS cube is in the engine (always has been) but i had braked couple of times rly hard and brakes just locked and scream. Does all Skylines have ABS cube? That boost sensor https://www.sau.com.au/forums/topic/367633-wtb-r34-gtt-turbo-pressure-sensor-pics-inside/ Is this it? I need to ask but i have a picture of engine bay and i do not see that (100% is not in that place) If i do not have this the car can do what mine is?(cutting around 4000 rpm) Here is the pic of my engine bay(only one i have) BUT i think i dont have that cuz loom was used from my RB20DE NEO and i know (obviously) that it does not have boost control or any wire to that...) so maybe that is the problem? (i dont know for 100% if that car where the engine is from had that)...but i dont have the loom from that
    • MBS206
      S1 rb25/s14 starting problem

      By MBS206 · Posted

      I'm with you here. It's either loom has an issue, OR, injectors are not functioning properly. It could even be they're just constantly dribbling, hence the wet, but not firing.
    • Duncan
      S1 rb25/s14 starting problem

      By Duncan · Posted

      Depending on how long the car sat it is very possible for injectors to be stuck open or closed, I'd get them cleaned and flow tested. Other than that, obviously when the loom changes and the car doesn't start any more....the loom is suspect so some tracing / comparing may be required
    • 25zenki
      S1 rb25/s14 starting problem

      By 25zenki · Posted

      Harness is for a s1 Rb25det, and it is engine and lower harness.  the old harness had broken off plugs and was in very rough condition/exposed wires and splices etc. it is not able to be put back on the car, I could visually inspect to see if they had rewired any pins on the ecu plug. The fuel pump definitly isn’t turning off it’s an external pump and very loud you can hear it. Will look at the other harness tonight, am also going to pull the fuel rail and watch the injectors spray, will update here with what I find. Pretty sure at this point it has to be something to do with injectors because car will fire up on starting fluid and cas is clicking the Injectors. Fuel pressure is steady 43psi 
×
×
  • Create New...