4ringpieces
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« on: August 15, 2017, 05:50:03 AM »
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Yes I know of the "300lbft limit"
But I'm wondering how many of these rod failures have occurred on tunes with a raised rev limiter?
I see the other day on the internet a 1.8t blew a rod on a dyno with less than 300lbft, was believed that the rod kinked at high rpm on a run before going by strange graph reading, the rod then failed on the after run in which it failed and exit'd the engine.
Guess I'm speculating that raised limiters could be half the issue.
But how can you inspect a rod for compression or tensile failure? As normally the rod is destroyed quite badly.
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adam-
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« Reply #1 on: August 15, 2017, 06:28:29 AM »
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SB_GLI
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« Reply #2 on: August 15, 2017, 07:57:25 AM »
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I folded a rod on my 1.8t this spring. My rev limiter was not raised. My tune kept torque at a "safe" level until after 4,500 to try avoid conrod failure. I ran this way for a few years and it finally decided to give up one day.
My take, if you are running around 300ft/lbs with stock rods, it's just a matter of time until failure ensues.
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vwaudiguy
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« Reply #3 on: August 15, 2017, 08:59:51 AM »
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I folded a rod on my 1.8t this spring. My rev limiter was not raised. My tune kept torque at a "safe" level until after 4,500 to try avoid conrod failure. I ran this way for a few years and it finally decided to give up one day.
My take, if you are running around 300ft/lbs with stock rods, it's just a matter of time until failure ensues.
Possible to get details on your hardware? |
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"If you have a chinese turbo, that you are worried is going to blow up when you floor it, then LOL."
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SB_GLI
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« Reply #4 on: August 15, 2017, 11:50:15 AM »
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You bet.
550 ev14 injectors,
larger than stock maf,
Full 3" exhaust with high flow cat,
F21 mixed flow Frankenturbo
WMI injection,
larger SMIC
and slammed on racelands bro! (jk)
Now it's all that with the addition of a built bottom end.
I even have logs from that day just before the catastrophic failure showing how it was running very well.. next to no timing pull, no boost overshoot, steady 20-21 psi... etc. IMO you roll the dice every time you stomp the pedal if you are close to 300 ft/lbs.
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« Last Edit: August 15, 2017, 11:53:28 AM by SB_GLI »
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vwaudiguy
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« Reply #5 on: August 15, 2017, 05:17:01 PM »
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Thanks for the details. Funny story. I had a guy ingest water once, we purged the cylinders of the water, and he drove it like that for 50k until he brought it back to do rods. When we removed the rods we noticed every rod was bent (a nice soft radius noticeable to the naked eye). Guy said he didn't notice anything strange.  |
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"If you have a chinese turbo, that you are worried is going to blow up when you floor it, then LOL."
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nyet
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« Reply #6 on: August 15, 2017, 05:40:44 PM »
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Thanks for the details. Funny story. I had a guy ingest water once, we purged the cylinders of the water, and he drove it like that for 50k until he brought it back to do rods. When we removed the rods we noticed every rod was bent (a nice soft radius noticeable to the naked eye). Guy said he didn't notice anything strange. I bet the lowered compression allowed it to make a ton of timing! |
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Carsinc
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« Reply #7 on: August 17, 2017, 04:44:25 PM »
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Yea, I tell everyone the same... Oh you want to upgrade the turbo buy rods, you do want to buy rods
keep the stock turbo. I dont like piddle paddling around a limit trying to guess what wont explode.
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Dejw0089
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« Reply #8 on: October 26, 2017, 12:14:38 PM »
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Anyone can tell me if I have k04-023 stock turbo then if I have boost 1.3 bar - 4500 RPM and 1 bar -6000 RPM my rod were driven near limit? or it is safe?
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KasperH
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« Reply #9 on: October 26, 2017, 12:19:50 PM »
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Anyone can tell me if I have k04-023 stock turbo then if I have boost 1.3 bar - 4500 RPM and 1 bar -6000 RPM my rod were driven near limit? or it is safe?
I've been doing this the past 6 months on 180 bhp rods, and none of them have tried to escape (yet) But it all depends on engine health |
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_nameless
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« Reply #10 on: October 26, 2017, 12:51:53 PM »
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my beetle s line was on a k04-023xl 26-27 psi spike hold 20 psi to redline on e85 and it lasted 2 years like that
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If you are in the market for a tune and would like the ease of downloading and flashing a dyno tested tune for a fair price check out https://instatune.sellfy.store/ |
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adam-
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« Reply #11 on: October 26, 2017, 12:53:18 PM »
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Engine health does not beat metallurgy.
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KasperH
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« Reply #12 on: October 26, 2017, 01:17:22 PM »
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Engine health does not beat metallurgy.
True, but if engine have been beaten on and have damaged bearings and contact surfaces. The risk is even higher |
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« Last Edit: October 26, 2017, 02:26:50 PM by KasperH »
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mister t
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« Reply #13 on: October 27, 2017, 07:32:05 PM »
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Want to know why rods bend?
Answer: DETONATION!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
I'd bet my life that the vast majority of unexpected rod failures are always preceded by detonation. It's probably imperceptible in many cases, but I can promise that it occurs just before a rod lets go.
So long as you don't detonate, I think that you can probably exceed the 300 ft/lb limit for quite some time without damaging the engine. However, if you're right on the ragged edge and start detonating at peak load, your stock rods are gonna let go unexpectedly.
I think it makes a very good case for water/meth on any stressed stock rod setup. But that's just my opinion...
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Dejw0089
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« Reply #14 on: October 28, 2017, 05:57:07 AM »
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Want to know why rods bend?
Answer: DETONATION!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
I'd bet my life that the vast majority of unexpected rod failures are always preceded by detonation. It's probably imperceptible in many cases, but I can promise that it occurs just before a rod lets go.
So long as you don't detonate, I think that you can probably exceed the 300 ft/lb limit for quite some time without damaging the engine. However, if you're right on the ragged edge and start detonating at peak load, your stock rods are gonna let go unexpectedly.
I think it makes a very good case for water/meth on any stressed stock rod setup. But that's just my opinion...
Ok so I must say my car isn't stressed because I have stock k04-023 turbo and 250HP so I can't reach 300 ft/lb. My rod bend in normal drive low load and RPM and I logged CF for see does I have detonation and for all RPM's I have 0CF for all 4 cylinders (I use stock ignition map). |
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