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Melted a piston - unsure why.

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Old 07-10-2018, 07:16 PM
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There is a flow match guarantee.... You just DEFINITELY have to flow match them to assure this. You can't just just decap 8 injectors and slap them in, likely too much variation. I decapped and flow tested 30 injectors using the arduino flow bench I built in my signature. It took 30 to come up with a matched set in my case. Around here truck injectors are practically given away along with other rusty unexotic "low performance" truck parts.

Decapping is definitely a viable solution for injectors but they MUST be flow matched to get a matched set. Either build a flow bench like I did or send them somewhere to be flow tested.

Last edited by ElQueFør; 07-10-2018 at 07:24 PM.
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Old 07-11-2018, 05:11 PM
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Originally Posted by 99camaroturbo View Post
They were $360-370 from VS, no not flow matched. They have been flowed and showed a 9cc difference from most to least. #1 that got hurt was right in the middle of the spread.
A 9cc difference at what pulsewidth? Did they do any dynamic comparisons at various pulsewidths? Only reason I mention this is because there is a hell of a lot more to matching injectors then just what they flow at a single measured pulsewidth. This is where decapped injectors also **** the bed because they look close at whatever pulsewidth they are tested at but are terrible at other pulsewidths. There is a reason that GOOD flow matched injectors are quite expensive compared to cheap ones.
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Old 07-11-2018, 05:39 PM
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If timing melted that piston it's because it was too low with too much fuel! AFR is way too rich. Unburnt fuel gets past the rings and accumulates. When it ignites the result is a torch flame that burns out the land and rings are so hot the become like a wet noodle and the pressure forces them down.
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Old 07-11-2018, 06:16 PM
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Default Matched Fuel Injector WITH Dead Times

Hi LM, Thanks AGAIN.

NEXT, (Nic) I ONLY PROVIDE fuel injectors in MATCHED SETS with Dead Times !

There is No COST INCREASE as I sell Many sets, THUS an easy said.

MY cost is normal to that of a quality fuel injector. (eight 45 .lbs = $360.00)

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Old 07-11-2018, 06:18 PM
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Default Matched Fuel Injector WITH Dead Times

Hi LM, Thanks AGAIN.

NEXT, (Nic) I ONLY PROVIDE fuel injectors in MATCHED SETS with Dead Times !

There is No COST INCREASE as I sell Many sets, THUS an easy said.

MY cost is normal to that of a quality fuel injector. (eight 45 .lbs = $360.00)

Lance
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Old 07-11-2018, 06:54 PM
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I tested my decapped injectors at something resembling 3 different pulsewidths. Also did a static test. Flow was consistent. Granted like I have said, I had to decap some 30 odd injectors to get a matched set so there is a lot of variation, but you can find a set that does work well with a little patience. JoeNova built a flow bench fancier than my own and his code more closely resembled real world injector use. I'm sure there are infinitely more precise and technically correct ways to test them vs an arduino flow bench but it's working for me.
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Old 07-11-2018, 07:17 PM
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Originally Posted by pantera_efi
Hi LM, Thanks AGAIN.

NEXT, (Nic) I ONLY PROVIDE fuel injectors in MATCHED SETS with Dead Times !

There is No COST INCREASE as I sell Many sets, THUS an easy said.

MY cost is normal to that of a quality fuel injector. (eight 45 .lbs = $360.00)

Lance
Really 45lb injectors? That's way to small for any turbo ls
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Old 07-11-2018, 07:35 PM
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Originally Posted by MY_2K_Z View Post
Really 45lb injectors? That's way to small for any turbo ls
Be CAREFUL! I was ONCe ToLd that HE'S? forgotten more THAN most On THIS forum! AppARently GOING tO scHool was ONE of the THINGS forgotten. Reading those nightmare inducing groups of words make me wonder if kingtalon was really so bad.
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Old 07-11-2018, 08:12 PM
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Originally Posted by Loud Mouse View Post
If timing melted that piston it's because it was too low with too much fuel! AFR is way too rich. Unburnt fuel gets past the rings and accumulates. When it ignites the result is a torch flame that burns out the land and rings are so hot the become like a wet noodle and the pressure forces them down.
Youre crazy if you think low 11s on 91 octane is "way too rich". Thousands upon thousands of boosted and nitrous cars run that and richer in everything from the LS to Subarus to 240s and don't blow up. Between causing damage from being too rich or having too much timing I would say 90+% of failures are from too much timing compared to too much fuel.
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Old 07-11-2018, 08:34 PM
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Too much timing would have caused excessive heat in the cylinder and burn the piston from the top down. Plug would also have shown peppering which would have been an indication of the cylinder being too hot.. The top of the piston is still intact
but if you want to believe 1000s of engines compare to yours, rock on. I'll check each and every one and tune it for what it likes. LOW TIMING and excessively RICH fuel will burn **** up. Adding timing makes HP, pulling timing makes the engine labor (high egts). I have been able to run power adders at very near naturally aspirated timing and adding fuel based on what makes the engine happy. Currenty running LS3 with 19° timing and high 11 afrs. Cylinders are very cool with max engine temp @ 185° in this hot *** Florida heat. IATs 15 over ambient. Have seen other simular engines running 22° and making more power than I am with more boost on pump 93 but they are in a automobile which doesn't present the load to an engine as does a propeller. If you can build an engine, tune it and make it live on an airboat, anything else is a breeze. Airboats are very hard on engines when even slightly off the tune much less far off...

Last edited by Loud Mouse; 07-11-2018 at 09:16 PM.
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Old 07-11-2018, 09:20 PM
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I not saying you're wrong, but that just runs counter to what just about everyone else here---including myself has experienced. It'd be easier to believe with some dyno sheets or something. I mean look at all the pump gas stuff from westech...all low 11's afr and fairly low timing.

BTW that piston to me looks like he butted the second ring, and continued to beat on it until it burned down
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Old 07-11-2018, 09:39 PM
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What I think people are doing with the SBE is pulling timing to keep from bending the rods thus hurting the power output, then applying more boost to get the power back(softer on the rod). Yes that type of tuning works to make the stock engine live but isn't necessary for the typical performance engine. IMHO

In roots blown SBCs running all out 32 to 36 timing with 23° heads. Very few problems and loosing a piston wasn't one of them..
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Old 07-11-2018, 10:10 PM
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I was under the impression that ls heads just dont need that much advance as compared to the old sbc days. And even less so when boost is added.

We all manipulate timing to put the power to the crank at the best possible angle, but I don't think anyone in the know is doing that to avoid bending rods. Most bent rods we see here are the result of applying the power at an inopportune time via pre-ignition or detonation---via lean afr's or too much timing at high cylinder fill volumes.

<----Team Baby Soft since 2016
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Old 07-12-2018, 12:19 AM
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A more efficient combustion chamber design needs less timing advance in general, so I would expect the LS to need less timing compared to a SBC, generally speaking.

Myself I have had good luck with keeping the timing conservative (91 pump) and keeping the fueling a little on the fat side. Low 11 AFR in BE or PE.....
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Old 07-12-2018, 12:48 AM
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Originally Posted by Loud Mouse View Post
If timing melted that piston it's because it was too low with too much fuel! AFR is way too rich. Unburnt fuel gets past the rings and accumulates. When it ignites the result is a torch flame that burns out the land and rings are so hot the become like a wet noodle and the pressure forces them down.
how does that correlate to #6 rod being bent with zero piston damage?
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Old 07-12-2018, 05:15 AM
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Originally Posted by ddnspider View Post
Youre crazy if you think low 11s on 91 octane is "way too rich". Thousands upon thousands of boosted and nitrous cars run that and richer in everything from the LS to Subarus to 240s and don't blow up. Between causing damage from being too rich or having too much timing I would say 90+% of failures are from too much timing compared to too much fuel.
I dont think I've ever seen a car blow up from running too rich...and certainly never melt a piston. It's idiotic for someone to even suggest it !

Many OEM turbo cars will run into the 10's all day long, some right at the bottom, they do it for long term safety so you could literally hold it flat out forever.

Piston melting is from too lean/ too much timing and/or detonation. Every single time.
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Old 07-12-2018, 06:40 AM
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Originally Posted by Loud Mouse View Post
Too much timing would have caused excessive heat in the cylinder and burn the piston from the top down. Plug would also have shown peppering which would have been an indication of the cylinder being too hot.. The top of the piston is still intact
but if you want to believe 1000s of engines compare to yours, rock on. I'll check each and every one and tune it for what it likes. LOW TIMING and excessively RICH fuel will burn **** up. Adding timing makes HP, pulling timing makes the engine labor (high egts). I have been able to run power adders at very near naturally aspirated timing and adding fuel based on what makes the engine happy. Currenty running LS3 with 19° timing and high 11 afrs. Cylinders are very cool with max engine temp @ 185° in this hot *** Florida heat. IATs 15 over ambient. Have seen other simular engines running 22° and making more power than I am with more boost on pump 93 but they are in a automobile which doesn't present the load to an engine as does a propeller. If you can build an engine, tune it and make it live on an airboat, anything else is a breeze. Airboats are very hard on engines when even slightly off the tune much less far off...
Yes I will believe 1000's of engines compare to mine....because they're all air pumps and boost is nothing but a measurement of restriction. They all require a certain amount of spark advance and AFR to run. I tune in "hot *** Florida heat" as well and only 93 no meth.....and never an engine failure. Explain that. I don't understand why you and Pantera refuse to acknowledge 2 possibilities:
  1. Timing advance may be off. The 15* of advance quoted by the OP could really be 20*. You're going to say his boost level with 20* of advance and 91 octane is perfectly fine? Give me a break.
  2. If you want to make the rich argument, then acknowledge it's possible there was an injector issue or FP issue. The average of 7 cylinders of 11.5 and 1 cylinder at 10.0 is 11.3 and the wideband would read 11.3 and appear okay.

Originally Posted by stevieturbo View Post
I dont think I've ever seen a car blow up from running too rich...and certainly never melt a piston. It's idiotic for someone to even suggest it !

Many OEM turbo cars will run into the 10's all day long, some right at the bottom, they do it for long term safety so you could literally hold it flat out forever.

Piston melting is from too lean/ too much timing and/or detonation. Every single time.
Thank you!!! Was about to bring up the OEM, but these guy's must know better
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Old 07-12-2018, 07:21 AM
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I own 2 oem vehicles, 2008 single T and 2015 twins turbos and neither 1 is anywhere near 10s for afr. Not even close.
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Old 07-12-2018, 08:03 AM
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30 seconds of Google shows that other boosted OEM's, Subaru's in particular, have had their stock WOT AFR in the 10's. I don't tune for 10's, but it doesn't blow stuff up unless there are extenuating circumstances.
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Old 07-12-2018, 09:02 AM
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Originally Posted by Loud Mouse View Post
I own 2 oem vehicles, 2008 single T and 2015 twins turbos and neither 1 is anywhere near 10s for afr. Not even close.

So where are they ? post a log ? showing an independent wideband installed pre-cat ? and under heavy load
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