what caused my cracked ringland(s)

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05-17-2013, 07:53 AM

#11

BLU CIVIC

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Re: what caused my cracked ringland(s)

Quote:

Originally Posted by Fabrik8

Why did it happen? That's harder to track down without seeing what happened real-time, with a datalogger or whatever. You'd need to see the A/F ratio and ignition timing and ideally something like EGT also. It could be the tune, or it could be a problem with the fuel system or ignition system, etc. I'm not going to throw the tuner under the bus without knowing how complete the tune was and how conservatively it was tuned, etc., but the tune has the most ability to impact engine operation if everything else is working properly (ignition, fuel system, etc). Don't automatically assume the tune was the issue though, unless you have some reason to suspect that.

What do the tops of the pistons and the combustion chambers look like? Are they pitted at all? I don't mean melted, I mean pitted like they've been sandblasted...

yeah, I figured it'd be hard to pinpoint and considered changing tuners, but i haven't had a single problem in the 5 years he's been working on my cars. these are a couple pics that my friend took of the offending piston and can get pics of the rest of the pistons

Quote:

Originally Posted by sleeperteg

In all seriousness though, how long were you running this setup? Maybe it was running way too lean for some reason and you got bad pre-ignition or maybe ignition timing is off

car was initially tuned 3/12 and made 249/184 @ 9psi and then retuned on 10/12 and made 296/229 @ 13psi.

Quote:

Originally Posted by power2weight

Are the injectors new? Did you send them off to be flow tested if they're used? Stock fuel pump? How many miles were on the spark plugs?

using Chrysler 550cc injectors. were never flow tested, but used them for several years. Having them cleaned and flow tested before i get tuned. Fuel pump is a Walbro 255 and just recently (probably a month or 2 ago) changed spark plugs. this is how my old ones looked 11 months after going turbo

05-17-2013, 08:18 AM

#12

99formula

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Re: what caused my cracked ringland(s)

Hurting a ring land makes me think either too much fuel or detonation.

Mostly too much fuel.

That's coming from a nitrous user though. The FI guys can seem to run much richer than us without hurting shit.

05-17-2013, 09:05 AM

#13

Fabrik8

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Re: what caused my cracked ringland(s)

Quote:

Originally Posted by 99formula

That's all about combustion dynamics and how/when energy is released; nitrous affects the duration/shape/timing of the cylinder pressure differently than forced induction.