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Old 07-18-2013, 02:59 PM   #181
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That's a very impressive failure.
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Old 08-01-2013, 02:28 PM   #182
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Saw this thread during my build and thought I would luck out with my setup. Well, obviously no one is immune Figured I'd share my latest disaster.

Check out the pics for the carnage. The cylinder scoring wasn't horrible since I shut the engine off as soon as I heard things going to hell, lol. #1 had a portion of the crown removed, and #1 and #4 had severely cracked skirts. #1 spark plug was mechanically crushed from the debris.
No wideband or datalog readings, unfortunately. The engine was running rock solid for 4 months on this tune, but the day that this happened it was about 90 degrees out so I'd imagine the IATs were sky-rocketing thanks to my small-ish Mishimoto z-line intercooler and in addition to running at 20-22psi daily through a GT2871R.

Always used 93 octane and BKR8E-11 plugs. I don't remember what the p2w clearance was, but it was within spec when I measured it according to the Miata workshop manual.

Machinist said 100% severe detonation, likely from too aggressive timing. Bottom-end assembly looks OK - crank and bearings still good, and pistons were starting to melt in intake valve relief cuts (cats tongue feel). I'm going with 83.5 (+.020) Wiseco 8.5-8.8. Also looking into Meth injection for throttle>70% & over 10psi. I was also thinking of upgrading intercooler and being more aggressive with IAT dependant retard and fueling.
Attached Thumbnails
Built motors and detonation-45213_10201136497547783_1711508257_n.jpg   Built motors and detonation-156317_10201136497587784_1282164224_n.jpg   Built motors and detonation-565768_10201113716618274_1915210193_n.jpg   Built motors and detonation-1017097_10201136497307777_2142322288_n.jpg   Built motors and detonation-1098334_10201136497427780_211798894_n.jpg  

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Old 08-01-2013, 02:37 PM   #183
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Quote:
Originally Posted by JustinOMGWTF View Post

Machinist said 100% severe detonation, likely from too aggressive timing.
Please post a screen shot of your timing map.
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Old 08-01-2013, 02:53 PM   #184
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stock pistons, 22psi, shitty IC, too much timing...

Last edited by Braineack; 08-01-2013 at 03:19 PM.
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Old 08-01-2013, 03:02 PM   #185
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Quote:
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Also looking into Meth injection
*water injection
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Old 08-01-2013, 03:14 PM   #186
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This isn't the most recent timing map, but I haven't touched the boost region since the tune.
Built motors and detonation-forumrunner_20130801_141004.png


Did plenty of research before hand. Plenty of success with 9:1 stock pistons, high boost, and eBay intercoolers. Not everyone has deep pockets.

Bigger greddy intercooler, meth, and tuning back timing up top. Rebuild #6!
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Old 08-01-2013, 03:20 PM   #187
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at 260kPa, you run what I do at 195kPa.
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Old 08-01-2013, 03:26 PM   #188
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Ha, that's a manly map. I'd run that with lotsa w/i or e85, but not just on pump gas.
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Old 08-01-2013, 03:32 PM   #189
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Quote:
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Plenty of success with 9:1 stock pistons, high boost, and eBay intercoolers.

Rebuild #6!
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Old 08-01-2013, 03:49 PM   #190
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I ran like 3* less than that on gas.
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Old 08-01-2013, 03:59 PM   #191
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with a precision 600 and colder weather, no?
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Old 08-01-2013, 04:05 PM   #192
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99 head with intake cam retarded 7 degrees, if that matters.

This was Dyno tuned on a mainline dyno by xenocron.

Rebuild #6 for various reasons:
1. Initial rebuild
2. Thrust bearing failure
3. Crank bearing issue
4. Head gasket explosion
5. 99 head swap
6. Detonation

No matter how much money you throw at a car, there's always going to be something. It's all about risk.
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Old 08-01-2013, 04:12 PM   #193
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Intake cam retarded 7 degrees!?

Also, Im surprised at xenocron, I thought they would be a little better than that.
Although its a bit weird it held together for so long before popping. Whats your fuel system like BTW? You running used injectors?
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Old 08-01-2013, 04:24 PM   #194
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ITT: 99 reasons to run e85
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Old 08-01-2013, 04:26 PM   #195
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Quote:
Originally Posted by Full_Tilt_Boogie View Post
Intake cam retarded 7 degrees!?

Also, Im surprised at xenocron, I thought they would be a little better than that.
Although its a bit weird it held together for so long before popping. Whats your fuel system like BTW? You running used injectors?
There was a reason behind that cam adjustment. Check out my build thread if you want all the details, but here's the excerpt:

* Cam gear proved to be a great investment. Picked up 26WHP by just retarding intake cam 5 degrees!

Final setting for the gear was 7 deg with no improvement or performance decrease - so it was left as-is. Check out the attached pic.

Injectors were used 750cc RC's, but I had them cleaned and flowed at SouthBay fuel injectors. Perhaps it's worth revisiting to make sure they're still within close proximity of one another?

I used an electronic det can for some time after the build and constantly monitored AFR and IAT. I tried not to beat on the engine when the ambient temps rose, but obviously things were just too aggressive to last. I'm sending the latest project file back to the tuner at Xenocron to dial back timing a bit, and I'm buying a bigger intercooler tonight, forged pistons, and water injection. Any other recommendations?
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Old 08-01-2013, 04:29 PM   #196
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yes, chuck those RC's into the trash where they belong and pick up some ID's
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Old 08-01-2013, 04:42 PM   #197
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Quote:
Originally Posted by 18psi View Post
yes, chuck those RC's into the trash where they belong and pick up some ID's
Trying to avoid getting retuned. Besides, I've run RC injectors on my last three turbo builds and had zero fuel related issues.
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Old 08-01-2013, 04:45 PM   #198
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They work, they just have poor atomization compared to modern injectors.
The tune is going to have to be re-worked anyway, it shouldnt be a big deal to offset the fuel table for different injectors.
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Old 08-01-2013, 05:16 PM   #199
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Quote:
Originally Posted by Full_Tilt_Boogie View Post
They work, they just have poor atomization compared to modern injectors.
The tune is going to have to be re-worked anyway, it shouldnt be a big deal to offset the fuel table for different injectors.
Funny that SouthBay didn't have anything to say about the RC's either, but I have been hearing a lot of great things about the ID's. I'll look into them.
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Old 08-01-2013, 05:37 PM   #200
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Quote:
Originally Posted by JustinOMGWTF View Post
Not everyone has deep pockets.

Bigger greddy intercooler, meth, and tuning back timing up top. Rebuild #6!
How about a decent knock sensor?
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