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Detonation on 1 & 4
Short version: MSM dedicated track car rebuilt last winter MSM MS3Pro PnP ECU that has been in car for over 50 track hours PRIOR to rebuild Wiseco 8.5:1 83.5mm pistons Eagle rods FlowForce 640ish injectors Stock turbo Stock ignition coils 93 octane Some kind of Saab intercooler 13psi about 218 whp 10.5-11 AFR It ran about 10 track hours cylinders 1 and 4 failed due to detonation Why 1 & 4 ? https://cimg1.ibsrv.net/gimg/www.mia...6eb5d204c.jpeg4 is on the left https://cimg2.ibsrv.net/gimg/www.mia...ecab9e86b.jpeg4 and 1 https://cimg3.ibsrv.net/gimg/www.mia...72642959d.jpeg1 https://cimg4.ibsrv.net/gimg/www.mia...7e03af772.jpeg4 https://cimg5.ibsrv.net/gimg/www.mia...129977571.jpeg1 on the left https://cimg6.ibsrv.net/gimg/www.mia...471b16a52.jpeg2&3 |
what coils?
whats your timing map look like? |
Originally Posted by mx5-kiwi
(Post 1492555)
what coils?
whats your timing map look like? https://cimg3.ibsrv.net/gimg/www.mia...cb621d0aa3.jpg |
duplicate deleted
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Im FAR from any kind of expert but your map seems pretty conservative to me.....MT crew pelase correct if im wrong.
Don't 1 and 4 share the same coil? perhaps a coil or ecu ignition failure? We lost an engine once in simialr style when the battery terminal was loose after electricain didn't toghten it. + lead was coming on and off and ended up with detonation damage. |
Yes, 1 and 4 share a coil. I’m having trouble understanding how a loose connection would cause detonation. I’ve detected no misfire. EGTs appeared to be lower on 1&4 than on 2&3 At this point I think that was due to the detonation. |
We figured the bad power supply was upsetting the ecu and its internal timing thus messing with the ignition timing. I felt nothing in that circumstance either (well until the engine failed, i felt that :) )
Its highly unlikely but worth checking. Your map seems conservative and your efr's 'seem' quite rich so it has to be something putting the timing off....incorrect dwell, timing trigger setting or something liek that. Anyway, im stretched already so hopefully someone with more experience can chip in. |
That's certainly not a conservative spark map on pump gas.
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Way too much timing on an MSM, I typically can only get 14 degrees in at 12+psi.
You were knocking when you were tuned. |
Re the map..my mistake. Brain fart, had my numbers reversed.
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This map is a disaster
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Originally Posted by nitrodann
(Post 1492595)
Way too much timing on an MSM, I typically can only get 14 degrees in at 12+psi.
You were knocking when you were tuned. I have a Chatterbox spliced into the OEM knock sensor to listen in. Would anyone share a successful timing map for reference? Any thoughts on why 1&4 are severely damaged and 2&3 have none? |
Too much advance in boost. I don't have access to my computer to share mine but 20 degrees plus is too much in your top two rows.
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Originally Posted by yossi126
(Post 1492609)
This map is a disaster
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Originally Posted by sixshooter
(Post 1492613)
Too much advance in boost. I don't have access to my computer to share mine but 20 degrees plus is too much in your top two rows.
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You are a solid 8-10deg beyond what is safe on 93 octane from 150kpa up. It's been knocking, badly, since day 1
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Originally Posted by Savington
(Post 1492641)
You are a solid 8-10deg beyond what is safe on 93 octane from 150kpa up. It's been knocking, badly, since day 1
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As previously stated, your timing map is way way too advanced. Especially top two rows midrange rpms.
here is my timing map, which I consider pretty aggressive, and your map is way more advanced than mine. https://cimg7.ibsrv.net/gimg/www.mia...2195467fb6.jpg Also check that broken piston chunks didn't damage your turbine wheel. |
Originally Posted by borka
(Post 1492683)
As previously stated, your timing map is way way too advanced. Especially top two rows midrange rpms.
here is my timing map, which I consider pretty aggressive, and your map is way more advanced than mine. https://cimg7.ibsrv.net/gimg/www.mia...2195467fb6.jpg Also check that broken piston chunks didn't damage your turbine wheel. |
Many knock sensors don't work well. Use an actual listening device.
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