|
prj
|
 |
« Reply #15 on: October 03, 2013, 06:13:05 AM »
|
|
|
The problem is your AFR request and that you never looked at your EGT's. This is running WAY to lean up top.
Req. lambda makes me cringe... leaner to redline, really?
I guess you have now learned from this, just there are a bit less costly ways to learn - such as picking up a book about forced induction motors :/
|
|
|
|
|
Logged
|
|
|
|
krazydbiker
Full Member
Karma: +4/-1
 Offline
Posts: 202
|
|
« Reply #16 on: October 03, 2013, 01:50:46 PM »
|
|
|
i have to agree with prj some, without having EGT sensor, those AFR's are kind of high, but you are running WMI, that picture looks like detonation, i had a failed spark plug cause detonation with proper fueling and the piston looked exactly the same.
edit: just noticed the rest of what i typed didn't go, how did the plugs look on the other bank?
|
|
|
|
« Last Edit: October 03, 2013, 04:17:47 PM by krazydbiker »
|
Logged
|
|
|
|
zillarob
Full Member
Karma: +13/-1
Offline
Posts: 152
|
|
« Reply #17 on: October 03, 2013, 05:01:35 PM »
|
|
|
That looks just like a Subaru with a cracked ring land.
Were the pistons even designed to handle what you are asking of them?
|
|
|
|
|
Logged
|
|
|
|
krazydbiker
Full Member
Karma: +4/-1
Offline
Posts: 202
|
|
« Reply #18 on: October 03, 2013, 07:12:44 PM »
|
|
|
That looks just like a Subaru with a cracked ring land.
Were the pistons even designed to handle what you are asking of them?
im not sure which post your talking about, but if it is mine, yes, this is a stock motor with a stock tune, 360 HP twin turbo engine, plug porcelain cracked causing hot spots. |
|
|
|
|
Logged
|
|
|
|
|
Carsinc
|
|
« Reply #19 on: October 03, 2013, 08:19:38 PM »
|
|
|
I'm with everybody else, thats lean you need more fuel.
|
|
|
|
|
Logged
|
|
|
|
|
airtite
|
|
« Reply #20 on: October 03, 2013, 11:20:24 PM »
|
|
|
The problem is your AFR request and that you never looked at your EGT's. This is running WAY to lean up top.
Req. lambda makes me cringe... leaner to redline, really?
I guess you have now learned from this, just there are a bit less costly ways to learn - such as picking up a book about forced induction motors :/
I was under the impression that 850C egt temp was well within safe limits? |
|
|
|
|
Logged
|
|
|
|
|
airtite
|
|
« Reply #21 on: October 03, 2013, 11:23:34 PM »
|
|
|
i have to agree with prj some, without having EGT sensor, those AFR's are kind of high, but you are running WMI, that picture looks like detonation, i had a failed spark plug cause detonation with proper fueling and the piston looked exactly the same.
edit: just noticed the rest of what i typed didn't go, how did the plugs look on the other bank?
prior to the failure, I had done a plug check on the last service and the plugs looked perfect, light tan color with absolutely no heat damage to the electrodes. |
|
|
|
|
Logged
|
|
|
|
|
airtite
|
|
« Reply #22 on: October 03, 2013, 11:25:44 PM »
|
|
|
|
|
|
|
|
Logged
|
|
|
|
|
rnagy86
|
|
« Reply #23 on: October 03, 2013, 11:53:12 PM »
|
|
|
Is that during a 6th gear WOT pull? You won't really have EGT problems in 3rd gear.
|
|
|
|
|
Logged
|
|
|
|
|
airtite
|
|
« Reply #24 on: October 04, 2013, 12:00:24 AM »
|
|
|
Is that during a 6th gear WOT pull? You won't really have EGT problems in 3rd gear.
yup 3rd gear. |
|
|
|
|
Logged
|
|
|
|
|
rnagy86
|
|
« Reply #25 on: October 04, 2013, 12:05:56 AM »
|
|
|
yup 3rd gear.
Well I assume your EGTs were spiking way more than this during your 6th gear pull on the highway. |
|
|
|
|
Logged
|
|
|
|
|
airtite
|
|
« Reply #26 on: October 04, 2013, 12:09:58 AM »
|
|
|
Well I assume your EGTs were spiking way more than this during your 6th gear pull on the highway.
fair enough I never logged any 6th gear runs, surely if the EGTS were that high the damage would be on the exhaust side of the piston and not on the inlet side and if it was EGTs surely the damage would have been uniform across all pistons on not just those 3? |
|
|
|
|
Logged
|
|
|
|
|
prj
|
|
« Reply #27 on: October 04, 2013, 02:10:24 AM »
|
|
|
I was under the impression that 850C egt temp was well within safe limits?
That is calculated EGT. It's not actual EGT. Did you measure your EGT using an actual probe and a gauge or not? 850C post turbo is close to 1000 before turbo on a turbocharged car, it's the limit. On a supercharged car 850C is probably ok depending on the location probed. Definitely OK in the exhaust runner. However, if this is from stock EGT model then this is at least 200 degrees off after supercharging it, so this perfectly explains what happened to your engine. With high EGT it does not matter on which side the damage is, it's just going to let go at the weakest point. I don't see any serious det marks either. As to all cylinders being damaged - not neccessarily. One side can run hotter than the other. |
|
|
|
« Last Edit: October 04, 2013, 02:24:21 AM by prj »
|
Logged
|
|
|
|
|
airtite
|
|
« Reply #28 on: October 04, 2013, 02:39:38 AM »
|
|
|
thanks PRJ, well like you said this has been a fairly expensive exercise but one that I have learnt quite a bit from. Will be a bit more cautious next time round. Block should be arriving next week and can start the rebuild.
|
|
|
|
|
Logged
|
|
|
|
|
prj
|
|
« Reply #29 on: October 04, 2013, 03:36:55 AM »
|
|
|
Next time you are tuning it install actual EGT gauges, work on KFLBTS so that it keeps EGT's low.
And I would request richer LAMFA across the board as well, it should make more power at 0.82-0.84 than it does at 0.88, and then use BTS to go richer from there to keep EGT's down.
|
|
|
|
|
Logged
|
|
|
|
|
