Blown up WRX
17 September 2002, 05:39 PM
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My 99WRX melted a piston on the M4 about 2 weeks ago and I'm being told this is as a result of using 'only' 97RON fuel instead of 100RON; it's only done 52,000 miles. Has anyone else suffered this? It's £3,000+VAT for a new engine (fortunately it's under warranty).
17 September 2002, 05:46 PM
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Do a search on 'big end number 3'.... its a common problem especially on STi model impreza's, and may not be just down to the fact you used 97ron petrol..
Do you have any mods....
Dan
Do you have any mods....
Dan
17 September 2002, 06:08 PM
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Just add yourself to the list of engine failures, its under drivetrain i think but yours is definately det related if you melted the piston 
(alot of people also add octane booster or get a remapped ecu 
)
Tony
(alot of people also add octane booster or get a remapped ecu )Tony
17 September 2002, 06:24 PM
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But surely even using 97 octane after 50K miles the ECU had learnt to only boost to a safe level suitable for 97 octane fuel?
The ECU learns when the engine dets and stores that info, that's why some people see a benefit on doing an ECU reset because it resets to factory default assuming 100RON.
Am I missing something here?
The ECU learns when the engine dets and stores that info, that's why some people see a benefit on doing an ECU reset because it resets to factory default assuming 100RON.
Am I missing something here?
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17 September 2002, 06:37 PM
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Det is normally caused by running a fuel that the car isnt adjusted for (pinking in the old language).
Basically your fuel is exploding before the piston has reached the top of its cycle, this causes damage to the head of the piston and increases temps.
Running with octane booster probably would have cured this problem (as it increases the RON in the fuel) but the best way is to have an ecu mapped for that type of fuel your running (do a search on ECUTEK)
Tony
Basically your fuel is exploding before the piston has reached the top of its cycle, this causes damage to the head of the piston and increases temps.
Running with octane booster probably would have cured this problem (as it increases the RON in the fuel) but the best way is to have an ecu mapped for that type of fuel your running (do a search on ECUTEK
)Tony
18 September 2002, 12:36 AM
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all this worrying talk of detonation, i really dont fancy blowing up my propulsion, give us some advice you technical buffs, if i'm running optimax, tek2, piperx induction and fully decatted magnex, what are my chances of det !!!!!!!!!!!
cheers.
cheers.
18 September 2002, 08:59 AM
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HAve been running MY01 WRX on Optimax after 1500 miles as I noticed the engine would not pull through 5500 rpm smoothly. IT now has a bit of a dead spot at 6250 ish but have not had the ECU re-mapped. Big differnece with the fuel, would not now even consider running it on normal unleaded.
18 September 2002, 09:41 AM
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In some cases you can hear det when its really bad, in others you cant.
I was in my local petrol station late last night in north london where a small group of us with jap cars have a gathering, and a scoob (uk version) pulled up. It was only a young kid and he put in 95 ron. All i can say is, as he booted it out of the station i could hear the det pretty clearly! All i was thinking was THAT ENGINE IS GOING BLOW V V V SOON
Cheers
Gerry
I was in my local petrol station late last night in north london where a small group of us with jap cars have a gathering, and a scoob (uk version) pulled up. It was only a young kid and he put in 95 ron. All i can say is, as he booted it out of the station i could hear the det pretty clearly! All i was thinking was THAT ENGINE IS GOING BLOW V V V SOON
Cheers
Gerry
18 September 2002, 10:10 AM
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Gez: Please could you explain (as best you can) what the sound sounded like?
I've heard the 'det' .wav file, but I'd be suprised if you'd be able to hear det like that when he booted it.
I've heard the 'det' .wav file, but I'd be suprised if you'd be able to hear det like that when he booted it.
18 September 2002, 10:20 AM
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Generally, if you can hear the car detting, be prepared for a big bill
At the cost of putting some octane booster in compared to the bill for fixing the car, is it such a problem?
At the cost of putting some octane booster in compared to the bill for fixing the car, is it such a problem?
18 September 2002, 10:24 AM
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Question for you all.
In the morning (or on a cold start) when you gently accelerate with <3000rpm on do you hear a noise until the engine is warmed up that you don't after. Not talking about piston slap here, I know what that sounds like.
The noise is more of a whistle/ticking/induction sound and seems to come from the drivers side of the vehicle. (I have a Blitz filter setup).
Also if you press on a little more throttle does the sound go away.
I have had this for ages and just wondered if it was combination of mods. The car doesn't seem to be any the worse for it and I'm fairly sure it's not det as it's so low in the rev range and so pronounced after so long if it was det the engine would be pulp.
[Edited by Sheepsplitter - 9/18/2002 10:27:26 AM]
In the morning (or on a cold start) when you gently accelerate with <3000rpm on do you hear a noise until the engine is warmed up that you don't after. Not talking about piston slap here, I know what that sounds like.
The noise is more of a whistle/ticking/induction sound and seems to come from the drivers side of the vehicle. (I have a Blitz filter setup).
Also if you press on a little more throttle does the sound go away.
I have had this for ages and just wondered if it was combination of mods. The car doesn't seem to be any the worse for it and I'm fairly sure it's not det as it's so low in the rev range and so pronounced after so long if it was det the engine would be pulp.
[Edited by Sheepsplitter - 9/18/2002 10:27:26 AM]
18 September 2002, 10:36 AM
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Guys, detonation and pinking are different. Pinking is pre-ignition, ie the fuel mixture igniting before the spark. This is typically at slower speed when the volumetric efficiency is higher and is generally not a problem.
Detonation typically occurs because the chamber is too hot and is all about the flame front not travelling from the spark outward at the correct speed. Either the flame front progresses to fast and, because the spark fires before TBC, you get too much pressure occurring too soon, leading to a shock running down through the rod. Or you can also get a situation where the mixture ignites at another place in the chamber due to heat radiation from the ignition at the spark, now leading to 2 flame fronts and again the mixture being fully burnt to quickly. Because the mixture is being fully burned too quickly, you also get additional localised heating which now of course worsens the whole situation and on the next cycle....it happens again.
The excessive heat can lead to melting pistons. Also the shock caused causes large additional loads on the big ends.
The excessive heat in the chamber causing the detonation can be as a result of lots of things, however the most likely is a lean mixture. The likelyhood of detonation is worsened by running fuel with a low RON.
Detonation typically occurs because the chamber is too hot and is all about the flame front not travelling from the spark outward at the correct speed. Either the flame front progresses to fast and, because the spark fires before TBC, you get too much pressure occurring too soon, leading to a shock running down through the rod. Or you can also get a situation where the mixture ignites at another place in the chamber due to heat radiation from the ignition at the spark, now leading to 2 flame fronts and again the mixture being fully burnt to quickly. Because the mixture is being fully burned too quickly, you also get additional localised heating which now of course worsens the whole situation and on the next cycle....it happens again.
The excessive heat can lead to melting pistons. Also the shock caused causes large additional loads on the big ends.
The excessive heat in the chamber causing the detonation can be as a result of lots of things, however the most likely is a lean mixture. The likelyhood of detonation is worsened by running fuel with a low RON.
18 September 2002, 10:39 AM
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I was one of a few owners who had detting occur when running on Optimax, which is supposedly a higher octane than SUL and better for your engine 
Was back to SUL and octane booster for me.......
Was back to SUL and octane booster for me.......
18 September 2002, 11:15 AM
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Nichop,
Glad you cleared that up..
I have pinking if I go up a hill for example and am at low RPM (not enough to labour the engine, but low) in a highish gear and try and increase speed by adding more throttle..
change down and it goes...
But cannot hear Det...
JGM
Glad you cleared that up..
I have pinking if I go up a hill for example and am at low RPM (not enough to labour the engine, but low) in a highish gear and try and increase speed by adding more throttle..
change down and it goes...
But cannot hear Det...
JGM
18 September 2002, 11:27 AM
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Co55ie,
Car is UK car running on Optimax or 97ron.. standard bar a ITG panel filter and an STi backbox... not much different to standard..
did the same before adding the filter..
I might be mistaking the noise?
JGM
Car is UK car running on Optimax or 97ron.. standard bar a ITG panel filter and an STi backbox... not much different to standard..
did the same before adding the filter..
I might be mistaking the noise?
JGM
18 September 2002, 11:33 AM
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This is intended for Sheepslitter! Basically it was myself and a mate whos pretty clued up on jap cars and an awsome mapper who heard it. As the scoob left the petrol station and booted it in first, at mid range to top end a noise between a loud spark, rattle and pop was coming from under his bonnet and not from the exhaust. This happened again in second gear but higher up the rev range. My friend has heard cars det like this only on a RR. The last time he heard a scoob like that was just before the engine let go. Hope this helps!
Cheers
Gerry
Ps: whats the URL of the detting noise WAV file????
[Edited by Gez - 9/18/2002 11:37:07 AM]
Cheers
Gerry
Ps: whats the URL of the detting noise WAV file????
[Edited by Gez - 9/18/2002 11:37:07 AM]
18 September 2002, 11:43 AM
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Gez: Thanks for that. Sounds like you guys were well qualifide to detect det.
Sorry I don't have the URL for the det .wav, but it was posted on here a while back (can't find it in search).
Sorry I don't have the URL for the det .wav, but it was posted on here a while back (can't find it in search).
18 September 2002, 11:50 AM
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I think the guy who owns thie scoob im talking about doesnt really know how to treat the car! Apparently, from what ive been told, he has raised the boost to some silly level, decatted the car etc and hasnt even thought about the fuelling. That spell danger to me.
Cheers
Gerry
Cheers
Gerry