cracked piston

[soopersubaru]

 boon']

[quote name='WRXONP said:

lol blow off shouldn't open when driving in vac . that's a very poor bov yah . and i use full atmo bov on stock ecu fine

/quote]

How brown is your bumper from all the half-burnt fuel falling out the back

Guess some dont care about black smoke....just like the launch feel as they climb up the gearbox :

Might seem ok on a stock computer....However it is shortening the life of your engine.

And with nice hot air from the pod filter tucked in the corner....Less horsepower for your bucks too!

Your car...your money...your decision....Just telling peeps what i know.

If Fuji heavy industries fitted a closed loop system. The computer would/will have a carefully set up map for this.....Now make the system open....Did you change the program to suit this???...If you have...All good!

Other than that the opened system is now trying to compensate for the perceived huge air demand as detected by the AFM and a full rich situation occurs, This in turn damages the top compression ring/piston,,,,,Therefore decreasing engine life.

[WRXONP]

i love black smoke . every time Im on 20 Pound i get black smoke :-) 11.5 air fuel ratio . . . . they fit a recirculated blow off factory because they have to. every car does . . . running slightly rich for a second is nothing bad . . . if it was my car and all my other cars and a heap of people here would have blown a long time ago ! plus watched the air fuel on a dyno while blow off is venting . doesn't do didley skwat .

[soopersubaru]

 WRXONP said:

i love black smoke . every time Im on 20 Pound i get black smoke :-) 11.5 air fuel ratio . . . . they fit a recirculated blow off factory because they have to. every car does . . . running slightly rich for a second is nothing bad . . . if it was my car and all my other cars and a heap of people here would have blown a long time ago ! plus watched the air fuel on a dyno while blow off is venting . doesn't do didley skwat .

Running rich under vacuum when the bov is open to atmosphere.... .for a second as you put it.....

(10 to 15 ignitions)..Will cause damage......Eventually a piston, probably No 4 will crack the land between the top two rings and burn the inside of the top compression ring..Further hammering....i.e. racing around a track or down a closed road will lead to detonation as the fuel accumulates between the ring and the piston...Raw fuel accumulates here each time you get off the gas and go to full manifold vaccuum/full blow off....(Standard mapped computer only).......Because there is very little air available and the AFM is telling the computer there is, so the injectors go to almost full fuelling rate.(near 3.5:1)

Of course this fuel residue does burn away as proper combustion is returned (Approx 1500 revs or 750 ignitions later) (3000 rpm indicated would take 15 seconds)(6000 would take 7.5 seconds,,, and by now you are probably running rich again before the next gear change)

Black smoke at the gearchange is detrimental to engine life! End of!

Richer is better at hi revs/boost/ Horsepower(11.5:1) for different reasons/Cycle duration, increased squish/swirl dynamic compression, lower combustion/cylinder temps.

This combustion does not clear the accumulating fuel residue....Or create it.

[WRXONP]

lol ran atmo blow offs for years . no detonation causing any failure from a blow off valve

[Joker]

dont mean its right

atmo bov never been recommended on Subaru with stock ECU, fouls plugs quicker or something along that lines as well

[Guest]

 WRXONP said:

lol ran atmo blow offs for years . no detonation causing any failure from a blow off valve

Brad, think where the problem with opinions here is that ..

You have done mods' that aren'nt technically right or are pushing parts past their limits (remeber our injector DC% coversation)

I see your point, that you have not had a failure - however this doesnt make your work right

The point here is ext vent bov with std ecu CAN cause issues

and my point was that injectors have a safe DC%

You chose to go outside the boundaries of what the rest of the world has proved to be safe then so be it

But dont keep saying - "I have never had a prob" etc, or infur that we dont know what we are talking about - Because we do !

Our opinions come from many more years than yourself , and are only trying to help you keep the EJ mill from exploding

Cheers Rick

[WRXONP]

well just wondering what's the explanation behind some cars being fine and some not ?

[Shale]

Ticking time bomb. It takes time.

[WRXONP]

Oh no . every one running stock ecu with blow off valve watch out . . . tick tick tick

[Shale]

It's a combination of things that will eventually lead to epic fail. There's also the engine itself...some take the abuse until the owner writes the car off, others will pop with the slightest provocation. There's more to it than a short list of mods.

[WRXONP]

BOOM !

But seriously every thing has a reason . fact . every action has a reaction . . so why do some re act very bad (Some say) to a venting blow off yet most it doesn't effect . . . must be a reason . ecu reset ? difference ecus ?

[Shale]

History plays a massive role.

Consider the different states of different motors by the time they're second-hand. Different octane, different oil, different driving style and road conditions. How cold were the cold starts, and how frequent? Clock up 100,000km on several identical cars with different drivers and you'll have several different motors.

Just like some TTs will chug on forever (like JoKer's and Drunkenmonkey's), others will let go with very little provocation (Reuben's), or none at all (chrisjunkie's). Some come to us already rebuilt because of past bearing failures (Jasn00's). Out of all those we have 4x EJ20Rs and one EJ206, in varying states of modified or not. All the 20Rs are in GTB-Ltds in the above example. Oddly enough as far as I know, the two white ones are stonkin' on like there's no tomorrow but the other two have failed and since been replaced.

My personal feeling with that particular EJ206, given how cheap the car was and in what state it was delivered - despite being completely and utterly stock - it had been poorly maintained, and Chris' loving maintenance of it in its first 3 weeks under his ownership had successfully flushed out the sludge that was once oil...including the sludge that had been holding what was left of the bearings together. It made the magic nugga-nugga sound not long after that service...

History... past driving conditions and maintenance... play an enormous part in that big equation. This is why there are no absolute answers, just strong recommendations. Some are stronger than others. It pays to listen to the wise old hands here.

[WRXONP]

that's not really any thing to do with bov ? when the bov opens the Maf reads the air that is leaking. that would happen regardless of car and mods .but yet some do things others don't ? wear on a engine can't change what the ecu does when bov leaks . . . . this is quite far off topic and quite stupid . . . its a blow off valve !

[WRXONP]

imagine the can of worms that would open if we started the talk about compressor surge being oh so bad lol. club sub sure is debatecentral.com and gets off topic

[Shale]

It can change the final result. But I'm looking at the forest, not the trees.

Srsly, you'd massively benefit from using the flappy bits on the side more than the flappy bits on the front.

[funkytown]

Hahahaha shale... QFMFT

[Joker]

I have 50/50 atmo and blame it for 350km per tank.....

[WRXONP]

i have a sequential on soft and vents at 0 on gauge . . . i all ways vent it too . still get 500+ A tank . theses so many variables that change fuel economy . . . but this whole talk is about as use full as ears on a forum ha ha back to op have you had test done yet . just drop motor at a shop and pay 0.5 hour labour and get it checked

[Joker]

boom goes the dynomite

variables....

[Guest]

Brad, you take this so personally, Why? I dont know

maybe its the inexperience, but when advice is offered you get all smart and tall poppy about your set up

personally do you think it makes one bit of differnce to my day if your engine has a failure - Nope

But it is funny when you have problems like ya O2 and possible headgasket issue that you come running for advice

I will finish my 5c with

Only fools and children pass comment on things half done or things they know nothing about

[WRXONP]

didn't say that . it basically started with a bov leaking at 15 inchs of vac while driving. then turned into atmo bovs being the worst thing since hiroshima . . . yet i was actually asking questions ? and in which ALL Is off topic lol . . . the whole point ? ? ? ?

[rex-leggy]

 Shale said:

It can change the final result. But I'm looking at the forest, not the trees.

Srsly, you'd massively benefit from using the flappy bits on the side more than the flappy bits on the front.

lmfao my laugh for the day

[WRXONP]

my laugh of the day is trying to picture some one using ears on a forum ! i will stop ha ha . . cos the whole lot is going no where ! ! hopefully the op gets his test done so he knows what needs doing

[soopersubaru]

 Shale said:

It can change the final result. But I'm looking at the forest, not the trees.

Srsly, you'd massively benefit from using the flappy bits on the side more than the flappy bits on the front.

Mr WRXONP please listen....The only way to mod is the right way!

Others that prefer the open loud style blow of who have no issues, will be running an after-market computer or program,

(or they are lying about performance, problems etc.) and are probably changing their oil and filter at least every 5000K (drive it hard maintain it harder attitude!)

Back on the subject:-.......Cracked piston "can" be caused by this venting style of blow off IF the stock computer is still the same. like i said earlier....Put it back in the car with the same set up and KKKK bang will occur before it should!

[WRXONP]

i would say the problem is from detonation not the blow off valve . . but that's my 2 cents . what fuel you run ? what plug and what gap etc . . plus allot more factors allow detonation to occur which knocks the ring land off