Boost Kills - Warning

[enigma]

OK, Rich (zentac) popped round tonight after work and we decided to start attacking my old engine.........I can confirm it is poorly sick!

However, if I can run a 12.789 1/4 with it as it is.......well there is more to come!

Derek....what are you messing about at?! :evil2:

One tip, if you up the boost - ADJUST YOUR FUELLING :inquisiti

Here is the engine with the rocker cover off..........we didn't know it but we could have worked out here one of the reasons why my engine was running on 5!

[enigma]

Anyone spot it? it is very obvious!!

Anyway here is a pic of the back turbo.....just because really!

[SGHOM]

ooh !! oily ! :embarasse /help not good !

[enigma]

With the bolts removed from the head and the injector rail and inlt removed we can see the effects of a bonnet vent.......rusty block! :rolleyes4

[enigma]

OK, head off, front middle piston

[enigma]

And the front right..........

[enigma]

Bits of piston smashed repeatedly against the head is bound to cause some damage /help

[enigma]

But thankfully the bits seem to have passed through the turbo without causing major damage :)

[enigma]

Now just a handy tip, when you take over from someone removing a nut, make sure they were turning it the right way, or you will continue tightening it until it shears and part of your anatomy comes in to contact with something hard and sharp

read finger and cam pulley

[enigma]

Now with the front head off and 2 pistons mullered its time to look at getting the rear head off

It reveals that the left rear is also looking a little worse for wear :rolleyes4

[enigma]

OK, so if I can run 12.789 with 3 buggered pistons :evil2:

BUT - this was not the reason that my engine was running on 5, well it was, but who can tell me why the front right was not firing? Penny for the correct answer (apart from zentac)

[SGHOM]

head gasket ?? :embarasse

[zedy1]

no comoression :rolleyes4

[enigma]

Both wrong

[Roadrunner]

No cam follower??

[enigma]

No cam follower??

No one likes a smart ass!! :thumbsup:

[enigma]

seems like a bit of piston had prevented the valve from closing, the cam rotated so the follower was off the lobe and pop the follower fell off! Could have run for another 40,000 miles if I had just put it back on! ;)

[enigma]

I guess the pics may explain my cars habit of eating spark plugs!!!

[enigma]

My first piston probably went at the time it chewed its first plug - 12/01/2004 the others have gone at Well Lane, Japfest (X2!), and road driving over the last 12 months. Christ these engines are strong! :thumbsup: :rolleyes4

[Kieran]

Wow.... Interesting stuff.... So each time you had the 'Fart of Doom' it was another bit of piston coming away then? :inquisiti

[aaron68nz]

So if boost kills what sort of boost levels did the killing?

[enigma]

So if boost kills what sort of boost levels did the killing?

Its not the peak boost that I have had problems with, its more the much increased boost at lower revs - I guess I have been off the map! :embarasse

[paulmc]

Are you sure it was the boost though and not the 450bhp with nos. There does not seem to much det damage from the pics, Usually there are thousands of tiny marks on the pistons and head, it also looks like the pistons broke. Too much boost and not enough fuel they tend to melt around that area.

It may be is a diff story in the flesh though, pics dont always tell the whole story.

How much boost were you running anyway?

[enigma]

Not NOS related at all, the first piston went long before I installed the NOS! There are millions of marks all over the top of the piston and the head, but this is more likely to be caused by the repeated mincing of piston until it would fit through the exhaust valves!

The characteristic piston breakage is identical to that suffered by PJ last year before his full engine rebuild. It is definately the weak point! In all cases the boost I was running was less than 1 bar, but the aggresive way it comes on is probably more the problem.

To be honest with you it is no worse than I expected (apart from the follower coming off) I have known about it for an awful long time.

I suspect when the first piston went that there was compression leakage in to the crankcase, this pressurised the oil system and forced more oil mist than normal out of the breather and back in to the intake. This oil mist lowered the effective octane rating of my fuel and consequently led to further detonation in other cylinder. The broken piston served to reduce the compression in the affected cylinder which will have suppressed further detonation problems which is probably why the first piston to go lasted over a year in its broken form.

Anyone that was at Japfest last year knows the sound that my engine made and we all thought it was terminal back then! That was probably the second pistons demise!

It is incredible to imagine that this engine took 100BHP of NOS with at least 2 pistons in a very sorry state! Yep I didn't install the NOS until late last year, long after I knew there was a problem! Some may think I am mad, but I know I am!

[paulmc]

hmmmmmm, 1 bar boost is quite low but if there is a lack of fuel det det bang, need to look at the fueling when i get home :embarasse

your theory re oil in the inlet is spot on though, the cossie boys suffered this for years and many engines went bang cos of it.

[zentac]

It certainly was an interesting evening, cheers Dave.

[Dan_G]

I dont like the sound of all this. eek!

think I'm gonna invest in some water injection...... and block off my oil breather pipe... and fit a Power boost valve...... and an extra injector in the inlet manifold and fit a knock sensor and a lambda sensor... :rolleyes4

and and..... /help

So bottom line is wot exacary?

our engines are poo..... ?

:rolleyes4

[Nick Mann]

Bottom line is our engines are very strong!

I think the message is that if you play with your boost, make sure you have an idea of what is going on or be prepared to suffer a bit of detonation. I only know of one 6A13TT that has been destroyed by something other than detonation on increased boost, and that was a broken accessory belt taking teeth of a cam belt. I'm sure I know of three that have died due to detonation, and I think there is another that I have forgotten about!

Interesting reading, BDA! So what are you going for this year? 12.5? Sub 12? :rolleyes4

[enigma]

Interesting reading, BDA! So what are you going for this year? 12.5? Sub 12? :rolleyes4

On the grounds of common decency, I shant be making any promises this year!!! ;)

[paulmc]

I dont like the sound of all this. eek!

think I'm gonna invest in some water injection...... and block off my oil breather pipe... and fit a Power boost valve...... and an extra injector in the inlet manifold and fit a knock sensor and a lambda sensor... :rolleyes4

and and..... /help

So bottom line is wot exacary?

our engines are poo..... ?

:rolleyes4

Dan,

Not good if you block off the breather pipe you will end up with oil everywhere as the gaskets all start to blow. get yourself a breather of some sort. best to get one that seperates the oil and returns it to the sump. Bailey do them or just keep an eye on the evo site they come up for sale often.

save all the hassle and buy an e-manage no need for extra injectors etc

[zentac]

On the grounds of common decency, I shant be making any promises this year!!! ;)

I think I will be more competative this year so .... Let the games begin !

[enigma]

I think I will be more competative this year so .... Let the games begin !

You gonna buy a VR4 then?! :smug:

[Jimbo]

Very interesting reading, a great write-up that Dave :thumbsup:

Any thoughts I might have had of getting a boost controller are now once again on the backburner, but still, it's reassuring to know how strong our engines really are - truly incredible seeing the damage to those pistons knowing it was still running so well!

[zentac]

You gonna buy a VR4 then?! :smug:

You know Im quicker than you without NOS, so I just need to add NOS /yes

[enigma]

You know Im quicker than you without NOS, so I just need to add NOS /yes

I am thinking that 99/1000 of a second really doesn't cut it!

[Kieran]

I am thinking that a 'Nail it from 30mph through the gears' is a far more indicative test to see who is faster. /yes

[Dan_G]

Dan,

Not good if you block off the breather pipe you will end up with oil everywhere as the gaskets all start to blow. get yourself a breather of some sort. best to get one that seperates the oil and returns it to the sump. Bailey do them or just keep an eye on the evo site they come up for sale often.

save all the hassle and buy an e-manage no need for extra injectors etc

Only kiddin about blocking the breather pipe :D was thinking a catch tank like you mentioned..

no but yeah but.... e-manage... only problem with one of those is that I dont trust anyone in hicksville to set it up properly........ "Aye aye min, I ken fit I'm deein ye ken..." next thing you know you have melted engine...

I want my own 4wheel rolling road, then I do it all myself ... that would be ace fun... :happy:

need a lottery win..... /yes

[paulmc]

I am the same, no one gets near my car :thumbsup: as you say they aint got a clue. If I blow my car up playing well I can only blame myself. Not had one let go yet though ;)

[Andre]

How much boost whre u running to this engine to casue this PSI? where you using higher octance gas ? did you adjust your fueling ? how much psi are the stock pistons capable of holding? Are you rebuilding this engine for more performance ( port and polish , stronger pistions crank conrods, ? Can u post or send me some pics of your crank conrods and other engine components? If you can send me pics send them to the address below. Thanks

alandre@sunbeach.net

[Kenneth]

good stuff... i dunno what im saying cause im drungk but hey... interesting thread all the same!

lol, looksh lik ill have a few thitngs to think about befor i play to much wiht boosth. thanks BDA

[Jimbo]

good stuff... i dunno what im saying cause im drungk but hey... interesting thread all the same!

lol, looksh lik ill have a few thitngs to think about befor i play to much wiht boosth. thanks BDA

Ken, your typing's slurred mate! /lol Go an have a lie down /yes

[Kenneth]

Ken, your typing's slurred mate! /lol Go an have a lie down /yes

lol, yeah things were interesting at that point... because i touch type, i have problems typing drunk. Got too frustrating trying to correct my spelling, so I just gave up /help

[aaron68nz]

boost I was running was less than 1 bar, but the aggresive way it comes on is probably more the problem.

So running 0.9ish maximum I'm maybee best to leave in factory exhaust to prevent too fast a boost build up at low engine rpms. By the way have many people given regard to the fuel filter as I don't know how much effect on fuel flow a dirty one might have. Mechanics often say this filter is too often over looked.

[-LegnumVR4-]

Good to have someone looking into these engines. Thanks Dave for the pic and info :thumbsup:

[ako]

The one thought that comes into mind is just how is it leaning out so easily - 6 X 390cc injectors is a LOT of fuel, sure its not just excessive inlet temps causing detonation/melted pistons as opposed to going lean?

But still, I'm bloody surprised the thing survived as long as it did in the condition its in - would have loved to have cracked open my old 6A12, chances are it was worse :rolleyes4

[zentac]

I dont think its fueling as Ive leaned mine off across the whole range and Im running more bhp than most (except the nos people) unless its down to flow and the pump cant cope as mine is an uprated pump.

[enigma]

Nope.....uprated pump for me ;)

[ako]

Must be heat, or maybe timing related then.

One thing though - I'm not sure with the 6A13, but I know on my old engine it had a solenoid for boost control hooked into the workings of things. When the ECU heard knocking, itd pull back the boost - a LOT if need be. Running 91 octane once saw it pull boost right back to 7psi (From the 13-14psi it normally sat at) - fuel which shouldnt have been in there at all, but my GF meant well filling the car up at least :inquisiti

Thing that comes to mind is if you're running new boost control - as the majority do - a lot of people either take this solenoid out, or if they have EBC it ends up compensating for what the factory system is trying to do.

Its weird.. On the GTO / 3000GT's, their fuel/airflow cut doesn't occur until the ecu is registering 115% injector duty cycle.... 115%!!! Funny thing is though - the engines in them are incredibly prone to knocking, or detonation as its properly called. Throwing a datalogger on them will show them detonating, even in totally stock form in some cases - or at the other end of the spectrum, some can throw 15psi into them with no adverse effects whatsoever. On the unfortunate ones, the ECU will detect it some of the time, and try and pull timing to offset matters, but its just a bandaid. They still go "pop" if its left uncorrected.

Now... Why the hell did I write all that dribble? Simple.... I wonder just how many people on here are putting the usual "0.9 - 1 Bar boost" and assuming all will be fine - remember, those are damn tiny turbos, I know that at the compressor outlet my temperatures were throught the roof. (Only thing saving my engine was a novelty oversized intercooler :rolleyes4) ... When there could be almost inaudible detonation occuring? If you've got a bung knock sensor, or its unable to hear due to any number of things, you could be quietly, slowly killing off your rather expensive engine. Daves is just proof of this - the numbers say it can handle 400hp on the stock fuelling, but you can't rely on pulled timing to save an engine alone.

So... Who actually monitors anything on their engines? We're just starting to use the dataloggers to their full potential here, and now that I've seen them in action, just cringe at the "trial and error" methods used before.