So if boost kills what sort of boost levels did the killing?
1997 auto VR4 sedan type S, GReddy PRofec B-specII, after market transmission oil cooler, stock size Dunlop SP Sport Maxx tyres.
2001 manual Legnum VR4.
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!Originally Posted by aaron68nz
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?
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!
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
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.
It certainly was an interesting evening, cheers Dave.
Richard Batty
2.5ltr V6 Turbo FTO
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...
and and.....
So bottom line is wot exacary?
our engines are poo..... ?
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?
On the grounds of common decency, I shant be making any promises this year!!!Interesting reading, BDA! So what are you going for this year? 12.5? Sub 12?
Dan,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...
and and.....
So bottom line is wot exacary?
our engines are poo..... ?
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
I think I will be more competative this year so .... Let the games begin !On the grounds of common decency, I shant be making any promises this year!!!
You gonna buy a VR4 then?!
Very interesting reading, a great write-up that Dave
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!
You know Im quicker than you without NOS, so I just need to add NOSYou gonna buy a VR4 then?!
I am thinking that 99/1000 of a second really doesn't cut it!You know Im quicker than you without NOS, so I just need to add NOS
I am thinking that a 'Nail it from 30mph through the gears' is a far more indicative test to see who is faster.
Only kiddin about blocking the breather pipewas 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 f
need a lottery win.....
I am the same, no one gets near my car
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
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
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