Reducing flutter.

Post by **Ash** » Thu Sep 10, 2009 10:08 pm

after the 50th time of debate we come to tha same conclusion yet again. there is no winner! VTA BOV, plumback, no BOV/flutter, it just doesn't really matter!

PERSONAL PREFERENCE wins out everytime!

Damo · Post by **Damo** » Thu Sep 10, 2009 11:06 pm

tassuperkart wrote:Ahhhhhhhh then thats different!
geez, I was getting ready to give it to you as well Damo *wipes sweat from brow*!!!!!!!!!!
LOL
L8tr
E

BUT!

I don't fully dis-agree or whole heartedly agree with either side of the argument.
There are fundamentals posted that are accurate regarding stresses, how and why, but obviously personal opinion will dictate how much read out of someones post will be accepted. Thats just a given.

I personaly belive that there are many many variables that will contribute to the life/death of a turbo that go beyond the boost being run and whether or not a BOV is being used. A more valid question to ask would be what shaft speed is it working at? This works in our favor on a little engine, as you are hard pressed to get any semi decent turbo pushing 100k at any boost on the E15.

As for factory BOV's

1st things 1st, in order of importance in todays turbo'd engines the reasons the boffins would use a BOV are:

NVH. (1st place by no small margin.) purely to eliminate noise.

Tuning. Better drivablility without problem of AFM getting reversing signal.

Can be used to reduce pumping losses.

Turbo longevity. (Distant last.)

In the current day of composites and materials, turbos don't suffer anywhere near the failures that used to plague turbo's in the early days. This is mainly due to the fact that rotational weight has be reduced a massive ammount over the old school heavy prehistoric rubbish.

20 years ago I would have agreed that every turbo car should have a BOV to keep the turbs together, but not today.

Does not running a BOV shorten the life of the turbo? Possibly, but I would agree with android, to a group whom are not going to see 50,000ks on the same turbo anyway, I would think not running one would make no difference.

Personaly I have never run one, BUT if I had a $1000+++ turbo hanging from the side of my engine, I would for peace of mind!

Damo

Callumgw · Post by **Callumgw** » Fri Sep 11, 2009 7:06 am

Damo wrote: In the current day of composites and materials, turbos don't suffer anywhere near the failures that used to plague turbo's in the early days. This is mainly due to the fact that rotational weight has be reduced a massive amount over the old school heavy prehistoric rubbish.

I would disagree with this bit. there hasn't been a significant advance in material understanding in the last 20 years the would 'reduce' the impact of fatigue. Instead, in my humble opinion (imho) two main things have occurred that significantly reduce the loading cycles. First and foremost - water cooling. Thermal cycles are extreme in these devices, watercooling significant reduces the peak thermal load often the extent that turbo timers are no longer relevant (under most applications). Second is the widespread use of BOVs. These reduce the severity of the unload (or reversing load) by allowing the bleed of air ahead of the compressor, thereby reducing this part of the cycle. Fatigue is greatly influenced by the difference between the max and min load, by bringing these closer together the life can increase substantial. For some aircraft structures 10% change in these extremes returns 50% more life.

yes, significant.

C

Android 360 · Post by **Android 360** » Fri Sep 11, 2009 8:39 am

Damo wrote:Personaly I have never run one, BUT if I had a $1000+++ turbo hanging from the side of my engine, I would for peace of mind!

Hell yeah, if i had just gone and spent $1000+ on a turbo i'd be wanting to safeguard it, definately....

i just really dont think it matters if im running a 2nd hand t25 that cost me $200 - big whoop.

Post by **tassuperkart** » Fri Sep 11, 2009 10:03 am

Well youd find that youd live to regret those words if your "$200 - big whoop" T25 (which might have for all you know) had its guts boosted out of it over its life fitted to a club day 180sx drifter and has a total compressor wheel failure due to surging and your engine then ate the remains of that wheel and then died as a result.

You might well think differently then.

My point has been right from the beginning that ANYTHING fitted that can reduce or even eliminate one of the major conditions that lead/contribute to turbo failures, no I didnt say CAUSE, I said LEAD/CONTRIBUTE to turbo failure, ( I have never made the statement that a turbo will shit itself WITHOUT a bov) cannot be a bad thing and so therefore the benefits far outweigh any disadvantages.

Im pleased to see there is no argument anymore.
Ahhh,,, thats better!

L8tr
E

Android 360 · Post by **Android 360** » Fri Sep 11, 2009 10:14 am

tassuperkart wrote:Well youd find that youd live to regret those words if your "$200 - big whoop" T25 (which might have for all you know) had its guts boosted out of it over its life fitted to a club day 180sx drifter and has a total compressor wheel failure due to surging and your engine then ate the remains of that wheel and then died as a result.

cmon mate, it's pretty obvious when a turbo's been put through that sort of abuse..... if you went ahead and used it when it's painfully obvious it needs to be rebuilt then you probably deserve it, it may teach you a lesson or two

That's all from me on the subject, not in an arguing mood today, sorry

Post by **tassuperkart** » Fri Sep 11, 2009 10:53 am

Listen here Einstein, we are not just talking fucking shaft play here OK. Thats kids stuff. My wife can pick a "dodgey" turbo on that rationale.

Chroiist, my FJ20 T3 was so worn in the bearings you could make the wheels touch the housings and moved back and forwards about 0.015" agains the thrust bearing and IT WORKED PERFECTLY for many years boosted at 18 PSI. YET, it was rooted according to just about every backyard greasemonkey.
I put it to you that the wheel assembly was quite well balanced and since a bov was fitted for its entire life beginning from an import, ther is no reason a turbo will fail due to excessive shaft play.

So please dont insult anybody's here inteligence and hand out such a load of bollocks as

Android360 wrote:cmon mate, it's pretty obvious when a turbo's been put through that sort of abuse

because Il bet thats how you would test a turbo... thats right, look for some oil and cracks in the housings and wiggle the shaft.....yer go on, correct me.

Im talking metalurgical degredation and other stresses do to extreme thermal and mechanical loads imparted on bot the shaft and its wheels it over its life. POTENTIAL for failure caused by a lifetime of overheated and surged abuse.
This is shit you CAN NOT SEE, either by looking up its arse or wiggling its wheels which is the accepted dumbfuck method of testing a turbo for what life its had!
So how about you fuckingwell shut up, grow up and listen and learn some shit eh?
Jezuss you come out with some bollocks sometimes pal. Ill actually bet you can fight pretty well right?
That would be because youve been been beaten up since a very little boy for being a totoal smartarse pita and learned to fight back real early yer?

M8, talk intelligent like or just stay out what what you obviously know NOTHING about K.

L8tr
E

Android 360 · Post by **Android 360** » Fri Sep 11, 2009 11:53 am

*sigh*
i dont want to argue, maybe another day.....
you bore me with your 'i'm better than everyone' attitude. and i really don't have time for this today.

fact of the matter is you are talking about a ticking time bomb turbo, if a turbo's about to shit itself like that, it is ALWAYS obvious to see from a few basic checks. I may not have the equipment to do in-depth testing but in cases such as that you really don't need it. And don't you check the history of turbos you buy? You really should eh, it's important.

now why are you talking about fighting?
i dont want to fight you or anyone else. IRL im very much a lover and not a fighter but like many, I sometimes enjoy having a bit of a debate online.

So yeah, i really wouldn't like to fight because i'm pretty damn sure you'd win.

grow up dude, it's the internets.. take a chill pill, maybe have a break for a while so you can calm down. I'm going to ignore you for a while, i suggest you do the same with me.

blabber back all you like trying to prove how awesome you are,*edit* sorry ignore this bit, it was pretty mean and I really dont want to be mean today.*edit*

can this thread be closed? it's going in circles eh.

Post by **Ash** » Fri Sep 11, 2009 12:01 pm

You spin me right round, baby
Right round like a record, baby
Right round, round, round
You spin me right round, baby
Right round like a record, baby
Right round, round, round

Post by **tassuperkart** » Fri Sep 11, 2009 12:11 pm

Baaahahahahaha sry ANDROID your reverse psychology does not work on me.
Might work on feeble minded 14 year old schoolgirls and frail old ladies but youll have to try much harder than that with me.

Ive always said, never argue with an idiot, they drag you down to their level and then beat you with experience.!
In this case, Im in the company of greatness! So I give in.
You can have the crown of idiotness. *takes bow* and the sceptre of stupidity *bows lower*.

L8tr
E

Callumgw · Post by **Callumgw** » Fri Sep 11, 2009 12:13 pm

best change the catch cry at the bottom of your post's now E.

But seriously, I think it's time to get over this one. Can we move on?

Post by **tassuperkart** » Fri Sep 11, 2009 12:28 pm

Your right C, and, your right C.
Bygones.
L8tr
E

Kimmo · Post by **Kimmo** » Fri Sep 11, 2009 3:25 pm

ETONE wrote:hey hey hey why would Baz make a good doctor???

Cause he's got the DOSE for all them SICK CUNTS

PMSL : D

BLUE ET · Post by **BLUE ET** » Fri Sep 11, 2009 6:14 pm

you fuckin crack me up kimmo lol

Kimmo · Post by **Kimmo** » Fri Sep 11, 2009 6:18 pm

Campbell's winning this thread so far, I reckon...

Haven't come across a line that good in quite a while : D