turbodailydan

was just wondering how many people are running their turbo v-tec's without a blow off valve on a journal bearing turbo (standard 270 degree bearing) and if its been proven to cause any degree of wear/damage to the turbo itself?

does compressor surge actually damage the turbo in any way? (and when i say compressor surge i mean the type of surge from the turbo compressor when running without a BOV, and not surging caused by having a large turbo etc)

civic_r87111

Have u read the faq and the turbo tech on garretts site? That should answer all the questions u asked, it is vital that u use a bov. Is there actually ppl running turbos without a bov??

turbodailydan

well i have been running turbo's without a pressure release valve (bov) for years with no probs however none of them were turbo v-tec.. i have not yet seen anything concrete yet to suggest that compressor surge does infact damage the turbo.. so just interested to see if anyone knows or if there have been any turbo failures due to running without a BOV.

D-Rob

Compressor surge/stall puts a good amount of stress on the thrust bearing of the turbo.

That alone is a good bit of what's going to kill it.

- Derek

civic_r87111

I haven't seen this but I have heard of some guys breaking fins off the Compressor wheel from surge.

90Rexx

compressor surge will happen without a blow off valve, according to garrett it can destroy the thrust washer and damage the bearing.

also it can cause the nut at the end of the shaft to come loose and the compressor wheel can tear up the housing pretty quilcky if that bolt loosens up!

LightningTeg

Then you have bits of metal going into your engine.

Casey

iTrader: (5)

you can get a bov for 200 bucks...why wouldnt you run one

dpetro1

and im going to sound like a ricer but the bov is one of the best parts of being turbo.

1. sounds awesome
2. you can scare pedestrians (old people are the best)
3. and it never ceases to make me smile when you blow off next to some unsuspecting subby or evo and they get that look on their face like omg wtf that honda is turbo?

function and "form" i guess you could say

azandford

+1 on the sound
I love torturing old people. Sorry grandma....

Hemix

Screw that. Get a used 1g Eclipse BOV for $50 or less if you know someone with an Eclipse. Works great and it's cheap.

TheShodan

iTrader: (14)

I hope you're not talking about OEM turbo cars. They use a BOV too, they're just recirculated. Any worth anything is going to have some way of releasing that excess pressure.

HiProfile

Bypass, recirulated, relief, pop-off, etc. Different names, same function. THe only turbo setup in which a lack of that valve wouldn't cause damage is on a diesel. No throttle plate = no pressure back-up when you let off.

Since most people use "hybrid" Garretts on Hondas, they really need one. The compressor wheel is slightly oversized for the T3 shaft, and the forces involved can wreak havoc on the thrust bearing.

I know of at least one dyno-proven case where a thrust bearing **** the bed. They swapped a new turbo onto the car and gained ~50whp with NO OTHER CHANGES. The thrust bearing was ground to hell, shavings everywhere, but didn't leak. You may not notice a bad thrust bearing until you re-dyno it or other internals start making contact.

Ever seen a turbo in which the comressor or turbine wheel shattered? Not pretty...

charlay

factory euro/japan model nissan 200sx/180sx/silvia/RS13 models with CA18DET (pre 94/91(jap) use a T-25 turbo at 10psi, with no BOV, later models using SR20DET use a recirc that leaks a bit.

but really, anything more than a tiny amount of boost, and you should have some anti surge drvice/blow off/recirc.

turbodailydan

no not oem, i had a pulsar gti-r with a gt3071r running 1.8bar for 2years, no problems. also had a 4efte with a gt28rs on 1.6bar for over 2 years and no probs.

it makes sense that running without a BOV will put extra strain on something in the turbo, but i dont think ive ever heard of a failure due to this?..

TheShodan

iTrader: (14)

You ran a great risk then, my friend. It is best to use one. Its not just strain on the turbo, but the resulting damage from the reversion of the wheel/shaft.

Don't debate, just use it, and your turbo investment will live a long time.

turbodailydan

understood shodan, but surely 2 years at 1.8bar without turbo failure would suggest that a BOV doesnt make any difference in the short run..? (the turbo mentioned is still going strong on the car now which i sold to a friend) OR maybe it has more of an effect on journal bearing turbo's than roller..?

TheShodan

iTrader: (14)

Not necessarily. That could mean you were lucky this time around. That doesn't mean that it is virtue of now NOT using it all. This is one of those in which "just because you did it this time doesn't mean its to be done." There could still be problems with the turbocharger itself that may not have been felt while you were driving. I'd love for you to ship said turbo to me to have it inspected after such use, if what you're saying is true.

turbodailydan

true but in this circumstance this was the case. the turbo still pulls like it did the day i put it on new.. its suprising that alot of big power turbo cars run without BOV's here in the u.k where as every turbo motor you see in the states has one fitted, maybe you guys just like the noise

but yeah would be interesting to strip a turbo down after some high boost use without a BOV and see what its condition is.

turbo12a

I never use bov's. I love compressor surge The day I see a turbo fail because of this I will consider putting one on, but have yet to see any issues.

turbodailydan

you and me are in the minority by the looks of it mate lol

i guess i will keep running without a BOV until i see a turbo blow because of it..

TheShodan

iTrader: (14)

If decide to do so, and you purchase a turbocharger in the U.S. from a U.S. turbo company, and it fails for some reason, don't be surprised if the company you purchase it from may find it grounds to void any warranties that they may have expressed written or implicitly because you didn't run a BOV. That's just truth here in the states.