Frankie4skin

Alright

I'm curious what people think about Turbo blow off vavles and waste gates???
Are they essential, and what are your favorites??

perfect_circle

they are essential to the life of a turbo, a wategate, prevent the turbo from over spooling, and a bov prevents compressor surge, whn they air comes back towards the turbo after it is stoped by the closed throtle plate.

S2-13BT

Wastegates are essential if you want any control over your boost level.

BOVs are a big ****, a waste of money, and useless... IMO. BOVs are a personal preference thing. If you like the noise, get one. If you think a little air is going to damage your turbo, get one. Otherwise, spend your money on something useful.

REVHED

If that's the case why do all OEM applications use blow-off valves?

coldy13

BOV's do make the turbo last longer, it's more than just "a little air". Turbo's spin between 5-10 times faster than the engine, and making them spin backwards between shifts is not good for them. Yeah, it is fine to run it without one, as long as you're okay with the turbo lasting 1/2 as long.

FB II

82streetracer

iTrader: (1)

BOV is an essential part of any high horsepower, blowthrough setup.

turbos can spin in excess of 250,000 rpm, super fast spooldown due to compressor surge causes excess bearing wear and will eventually cause falure.

the blades dont weigh much but force=mass*acceleration and a few grams of metal has some serous mass at 200,000 rpm

S2-13BT

Because the general public wouldn't accept any factory car that made the flutter noise on every gear change.

It's really a matter of opinion. Read this thread on AusRotary. Warning, it's very long...

http://ausrotary.dntinternet.com/for...ic.php?t=17113

I'd say they can spin much faster than that, and I highly doubt the turbo actually spins backwards during shifts. The noise is simply the air being chopped by the blades of the turbo, as it's coming back down the inlet path. Do you have any evidence to back up the turbo lasting half as long theory? Does anyone? Other than BOV manufacturers that is.

FB II

S2-13BT...... i just want to apologize for doubting you and then i want to thank you for posting that link. i have been converted. it all makes sense now. i read the whole 13 pages and then read a few other links off of those. i mean it just really makes sense!!!!!!! i cant believe i wasted 350 dollars to get the BEST damn bov. i feel so fuggin stupid now. My HKS SSQV BOV w/ ALUMINUM MOUNTING FLANGE AND ALL PIECES NEEDED is now for sale!!!!!!!!!! pm ME

REVHED

It was a good read and raised some interesting points but there was nothing really conclusive one way or the other.

FB II

i plan to upgrade to a better turbo eventually so i'm going to use this setup as a TEST. my turbo has been rebuilt and has no miles on it as of yet. so i have a good starting point. WOOT!

oh and i dl'd a couple videos and got to really hear this amazing flutter and it by far is so much better sounding than any bov i have ever heard. dont get me wrong, the rice in me comes out when i hear the hks ssqv blow off but that flutter is bad assssssss! MUHUAHAHAAA

Brianhsval

If a blow off valve was required to make a turbo last then why is it a desiel turbo has no bov? A turbo is a turbo, and I never heard of a BOV on a desiel. Funny 425 CAT 500,000 miles and it never hurt the turbo.

S2-13BT

Diesels are different beasts. A BOV isn't applicable. Please correct me if i'm wrong.

FBII, no worries! I should point out that I do actually have a BOV on my car. It's wound so tight though, that it take s a sledge hammer to open it! At the moment it's blocking the whole wher ethe BOV is!

REVHED, you're 100% right. The argument isn't conclusive one way or the other. That's why I keep saying it's a matter of personal preference.

REVHED

Yep. That's why I'm just about to go in the garage and tighten the BOV up so I can decide for myself.

FB II

lol yea i have decided to keep my hks super sequential. i'm not gonna get the money i want for it so **** it. i'm going to do exactly what you are and tighten the **** out of it till it basically doesnt let much out. so maybe i can get BOTH sounds! hahahah now that might be awesome! WOOHOOOOOO!

Frankie4skin

Alright,

So top Dollar doesn't need to be spent!!!

Is that the Concensus?

9d7gst

To blowoff or not to blowoff. That is the question. Im going to test it. 97 Mitsubishi Eclipse. T3/T04B. I know what sound it makes without it. I like it but I was allways told it WILL bend the shaft. BUT, because the car if FALLING apart, ( Trans needs rebuilt, leaky headgasket, bad rings, P/S rack pukes) I dont give a **** it it does **** up the turbo.

We shall see. I rather drive the RX-7 anyway. The Eclipse being down gives me a reason. A good enough reason for my wife annyway. (KIDS + 2 seater = GET IN THE BACK)

Oh oh..... you pay for cheap ****, you get cheap ****. Unless the cheap **** came from your friend, who paid top dollar and never used it, then sold it to you making it cheap ****.

S2-13BT

I have a standard S5 turbo, making 178rwkw at about 14psi. I've done 4 trackdays (which must be at least 100 1:20 laps) plus plenty of spirited street driving, and a couple full power dyno runs without breaking the turbo yet.

The block and turbo are off the crate imports from Japan.

Nothings broken yet, and it's not showing any signs of damage. Last time I had my airfilter off, I checked for shaft movement and it was fine.

S2-13BT

Ppppsssshhhhhtttttt!!!!!!!





Stoopid double posts!

Brianhsval

[QUOTE]Originally posted by S2-13BT
[B]Diesels are different beasts. A BOV isn't applicable. Please correct me if i'm wrong.

Diesel is a different beast, but the principles of the turbo are the same. Forced air induction. They do not run backwards. Bigger turbo, 18 psi.

S2-13BT

[QUOTE]Originally posted by Brianhsval
[B]I have no idea what i'm talking about so flame me if this is way off the mark, but I was under the impression they don't have throttle bodies. So a BOV is not applicable, because there won't be a sudden shutting off of the air stream which then reverts back on itself and travels toward the turbo.

A turbo is a turbo is a turbo, so that's got nothing to do with it. Just the way the engine works means it's not really relevant to this topic.

Sorry if i'm an idiot!

REVHED

You're absolutely right. Diesel engines are un-throttled so there is need for a BOV. Engine speed and power is controlled by the amount of fuel being injected.

S2-13BT

Well, ya learn something everyday. Thanks man.