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View Full Version : Blow-off or External Wastegate


george85442
05-27-2005, 09:15 AM
Hello, I'm new to turbos, so of course I have a question.

I was cruzing in my car, when i saw a nice 87 T-type, i gave the guy thumbs up, and I think he wanted to show me that it's not a V8 Regal but a turbo V6 because he build up some boost and then let it go.....there was a loud sound of pressure being released (not a whistle like imports).My recently purchased 87 Turbo Regal doesnt have that sound, so I'm wondering what it is? Blow-off valve or External Wastegate, and is there any benefit from having one, or is it just a cool sound, or necesity of large downpipe.

Thanks.

I'm happy to join this great community. :)

PaCemkr86
05-27-2005, 09:11 PM
wategate is on the exhaust side of your turbo, that controls how much boost you want " PSI"

the blow off valve , is mounted somewhere between the throttle body and the intercooler, I mounted my Tial 50 mm right before the TB.
ALthough a TR donsnt need a BOV, due to them being auto trans, and most people on here will say you dont need one.
But your car should make some sort of noise without a BOV, somewhat like a sneezing horse sound.
How much boost you running?

george85442
05-28-2005, 04:04 AM
My car is stock, so maybe 14-15 psi? Maybe there is something wrong there?
Or maybe stock air box muffles the sound? 'Cause all i hear is tumbling sound...

PaCemkr86
05-28-2005, 11:02 AM
Im sure if you get a K&N or some type of performace filter, thats open " not like the stock one".
Go rip on it and let off, then you will hear the noise you are looking for

one like this
http://www.buickgn.com/NewEngine005.jpg

george85442
05-29-2005, 08:20 AM
Perhaps I have to look in to that...

(i'm not looking to achieve that sound,
it's just that i never heard it before on a TR)

Keller
05-29-2005, 11:06 AM
The stock air box definately muffles it. You will hear a bit of "compressor slam" on a hard throttle burst and quick release with an open element filter. However, try to avoid it, as it is bad for the turbo. Getting off it easy puts less stress on it.

spyrs69
05-30-2005, 11:03 PM
If I go stick shift (which I love), then I will definitely go with a pop off (aka-surge valve). The compressor slam is very bad and I can hear it on mine if I let off the throttle and I have the k&n element on mine routed just above the spoiler for cold air.
That is a finely detailed engine bay and I am jealous. Any tips on how you cleaned that up so nicely (aside from addition of new parts). I was looking to use some type of mild degreaser/cleaner and following up with a pressure washer. Any suggestions are appreciated.

Keller
05-31-2005, 12:58 AM
Best way to keep things clean:

- Don't drive the car - keep the miles off
- Don't drive the car in nasty weather
- Don't let leaks persist (oil, coolant, trans fluid, etc)
- Change things out to new parts

Sad but true...some cars look new under the hood because, well, they are! You can't drive a car and keep it spotless.

Simple Green is said to be a great underhood detailing fluid.

Now back to the blow-off/external wastegate chat...

Turbo2nr
06-12-2005, 07:33 AM
I have owned many different turbo cars. I thought a BOV would be a small waste of money for a TR. But, after installing a Turbonetics T70, I have experienced compressor surge for the first time. Bucking and surging just after a shift, because the turbo is spinning to fast for cruising (I think to the left of a compressor map, right?)
After installig a BOV (Turbosmart), car smoothed right out. You can hear a small release of air at part throttle shifts, and car runs like butter. :cheers:

Of course after a burnout or big boost, the BOV sound is 100% better to my ears than blablablabalbabal.

PaCemkr86
06-12-2005, 02:51 PM
i couldnt agree with you more

buddiiee
06-13-2005, 07:21 AM
keller said that getting off the throttle too quick is bad for the turbo. well how bad is it? i mean, what choice to you have? you telling me they designed this car to fail?
thats unavoidable. you have to sometimes get off the throttle quickly. so you mean to tell me that everytime i hear that weird tumbling sound when i get off my gas quickly, im messing something up.. how? and how many times do i have before i break something? (maybe i should have stuck with 350's. theyre much more solid of an engine.. computers.. if i could find the person who invented them, id choke him)

Turbo2nr
06-13-2005, 11:52 AM
On a stock turbo under normal driving, everything is OK. But when you make 2x-3x the power of the intended amount, and are using a big turbo, the condition gets worse, but most of these cars do not get driven daily running like that. Yes, it as a little bad for the turbo, no big deal though. Some stock cars go over 200,000 miles on the stock turbo.