I dont think I like this ODD TURBO Noise

[TonyTtops]

So I purchase my first 87 GN yesterday . Fast, real FAST!! The guy who I purchased it from upgraded the turbo intercooler and intake. NO factory AIR BOX!!! So when the turbo spools up and gives the boost it sounds great with lots of power and no heasitation. When the turbo is spooling down after a shift or I let off the gas it sounds like it is sputtering rapidly . What does this mean. And how do I Fix it. Can someone also explain to me what the purpose of a blow off valve is? Sorry for not being up to speed. This is my first car that has a respirator!!

 

[jurassic five 7]

Well congratulations on getting a TR!

The sputtering, is more like a fluttering right? If so, that's what they call a waste-gate. Its a different form of way to get rid of the built up pressure in the intake/exhaust.

Waste gates are used on exhaust and BOV's are on the intake. No need for a BOV on a GN.

Do you have a scantool?

What's done to the fuel system?

Give us some more info to what's done to the car so we can help you from determining possible problems and things you shall do the car to make sure it runs 100%

Have fun and dont blow it up!

-Adam

 

[BlackBandit]

The sound is normal, but it's not the wastegate. What happens when you let off the gas under boost is that the air that would normally go into the engine hits the throttle blade and reverts back towards the compressor. The noise you're hearing is the compressor basically "hitting" this air. It's normal. The point of a BOV is to both eliminate this because it loads up the turbo bearings and to prevent the turbo from spooling down as fast. This is why manual trans cars use them. Because if they didn't they would have to spool the turbo more after every shift. Some BOV's recirculate air. This setup keeps the ecm from adding fuel to the engine for air that doesn't make it to the engine but has been measured by the maf. Turbo Buicks don't need this setup because the ECM cuts fuel durring decel. Some say you need a BOV but take note of how many are very successful at running without one and having NO turbo failures. Are they "better" for the turbo? Probably. Do you need one to keep a turbo alive? No. The benefits of them really are debatable.

The wastegate re-routes exhaust gas past the turbine when a desired boost level is achieved. This is how you regulate the boost level as if you didn't the boost would just increase until it couldn't anymore. That would be bad. HTH and welcome to the Buick world. Do some searching on here and check out this site Turbo Regal Web Site. Also, if you haven't done it yet do the "spring cleaning" from that site. Welcome again. james

Edit: if you don't have a scan tool don't drive the car hard. You have to monitor detonation or the engine won't last long. Again, do some searching on the subject. I personally would recommend a Scanmaster as you can use it all the time. If you do have a scan tool then disregard.

 

[TonyTtops]

Black Bandit and jurassic five7 Thanks for the input. I will be getting all of the specs on the aftermarket parts. At that point ill get back to you guys. Thanks for the help. AS for now I will be easy on the car besides I just got it!!