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Need tuning help!!
- Thread starter wahoo50
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I do not feel a loss of power, just concerned about making sounds and not knowing whats causing it. I'm running a Stage II motor with a FAST system so I don't use a MAF. My 60 turbo is small for my engine but I plan to upgrade to a 76 and front mount this month. This may cure the problem for me.
FlightTest
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Do you happen to have a compressor bypass valve (a.k.a. sneeze valve) on the car?
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I don't. Who are you asking?FlightTest said:
I have the same problem, and always have, and I dont have a huge IC. Just a Dutt neck. Plus it even did this when it had the stock IC. If I go higher than 14psi at part throttle, is flutters bad...kinda like a ta ta ta ta ta ta ta ta. Ive got some bypass valves here that I was planning on using, to make a dual bypass setup on the buick. But I think I'm going to run into tuning issues since buick wrote all the tuning code around having no bypass setup.
Ive always believed its the same thing as what gnx139 is saying. My homemade boost control causes the turbo to act like an on off switch. The boost comes on ridiculously fast, and having it at part throttle...(throttle blade halfway open) creates an air dam for a turbo thats flowing too much air too fast. I can get 20psi at half throttle, and about 3 extra pounds of boost at full throttle. I have to wonder how the engine can be flowing so much air at half throttle.
Honestly, I think going to a bigger TB will solve most of this. Alot more air is able to pass through the TB at lower throttle positions.
By the way, my boost doesnt bounce and never has. But the turbo does pulse really loud.
Ive always believed its the same thing as what gnx139 is saying. My homemade boost control causes the turbo to act like an on off switch. The boost comes on ridiculously fast, and having it at part throttle...(throttle blade halfway open) creates an air dam for a turbo thats flowing too much air too fast. I can get 20psi at half throttle, and about 3 extra pounds of boost at full throttle. I have to wonder how the engine can be flowing so much air at half throttle.
Honestly, I think going to a bigger TB will solve most of this. Alot more air is able to pass through the TB at lower throttle positions.
By the way, my boost doesnt bounce and never has. But the turbo does pulse really loud.
FlightTest
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The reason I was asking is that I had problems with my sneeze valve on the car with those exact symptoms like wahoo50. The problem was that at small throttle settings under load like on the freeway, the turbo would build a lot of boost but since the throttle body was mostly closed there was a large differential of pressure between the intercooler and the intake. This would cause the sneeze valve to stay open and vent pressure outside. The car would chug black smoke like crazy and buck a bit. If you opened the throttle just a little more it would be fine since the pressures were closer. I ended up adjusting the sneeze valve much tighter so it needed about a 15 PSI differential to open. Once adjusted it worked much better. I realize the problem may be many other things but this is just a heads up to what happened to me.
It's the SURGE man. And it can't be gotten rid of. It's like some terrible disease from the car Gods. I took the TA48 off today and will put on the 3255e and see if that helps. Got to work all night for the next 4 days, so it will take me a while to get back to her. I have considered a bigger throttle body. Maybe one of those 62mm reworked ones that Steve Monroe does. That might help. My PTE has that huge 3" up pipe then the small reducer into the stock throttle body. That could be the back up point.
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I have the CH CH CH CH CH at part throttle also. But no stumble or surging.
Is it just the noise that bugs you guy,s?
Or does it effect drivability?
Is it just the noise that bugs you guy,s?
Or does it effect drivability?
Thanks for all the input. Flight Test- I do not have a sneeze valve. Maybe I should include one. I do have a Big Boy intake with a 70MM throttle body and standard size piping. When I add the FMIC and 76 this month, I will upgrade to 3" piping. But I don't want to experience periods of too much fuel like your car. Your thoughts?
FlightTest
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Wahoo50,
The sneeze valve is OK, but I would get things sorted out first. It adds one more variable to mess with. I have a TE-63-1 turbo with an old ATR front mount intercooler that I converted to 3" tubes. The intercooler came with a sneeze valve pad built in so I installed one long ago. I am skeptical that changing the throttle body etc will change anything because even though the throttle body is bigger it will allow the same volume of air through and very low throttle settings. At cruise the car only needs so much air to maintain speed so the larger throttle body will actually be opening less than the stock one to allow the same amount of air by. I purchased a 62mm throttle body long ago and noticed no difference in performance at all. I know some people have been happy with them, but there are also several people running 10's on a stock throttle body. If and when you get a bypass valve you will have to tune a tweak it a bit to get it not to open at part throttle like when accelerating moderately on the freeway. I think with the bigger turbo you will have very few problems with turbo surge.
With the big intercooler piping etc, I think that a sneeze valve will help with the life of your turbo (my opinion!). There is quite a bit of volume with the big piping and the front mount that all has to go backwards through the turbo when you let off the gas. It can be pretty hard on the turbo bearings.
Good luck!
The sneeze valve is OK, but I would get things sorted out first. It adds one more variable to mess with. I have a TE-63-1 turbo with an old ATR front mount intercooler that I converted to 3" tubes. The intercooler came with a sneeze valve pad built in so I installed one long ago. I am skeptical that changing the throttle body etc will change anything because even though the throttle body is bigger it will allow the same volume of air through and very low throttle settings. At cruise the car only needs so much air to maintain speed so the larger throttle body will actually be opening less than the stock one to allow the same amount of air by. I purchased a 62mm throttle body long ago and noticed no difference in performance at all. I know some people have been happy with them, but there are also several people running 10's on a stock throttle body. If and when you get a bypass valve you will have to tune a tweak it a bit to get it not to open at part throttle like when accelerating moderately on the freeway. I think with the bigger turbo you will have very few problems with turbo surge.
With the big intercooler piping etc, I think that a sneeze valve will help with the life of your turbo (my opinion!). There is quite a bit of volume with the big piping and the front mount that all has to go backwards through the turbo when you let off the gas. It can be pretty hard on the turbo bearings.
Good luck!
I notice a couple of you indicating you have the same problem as the original poster. How long have you experienced this issue and have any of you had any turbo failure or experienced an increase in oil consumption.
I ask because surge especially under the conditions you mention here where it is repeated is not healthy for the turbo. It is my opinion this sort of behavior can cause the turbo to fail. So it is something you want to resolve unless the other posters in this thread are saying they have had this issue for years with no ill effects to turbo.
I ask because surge especially under the conditions you mention here where it is repeated is not healthy for the turbo. It is my opinion this sort of behavior can cause the turbo to fail. So it is something you want to resolve unless the other posters in this thread are saying they have had this issue for years with no ill effects to turbo.
I've always noticed it on mine. I didn't really thing it was a big deal. The car seemed to run o.k. when it was doing it. I thought that maybe it was a characteristic of the buick motor. I have a TA49 on a TTA with a Tony Dequick intercooler. How come it seems like most buick guys are against blow-off valves?
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I don't get it! Bigger turbo but it surges less?!
So where do you think the unused air is going now? Can you still hear it come back through the turbo?
So where do you think the unused air is going now? Can you still hear it come back through the turbo?
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Thats very interesting. If thats the case, its got to have something to do with the turbo design. Post pics of your new turbo. I would like to see it.
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Don't stop now, lets keep this thread going
gnx139, waiting for you to post pics of that turbo.
If there is something unique about it that helps with the back preasure, we would like to know.
gnx139, waiting for you to post pics of that turbo.
If there is something unique about it that helps with the back preasure, we would like to know.
