Normal turbo sound
#1
Normal turbo sound
Hello!
I´m a new member here, from Spain, so a salute for all of you, and please excuse my english!
My background is,I have an 86' 951 i bought in a less than perfect state 15 year ago...was not expensive but the poor car was beaten up, eating almost 1 liter oil per 160 miles or so. Imagine...
5 year ago I overhauled it, was a lengthy and very expensive overhaul, a few times the price of the car, iti ncluded new pistons with rings, new transaxle, new turbo (k26/6 since I wanted original specs) head work...etc etc. Quite expensive but I got an almost perfect mechanical state, no oil consumption at all and great performance. I also added a lindsey boost enhancer that really did it's job.
More recently I did some maintenace changing part of the steering, new shocks, new clutch pump, etc. This was the last maintenance, 2 months ago. Not cheap also....
So with this background, here is my question related to the topic...
Yesterday was driving through a tunnel, when I noticed the sound ofthe turbo spooling up and down while accelerating. And I thought "how cool the turbo spooling"... But after exiting the tunnel I turned off the stereo and while accelerating, I still heard the turbo spooling up and down...very subtle, a very light " pssttttt.....psssssst". Then i tought "did I heard this before?? Is this normal?" I kept driving and I still heard the very subtle sound of the turbo spooling up and down. When above 3k rpm, I heard nothing, and at the end of the trip when the car was hot, the sound was even more sobtle, almost non noticeable.
So now I dont know if i'm too paranoid about this...I remember when the car was not repaired and i had the original busted turbo that it was quite noisy, but i cant remember hearing it after the overhaul.
So...are you supposed to hear a little bit of turbo spooling on a stock car? Or should you hear nothing? I checked hoses and apparently they are ok, and oil consumption semms normal, almost zero.
I'd like to know if i'm too paranoid or not...what is your opinion??
Thanks!!
I´m a new member here, from Spain, so a salute for all of you, and please excuse my english!
My background is,I have an 86' 951 i bought in a less than perfect state 15 year ago...was not expensive but the poor car was beaten up, eating almost 1 liter oil per 160 miles or so. Imagine...
5 year ago I overhauled it, was a lengthy and very expensive overhaul, a few times the price of the car, iti ncluded new pistons with rings, new transaxle, new turbo (k26/6 since I wanted original specs) head work...etc etc. Quite expensive but I got an almost perfect mechanical state, no oil consumption at all and great performance. I also added a lindsey boost enhancer that really did it's job.
More recently I did some maintenace changing part of the steering, new shocks, new clutch pump, etc. This was the last maintenance, 2 months ago. Not cheap also....
So with this background, here is my question related to the topic...
Yesterday was driving through a tunnel, when I noticed the sound ofthe turbo spooling up and down while accelerating. And I thought "how cool the turbo spooling"... But after exiting the tunnel I turned off the stereo and while accelerating, I still heard the turbo spooling up and down...very subtle, a very light " pssttttt.....psssssst". Then i tought "did I heard this before?? Is this normal?" I kept driving and I still heard the very subtle sound of the turbo spooling up and down. When above 3k rpm, I heard nothing, and at the end of the trip when the car was hot, the sound was even more sobtle, almost non noticeable.
So now I dont know if i'm too paranoid about this...I remember when the car was not repaired and i had the original busted turbo that it was quite noisy, but i cant remember hearing it after the overhaul.
So...are you supposed to hear a little bit of turbo spooling on a stock car? Or should you hear nothing? I checked hoses and apparently they are ok, and oil consumption semms normal, almost zero.
I'd like to know if i'm too paranoid or not...what is your opinion??
Thanks!!
#3
You lost me with the "and down" part.
My 951S with the stock K26/8, I hear it spool up then a constant "wheesh" under boost, with the windows down and some surface to help reflect the sound off of (even a guardrail or jersey wall)
Whether or not you can hear it, if it seems to be boosting properly then it's doing its job
My 951S with the stock K26/8, I hear it spool up then a constant "wheesh" under boost, with the windows down and some surface to help reflect the sound off of (even a guardrail or jersey wall)
Whether or not you can hear it, if it seems to be boosting properly then it's doing its job
#4
You lost me with the "and down" part.
My 951S with the stock K26/8, I hear it spool up then a constant "wheesh" under boost, with the windows down and some surface to help reflect the sound off of (even a guardrail or jersey wall)
Whether or not you can hear it, if it seems to be boosting properly then it's doing its job
My 951S with the stock K26/8, I hear it spool up then a constant "wheesh" under boost, with the windows down and some surface to help reflect the sound off of (even a guardrail or jersey wall)
Whether or not you can hear it, if it seems to be boosting properly then it's doing its job
My grilfriend has a little turbodiesel and has a very similar sound when driving throug tunnels or reflective surface...you press pedal, hear turbo spooling, then maybe boost control reduces pressure and then turbo spools down.
If I drive with a constant acceleration, I can hear almost nothing about the turbo spooling, as above 3k rpm or so other engine sounds appear and mask everything.
The only thing worying me is that when I had the old busted turbo, sound was very noticeable, maybe because was worn out and out of balance. I read some opinions that a good shape turbo should make no noise at all in a 951. But I´ve also read opinions like yours that it´s normal to hear it a bit.
As you said, I hope, as pressure is looking good, I should not worry at all.
#5
I think it's time to pull the j-boot off the turbo to look at the wheel blades and check for shaft play. If all looks good there, check the turbine outlet/downpipe connection to see if there is a gap. Several years ago, I got a mechanic to do a clutch job for me and he forgot to bolt the downpipe back on the turbo. The turbo noise was quite noticeable.
#7
I think it's time to pull the j-boot off the turbo to look at the wheel blades and check for shaft play. If all looks good there, check the turbine outlet/downpipe connection to see if there is a gap. Several years ago, I got a mechanic to do a clutch job for me and he forgot to bolt the downpipe back on the turbo. The turbo noise was quite noticeable.
I have an vdo boost/vaccum gauge and mine's peak at almost 1 bar with this cold weather. Pressure when coasting with no power is about -20 in.hg, so I bet there are no leaks for now.
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#8
If you never rebuilt the wastegate then you may want to consider that. I had one look fine but had hairline cracks along the valve seat. And you may have a broken down pipe seeing how they are known to collapse the inside pipe on occasion. Lots to go wrong with the 951/952's. But good service and being keen on noises like your doing helps keep them at there best.