What is it that makes a turbo or a supercharger system loud?

Is it the size of the unit? The Wastegate? The Bov? The placement of the unit: i.e. is a front or rear mounted turbo louder? Are twins louder than a big single? Are turbos louder or are s/c's louder? Does the exhaust setup make any given setup make more FI related noise or noise in general? Do turbos run mufflers at all?

Really, any information relating to the sounds of FI is welcome here!

Finally, what would one do to make their car sound like a 747?

Thanks, everyone.

 

um loud? thats a little blan...need more detail as what your referring to...

superchargers whine...turbo's spool. The BOV is usually a very destinctive sound, like rushing air or whatever during every hard shift/let of the gas pedal. Well my guess would be a rear mounted turbo would be louder if ur standing at the back of the car and a turbo in the engine bay would be louder if your in the front of the car. Turbo's are mufflers, they do a super job of blocking the exhaust and therefor quietting it down alot. I've heard a t-76 car idle with an open turbo housing (IE: no exhaust) and it wasn't very loud.

 

So would the loudest possible turbo setup be one with an open turbo housing? Is there any reason not to do this?

 

So nobody has any info on this?

 

well what is really the point of your questions? there's a LOT of variables and no real "blanket" answers...

 

1. Does the size of the turbo or s/c unit affect exhaust sound and volume and if so how?

2. Does the Wastegate size and configuration affect exhaust sound and volume and if so how?

3. Does the blow-off valve size and configuration affect exhaust sound and volume and if so how?

4. Does the placement of the unit affect exhaust sound and volume: i.e. is a front or rear mounted turbo louder?

5. For turbos, are twins louder than a big single or vice versa?

6. In general, are turbos louder or are s/c's louder?

7. Does the exhaust setup make any given setup make more FI related noise or noise in general? Like would any given exhaust affect the sound of a s/c or would the exhaust have nothing to do with it?

8. Do front mounted turbos run mufflers at all?

9. Do rear mounted turbos run mufflers at all?

10. Finally, what would one do to make their car sound like a 747? Does anyone have a setup where the FI related sound (i.e. whooshing, spooling) is just so loud that it can be clearly heard over the regular exhaust even at WOT?

11. Does anyone have any other misc. info that might be helpful, relating to the other questions?


Thanks, everyone!

 

click here

Is this the sound your talking about?? Turbo car always sound cool. This is My frineds car in the video, and yes, you can hear the turbo everywhere, from inside to out. A open exhuast will give you that sound.

 

Yes, that's what I mean. I've heard others that are even more so like that.

 

Turbo noise is more a function of the intake configuration than the turbo itself. Most factory turbos have a silencer in the intake path to reduce the turbo noise. A common modification for tuners is to either hack (modify), or completely remove that silencer.

Most of the available aftermarket BOVs are designed to be loud...the TurboXS RFL is a good example. I'll let you figure out what RFL means, but I will give you a hint. Real F_ _ _ ing Loud. *s* Some BOVs vent to atmosphere. Some recirculate the waste gases. And some, called Hybrids, can do either, or both at the same time. The design of the overall turbo system determines which type of BOV must be used. The Subaru uses a recirculating type.

BOVs do not affect exhaust sound.

Generally, SCs are louder...which is one reason they aren't used more on production vehicles. Ford used helical rotors on the T-Bird SC in order to reduce SC noise.

As with any other car...some factory turbo'd cars run mufflers...some run just a resonator.

Wish I could answer more of your questions, but I'm not an expert on the subject.

 

Centri S/Cs are usually louder at idle than roots type and turbos. I know the cut of the impeller blade is one factor that will change the volume of the blower whine. The roots style blower and turbos will generally get louder as more throttle is used, where as my centri seems to get drown out by exhaust(at least inside the car). Outside people say they hear the blower long before the exhaust when I drive up, so it's hard to say. As was said above, I'm not expert, this is just what I've gathered with my own two ears.

Mike

 

Thank you both, this is the kind of info I am looking for... keep it coming.

So I hear that it is the intake configuration and the "cut of the impeller blade" that make the differance, at least with front mount turbos and centri s/c's.

What is this "cut of the impeller" and does it affect anything else besides the sound?

What would one's options be for differant "cuts" and what would they do?

 

Well my D1 is straight cut and pretty loud on the scale of blowers. I know from some of my Mustang friends, I've heard the difference between the SQ(super quiet) blowers which have a curved cut and the straight cut Vortech and the straight cuts are louder with all else being equal. Don't know the physics behind why, but that seems to be the rule of thumb.

Mike

 

So you want the loudest possible FI car that sounds like a 747 but I think you are forgetting the most important part....POWER

 

1. Blower itself has a minimal effect on sound output, beyond increasing horsepower (which increases noise). There is of course the gear whine and blower rattle, but that's typically drowned out by the motor once under power. A turbo on the other hand, will change the exhaust volume based on the size, trim, and A/R ratio of the exhaust side. Generally the larger the housing, and/or the larger the A/R ratio, the louder it will be. The larger the A/R, the larger the nozzle, the more flow, the more noise..

2. The wastegate only affects noise level when its open -- ie. high boost where its bleeding off exhaust flow. WHERE it dumps obviously has a big effect on output (back into the exhaust tract or dumped to atmosphere).

3. Again, only while its open -- ie. high boost where its bleeding off intake flow, such as when the throttle is snapped shut. Also as before, WHERE you dump it has a large effect. Dumping into the airbox is nearly silent, whereas dumping to atmosphere gives you the riceboy whoosh...

4. Theoretically there wouldn't be much difference, everything else being equal.

5. It all comes down to the area of the exhaust housing.. You could have either setup be more quiet or more loud, depending on the choice of components.. In general, twins would tend be quieter due to more turbine wheel surface area in the exhaust stream, but only if the area of the exhaust tubing were equal (two smaller pipes vs. one bigger pipe).

6. Two completely different sound characteristics, kinda hard to compare them directly. In general, a blower car will be louder than a turbo car..

7. The exhaust system on a blower car would react the same as if on a nitrous car, or N/A car.. It wouldn't change anything simply because its a boosted car.. On the other hand, due to the way it operates the exhaust system directly effects how a turbo car will run and sound.

8. Depends on who built the setup
9. Depends on who built the setup

10. Go to eBay and buy the stupid ricer toy that slips in your exhaust pipe. Or, buy a stupidly small turbo and put it somewhere in your exhaust pipe -- then dump everything (the remaining three orifices) to atmosphere. Its retarded and it'd be slow, but you'll make a car sound like a jet.

11. Yes, but only by asking a question... Are you wanting to build a fast car, or a ricemobile that goes "whoosh?"

 

Blowers make more noise at idle than turbos.

My Vortech Mondo Bypass is very loud too.

 

I would like to make one comment to correct the misconception that aftermarket BOVs are simply bought for the " riceboy" whoooooosh (God, I hate that term). Most factory BOVs are not capable of handling the higher boost produced by large aftermarket turbos. Though I will concede that the majority of loud BOVs you come across on the street are on the car with one purpose in mind...to make noise...there are some cars out there that may sound "rice" (Damn, I said it again), but will surprise you if provoked. So, don't be mis-led...some of those loud-*** BOVs are actually about "go", as opposed to "show".

 

Most as you said are bought for the noise...

My quote from many years ago:
The riceboy / ricer / rice stereotype didn't form out of nothing But you're absolutely correct -- that's not the ONLY reason they're bought...

 

Glad to see we agree on something. *grin* As you seem like a pretty sharp guy, I think you'd also agree that rice isn't exclusive to the import crowd. I've seen some pretty riced-out Detroit Iron on Houston streets, as well. Like the kid down the street from me who sports a 4' aluminum wing and baby poo yellow SS stripes on his V6 Camaro. *L* Anywho...it's all good.

 

Just because I am asking about the sound does not mean that I am not concerned with performance! I fully plan on building up a 10 second car, eventually.

Is there some reason why I can't have a car that sounds good and runs fast? Is there some reason why any of the advice above would make the car slower? I surely wouldn't do anything to improve sound that would hurt performance and I didn't mean to imply that.

Plenty of people post in the external engine section about the sound that can be had from aftermarket catbacks. You won't get a big differance in performance between a loudmouth and a gmmg, but nobody calls the gmmg people "rice" because they want their cars to sound cool! And they pay a lot more money for that, too, but I don't think I'll be paying more money just to remove a silencer! You guys need to chill out.

To the others, who were helpful, thanks and keep it up!

 

Black-Knight,

In all honesty, I think you'd be happier with a supercharger than you would with a turbo. One of the main reasons small displacement motors use a turbo for forced induction is because it's basically "free power". It works off the engines waste (exhaust gases), and there is no parasitic loss. When you don't have much displacement to begin with, you really can't afford to give up the HP required to drive a supercharger. On the other hand, with the larger displacement and gobs of available torque of a V8, that loss isn't quite as big a concern.

I'm pretty much an old school guy, and I haven't spent a lot of time around Domestics over the past 20 years or so. Your fellow LS1 brethren can probably point you in the direction of a good SC setup better than I can. Whichever way you decide to go...good luck, and have fun with it. And be sure to come back and post your numbers when you're done.

Richard