turbo spool sound

[hallperson]

i have a 95 gsx and have gone thru multilple evo 3's and big 16g's. i was wondering why some turbos that are the same size you can and cant hear spool? i had a MHI evo 3, it sounded like stock, you really couldnt hear anything. then i had a evo3 from turbochargers.com, you could hear that turbo get into boost. it would litterally scream and you could hear it like 5 cars away. thanks for any input

 

[hopwoodp]

It depends. But, if your turbo spools up really loud, it usually indicates that you have a boost leak and the turbo is working alot harder to pressurize your system. You will wear out turbos really quick if you have a leak. Also, a hard intake pipe and a free flowing air filter(not the stock air box) will also help you hear the spool up alot better. But, how you make it sound, it seems to be spooling pretty loud and you might consider doing a boost leak test.

 

[hallperson]

i run all hard pipiing with a fmic and a injen intake. but i know what you mean with it leaking thru the exhaust. the thing is, there are no leaks. i aslo have had boost leaks b4 and it never made a sound like that. but something similair to this topic, i am a diesel mechanic, are fleet has many newer trash trucks, these trucks you dont here spool. but we have one truck that as soon as you put it in drive you here that turbo spoolin. it sounds like you are at a tractor pull event but yet runs stock oem exhaut.

 

[hopwoodp]

I used to have an Evo III 16g turbo before and at the same boost levels it is alot louder than my 20g.

I know 14b's and t25's are alot louder unless you are at lower boost. I wasn't refering to exhaust leaks but, on the intake side. You want to check up to 20 psi and try not to go any higher otherwise you may blow some seals on the throttle body or blow a hose.

 

[hallperson]

i had a evo3 run over 30 lbs , noticed that when my a/f guage went way lean but that was becasue the boost controller was put on backwards

 

[hopwoodp]

I accidentally did that before and blew a bunch of hoses.

 

[damnslowtsi]

You can hear your turbo working not only 'through' the intake side but the exhaust as well. In that case of course you will hear the turbine. I remember when I put a 3" exhaust from my totalled Laser onto the current one which was at the time completely stock, I started to hear that 14b pretty much all the time. It dumps in front of the right rear wheel and I always have windows rolled down a bit so that helps things too. MHI turbos may be noisier than Garretts in this respect.

 

[PieEyedPiper]

My take.

I'm in the process of switching to a 14b.
People ask me all the time if my T-25 is an upgraded turbo because of how loud it is. I have zero boost leaks, cause its my favorite thing to do every Saturday morning, pretty much. I run ~16psi, the turbo has zero shaft play, I have hard piping with the stock snorkel and a cone filter.

But why is it so loud (in a good way) and menacing? I figure the relatively small size has a lot to do with pitch and tone, but my thoughts are that the reason identical turbos might differ in "sound output" is because of minute differences in the machined tolerances. Sound is friction/vibration, after all.

But as a definitive answer? I have no clue

 

[mach4g63t]

People can knock t-25's, but with hard pipe and exhaust and a good air filter they'll almost always out scream anything on the road. hell, when I had my 2g I used to out scream dualie diesels. i think it has to do with the hardpipe, 'cause my 1g has stock pipes right now and it's just like my 2g was with stock. when i got hard pipes... the screaming began. Metal will reverberate a lot more and thus allows the sound to sort of echo. Plastic/rubber will muffle it.

 

[JrCRXHF]

I have a t3/t4e from turbonetics on my honda and this is the loudest turbo i have.

Next is the EVO IX's turbo

Last is my DSM's evo3

I think it has to do with the size of the wheel and how much air is moved when the edge of the intake port starts to go sonic is when you here most of the turbine sound. At school we put a GT12 on a 600cc GSX-R motor and u could hardly hear the thing at all with no filter on the engine stand and a 2 foot pipe off the back side. But this motor had to run through a 20mm restrictor so it could not get the max amount of air. But i don't have any hard proof of this but owning 3 turbo cars.

 

[whiteflash]

i was kinda disappointed when i first heard my 14b, not as loud as the almighty t25

 

[TurboAnything]

I have to say i got a bullseye S256 and it is very noisey even at 15 psi it screems.

 

[dsm-onster]

I always hear my turbos when I test run them w/ no downpipe . I can hear my small 16g at idle w/ full 3" exhaust, no cat, and a non-baffle muffler.

I can hear the 1g BOV blow off, even though I'm now recirculating, because of running the hard intake pipe. Since the hard pipe helps me hear the BOV, then I have to think that helps magnify turbo spool noise.

But regardless, the bigger exhaust has always been the chief contributor to the turbo noise for this car the KA-t, my fathers GN, and my old turboford.

Turbos w/ compressor covers designed to counter surge are very loud.

 

[hopwoodp]

I always hear my turbos when I test run them w/ no downpipe . I can hear my small 16g at idle w/ full 3" exhaust, no cat, and a non-baffle muffler.

I can hear the 1g BOV blow off, even though I'm now recirculating, because of running the hard intake pipe. Since the hard pipe helps me hear the BOV, then I have to think that helps magnify turbo spool noise.

But regardless, the bigger exhaust has always been the chief contributor to the turbo noise for this car the KA-t, my fathers GN, and my old turboford.

Turbos w/ compressor covers designed to counter surge are very loud.

That makes sense. So, what about the regular turbo inlets? Like the 20g, t04e covers, and so on?
The only explanation I got on that (larger than stock turbo being loud) was that there is most likely a boost leak causing the turbo to work a lot hard(spin much faster) to compensate for the leak(if it can).

 

[dsm-onster]

That makes sense. So, what about the regular turbo inlets? Like the 20g, t04e covers, and so on?
The only explanation I got on that (larger than stock turbo being loud) was that there is most likely a boost leak causing the turbo to work a lot hard(spin much faster) to compensate for the leak(if it can).

I'm not disputing you . Any turbo will make more noise when worked too hard. And, it is a sure indicator of a boost leak, if you've done no mods and suddenly your turbo is whining. . . Also, a compressor wheel bumping a compressor cover will be loud and whiney. This would mean a thrust bearing is gone.

Was the origninal posters t-chargers.com 16g an MHI 16g or a GT turbo ? That will mean alot.

Also, he made no mention of the mod history. When did he do what mod before he heard the noise?

I don't know about the fleet truck that oddly has a turbo noise vs. the other trucks. . . hopwoodp has a point. Do you run boost leak tests at the shop where these trucks are maintained? Does a particular driver drive this truck that doesn't drive the others? Add a "bad seed" turbo to a rough driver/route and you could have a prematurely failing turbo. I've had several turbos perform well (but be noisy) just before failure.

 

[hopwoodp]

I'm not disputing you . Any turbo will make more noise when worked too hard. And, it is a sure indicator of a boost leak, if you've done no mods and suddenly your turbo is whining. . . Also, a compressor wheel bumping a compressor cover will be loud and whiney. This would mean a thrust bearing is gone.

Was the origninal posters t-chargers.com 16g an MHI 16g or a GT turbo ? That will mean alot.

Also, he made no mention of the mod history. When did he do what mod before he heard the noise?

I don't know about the fleet truck that oddly has a turbo noise vs. the other trucks. . . hopwoodp has a point. Do you run boost leak tests at the shop where these trucks are maintained? Does a particular driver drive this truck that doesn't drive the others? Add a "bad seed" turbo to a rough driver/route and you could have a prematurely failing turbo. I've had several turbos perform well (but be noisy) just before failure.

I could never have a dispute with you again. You already proved me wrong once. I'm not trying to let that happen again.

What I wanted to know is how the regular compressor housings compared to the ones that have the anti-surge cover(garrett type "S"?).

I think I can understanding that
(Turbos w/ compressor covers designed to counter surge are very loud) from my experience of being a jet engine mechanic and jet engine/ aux power unit - tester/troubleshooter.

I have also worked on a turbo diesel 20k forklift ( had a large T4(?) turbo w/ a 3" exhaust off the turbo) and it made very little noise. The exhaust didn't block it out but, it was noticeable.

 

[fulanititoo8198]

When I had a 14b it was almost silent. My pte turbo is loud once the gate opens up, obviously.

 

[dsm-onster]

What I wanted to know is how the regular compressor housings compared to the ones that have the anti-surge cover(garrett type "S"?).

I think I can understanding that
(Turbos w/ compressor covers designed to counter surge are very loud) from my experience of being a jet engine mechanic and jet engine/ aux power unit - tester/troubleshooter.

I have also worked on a turbo diesel 20k forklift ( had a large T4(?) turbo w/ a 3" exhaust off the turbo) and it made very little noise. The exhaust didn't block it out but, it was noticeable.

Oh buddy, I don't know much more than I shared. It seams that exhaust has alot to do w/ the turbo whistle from my experience. Large turbine wheels let more flow out. And more air out means that that vibrating air can be heard farther and be louder. But my experiences couters yours w/ the forklift t4.

I know a leaner mixture has also altered the note of my 60-1. So I suppose there could be some thing about the type and mass of gases exiting the turbine wheel which could alter or magnify the note. I know diesels love more fuel and smoke lots when they are in a real "pull". Could the smoke muffle the whine?

I've heard a PTE 6152 w/ the E cover and later w/ the the SP upgrade cover, and the SP cover YELLS on boost.

Also, the extended tip turbos seam to really whine. There's more blade and higher speed (less rotating inertia gives the extended tip tech the edge) to yield a larger disturbance that our ears can hear.

 

[hopwoodp]

Oh buddy, I don't know much more than I shared. It seams that exhaust has alot to do w/ the turbo whistle from my experience. Large turbine wheels let more flow out. And more air out means that that vibrating air can be heard farther and be louder. But my experiences couters yours w/ the forklift t4.

I know a leaner mixture has also altered the note of my 60-1. So I suppose there could be some thing about the type and mass of gases exiting the turbine wheel which could alter or magnify the note. I know diesels love more fuel and smoke lots when they are in a real "pull". Could the smoke muffle the whine?

I've heard a PTE 6152 w/ the E cover and later w/ the the SP upgrade cover, and the SP cover YELLS on boost.

Also, the extended tip turbos seam to really whine. There's more blade and higher speed (less rotating inertia gives the extended tip tech the edge) to yield a larger disturbance that our ears can hear.

Yeah, I don't know much about larger turbine wheels in relation to noise produced. But, an unrestricted exhaust will allow you to hear the whine more. Smoke, I don't really know the affect different gases have on sound waves.

Our 20k forklift smoked alot under heavy load and at the higher rpms. I had to change out the injectors, valve cover seals and a few other things but, the smoke was mostly coming from the exhaust manifold and turbine housing.

We used JP5 for our forklifts and I know it would cause them to smoke more. But, we had a 1000 gallon fuel tank(of JP5) on my test cell and we just used that for all our diesel forklifts.

 

[RipperXX]

My MHI E3 sounds waaay louder than my 14b ever did. Well there was the time some jerk pulled my MBC off and it shot to like 26psi then it sure screamed


Oh and a friend of mine who had a 2G with a Big 16g his was loud too. not just spool but the whole time he was boosting. Corse I heard it as it passed me But I was stock then. I deffently had the jump on him though 2G FWD larger turbo vs 1Ga 14b. I would shoot away about 3 cars or so and he would just ease on by around 60mph..

That was ages ago though

 

[HyperGSX]

My old Evo3 was super silent, couldnt even tell it was a turbo car. The t25 could be heard from blocks away

 

[FullthrottleGST]

I had both the regular 16g and evo3 also. the regular seems to be louder.

 

[Jimmy Jr.]

I believe the spooling noise you're after is a result of vacuum turbulence. If you buy a GT42R many times it comes with a Velocity Stack to put over the intake port. Without the stack the air has to flow over the sharp lip whereas with the stack the air is being pulled over the rounded edge and flowing much more smoothly into the turbo. The spool sound is the result of the air rushing over the sharp edge. Like the others said. Get a hard intake pipe, get a large filter and instead of mounting the filter over the edge of the pipe push it down the intake pipe further so that the air has to rush over the edge of the pipe inside the filter. You could weld a piece of metal inside the charge pipes somewhere. The air rushing by it will make the sound too. As you've probably realized, all these ideas are somewhat retarded because although they might not restrict flow THAT much they are merely a meaningless pursuit of a ricer like mentality for the "COOL" factor.

 

[hopwoodp]

Yes, running a hard intake pipe will make the turbo spool and BOV more pronounced. I learned this when I switched from my stock intake pipe to a dejon tool pipe and both sounds became louder and crisper(for the bov). Thats also where I draw my conclusion that the stock intake pipe is also designed to silence the sounds from both these sources by using the ribbed(kinked flex section) shape of the lower part to muffle it.

 

[RayPeters]

The sound level generated by any turbo is a function of air turbulence behind the leading edge of the blades. For the same reason you can hear any fan, the blades cutting through the air cause a disturbance. The larger this disturbance, the more noise you hear. I agree with comments about hard piping etc making it louder, but louder isn't better. A 14b is also quieter than most other compressor wheels because of the single height blades. The t-25 makes noise because the angle of the blades is agressive to obtain flow in the small intake hole. If you have 2 identical model turbos and one is noiser than the other, my bet is that the quiet one actually flows more air, but all your ricer buddies won't be as impressed.