Dump Pipe: New Sound

by **mynameisdaniel** » Tue Jun 26, 2012 11:19 pm

Installed a PHAT GT dump pipe last week and today I was driving and gave the car a bit of a push while going up hill in second. Haven't really tried putting the engine under lots of load since. I noticed a sound I hadn't heard before from the turbo. Almost like air turbulence as the air went from the turbo to the dump. Just wanted to make sure that it's a normal sound because of the increased flow around there. I noticed I could get it to happen pretty much anywhere above 4,000rpm.

Hoping it's not a leak, the car pulled very well to the end of second. If it was leaking would I loose pressure or get a CEL? I did triple check all the turbo bolts and did them up in a diagonal order when I installed it, although I didn't replace the gasket.

Anyone else got the same sound? You can hear it through the firewall quite clearly.

by **B4ITZUP** » Wed Jun 27, 2012 7:24 am

sound normal

if you have a pod or after market panel filter, you can hear it louder and earlier, if you like the noise

by **JDGT05** » Wed Jun 27, 2012 8:51 am

Sounds normal, all though have you had it tuned since you had the dump pipe installed? Do you have full exhaust or the dump pipe with stock catback?

by **mynameisdaniel** » Wed Jun 27, 2012 12:14 pm

Thanks guys, just to be clear. This is different to the intake sound (very faint stock obviously) but the intake is a smooth sucking sound where this has a bit of a pattern to it. If I just rev the engine in neutral I only get intake sound not this sound.

Nah no tune yet, only the dump so far but going to do the mid section as soon as I have the money for it.

by **Rome_BRZ** » Wed Jun 27, 2012 4:40 pm

mynameisdaniel wrote:Thanks guys, just to be clear. This is different to the intake sound (very faint stock obviously) but the intake is a smooth sucking sound where this has a bit of a pattern to it. If I just rev the engine in neutral I only get intake sound not this sound.

Nah no tune yet, only the dump so far but going to do the mid section as soon as I have the money for it.

Are you talking about a slight howling? Like when it's really windy outside sometimes? Like a raspy howl? If so I know what you're talking about lol it's just very hard to describe what the sound is

by **mynameisdaniel** » Wed Jun 27, 2012 4:47 pm

Rome_STI wrote:
mynameisdaniel wrote:Thanks guys, just to be clear. This is different to the intake sound (very faint stock obviously) but the intake is a smooth sucking sound where this has a bit of a pattern to it. If I just rev the engine in neutral I only get intake sound not this sound.

Nah no tune yet, only the dump so far but going to do the mid section as soon as I have the money for it.

Are you talking about a slight howling? Like when it's really windy outside sometimes? Like a raspy howl? If so I know what you're talking about lol it's just very hard to describe what the sound is

That's actually a very good example! Yeah it's a similar sound to as if wind is pulsating through an open window. Is that good news or bad news though? Josh (sbv) was kind enough to offer to have a listen to it to see if it sounds right or not.

by **Rome_BRZ** » Wed Jun 27, 2012 5:07 pm

mynameisdaniel wrote:
Rome_STI wrote:
mynameisdaniel wrote:Thanks guys, just to be clear. This is different to the intake sound (very faint stock obviously) but the intake is a smooth sucking sound where this has a bit of a pattern to it. If I just rev the engine in neutral I only get intake sound not this sound.

Nah no tune yet, only the dump so far but going to do the mid section as soon as I have the money for it.

Are you talking about a slight howling? Like when it's really windy outside sometimes? Like a raspy howl? If so I know what you're talking about lol it's just very hard to describe what the sound is

That's actually a very good example! Yeah it's a similar sound to as if wind is pulsating through an open window. Is that good news or bad news though? Josh (sbv) was kind enough to offer to have a listen to it to see if it sounds right or not.

Mine's been doing that ever since I installed the dump and pod filter (were done on the same day). I always assumed it was the pod filter causing the noise. It makes sense why it makes the noise, it happens at realatively low revs for me, like not enough air is passing through to make the full intake noise, so it makes the noise I described instead.

That said I haven't had my car tuned yet, has yours been? Maybe a tune eliminates this noise. Either way I don't really notice it enough for it to bother me anyway

by **mynameisdaniel** » Wed Jun 27, 2012 5:23 pm

Hmm okay I can still kind of hear my intake too, that sounds smooth still. Was driving again today testing it, flat out in second it starts at about 3,000rpm then gets louder and louder. It sounds like a leak but doesn't at the same time. Maybe I'll try and put up a video if I have a spare minute tomorrow. I don't mind the sound, just want to make sure it's healthy, it's only when pushing the car otherwise the car is nice and quiet.

No tune yet, going to do a few more mods first then do a tune to 'fix' my fuel consumption

by **B4ITZUP** » Wed Jun 27, 2012 5:57 pm

could be the waste gate flap
around 3,000rpm is when it start to open up, sometime mine sound like a kid rattle toy on certain load

by **sbv** » Wed Jun 27, 2012 6:19 pm

^^The more you describe the noise, the less it sounds like a leak as a leak is generally more of a hiss (sometimes with a bit of a whistle). Mind you, one leak typically sounds different to the next.

Logically though, just having upgraded the dump you would expect it is most probably a leak... I'll have a listen some time anyway and give you my 2 bobs worth

by **rooby** » Wed Jun 27, 2012 8:40 pm

Mine makes the same sound. The sound you are referring to is definitely the dump, not the intake.

I can hear both noises in my car.

You can notice it best if you are driving beside a concrete barrier or wall or something with the window open so the sound echos back at you.

by **Dropz** » Wed Jun 27, 2012 8:48 pm

If you are at dinner tomorrow night Dan I can have a listen for you.

by **Stomps** » Thu Jun 28, 2012 1:47 pm

Rather than thinking about it in terms of rpm... think about it in terms of boost level... does it only start when the car makes full boost? Check this in various gears under load... if is a turbulence sound being made sheen the car his full boost, I'd be meaning towards your waste gate...

Not sure about these cars, but my old supra and soarer got this quite a bit after fitting exhaust.. you gotta remember that any freeing up you do behind the turbo (mainly dump pipe) will increase your boost slightly.. like I said I'm not sure what these turbos run at and what the wastegate spring is rated at, but if it releases enough back pressure and your boost rises enough, it could be causing the wastegate to open and close quickly... if I've go tthe right sound in mind.. remember, stock internal wastegates aren't exactly efficient at preventing boost creep..

Easy way to test this theory is to set up a boost gauge... watch to see if the boost spikes up and down under full load and WOT..

good luck, keep us posted on the results..

by **Dropz** » Thu Jun 28, 2012 1:53 pm

Taylor's did that before his last tune if I recall correctly.

by **Stomps** » Thu Jun 28, 2012 2:14 pm

Makes sense why the tune would get rid of it... as long as the factory wastegate is strong enough to hold it, lowering the factory boost level down will prevent it from happening... it won't stop the boost creep, but will move it fast away enough from the stuck wastegate limit...

It's a lot harder to hear with these cars because they actually have decent sound deadening... my gutted old supra you could hear it plain as day.. air turbulence noise combined with a metallic flapping...

Was a monumentally cool way to kill old turbos/engines... (wouldn't recommend it in a lib)