GTI Exhaust Questions/Options

[McDub]

Last friday i got my 2.5" Billy boat turbo back exhaust installed (i believe it's the same as the APR one just without the re-branding)

I've never put an aftermarket exhaust on my car before so i sort of wanted to try it out for the novelty, but the real reason i did it was because i wanted to put on the larger downpipe and new cat because for one i wanted more power, but also i was concernced my stock cat was blocked up (turned out to be fine i think)



I got it dynoed right before and after the exhaust. Before exhaust it was 88kw (so 20% drivetrain losses of a 110kw motor, that's about spot on to how it should be stock)

Then after exhaust it gave a bit over 96kw, so a 9% increase, not too bad.

The main issues i have is with the sound (not to mention the downpipe knocking the chasis or steering column occasionally... need to get that looked at)

I havn't really spent much time in modified cars to compare, but i can't say i'm a huge fan. Sounds quite nice and low at idle and not too loud, has the occasionaly nice little burble to it when the car just starts to idle from decelartion also, and sounds fairly nice when accelerating, but it's more the occasional drone that puts me off.
When engine braking down from about 3000rpm to around 2200rpm, the cabin drone is fairly loud. I'm also not a big fan of the drone on freeways when you're around 2800-3000rpm.

So point of this thread is to get opinions on what i could do. I don't like the sound of the stock gti, because i can hardly hear anything coming out of the exhaust, all you seem to hear is the metalic sound of the motor and gears etc, not that sweet sound of combustion. But at the same time, i don't want my car to sound too modified.

I was thinking of just selling the whole cat back, but maybe there are more options for me? What do you think about just replacing the stock box? Or replacing just the stock resonator? Or selling the cat back, and putting the stock cat-back back on, but chainging the muffler to a completely different one more suited to my tastes?

(i'm obviously keeping the 2.5" downpipe with cat on, its just after the cat that i'm wondering what to do)

Thanks

pic to keep things interesting..

[Manaz]

Is the BB exhaust centre-resonated? If not, that may help kill the drone...

[JustCruisn]

The stock end muffler will make it a lot quieter without reducing power. That's how mine is setup, not much to hear from the drivers seat but sounds just that much more impressive in the rear seat.

The drone is more of a problem in hatches.

[McDub]

yeah it's got a small 3" resonator, probably doesn't do much.

is yours resonated JustCruin? any particular brand or custom?

Thing is, i could probably sell the whole cat back for ~$900. but if i put the stock muffler back on, obviously won't get that, so seems like an expensive decision for what will probably just make it sound like stock?
you say more impressive in the rear seat, do you know if it sounds any louder from outside?

[Rybky]

I think all exhaust replacements result in some drone.

I had a HKS Hyper cat-back on my S2000 and that droned liked hell right around the rev range you experience it, sounded amazing the rest of the time though! I just learnt to drive around it, keeping the revs out of the problem range by choosing a different gear.

On my last car, Nissan X-Trail, I had a complete custom system fitted which was not loud, just deep and did not drone much, only when the engine was under heavy load (going up hill).

Happy to be corrected but I think the less restriction in the system the more likely you are to get drone. Might be worth trying the stock muffler or a custom muffler maybe. Perhaps talk to a specialist about it, I used Hi-tech Mufflers up in Darlinghurst for my custom system.

Adam

[TazzyVR6]

Hmm, I have an APR 2.5" TBE and it doesn't drone at all... I don't even notice it on smooth highway/no cd player highway. IMO it could be louder! Shows it's all about personal opinion. Mine had just the 2.5" downpipe with the full standard catback on it to start with and if you go that way you wont have any exhaust note at all, so don't do that! Perhaps try a larger centre muffler?

[JustCruisn]

Perhaps try a larger centre muffler?

Probably a good option.

I got mine 2nd hand from a forum member, I then added a hi-flow cat. 2.5" turbo back with only an end muffler. It was way too loud. I found out the place I got it all installed did a dodgy, did not connect rear hangers and centre hanger was backwards, it rubbed on the body in places.
I fixed the hangers myself, but after a few days I took it to another place and had them put the stock muffler on it. I like how it sounds and got the performance I was after.
My car is a mum and bub car - so loud was not the intention.


Also does stainless make a sound different to mild steel ??

[McDub]

Hmm, I have an APR 2.5" TBE and it doesn't drone at all... I don't even notice it on smooth highway/no cd player highway. IMO it could be louder! Shows it's all about personal opinion. Mine had just the 2.5" downpipe with the full standard catback on it to start with and if you go that way you wont have any exhaust note at all, so don't do that! Perhaps try a larger centre muffler?

ha, yeah i actually used your opinion on your exhaust to go ahead with my the billy boat one!
i wonder if maybe they're not the same... but from looking at the pics, they look identicial, and i think ECS also said they were the same.
but your right, it could just be personal opinion. as i said, i havn't really ridden in many cars with aftermarket exhausts, so maybe i'm just being fussy, i can be like that. though surely when you engine brake at around 3000rpm, you get a drone sound in the cabin? maybe we have different ways to describe drone, but i don't think it's that ambiguous!

i had a simillar dissapointment when installing the yellow BFI dogbone mounts. people on here said that it didn't make the cabin vibrate much at all, but to me it was a P.I.T.A, litterally in fact, i could feel the engine vibrate through my seat somewhat! So i ended up going back to stock, and now have changed to an 034 motorsport street density dogbone which i'm happy with (basically feels same as stock)

hmmm. still undecided. gonna get Custom Code reflash for the car hopefully tomorrow, so will have a bit more fun with the exhaust as it is before i quieten it down...

then i might go to castle hill exhausts and ask them what they can do for me without spending too much more.

[McDub]

I just thought of one possible thing, i have the downturned tips, and you've got the tips coming straight out from memory, i wonder if that's the reason i have drone?? would make sense if the sound is bouncing to the ground and then back up into the cabin!? That might be a cheapish fix???

actually there's one more thing i can think of. when i looked down the downpipe, the pipe/lip on the cat side of the flexible joint when you look inside, sort of sits proud. i took this pic before installing it. see what i mean? i wonder if that's a problem. defintely looked like pretty poor workmenship to me.

[TazzyVR6]

ha, yeah i actually used your opinion on your exhaust to go ahead with my the billy boat one!
i wonder if maybe they're not the same... but from looking at the pics, they look identicial, and i think ECS also said they were the same.
but your right, it could just be personal opinion. as i said, i havn't really ridden in many cars with aftermarket exhausts, so maybe i'm just being fussy, i can be like that. though surely when you engine brake at around 3000rpm, you get a drone sound in the cabin? maybe we have different ways to describe drone, but i don't think it's that ambiguous!

Sorry...
I think I did say that the previous owner had the full system on first then had the catback removed because they (she) thought it was too loud... But yeah, I know what drone is. A friend of mine had a crappy old corolla with a big cannon and that sounded like some military grade torture equipment, it was a really loud drone that reverberated in your head, I had headaches after 20min!! But I don't get anything like that with the APR, yes it's loud (you think 3000rpm is loud under load, try 6000rpm!!! ) but I have never gotten that droning feel where it's 'in' your head and completely unbearable...
When I got it I went through about a week of liking it, then I sorta thought "gee, maybe this is to much", but now i'm used to it and love it to death!

[TazzyVR6]

Our driving style might also be different. I usually shift up at 4000 (less in the city due to noise) and I'm not usually calling up more than 2000-2500 downshifting in normal driving. I can drive very quietly if I want to avoid attention...

[McDub]

nah it's not driving styles, though that does affect it a little, but i don't think it's the reason for our different "reviews"

Sorry...
I think I did say that the previous owner had the full system on first then had the catback removed because they (she) thought it was too loud... But yeah, I know what drone is. A friend of mine had a crappy old corolla with a big cannon and that sounded like some military grade torture equipment, it was a really loud drone that reverberated in your head, I had headaches after 20min!! But I don't get anything like that with the APR, yes it's loud (you think 3000rpm is loud under load, try 6000rpm!!! ) but I have never gotten that droning feel where it's 'in' your head and completely unbearable...
When I got it I went through about a week of liking it, then I sorta thought "gee, maybe this is to much", but now i'm used to it and love it to death!

yeah i know you said that, i'm not blaming ya! haha. I pretty much new i would at some stage want to make it quiet again, just didn't expect to want to do that just after a week or two!

the only time i find it a little "in your head" is when hard engine braking at 3000rpm. regarding it being louder at 6000rpm, it sounds great to me there! yes it's loud, but i don't get drone.

So i think it is either my downpipe has been fabricated poorly as per that pic on the previous page, or its because i have down turned tips, or a combination.
I'll email ecs that pic of the downpipe and get them to check with billy boat.

oh and tazzy, i know i've asked you this before, but is your rear valance with exhaust cut out a standard OEM option with the GTI?
because i rarely seen any in australia, so am wondering how i'm gonna source one if I decide to change to straight tips.

thanks

[audi-tone]

has it settled? all exhausts (i believe) need to bed in a bit.. mine took maybe 2weeks and is nice and deep and no real drone (custom 2.5 turbo back (mild steel mind you))
maybe give it a couple more weeks?

[Manaz]

has it settled? all exhausts (i believe) need to bed in a bit.. mine took maybe 2weeks and is nice and deep and no real drone (custom 2.5 turbo back (mild steel mind you))
maybe give it a couple more weeks?

Absolutely. The difference between a brand new exhaust and one that's about a month old (with regular driving) is quite pronounced.

[TazzyVR6]

has it settled? all exhausts (i believe) need to bed in a bit.. mine took maybe 2weeks and is nice and deep and no real drone (custom 2.5 turbo back (mild steel mind you))
maybe give it a couple more weeks?

Good idea, it took me a few weeks to really like mine.
The rear valance I have here is a standard Golf 4-motion valance. Should be able to get it from any VW service department...