exhaust noise

[rd070707]

last week i decatted the hdi and replaced the back box for a straight section of pipe. I have just kept it at 2.25" for now but im surprised it barely made any difference to the noise, there isnt much grunt tbh.

is the midbox enough to keep it a good bit quieter? I have heard other hdi's with straight through and decat sound much louder

[Poodle]

The standard midbox won't be damping it by that much, a sports backbox will make a big difference to the sound.

[rd070707]

would increasing the diameter help too? i dont understand if i have basically a straight through except for mid box why its so quiet lol.

[Jonny81191]

If you're comparing it to a straight piped petrol, it will be quieter, the turbo silences it a lot.

[rd070707]

no to other hdi's and dturbos. might just consider going for a full straight through 2.5'' with a dummy box

[Jonny81191]

How have you decatted it?

[rd070707]

yep only gutted out though

[Jonny81191]

Could be that that's causing it, are you sure you got all the stuff out? There might be a bit stuck in it or something. If you can weld, just stick some pipe in to replace it.

[rd070707]

yep 100%. im thinking of getting some 2.5'' pipe and weld up a custom one with a dummy box

[Ricky]

My DT has just the mid box and its a lot louder than standard.

[CJ_Derv]

Straight thru 2.5 stainless with just a backbox not too noisy deep tone and then spunds like a perv on boost

[Poodle]

Just thought - yours isn't mapped is it? A stage 1 will make a significant difference to the noise.

[rd070707]

Yeah its standard as I want to do my injectors first. Bloody thing feels like its missing all the time now

[Toms306]

Mines straight off the cat atm since the pipe snapped, and its really fecking loud, both at idle and cruise, under load is almost unbearable (but really adictive also with the gurgling warble lol). All I've lost is the midbox and backbox......

[Poodle]

...All I've lost is the midbox and backbox......

So yeah, you know, pretty much the whole exhaust then...

[Toms306]

Lol, but not the cat...which I thought was supposed to be the most restrictive part lol! And people say the turbo quietens it down too. It really doesn't lol, put it this way, cruising at 3k rpm I can't understand a passenger shouting...

[rd070707]

Okay problem sorted I'll just illegally remove my whole exhaust lol

[Toms306]

Remove it? It's French, it'll fall off sooner or later.

[Tom]

I drove around with no exhaust before straight off the turbo, it was great fun, wasnt even that loud really :p

[Poodle]

Tom is a drama-queen, we know this.

The cat is restrictive, but it's also not designed for noise reduction, unlike the rest of the exhaust... :p

[Jonny81191]

I drove around for a bit with no exhaust off the back of my new turbo, and no intake piping on the side sounded absolutely awesome, but wasn't silly loud, quieter then most of the chavs in corsas and puntos anyway.

[Toms306]

Maybe my engines just more broken than yours are then....it really is loud. Everyone around looks over when I start it up. but its ok, they can't see through the smoke screen.

Fair enough its not as loud as my neighbours EVO though....

[Poodle]

We knew that too hahah. :p

Why don't you add a dump valve? Then no-one will know the difference.

[Piggy]

I picked up a 1993 1.3spi mini once which had the exhaust fall off...just after the manifold....

loud as godzilla....

was hilarious to see people turn and imagine to see a great big sportscar or thumping bike and see a old cream mini!!!

was a lot of fun down sidestreets tho

[Toms306]

was a lot of fun down sidestreets tho

This is true, the echo off the walls is epic! Yet people still walk in the road seemingly not noticing the car.

[Poodle]

When they do this you need to redline it, watch thm jump out of their skins hahah.