Can I get my exhaust to pop, crackle etc when lifting off??? - Alfa Romeo Forum
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  (Post Link) post #1 of 39 Old 16-07-10 Thread Starter
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Help Can I get my exhaust to pop, crackle etc when lifting off???

I want to get the beautiful sound of the exhaust popping and cackling as I lift of the loud pedal. How does this happen and can I do anything to make it happen????

Setup I have:

V6 Engine (GTV)
CDA BMC induction kit
Powerflow Centre box
Supersprint Quad Exit Exhaust



Sounds great at idle and thorughtout rev range. But no snap, crackle and pop when backing off.... .... I would love to hear the pops, any ideas?????
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  (Post Link) post #2 of 39 Old 16-07-10
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all straight through silencers and keep the pipes as straight as poss.. cherry bombs are cheap.. just get stuck in with some pipe and a welder..might have to bin the cat
 
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all straight through silencers and keep the pipes as straight as poss.. cherry bombs are cheap.. just get stuck in with some pipe and a welder..might have to bin the cat
MOT??? Will it pass? I can't be bothered with the hassle of changing things before and after MOT's unless its very simple?
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  (Post Link) post #4 of 39 Old 16-07-10
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My bike used to do this before I had the fuelling corrected on the dyno. Well sorted fuel maps shouldn't pop unless you have valve overlap or something like that.

You could try a decat so the unburned hydrocarbons aren' converted to CO2, it may work
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Over fueling, is that what does it? Its unburnt fuel in the exhaust? is that right?
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  (Post Link) post #6 of 39 Old 16-07-10
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Yes, that is the cause as far as I am aware. Some high performance turbo cars put unbuned fuel through the engine on purpose to help the turbo spin (anti-lag) and that creates a nice bang too.
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  (Post Link) post #7 of 39 Old 17-07-10 Thread Starter
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A decat will mean MOT issues wont it?
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  (Post Link) post #8 of 39 Old 17-07-10
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You need a decat with a decent high flowing exhaust, 1 box should be enough but it will be quite loud.

My last GTV TS had a full race exhaust including manifolds and a few friends witnessed flames out the back on over run
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  (Post Link) post #10 of 39 Old 17-07-10
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My 156 2.0 TS with 2,25" stainless steel straight through silences and racing cat made a nice burp when lifting off, and bliping the throttle.
It also did the occasional bang when I took it to the redline and made a quick gear shift.
But it also had C&B cams and no ecu optimization, so it migth not do it if the ecu was properly optimized.
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My old 33 used to do this, I loved the sound
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  (Post Link) post #12 of 39 Old 17-07-10
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Pour some of this in your fuel tank when you fill up, sounds just like a rally car!
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Pour some of this in your fuel tank when you fill up, sounds just like a rally car!
Really!? Ok I am up for trying it out.
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  (Post Link) post #14 of 39 Old 17-07-10
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Check this out:

V6 Cup

YouTube - New Zorst

Straight through from the cat back... stainless... (except your pants) Tip on the the over run slightly touch the pedal, but not enough to propel the car, if you know what I mean. v gentle.
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  (Post Link) post #15 of 39 Old 17-07-10
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Is that your car?
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Is that your car?
DO yo mean me? If so then "Yes". Why?
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  (Post Link) post #17 of 39 Old 18-07-10
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This'n?

I'm tempted to get a longlife zorst if it sounds like that!!! There's a LL centre not 10 miles from me!
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  (Post Link) post #18 of 39 Old 19-07-10
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This'n?

I'm tempted to get a longlife zorst if it sounds like that!!! There's a LL centre not 10 miles from me!
Yep it is mine, although it looks alittle different at the moment.....

http://i791.photobucket.com/albums/y...4/DSC_0004.jpg

Last edited by Der Teufel; 19-07-10 at 12:48.
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  (Post Link) post #19 of 39 Old 19-07-10
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How much did that set you back? cat-back is it?
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  (Post Link) post #20 of 39 Old 19-07-10
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How much did that set you back? cat-back is it?
370 I think perhaps a little more.

It runs straight from the cat...the two centre boxes are removed and the rear box is smaller about the size of a cornflakes packet. The rear DTM style (my favs) were picked by me from a selection of rear pipes. NB these make no discernable difference to the sound. The pipe is almost straight and runs high and flat and through the rear wishbone so no kinks. Took a little fiddling with but an excellent job.

There are no problems with MOT but a word of warning, I believe it is 119db so some tracks wont allow it on track days.

DT

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  (Post Link) post #21 of 39 Old 19-07-10
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PS its not worth mucking around with the cat.
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  (Post Link) post #22 of 39 Old 19-07-10
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I'm not afraid to tackle the exhaust system DIY style, but was just wondering how much it was from LL cheers for that.

I just spotted this on the bay, which would suit the alfa 156's rear perfectly both in shape and appearance, and was thinking about using these or some of this to just switch the backbox on my 156. The original backbox's shape is a right pigs ear of a thing, so it would require some creative thinking to fit universal box.

I want something deep and sporty but not too loud, and doesnt look chavtastic


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  (Post Link) post #23 of 39 Old 19-07-10 Thread Starter
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There are no problems with MOT but a word of warning, I believe it is 119db so some tracks wont allow it on track days.

DT
The LOUDER the better. Brilliant. How do you measure the decibles? I want to see how loud mine is.????
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  (Post Link) post #24 of 39 Old 21-07-10
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Its not necessarily fuel that causes over-run popping, its actually the addition of oxygen into the exhaust system. If you've got a small hole in your system, the burnt exhaust gasses (which on over-run can still be fuel rich) are allowed to burn again with the oxygen that is introduced to it. An inlet leak can also introduce oxygen into the system. My Kawasaki GPZ turbo had an inlet leak and that used to sound raucous on the over-run!
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  (Post Link) post #25 of 39 Old 21-07-10
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Rather than drill a hole at the start of the exhaust system, is there another way to introduce o2 into the pipe?
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