68 replies to this topic

[CHILL Gone DUTCH]

Conclusive there all loud

[Jetpilot]

Thanks Chilli, the two on that video sound fantastic though, some more digging required.

 

Will pull my current exhaust and see whats going on inside for now.

[MAXR]

 

Ermmmm, no.  

His exhaust specialist uses a 2 layer approach. From vendor www.powersprint.eu, the first layer is steel wool that can take 1200 degrees. (SSF-HT)  The second layer is comparable padding as to the acoustafill. His version is called "1000 plus", rated to 1000 degrees. (acoustafil PTX is rated to 800 degrees, and acoustafil ZT1 is rated to 900 degrees)

 

 

 

I had one race exhaust company insist that they loosely twist course wire wool & wadding in a spiral, then fill the silencer.

[Gadget2]

I seem to remember somewhere of someone (Matt Bentley?) producing an exhaust using Flowmaster silencers - units that use resonance chambers rather than wadding and wire wool.

[ultimate]

Its hard for me to explain it in english but i will try ;-)

 

I was using a full 3" tullet with a very big HJS cat on my 2.0 engine with water/ethanol injection and maxed out harrop (70mm pulley)

 

This was extremly loud and i was catched by the german police. I had to find a fast reachable solution to get the car silent.

So i mounted a N/A backbox to the rest of the 3" sytstem by welding a big pipe to the inlet side of the N/a backbox.

Car was very silent and i could pass the police tests... see pic: http://www.pic-uploa...G_2644.jpg.html

I know that this is crap but i needed a very fast solution to get the car silent.

 

I was driving it like this for the rest of the year because i had more fun with the car without that bloody loud sound.

The horsepower i was feeling was okay up to 7000 U/min. Over 7000 it was slower than before.

 

On a dyno I reached 350hp @ 6500 rpm (!!!) with this setup. I told him not to rev higher than 6500 because of the n/a backbox so i dont know what numbers might have come up to 7700. The boost level was NOT higher than before!

 

I tried the turbo backbox than in the same way but with a reducer to not have the "hard step" from 3" to 2,25 from the turbo backbox.

It was louder than with the n/a backbox but okay. The sound is terrible, the car sounds like it has a cold nose :-(

 

BUT: the accelaration over 7000rpm was much,much,much better than with the n/a backbox. I was not on a dyno but  compared the accelaration times logged by obd tuner.. And there was nearly no difference between the tullet 2years ago and the turbo backbox.

 

I think, a big exhaust manifold, big piping to a very very good (and big) cat is much more important than the backbox

 

I hope, you understood my english writings, sorry :-(

[Bargi]

There will be various 3 inch exhausts at Zandvoort in a few days.

I'm guessing the dyno day didn't happen, maybe someone has a DB meter and we can have an old school SPL sound off at lunch time

[oakmere]

So what is required is an N/A design back box built with 3" pipe work. The design is not difficult if you can weld but performance builders like to stick with the very simple straight through design to maximise profits.

[Jetpilot]

Thanks for the info Ultimate Sounds good Bargi would be interested in set ups and dbs from Zandvoort. The problem is most will work with whats available off the shelf, custom back box size/shapes would probably be prohibitively expensive due to the labour, even considering costs of current systems available.

[Exmantaa]

First part of the exhaust is indeed pretty important. (still need to make myself a 70mm downpipe + big 121mm cat)

Massive heat and volume there, but after the cat the temperature drops down a lot and so does the required volume flow. Maybe a big reflection muffler is the answer to quieten the big SC's

[tibby]

:-)

[Bargi]

That's defo a "Back box"

[Nev]

:-)

 

Wow!

 

Whats the airflow/design inside the backbox please?
 

Also, how quiet is it and what diameter is the pipework please?

Edited by Nev, 12 August 2016 - 06:22 AM.

[tibby]

Hello, I do'nt have any info about this system. Here's the Facebook link, maybe there's more info over there (i do'nt have Facebook) https://www.google.b...129422649,d.d2s YouTube: https://www.google.b...471090167178059 https://youtu.be/HsOdpu69vIk grtz

[Jetpilot]

Interesting

[alanoo]

So what is required is an N/A design back box built with 3" pipe work. The design is not difficult if you can weld but performance builders like to stick with the very simple straight through design to maximise profits.

 

Flowmaster make very cheap chambered designs too

Available in stainless, 2.5, 3 or even 3.5 inch pipework.

pretty sure we could find one that fits, something like one of those : http://www.flowmaste...0-series-delta/

[Jetpilot]

I have bought a 2nd hand na back box and going to take it to a friend who is fabricator, the plan is to cut it open, see what we have and basically make a new box to the same dimensions and change any pipework to either 2.5 or 3". 

 

The only thing that wont be able to do is run it to cs to update the map, which concerns me a little.

[fezzasus]

I have bought a 2nd hand na back box and going to take it to a friend who is fabricator, the plan is to cut it open, see what we have and basically make a new box to the same dimensions and change any pipework to either 2.5 or 3". 

 

The only thing that wont be able to do is run it to cs to update the map, which concerns me a little.

 

[Jetpilot]

Very helpful, thanks Fezz

[MartinS]

Whats inside a miltec exhaust? Packing or chambered.

My 2tubular has emptied al its packing and sounds great but is now getting me grief on track.

 

Am thinking of opening it up and seeing if it can be improved by a local exhaust specialist.

 

Martin S

 

 

[Bargi]

Milltek NA is definitely baffled. Dunno about turbo.