42 replies to this topic

[WazzaVX220]

Hello Chaps,

 

Just wanted to test the waters and see what other Supercharged VX owners have experienced so far with:

 

Noise / Noise problems on UK Trackdays.

 

My poor old little shagged 2.2 with just the Viper induction and two-inch Milltek (plus Piper Manifold) is Very quiet on Noise Tests (89-90 static), so i'm not used to any Noise problems....

 

With Vocky's help, she's gonna be putting out a solid 300 with Forged bits, porting and Supercharger, so the situation will be quite different in a few months time!

 

Was going to go for a Full 3" Tullett System, plus the Necessary big Induction system / intake.

 

How are you Supercharged boys getting on with Trackday Noise Tests these days?

Is there much difference in noise between a 2.5 Exhaust and a 3.0?

 

Does the Supercharger whine / induction noise contribute much to the Driveby noise meter readings?

Can one attach a "dongle" to the exhaust tip to help reduce sound?

 

Etc etc etc etc.

 

Many Thanks in advance for any tips and advice   

 

 

 

 

[smiley]

The 3" is a lot louder then the 2.5" system. With 300 you could still use the 2.5" in my opinion

 

The magnaflow cat's that Tullett uses in both their 2.5 and 3" systems are known to fail after a while. They have the option to get a HJS one welded in if you ask, but that is much more expensive.

 

The backbox can be filled with either PTX (up to 800 degrees) or ZT-1 (up to 900 degrees).

Experience so far is that with high power setup's, this stuff is blown out quite fast. 

 

Make sure to mention they weld in another entry for a wideband when you order one.

 

I run the 2.5" system with my 335hp harrop.  

Edited by smiley, 31 March 2018 - 05:32 PM.

[Acidpopstar]

Don’t bother with 3”. I’m now running around 290 (confident I can get 300 with some mapping) with 2.5” Larini decat, Piper mani, standard turbo back box and a Saab airbox. Vastly reduced SC whine will be no problem on drive bys and can’t see any problems with static either. Sent from my iPhone using Tapatalk

[Exmantaa]

Forget the 3" Tullet. It's LOUD and not necessary at all for ~300Hp.

 

To quieten things down on track;

- Use an enclosed airbox with decent trumpeted intake tube.

- Fit a good quality (and big diameter) sportkat in your downpipe, as the standard Tullet ones tend to come loose with the SC power. (as Smiley said) These help with noise and seem to dampen the pulses for the muffler...

- The Tullett double endpipes are like a trumpet. Replace by a simple straight (single) exit pipe, or an endtip that has some dampening material inside.

- Keep an eye on your stuffing material. There is the High temp stuff, but it looks like the material is simply blown out by the SC pulsing.

 

PS; we run ~350 Harrop Hp's with a 2.5" system like this.

Edited by Exmantaa, 31 March 2018 - 10:35 PM.

[WazzaVX220]

Thanks very much chaps!!!

 

I want to do it "right" the first time, so looks like i need some bits....

 

Now where does one get a Saab Airbox?  Any particular Model?

[JG]

There is no way to do it right. Until someone designs a decent backbox we are confined to compromises. 

 

That said my 2.5 system is fine on UK track days. 

[smiley]

As exmantaa mentions you can ask tullett to put in a single end tip, or ask them to internally block one of the end tips so it still looks oem.

They also sell db killers you can put on the tips yourself if needed.

 

If you are end up with back box filling that get's blown out:

you could try German filling: www.powersprint.info

They advise to wrap the perforated tube in the backbox with their SSF-HT steel whool (up to 1200 degrees) Then wrap the rest with their 1000 PLUS wadding (up to 1000 degrees) I have been running that since last years with a few trackdays done and the padding still in. Hopefuly after this year i can make a good conclusion if this stuff is worth the price and their vision on how to do this.

 

 

Edited by smiley, 01 April 2018 - 05:18 PM.

[WazzaVX220]

The Plot Thickens......

 

 

[smiley]

Some run fine with either PTX or ZT-1.

It's a bit of a mistery what exactly breaks the wadding apart so it get's blown out.

 

As you see in the YouTube, it's still white, but shreaded into small pieces. Pulsing is the theory.

 

[Rosssco]

The Plot Thickens......

​The opposite of what most wadding does..  

You could probably just get a standard turbo rear silencer and open that up, enlarge some of the inlet and internal pipework to equivalent 2.5" and remove some the internal baffling (a bit like the Pipo mod). Just don't go mental as presumably you will reduce the noise attenuating properties the larger you go..

[alexb]

The NA and turbo silencer, as far as I can see, have two expansion chambers and one chamber that acts like a resonator. The efficiency (attenuation) of the expansion chambers is determined by the ratio between the inlet diameter and the chamber diameter and length. By increasing the inlet diameter, the expansion chamber simply becomes less efficient. In my opinion it would be better to sacrifice the resonator chamber and use that volume to increase the volume of the two expansion chambers.

 

The above makes simply modifying a turbo backbox less attractive. Might as well start with new design.

[Acidpopstar]

Thanks very much chaps!!!
 
I want to do it "right" the first time, so looks like i need some bits....
 
Now where does one get a Saab Airbox?  Any particular Model?

https://rover.ebay.c...tm/132181659376

Modded by Johnnyboyhgt before fitting




Sent from my iPhone using Tapatalk

[Rosssco]

Pics of it fitted?

[Johnboyhgt]

Not best pic but you get the idea

Sent from my SM-G903F using Tapatalk

[WazzaVX220]

Thanks Acid!

 

Saab Airbox BOUGHT.

 

Would Love to see some more detailed Pics on how to position / install it in a VX.....

 

As for the Exhaust system, what happened to good ol' Milltek?

Were they quieter than the current Tulletts?

 

Presume a 2.5" Milltek full system (or backbox) with fresh baffling would do the trick?

 

 

 

[smiley]

I believe the NA miltek (2") uses baffling, but the turbo one (2.25" or 2.5" not sure) uses absorption. The NA version was discontinued iirc.

 

 

[WazzaVX220]

Thanks guys!  (Smiley)

 

That Powersprint Steel Wool seems like a good solution.

 

How much of it do you need to do the job on a 2.5" Tullett back box?

 

Does it have to be installed when making the Exhaust up initially i guess?

 

It's for a SC car running 300hp mainly on Trackdays, so would i need the 1200 degree stuff, or 800 OK?

 

 

 

[TheRealVXed]

My NA seemed to have got quieter on exhaust noise when I supercharged it.  Turn's out the induction noise is so much it just disguised the fact that the exhaust actually got louder.

 

Last measurement on a stage 2 SC with Larini cat back on it and a 200 cell sport cat is 101db... (to be fair was 98db as an NA...)  That restricts me from a lot of UK circuits.  But most of the really tight ones I'm not interested in anyway (Castle Coombe, Goodwood etc).

 

 

Edited by TheRealVXed, 03 April 2018 - 02:36 PM.

[Steve.i.am]

Presume a 2.5" Milltek full system (or backbox) with fresh baffling would do the trick?

Got the Milltek turbo backbox on mine and on static tests its usually less than 90db which is quiet, but it does have the OE cat still in it. I've never had a problem at tracks until the last one at Goodwood where it tripped the drive by - think its all intake noise - I have a cone filter so can put an airbox on it to quieten it down.

[smiley]

I wanted to make sure i would not need to order another batch, so got the 909721 steel wool, and the 909771 padding.

The steel wool i hade some left, and had quite some wadding left as now 40 to 50% of the backbox was filled with steelwool, so no that much room available for the wadding.

 

I got the highest grade out of frustration, as my ZT-1 got blown out on a single trackday and wanted the creme de la creme just to be sure.

And as i mentioned, we only 2 over here have it running since 2017. No idea if 800 is ok over the 1200. Your guess is a good as mine.

 

I read a few measurements of exhaust gas temp reaching 1000 just after the manifold. Not sure what is left of that near the back box.

 

Yes, it's easiest if allready in there.

I have no Idea how Tullett would respond to you sending them stuffing they do not ship themselves. Just ask them.

 

Edited by smiley, 03 April 2018 - 03:31 PM.