4396 replies to this topic

[smiley]

Key question is how hot the gasses are when they arrive at the backbox.

A german guy did some measuring up to 1000 degrees, but could have been measured near the manifold.

The ZT1 is rated up to 850 degrees celcius.

 

[CHILL Gone DUTCH]

http://www.thermalve...ºC/p-117-425/ This one techie

[techieboy]

http://www.thermalve...ºC/p-117-425/ This one techie

 

That's what was originally in there (and also what I replaced it with last year pre-Spa). I'd order new packing from Tullett but they couldn't get it to me in tine so as I was pushed for time I order that from Thermal Velocity. However, when the Tullett stuff did arrive in a black bin liner, it was the new AcoustaFil Boa stuff which is easier to work with as you can pack without removing the perforated tube.

 

http://www.thermalvelocity.co.uk/Silencer-Packing/AFILBOA/p-117-486/ 

[techieboy]

Key question is how hot the gasses are when they arrive at the backbox. A german guy did some measuring up to 1000 degrees, but could have been measured near the manifold. The ZT1 is rated up to 850 degrees celcius.

  I'd be interested to know myself but I think gas speed is possibly a bigger issue for us with such a short system, as you can feel the exhaust pulses at quite a distance from the tailpipes (on my car anyway).   I don't believe it's anything like 1000°C though. You've only got to look at the contents of the precat silencer to see it's nothing like that, as it hasn't expanded.   When I summon up the courage to remove the exhaust again over the next couple of weeks, I'll get yet another bung welded on for a thermocouple just before the decat silencer. In fact I can probably use the bung that's there for the wideband which has died yet again and relocate that somewhere else.

Edited by techieboy, 09 May 2016 - 08:44 PM.

[CHILL Gone DUTCH]

 

Key question is how hot the gasses are when they arrive at the backbox.

A german guy did some measuring up to 1000 degrees, but could have been measured near the manifold.

The ZT1 is rated up to 850 degrees celcius.

 

 

I'd be interested to know myself but I think gas speed is possibly a bigger issue for us with such a short system, as you can feel the exhaust pulses at quite a distance from the tailpipes (on my car anyway).

 

When I summon up the courage to remove the exhaust again over the next couple of weeks, I'll get yet another bung welded on for a thermocouple just before the decat silencer. In fact I can probably use the bung that's there for the wideband which has died yet again and relocate that somewhere else.

 

 

Ive put my wideband right near the back box after the first 180 bend and not had a issue with it there 

i will try the boa stuff

[smiley]

 

  I don't believe it's anything like 1000°C though. You've only got to look at the contents of the precat silencer to see it's nothing like that as it hasn't expanded.   When I summon up the courage to remove the exhaust again over the next couple of weeks, I'll get yet another bung welded on for a thermocouple just before the decat silencer. In fact I can probably use the bung that's there for the wideband which has died yet again and relocate that somewhere else.

 

 

Yes please. Very interesting in what comes out.

If it's way under 850 (for ZT1) or even 800 (for PTX), then it's indeed the pulses that kill the acoustafill.

 

Edited by smiley, 09 May 2016 - 08:45 PM.

[techieboy]

Ive put my wideband right near the back box after the first 180 bend and not had a issue with it there  i will try the boa stuff

Yeah, with hindsight, I should have added it after the decat silencer but the exhaust guy liked the location and it meant I could swap in the cat and still have the wideband in the right place if I ever needed to. Three sensors down. Another one to go back in.

[MAXR]

I was static tested at 99db today at Castle Combe. That's after both my silencers were packed with Acousta-fill. I'm not sure if it was the latest stuff from them or not, but it didn't do much good.

 

Perhaps there may be other car manufacturers 2.5" & 3" OEM rear boxes that could be fitted & or made re-packable? Are they better designed than aftermarket silencers?   

[smiley]

Are you using the wideband protector Techie?

http://www.innovatem...productid=16148

 

[smiley]

Perhaps there may be other car manufacturers 2.5" & 3" OEM rear boxes that could be fitted & or made re-packable? Are they better designed than aftermarket silencers?   

 

Ultimate had some interesting results bolting an NA backbox on his 3" manifold and downpipe.

Still made good power, but no measuring on backpressure change, and no track (ab)use.  

[techieboy]

Are you using the wideband protector Techie? http://www.innovatem...productid=16148

Yup, that exact one. Two sensors dead with the AEM kit. And another dead one with the 14point7 kit. All genuine Bosch sensors. Have got yet another sensor here to try with the 14point7 kit again. Luckily, I made all of the wiring plug and play so I can swap the controllers in and out as well.

[CHILL Gone DUTCH]

I was static tested at 99db today at Castle Combe. That's after both my silencers were packed with Acousta-fill. I'm not sure if it was the latest stuff from them or not, but it didn't do much good.

 

Perhaps there may be other car manufacturers 2.5" & 3" OEM rear boxes that could be fitted & or made re-packable? Are they better designed than aftermarket silencers?   

do you twin exhaust outlets max, as a single exit helps 

[MAXR]

 

I was static tested at 99db today at Castle Combe. That's after both my silencers were packed with Acousta-fill. I'm not sure if it was the latest stuff from them or not, but it didn't do much good.

 

Perhaps there may be other car manufacturers 2.5" & 3" OEM rear boxes that could be fitted & or made re-packable? Are they better designed than aftermarket silencers?   

do you twin exhaust outlets max, as a single exit helps 

 

 

 

I've just ordered one that's long enough to take a db killer.

[techieboy]

I was static tested at 99db today at Castle Combe. That's after both my silencers were packed with Acousta-fill. I'm not sure if it was the latest stuff from them or not, but it didn't do much good.

Are they still doing the measuring in the frigging scrutineers garage, just to make it even worse.
 

Perhaps there may be other car manufacturers 2.5" & 3" OEM rear boxes that could be fitted & or made re-packable? Are they better designed than aftermarket silencers?

I ordered a 24" 3 chamber stainless silencer from the States last week. So cheap, I thought it was worth a try.

I've got a couple of other mods to try first after consulting with another exhaust guy who deals with getting difficult race cars sorted. He recommended two different modifications to the perf tube. One is two put one or two crimps in it to change it into more of a 1" slot and then another one at 90° a bit further down the tube (makes it into kind of 3 chambers). That makes a useful difference according to him as it encourages the gas into the packing.

The second option was to try and get hold of a louvred tube instead of the perforated tube as again that slows the gas and actually scoops it into the packing. Reduces the flow by something like 5% but I don't think that's an issue for us with 3" systems, at least not with M62's anyway.

[haggi961]

If you look at the stainless steel metal on the silencer you can tell what sort of temp it's getting to.


I remember seeing Graham's vx on the dyno where the exhaust was glowing red

[Graeme Lambert]

If you look at the stainless steel metal on the silencer you can tell what sort of temp it's getting to.


I remember seeing Graham's vx on the dyno where the exhaust was glowing red

 

This one?

 

 

[haggi961]

Thats the one, cleary shows it's getting close to 900 degrees in places.

[CHILL Gone DUTCH]

Matt when you put your acustafil in did you rap it in tightly or losely

[techieboy]

I started off with it wound quite tight as it needed to be to use all of the supplied AcoustaFil. After spending a couple of hours trying to get the perforated tube and wrap back in (the Tullet perforated tube is offset at each end to get a bit more length) and seated, I ended up tearing off a few chunks to fit it which made it a bit looser. I reckon, if the tube was central to the casing, I'd have probably had 5 layers of AcoustaFil wrapped around the tube.

 

Hopefully, this new boa stuff will make life much easier. When I spoke to Tullet they advised packing it in quite densely and to use a bit of timber to pack it all in.

[siztenboots]

also smear the perf tube with grease for the full effect