NEW EXHAUST

[kaiserbilly1]

Apart from some work, this is also what I did today, with the help of Simon from Motor Sports World in Strathaven.







Looks good I think, but what' better it sounds great

[clive]

Bill, looks good and I think it is better having the exhausts nearer the sides. Looks like you have plenty ground clearance too!

[kaiserbilly1]

Hi Clive

Nice thing was that after the exhaust was fitted, I could give her a real blast.
Everything seems "tight", new shocks have already run in a bit, and the extra width in the exhaust bore only adds to the fun.

regards

Bill

[David Large]

I've just had a new stainless system made for my car too by MIJ in Walsall.
I'm very pleased with it it looks good and it sounds nice without being painfully noisy (I already have tinnitus fom a lifetime in construction).

Next time it is on a ramp I will take some pictures.

[Karl]

When I see Bill´s exhaust system, it makes me think that this is one of the few Cobras I have seen with a single silencer. Has anyone gone to SVA or has measured that you can stay below 101 Decibel with a single silencer system? In the USA manufacturers state that they can reach 95- 98 db with one silencer and still a good flow rate. Also, has somebody been thinking about using the H or X connections on the exhaust system?
In the USA this is quite a big issue. So far I heard: A connection from left to right is better than nothing; H- pipe better for low-down torque; X-pipe better for high revs. Any more thoughts?
Regards Karl

[Migge]

Hallo Karl,

hier was aus dem KHB Forum:

Hallo,

ein paar Anmerkungen zum T (oder auch X) Rohr:
Dieses Ausgleichsrohr wird bei V8 Motoren verwendet, um durch den Druckausgleich im unteren Drehzahlbereich eine Drehmomentanhebung zu erreichen.
Dies ist jedoch nur bei "offenen" Auspuffsystemen wirksam!
Wenn Rückstau produzierende Schalldämpfer verbaut sind, was bei stark Lärmreduzierten Anlagen der Fall ist, ist der Effekt mit T-Rohr gleich Null.

Zur Auslegung des T-Rohres:
Der Durchmesser sollte ca. 60-70 % der Hauptrohre betragen.
Die optimale Position ist direkt hinter der Zusammenführung der Hosenrohre.

Wenn man bei der grundsätzlichen Auslegung Auspuffanlage an Leistungssteuerung denkt, sollte man sich jedoch mehr mit der Auslegung der Headers beschäftigen. Eine 4in1 Auslegung sieht zwar gut aus und bringt auch eine geringe Leistungssteigerung gegenüber den Standardkrümmern im oberen Drehzahlbereich.
Effektiver ist jedoch eine 4-2-1 Anlage, speziell wenn bei der Zusammenführung auch auf die Zündreihenfolge geachtet wird.

Auch sind hierbei die Querschnitte und Längen von entscheidender Bedeutung für die Motor-Charakteristik.
Großer Rohrquerschnitt / kurze Länge = Leistungssteigernd im oberen Drehzahlbereich und Drehzahlerhöhend
Kleiner Rohrquerschnitt / große Länge = Drehmomentsteigernd

Gruß Jörg

Bin mir nicht sicher, ob es bekannt ist: http://www.cobra-roadster.com

Sorry guys for the german issue. It will never happen again:)

Cheers
Migge

[Dave289]

When I see Bill´s exhaust system, it makes me think that this is one of the few Cobras I have seen with a single silencer. Has anyone gone to SVA or has measured that you can stay below 101 Decibel with a single silencer system? In the USA manufacturers state that they can reach 95- 98 db with one silencer and still a good flow rate. Also, has somebody been thinking about using the H or X connections on the exhaust system?
In the USA this is quite a big issue. So far I heard: A connection from left to right is better than nothing; H- pipe better for low-down torque; X-pipe better for high revs. Any more thoughts?
Regards Karl

Hi Karl,

I also only have one silencer (per side), although mine are mounted much further back - under the boot floor and behind the rear axle. The silencers were hand-made out of stainless steel by a company in Sweden, and similar to those used on their Triumph TR7 V8 rally car. Ground clearance is not an issue, neither is noise - they passed the stringent German TUEV tests without any problems !!

I had the rest of the exhaust system (also in stainless steel) made up by a local specialist (Stueber in Overath). He initially made a system with an H-pipe, then tried again with an X-pipe - but he could not get the system to sound right, so we eventually went for two almost-straight pipes from the header pipes to the rear silencers. If the weather improves, I will get the BRA out of the garage and take some pictures from underneath !!

Regards,

Dave.

P.S. I was so impressed by the exhaust system on my BRA 289 that I got Stueber to make up a similar system in stainless steel (this time including big bore exhaust manifolds) for my Formula 27 V8 (Lotus 7 replica) !!

[Roger King]

I have Gerry's system, with the rear boxes deleted. This means there are two small glasspacks under the seats, not baffled (you can see unimpeded straight through them). They sound very like an original Cobra - I've tried it back to back - but I wouldn't recommend going anywhere near an SVA station with them, might break their machine.

No original cars had X- or H-pipes. Either will give a power increase, as mentioned in the above thread - but they do change the exhaust note noticeably. I have a JBA stainless H-pipe on the Mustang, which definitely gives more of a big-block type burble and less of a hot 289 crackle (if that helps).

Roger

[greenmachine]

So that's what Bill was doing when he was lying under the back of his car. he was polishing it,fussy or what!

Keith

[clive]

So that's what Bill was doing when he was lying under the back of his car. he was polishing it,fussy or what!

Keith

I thought that made you go blind!