v8 Exhaust
- Thread starter bgsteve
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Sound a lot better with two seperate pipes like TVR did it.
defrayne
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- St. Helens
it needs to be joined..... the tvr was joined too.. its to do with exhaust gas pulses purging the cylinders
discool
Well-Known Member
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- 13,620
Lots of info on the www about H pipes http://temp.corvetteforum.net/c3/joeveto/H_Pipe.shtml
vougese39
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- 1,039
the balance pipe needs to be about where the Y pipe joins.
another point is it will add extra weight which is not really needed. a single system can be made to be really loud and crisp.
i did a paper on exhaust hymonics for my qualifications at college and it is all down to three things air filter inlet and exhaust then the tail pipe a rolled exit will give a burble a slashed one a bark and a inroll end a roar. all effect the hymonics the length of the pipes and where they are also joined the standard system is tuned for mid range torque and quietness.
if you are starting from the front and working back i have used headman headers 1"3/4 pipe mated to the centre silencer stright through and a resonance rear silencer with inrolled end low down torque is increased but also incar noise which is a shame but worth it.
another system i have made is janspeed 4 branch headers and a janspeed sports system in stainless with a inrolled tail pipe again much the same as the first system but barks at high rpm rather than a roar.
another point is it will add extra weight which is not really needed. a single system can be made to be really loud and crisp.
i did a paper on exhaust hymonics for my qualifications at college and it is all down to three things air filter inlet and exhaust then the tail pipe a rolled exit will give a burble a slashed one a bark and a inroll end a roar. all effect the hymonics the length of the pipes and where they are also joined the standard system is tuned for mid range torque and quietness.
if you are starting from the front and working back i have used headman headers 1"3/4 pipe mated to the centre silencer stright through and a resonance rear silencer with inrolled end low down torque is increased but also incar noise which is a shame but worth it.
another system i have made is janspeed 4 branch headers and a janspeed sports system in stainless with a inrolled tail pipe again much the same as the first system but barks at high rpm rather than a roar.
discool
Well-Known Member
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That's interesting vougese39 I have a Janspeed cat back system with a inrolled end, I didn't know it made a difference. I clad to say my exhaust note is a distant hum inside the car and with the music is on I don't hear it at all. The reason I got an ES it's as silent as my old RR.
Looks like I must get someone to drive the disco around the block so I can hear the sound.
I did read a few years ago that the V8 exhaust sound changed for the worse when fuel injection was introduced, a carburettor V8 sounded better because of an inballance in the carbs that's why the old 60's yank tanks sound as they do.
Looks like I must get someone to drive the disco around the block so I can hear the sound.
I did read a few years ago that the V8 exhaust sound changed for the worse when fuel injection was introduced, a carburettor V8 sounded better because of an inballance in the carbs that's why the old 60's yank tanks sound as they do.
Teflon
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Manifolding multicyclinder engines to 'common' exhaust systems, rather than running seperate pipes per pot, as old motorbikes has lots of advantages (well on a four-stroke), and the main one, apart from saving weight, is that if you get the gas from one pot into the pipe behind the gas from the last pot to have 'dumped' you can even out the 'pulses' a bit, so you can get more 'flow' from a smaller, lighter, quieter pipe, and some useful 'scavenging' effects from the inertia of the main flow, 'sucking' through the headers at a pot where the piston has got close to tdc and effectively stopped pushing.
Anyhow; conventional four pot, has single bank of cylinders, each 180 degrees about, so collecting the four headers at a common joint, gas from one should hit the collector pretty much as the gas from the last has just finished.
On an RV8, the pots on one bank aren't timed at 180, and without sitting down and working it out, I cant remember what the intervals on each bank would be, but basically not 'even'...... as the firing order bobs back and forth between banks; so they work better if the manifolds are 'balenced'......
The architecture of the V8, makes it awkward to plumb for best 'scavenging' effect, hence there being so much debate over how 'compromised' the different systems are or aren't..... they all are, basically, just differently! But about the only common point of agreement is that they need some kind of balence pipe between the collectors on each manifold, or preferably a balence chamber, as in the main silencer box at the end of the Y-piece on the standard(ish) systems.
I'm pretty sure that the P6 and SD1 and other 'standard' systems with 'twin pipes' actually had a common centre box, while on outright race systems, manifolding tends to be tilted to put the collectors at the back of the engine block to get the four branch collector as close to the back of the sump as possible, so as short as practicable balence pipe can be run between maifolds in the gap between the sump and back-plate, if arranged as a 'split' system, or it's arranged as a 'short Y-piece' collector, with duel exit.
which, potted, answers your Q' as it would be better if the manifolds were joined & balenced before seperating again......
Anyhow; conventional four pot, has single bank of cylinders, each 180 degrees about, so collecting the four headers at a common joint, gas from one should hit the collector pretty much as the gas from the last has just finished.
On an RV8, the pots on one bank aren't timed at 180, and without sitting down and working it out, I cant remember what the intervals on each bank would be, but basically not 'even'...... as the firing order bobs back and forth between banks; so they work better if the manifolds are 'balenced'......
The architecture of the V8, makes it awkward to plumb for best 'scavenging' effect, hence there being so much debate over how 'compromised' the different systems are or aren't..... they all are, basically, just differently! But about the only common point of agreement is that they need some kind of balence pipe between the collectors on each manifold, or preferably a balence chamber, as in the main silencer box at the end of the Y-piece on the standard(ish) systems.
I'm pretty sure that the P6 and SD1 and other 'standard' systems with 'twin pipes' actually had a common centre box, while on outright race systems, manifolding tends to be tilted to put the collectors at the back of the engine block to get the four branch collector as close to the back of the sump as possible, so as short as practicable balence pipe can be run between maifolds in the gap between the sump and back-plate, if arranged as a 'split' system, or it's arranged as a 'short Y-piece' collector, with duel exit.
which, potted, answers your Q' as it would be better if the manifolds were joined & balenced before seperating again......
discopaul
New Member
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- 571
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- Chesterfield
i got a quote today for a custom zorst thay want £450 wich i thing is having my eyes out all i want is a 3"bore straight through to a rear X member tail pipe. and one sport box
discopaul
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At the mo i have a wet plug and it wont fire so i think i will start lean and work my way untill it starts
chappers90V8
New Member
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- 42
I built my own 3" single exit exhaust for 3.9efi, i bought stainless exhaust parts (bends, polished silencer, straights) from demon tweeks and welded them together, sounds and looks great!!
