Exhaust arrangement - a new take?
Discussion
I've read lots of posts about 4-1 and 4-2-1 and cross-overs etc but is it too simple to suppose that (ignoring space and cost) the best set-up would be if each exhaust port had its own exhaust pipe/tip?
Of course this wouldn't work with a turbo engine since all the gases would be required to spin the turbines, but what about a pro/supercharged engine?
Of course this wouldn't work with a turbo engine since all the gases would be required to spin the turbines, but what about a pro/supercharged engine?
[quote=J&j]I've read lots of posts about 4-1 and 4-2-1 and cross-overs etc but is it too simple to suppose that (ignoring space and cost) the best set-up would be if each exhaust port had its own exhaust pipe/tip?
Of course this wouldn't work with a turbo engine since all the gases would be required to spin the turbines, but what about a pro/supercharged engine?
[/quote]
in simple terms, port matching always works, the issue with V8's is that with conventional crankshaft/fireing orders, the ones you want to match are on opposite banks of the V making implemetation somewhat hard, hence why some have gone flat planed crank, and thus treat the engine (and thus exhaust) as 2 I4 cylinder engines.
this is not really relevent to forced induction engines as they do not gain from exhaust scavengine in the same was NA engines do.
Of course this wouldn't work with a turbo engine since all the gases would be required to spin the turbines, but what about a pro/supercharged engine?
[/quote]
in simple terms, port matching always works, the issue with V8's is that with conventional crankshaft/fireing orders, the ones you want to match are on opposite banks of the V making implemetation somewhat hard, hence why some have gone flat planed crank, and thus treat the engine (and thus exhaust) as 2 I4 cylinder engines.
this is not really relevent to forced induction engines as they do not gain from exhaust scavengine in the same was NA engines do.
The crossover and sequential firing in a single collector (scavenging effect) is reputed to be good for 30-40HP gain. Of course the GT40 is the one car that most people are familiar with utilising a true '180 header' design. A lot of Pantera owners have gone the same route and the exhsut tone is very different with the 180's especially once over 2500 rpm. The design is such that every other cyclinder in the firing order should go to a single collector. In both the Ford and Chevy case that means the two center cylinders 'cross over' to the opposite collector, although the pipes arrangement within the collector would be slightly different due to the fact the firing should be in a rotational pattern as the cylinders fire. In the Chevy case with firing order 1-8-4-3-6-5-7-2 then one side collector would consist of cylinders 1-4-6-7 and the other side 8-3-5-2. There is differeing argument on the importance of header length to the collector (or more about the effect of differing bend radii), but nominally they should be about the same length to ensure 'pulses' reach the collector at regular intervals.
It wouldn't be hard to do on the Ultima....
It wouldn't be hard to do on the Ultima....
Joules, I would think to take full advantage (5%+) of such a system would require serious R+D...careful matching of the cam, gearing etc as a tuned exhaust only provides major gains over relatively narrow section of the power curve and can lead to losses in other areas if not properly done.
A great power enhancer when correct but perhaps not in the realms of most builders on here.......would you not agree turbo's and superchargers are a simpler/better option at similar overal cost?
A great power enhancer when correct but perhaps not in the realms of most builders on here.......would you not agree turbo's and superchargers are a simpler/better option at similar overal cost?
When I was looking at exhaust configuration I came to the conclusion that the crossover system was more commonly found being used on Ford V8 engines and have still to this day never even seen a crossover on a Chevy engined street car. Books and the 'learned few' may well wax lyrical about such black magic but I fear that is where it ends and has no place and is not necessary for a road car, even one that may see some track work now and then.
738 driver said:
A great power enhancer when correct but perhaps not in the realms of most builders on here.......would you not agree turbo's and superchargers are a simpler/better option at similar overal cost?
No question there would be some development work to maximize gains, but most of that can be done on a computer these days and really any good set of headers should be properly designed for the task (my CanAm headers were CAD designed for optimal flow) as so many builders negate the importance of header and more so collector design and size. 180's do have a distinct sound and look, that in itself is enough reason for some to change over.The comparison between the various methods of power gain was outside the realm of the prior question, but that said if one is starting from scratch then I would agree that Turbos or Supercharging is more bang for the buck as you can take a realtively stock engiena nd bolton HP. In my case I have a 650HP naturally aspirated engine, would I consider 180 headers? I certainly wouldn't put it out of contention, I have a set for my Pantera and for that application they run about $2500.
GTW: I think the greater use in Ford applications is just a reflection of fewer mid engined Chevy powered GT cars.
The racing industry has moved away from 180 headers for the most part as they discovered a strategically placed 'X' pipe can result in almost similar gains, with a lot less weight gain and complexity of piping.
Im a huge fan of single exhausts on V8s, a V8 sounds much more urgent with a single. I dont like the lazy burble sound of twin pipes on cars... save it for the ski boats and 60's cruisers.
Here's mine - http://www.youtube.com/watch?v=COZYdldOPgs
Here's mine - http://www.youtube.com/watch?v=COZYdldOPgs
Guys,
Here's my atttempt @ a 180 style exhaust. I do agree it's alot of effort and for what some would consider minimal return. Personally I love the exhaust note up around 6-7K. A good friend loaned my the ICE "Lego" header blocks seen in the photos, without them the job would have been much harder to complete.
Chris
Here's my atttempt @ a 180 style exhaust. I do agree it's alot of effort and for what some would consider minimal return. Personally I love the exhaust note up around 6-7K. A good friend loaned my the ICE "Lego" header blocks seen in the photos, without them the job would have been much harder to complete.
Chris
Very nice stuff Chris!!!!
One muffler system that intrigues me is this one from Corsa. Mufflers deaden sound as a result of the gasses expanding... you can see in this pic that the muffler is off to the side. I figure this cuts the sound while maintaining flow at higher revs.
Thoughts?
One muffler system that intrigues me is this one from Corsa. Mufflers deaden sound as a result of the gasses expanding... you can see in this pic that the muffler is off to the side. I figure this cuts the sound while maintaining flow at higher revs.
Thoughts?
Thanks Crafty.
Yea I just don't know enough about the science behind exhaust muffling/flow. One thing is for certain- given all the sound control efforts @ tracks around the world, we'll all be the beneficiaries of better exhaust systems soon.
I've seen a lot of cat back systems that look like the one in your pic. I think it's because the newer vettes have this arrangement.
Chris
Yea I just don't know enough about the science behind exhaust muffling/flow. One thing is for certain- given all the sound control efforts @ tracks around the world, we'll all be the beneficiaries of better exhaust systems soon.
I've seen a lot of cat back systems that look like the one in your pic. I think it's because the newer vettes have this arrangement.
Chris
Was trying to find a better pic to show what looks like the muffler attached to a branch off the main pipe - the gasses do not go through the muffler.
Go to the link below and to the "product images" - its the one at the top left
http://www.corsaperf.com/corsaProductDisplay.aspx?...
Go to the link below and to the "product images" - its the one at the top left
http://www.corsaperf.com/corsaProductDisplay.aspx?...
Edited by crafty on Friday 17th October 05:20
hopefully not offtopic here, but along the lines of muffler technology, i came across this link
http://www.exploit-tech.com/For-Industry/Tech-Offe...
perhaps some of u out there with cfd and mech-e experience,
and no packing materials (btw, i repacked our standard ultima mufflers,
not very fun with itchy fiberglass)
(also wondering how often u guys hv replaced yr catconverters..)
http://www.exploit-tech.com/For-Industry/Tech-Offe...
perhaps some of u out there with cfd and mech-e experience,
and no packing materials (btw, i repacked our standard ultima mufflers,
not very fun with itchy fiberglass)
(also wondering how often u guys hv replaced yr catconverters..)
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