Exhaust X-PIPE
Discussion
while checking into the exhaust question I have got aware of the most common straight foward having two independent system and
the X-Pipe solution where the seperate exhaust systems are connected before going to the mufflers.
I also read about the approach to bring the equal firing cylinders into one tube.
It would be very interesting to know what are the advantages and disadvantages of the mentioned solutions ?
thanks
the X-Pipe solution where the seperate exhaust systems are connected before going to the mufflers.
I also read about the approach to bring the equal firing cylinders into one tube.
It would be very interesting to know what are the advantages and disadvantages of the mentioned solutions ?
thanks
Nothing wrong with the existing system.
Cross pipe will reduce noise and get rid of some of the harsh tones.
Matched pipes would be a monster to do but at least you may have more room to do it than on a front engine car. No idea how much improvement it gives but have to assume that if others are going to all that effort there must be something in it. I suspect it is only worth the effort when you have run out of other ways to find more power.
Steve
Cross pipe will reduce noise and get rid of some of the harsh tones.
Matched pipes would be a monster to do but at least you may have more room to do it than on a front engine car. No idea how much improvement it gives but have to assume that if others are going to all that effort there must be something in it. I suspect it is only worth the effort when you have run out of other ways to find more power.
Steve
X 2 on Steves reply except to add that certain engine combinations and /or operating conditions would definitely benefit from increased header diameters.
Tuned exhausts (matched pipes, x overs, etc) give very marginal 'all-round' improvements and usually concentrate any marked improvements to a narrow power-band.
Tuned exhausts (matched pipes, x overs, etc) give very marginal 'all-round' improvements and usually concentrate any marked improvements to a narrow power-band.
agreed
however the x pipe gives more torque without loss of horsepower.. on the ford engines it is anything from 8-12% which is a lot and yes it reduces noise but also changes the note of the exhaust to a more normal road car mnoise rather than course race engine( I like race engine burbble).
The tuned system will give more house power 5-8% and more torque but i personally can not give you data with the chevy engines as ive always run Ford and mopar in the past.. There is a previous thred about it and im sure Jeff in the USA will be the best to answer......
Dom
however the x pipe gives more torque without loss of horsepower.. on the ford engines it is anything from 8-12% which is a lot and yes it reduces noise but also changes the note of the exhaust to a more normal road car mnoise rather than course race engine( I like race engine burbble).
The tuned system will give more house power 5-8% and more torque but i personally can not give you data with the chevy engines as ive always run Ford and mopar in the past.. There is a previous thred about it and im sure Jeff in the USA will be the best to answer......
Dom
738 driver said:
Dom, the 10% Ford torque increase, was that on a performance matched and optimised engine, middle of the road or near stock unit?
HIthe figures were from a tuning show i visited who had on the dyno a 289, with edelbrock heads, rpm manifold, etc etc,, they threw it together for a customer to compare against his near standard 289.. dyno'd it then customer asked for it to be blue printed which they truely did and re-dyno'd it...
they estimated it as 8-12% to allow for other changes... Ie an engine is never the same....
I have also had conformation on the ford forums as 8-12% as well so with more than one saying it.......I took its as good...
It made me strip the top end on the Sunbeam i had and spend 2 weeks grinding and porting to see noticeableish differences but then i did not dyno that engine as ive now sold it....
As said if its standard i wouldnt bother again but if im removing heads and manifold there is no harm in playing.... The rule of thumb is make the port down wind bigger than up wind.....by 1mm if possible unless you can match perfectly.... You would be amazed refitting an inlet manifold will never go exactly the same position each time...Never.....so perfect ports are never perfect each time...Its the steps up down wind that kill horsepower due to turbulance of the inlet flow....
Dom
heres a short cut to a sunbeam tiger website that explains x over pipe.....
As said i can only vouch for ford but the same can be said for chevy
http://www.tigersunited.com/techtips/PaulickExhaus...
dom
As said i can only vouch for ford but the same can be said for chevy
http://www.tigersunited.com/techtips/PaulickExhaus...
dom
In the Tiger article, I would think the largest gains came from the addition of tubular headers, MSD ignition and roller followers/rockers.... as opposed to just the inclusion of a X-over pipe.
We really have to compare apples to apples when making improvement claims.....one single change at a time then a dyno run.... also in exactly the same ambient conditions too.... In a N/A engine, 10% change in air density alone will reap almost the same appropriate change in results!
Hence why in serious testing all runs are carried out in a controlled environment, not the general conditions at the time.
We really have to compare apples to apples when making improvement claims.....one single change at a time then a dyno run.... also in exactly the same ambient conditions too.... In a N/A engine, 10% change in air density alone will reap almost the same appropriate change in results!
Hence why in serious testing all runs are carried out in a controlled environment, not the general conditions at the time.
738 driver said:
In the Tiger article, I would think the largest gains came from the addition of tubular headers, MSD ignition and roller followers/rockers.... as opposed to just the inclusion of a X-over pipe.
We really have to compare apples to apples when making improvement claims.....one single change at a time then a dyno run.... also in exactly the same ambient conditions too.... In a N/A engine, 10% change in air density alone will reap almost the same appropriate change in results!
Hence why in serious testing all runs are carried out in a controlled environment, not the general conditions at the time.
Theres a exhaust company in Macclesfield called J P exhaust who are worth having a chat with.. He designs his own stainless exhaust systems and is very knowledgeable.. I had a long chat with him over cross over pipes a few years back and he will explain the gains and the fact on a full length system, even bending the pipes towards each other and then back away again(without actually connecting) acts like a x over pipe and gives gains in torque.We really have to compare apples to apples when making improvement claims.....one single change at a time then a dyno run.... also in exactly the same ambient conditions too.... In a N/A engine, 10% change in air density alone will reap almost the same appropriate change in results!
Hence why in serious testing all runs are carried out in a controlled environment, not the general conditions at the time.
his website is http://www.jpexhausts.co.uk/Site/Services.htm
When i visited he was explaining he was getting more HP out of non injection F3000 cars compared to injection cars because of the exhaust design he had just done.. Big headed....no...He's not that sort of guy..Very pleasant and down to earth..
And yes air temp has a major factor in HP and torque figures along with oil temp,humidity etc etc which is why ive always quoted 5-8% or 8-12%... Mind you alot of proper dyno rooms now compensate to allow for those changes.
Dom
Although I've not done it myself, I gather that with a cross-plane crank and no crossover some cylinders will see strong exhaust extraction and some will see interference, so you can't tune them properly.
By combining the right sets of primaries it is possible to avoid the interference and keep the secondaries energised. If you also have roughly equal length primaries then all cylinders see consistent behaviour from the exhaust which means the engine will respond to conventional exhaust/cam/intake tuning. You would have to actually do the tuning to achieve the benefits, but at least with the right exhaust design it becomes possible.
By combining the right sets of primaries it is possible to avoid the interference and keep the secondaries energised. If you also have roughly equal length primaries then all cylinders see consistent behaviour from the exhaust which means the engine will respond to conventional exhaust/cam/intake tuning. You would have to actually do the tuning to achieve the benefits, but at least with the right exhaust design it becomes possible.
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