I changed the center bearing on my project car on the weekend. It was not until I started to put the exhaust back on again that I noticed the 2 sides are not connected. There is no H/X pipe behind the cats, just some small mufflers. How much / what effect does the X have on the zed engine ? Quieter, more power etc ? Are there any problems running without the cross ?
Is this on the TT stef? X-pipe mixes the pulses which balances out any harmonics at the turbo end. There was a pretty comprehensive post recently about non-balance exhausts can cause premature turbo seal leakage, so thats one aspect of it. But by far the most proven benefit has been the reduction in drone from the exhaust, much more pleasant to drive on the freeway.
A properly designed Merge pipe will increase the power and torque (approx 3rwkw) as well as reducing drone and smoothing out the exhaust note. If the system is straight through, with or without a merge will not affect turbo seals. Damage to turbo seals and gaskets, etc would be from too much back pressure - the gas has to go somewhere. If they say the damage to the seals is from being too free flowing and over spooling - there is no difference on the turbo whether it is merged or not, if it is straight through. H pipes create turbulance in the system and rob power, kiss pipes reduce the volume of each pipe by around 30% which creates a restriction, and the pressed X pipes leave a cavity on the exit which restricts flow and causes turbulence and the cross sectional area in the middle of the X is only slightly bigger than the diameter of 1 pipe - ie restrictive. A properly designed merge pipe has full flow of both pipes. Cheers Greg
Nick,i think Greg runs www.surefloexhaust.com.au ,i reckon he may know a thing or 2 about exhausts lol Well mine is incredibly loud and i dont have any joining pipes,2.5 inch straight through,mandrel bent to magnaflow mufflers (with metalcats)ITS AN N/A So i have one of this uas x-pipe muffler,so im hoping it will tone it down abit and get rid of the raspy sound i have Ive been told the rasp is there due to turbulance (I was told this should help ) WOULD THAT BE CORRECT GREG ??
Never said it was gospel...as my last zed had fully split exhaust and had no trouble with seals, new turbo's though. But there has been a bit of conducive evidence which has me accepting it as being quite possible, if not probable. There may be other factors at play regarding the quality of the seal in the first place, but it has merits.
this has been raised many times over now. The General Concensus is a balanced exhaust = better performance, less stress on your turbo seals and less drone. If in any doubt, just go to an exhaust place and put a balance pipe in there (H pipe). Costs bugger all and can potentially improve your noise/performance. Try using search on this topic and you'll see everyones experiences - so you can make your own mind up over this.
Yes, it's on the TT I don't have any problems with noise, even though there are big cannons out the back. Very nice, slightly muted but still powerful sound. But, then I've only driven it around the block a few times. If its only a matter of sound and a couple of kw's I'll leave it until either the drone gets me or I want more POWER.
Hey Stef , idon't think u will need a x pipe for this exhaust it dosen't drone and imo is one of the best sounding for the zed (apexei megaphone) plus ur turbo seals don't leak Regards Trev
Matter of tubo seals I think it was mungyZ that worked out not having an H pipe caused smoking during idle which he found to be pulsations of the zorst pumping oil past the seals. Many ppl been bitten by this, replacing turbos etc when all that was needed was an X pipe.
I believe they have a merge inside them, so they will quieten and smooth out the exhaust note for you. It will quieten the system a fair bit. Balance Pipes or "H" pipes cause a lot of turbulance in the system as the gas from one side is entering the exhaust on the other side at a 90 degree angle and interferes with the gas flow. Some are pretty ugly as the holes are usually cut with the oxy and do not fit that well so they have chunky welds. They are the cheap and easy way, and if it helps (oil seals - who would have thought) go for it. Below is a link to our X pipe page on our website and it shows the different types of merge and the pro's and con's associated with them. We "Patented" our Full Flow "Merge Pipe" and this page shows the differences between them. http://www.surefloexhaust.com.au/xpipe.htm Cheers Greg
Yes and No... Obviously you know your stuff regarding exhausts. Benefits of having an X-pipe may be more promonent in seiously High-powered vehicles. We have covered this particular topic Many times over on this forum, ie: X-pipe V's H-pipe. And they are just simply so inconclusive they just go nowhere. I've personally had my car on a dyno with my H-pipe and another car with exacly same mods (including tune, boost, timing, etc...) using an X-pipe and they were basically the same. (in fact I was .5hp higher ) But that means bugger all IMO. At the end of the day, if we are talking around the 300-350hp figure, X or H means sweet F/A - Don't worry, I have always been wanting to see proof of a noticable difference in our Zed cases for years because I wanted to go for an X pipe. But after my extensive findings, there was no need. BTW, the H-pipe assembly that is shown in the link you had was a really dodgy install of a H pipe. I know my H pipe and probably most others wouldn't have such a rough job done that would have the balance pipe pertrude into the main lines that far, because that would be unacceptable.
After reading the replies, some questions come to mind. To get a good laminar flow, would it not be easiest not to try to join the 2 different streams , but let them run separately in a well designed system ? Can't you design a dual single side to absorb pulses as efficiently as with an X pipe ? Does the X help cover up any problems with a cylinder not being up to scratch ? What is the theory of increased performance of joining 2 different gas streams based on ? Gut feeling, measurements, science ?
VG30's firing order is 1-2-3-4-5-6, so you have cylinders firing alternately on each bank. When the exhaust exits the manifolds you have whats refered to as a pulse. Extreme high pressure on the leading edge and essentially a vacume on the tail of the pulse. The idea is that when they merge in an x-pipe or similar is that the tail end of the pulse from cylinder 1 "pulls" the leading edge of the pulse from cylinder 2. 1 thing to consider tho is that a turbo blurs pressure differences between pulses and the benefits of an x-pipe are severely reduced.
Well all i know is i had a cat-back fitted 12mths ago and had no smoke issues.........i thought..........till now. Now sometimes its the pass side..... sometimes the drivers side....sometimes a little of each. SO H-pipe going in on friday, soon see if it fixes it. Cheers Patrick
