I have 2 separate pipes all the way and have fitted two high flow resonators to stop the drone. I like the fact I can tell whats going on each bank by looking at the exhausts. I took away the factory restrictors and new mandrell bent 2 1/2" pipe to the aftermarket Hi flow mufflers, I have thought about fitting X pipes but will it affect the performance ?
I read somewhere it should increase the performance as you balance the exhaust gases which is better for the engine as both sides are equalized. This could be bull, but I remember reading it. It certainly won't affect it negatively.
noise cancellation suggests... to me that high pressure pulses are meeting lows and canceling themselves out at the X location. I guess that makes the flow through the exhaust more smooth (laminar as opposed to turbid) so more efficient. I suppose better flow gives higher exhaust vacuum so the cylinders empty & fill a bit easier so thats where the extra power is found. Or maybe drops the pressure across the turbos so more boost is found for the same flow. hmm but im always suspicious of non stock setups, im sure the nissan engineers had lots of knowledge, time and resources at thier disposal.
Hmmm, I've always seen stock setups as less than perfect. The Nissan engineers would want them flow to be a certain level and volume which may be have been sub-perfect performance wise but better in terms of sounds/look/cost etc.
Nissan didn't even try and design a decent free flowing exhaust... actually, I reckon they tried to detune the Z32 by putting restrictors in the exhaust.
my mistake Yeah that whole 205kw manufactured limit thing. My father spent many an hour modifying heads of mini's when he raced them in the 70's. They were considered too powerful for such a small car when testing so they detuned them by adding meat to the heads to restrict the flow. I like the way nissan have done it, restricting by detuning the bolt-on parts such as intake and exhaust. Much easier to mod. They mustve had an optimised design before they down-tuned it. Wonder what it looked like?
why the hell would they find methods of restricting the power output......i mean isnt it an advantage to sell a car saying its got more pwr?
i have bulit the x-pipe with a 200mm x 300 join we ran out of light so this weekend the welding out will be finished and ill post photos onec its done
what about cars they sold over seas, like america etc......did they also restrict theirs? man if they made a buggati in japan, would they make it to 206kw.....dam laws..
Yep ! The Jap M/cycles are the worst for 'restricted engines', even their so-called "AG Bikes" ( farming use ) are restricted ..... usualy by a baffle plate between the carby & head and in some cases a baffle in the exhaust port. Most bike shops remove the baffles before delivery to the famer. The baffles are there so that these bikes can be brought into the country and sold 'legally' and be compliant with our stupid noise limits....... one of the main reasons as to why HarleyDavidson bikes are now all belt driven, the noise from the old steel drive chain pushed the bikes over the noise limit !!! About 4 years ago the main manafacturers had a meeting and put a limit on the top speed of their road going 'sports bikes'.... the "gentleman's agreement was 320kph from factory, they have all stuck to this "agreed limit" so far. The cars are no differant !
ok, ill try and say this without being too much of a bitch about it... bulls#*t - there is a science behind it. 1)Fluid dynamics would point you in the direction of a 6degree inducer and exducer (collecter if you may) angle. (there is a cosine relationship in there) 2)I have read numerous books on exhaust system design and a few on pumping - (now to quote a wise man: "Pumping is pumping, doesnt matter what it is a slurry, potable water, air or emissions gasses its still f#cking pumping") that rant was one gentlemans words to his future employer and incidentally he did get the job ;P ... back the the exhaust sytem: if you are set on the diameter (for example) of 2.5in then many reasearch article and engineers would say an X-pipe length of ~175mm to 250mm long, thisi length is derrived from testing done and results found that x-pipe legth(l) to exhaust diameter(d) ratio was optimised between: l/d=7<10 and this legth range represents the "tuning" range of said x-pipe, in that there is scope to optimise where the scavenging occurs best at ie:where it has it's greatest effect on increasing the toque developed. (incidentally, many exhaust shops replace more than just the x-pipe section and thus back to back testing with a control sample is not often provided - hence possible shady results) 3)if any of the above seems greatly misleading or false i can provide my reference material when at home, as i cant remeber authors or title right now. 4)as for you making your own system, if you can do even a half decent weld with the TIG go for it, cut carefully and plan where your joins are going to be (from a servicability point of view) im still trying to master welding the ali with my TIG - its a fair bit harder than the stainless was. bets of luck with it ...rant over.
Well the Cat back section is made after a little bit of work we made the X-pipe and finished off the cat back system and i know it works. Without making any changes to the GIZMO EBC i got 3 PSI of extra boost. In saying that on the dyno yesterday i couldn't get any more that 13 PSI of boost. I have a new set of cats sittting here and as soon as i get my dumps and test pipes ill finish the exhust. Here are some Photos you can see the old cat back sitting next to the new one
Troy that would have to be the most different sort of X-Pipe I have ever seen. By the looks of the pics the two pipes don't appear to merge into each other or is that what you wanted to achieve? I find it strange that you would get extra boost from an EBC though as it should be regulating the solenoid to maintain setpoint. Also no wonder you get extra flow, it appears your old system was a lot more restrictive to what you have made with smaller diameter pipe and press bends. Good work for nocking it up yourself I did the rear section of my car on the ground and I swore never again
thanks for the positive feed back i hope the following answers some questions. It wasnt that bad a job i would do it again if fact i enjoyed making it the X-pipe section runs together where a section that is 30mm by 200 mm. The reason for the boost rise is the GIZMO isnt that smart it just sets the duty cycle of the soliniod and with the reduction in back pressure the turbos made boost easier so with the duty cycle
Hmm i just had an idea after looking at your x-pipe and thinking of the benefits of it I'll put my cats (read "restriction") downstream of it so that the flow resistances are run in parallel (ie halved) Sweet
i believe so as it's driven by exhaust gas temperatures - perhaps ceramic coating exhaust system pre-cat would reduce temperature drop and also gas expansion i guess that's why the STi's come out with like 2-3 cats? 1 is straight after the turbo... must be in an effort to meet emissions standards? first thing the aftermarket guys do is turbo-back exhaust system, and obviously do away with all those efforts
actually, on a turbocharged car, is there going to be any advantage to an X-pipe at all? don't mention scavenging or pressure pulses reflecting off the boundary layer of an open pipe end (end of exhaust) bouncing back up the exhaust system, dodging the turbine blades and helping to suck the last remaining exhaust gases out of the cylinder cos that sounds a bit far fetched right? on an N/A ok maybe its more complicated, but that big turbine restriction must eliminate the more subtle downstream influences on cylinder scavenging ?
