Has anyone experienced getting a sports exhaust system and found that the louder the system was the worse it ran. My ef got fitted with a system that was to droning in the car . The car was hardly drivable it was that bad. I got them to make it quiter and the tune improved somewhat but not good. I got a further noise ruduction and it improved again. Now i have it around standard and the tune is back to being normal. Strange or does this need a tickle on the computer once a sports exhast is fitted ??

Havent heard of that one before. What exhuast did you buy with what mufflers/res's, and what did you/they do to make it quiter?

if its that loud, get a hotdog at the front of the exhaust and the end.

Maybe something to do with backpressure

A lot depends here on what you mean by running worse...
I had the factory system on my EF Futura break off at the back of the muffler. So that was the hoop over the rear axle and the resonator tucked up beside the spare tyre well gone. Sounded a bit louder, but otherwise ran fine. A month or so later I have to admit its getting louder and louder. A quick VI reveals the welds on the front resonator are cracking. The car still ran fine - in fact you could practically hear each cylinder firing at idle, Car was still running fine when I dropped the system off and discovered a 200mm split on top of the muffler. Bolted on a Lukey 2.5 cat back system with only 1 small muffler and rear resonator and my neighbours are talking to me again. Point is the car ran fine at all times and still does. I'd be looking for another cause...

Cheers,
C

Ive experienced similar, i have an AU which was not a real performer but had a 2.5 in cat back system fitted and it drones like hell too, also i notice fuel ecomony drop back by nearly 100km to the tank and also lost a bit on the bottom but gained a bit more up top but not much that u would notice up top but plenty that u miss it down low? i was disapointed mainly in the mpg but expected that the extra juice would be put to good use?
But really i cant complain it is the missus car after all.

Exhaust gas velocity and back pressure are the 2 main goals in getting a sports exhaust right. Muffler choice, pipe size, pipe bends (mandrel/crushed), cat size etc all come into consideration.

Custom systems will always out perform some system that is mass produced and gets delivered by a truck and hung on a rack. But how much are you willing to pay!!!!!!!!!!!!!!!!!!!!!!

I ran a redback system, got the s**t with it. Got a fully custom sytem installed and the difference is noticeable.

Cheers!!!!!!!

Gas velocity is what it is all about....smaller pipes = higher velocity, but become a restriction as amount of gas (revs) increases. Larger pipes = lower gas velocity and therefore greater inefficiency as gases are cooler at a set point (and therefore heavier; note they also decrease in volume as they get colder but the difference in mass has a greater effect) and therefore being heavier require more force to be pushed through mufflers/resonators and the exhaust.

The funniest expression of all time is when people relate having smaller diameter pipes to create backpressure which "makes" low down torque...yes pipes that are too small create backpressure, but its the fact that smaller pipes are more efficient at low revs that you get more torque down low (read above).

Custom exhausts in my opinion are a waste of money for a street car unless you got oodles of money or get it cheap (this is assuming you get a decent off the shelf one with good mandrel bends)...the main difference is in the quality of mufflers/resi's and the cat. This is particularly true in a falcon where the majority of custom exhausts follow the lines of an off the shelf unit anyway, and the only difference is slight differences angles and better components.

the last system i put on my ef was a redback and it makes the car run rite again only you can hear the exhaust whistling (sort of) trying to choke the gas flow. but at least it now runs rite down low. My complaint is that with only a moderate note the car wont run and feels like you are driving with the choke out. the quiter it sounds the better it runs. any ideas??

I dont think the louder the exhaust the worse it will run, i think the louder it is, the more your expecting the car to go faster. All in your mind i think.

no wrong. this is not in my mind. my father was a mechanic for over 5o years and i picked up a bit ya know. this is low down running. like driving miss daisy type driving. the loudest note gave the worse low down running to the point it felt very sick. the more we changed it to make it stop droaning in the car the better it ran until i put the redback exhaust which, as i stated before sounds crap and whistles like a jet if you give it full throttle but runs rite. strange ay.

Apart from a blocked muffler or cat, your car problem will be caused by anything BUT the exhaust

well thats not true as i owned an fz 750 yamaha that i fitted a stainless 4 into one exhaust. the bike ran very similar. very very poor low speed performance that got worse the warmer the engine or temperature was. it turned out that the free flowing pipe had upset the flow of fuel air ratio and made it run very very rich at idle to low speed. This could be explained as the problem with my car only i thought the fuel injection would be compinsated by the computer.......but no..it does't seem so.

ffs ... so i take it your 100% sure that your headgasket is perfect, your intake air temp sensor, coolant temp sensor, tps sensor, map sensor, crank angle sensor, o2 sensor are operating perfect and that all the wiring from these to the ecu dont have any earth leaks, and your leads and plugs are excellent, coil pack is fault-free, and the ecu isnt spitting out any fault codes, and theres no vacuum leaks anywhere, and your fuel pump is operating properly, and the fuel filter is clean.... etc etc.

So your car is fault free, and the poor performance is the free flowing loud exhaust....?

well ets see noww....the car is running perfect now with no problems however i cant say that the mention data has been check for recomended setings . as i say, the car is running perfect with this exhaust soo.....??? dont sound like it has a problem.