dont confuse back pressure with pulse tuning and the like
a cat is a "legal" requirement and the engine is set up to run and fuel according to that exhaust restriction and of course at part throttle run closed loop as well
F1 come on its a totally different built engine... And I'm sure you do nee the back pressure there in normally aspirated engines I can't remember why now though I'll try and get the info again bud I mate wrong bud
F1 come on its a totally different built engine... And I'm sure you do nee the back pressure there in normally aspirated engines I can't remember why now though I'll try and get the info again bud I mate wrong bud
so you need back pressure in the exhaust....in a n/a engine you need gases to exit the best they can ie no back pressure if not on the exhaust stroke it is using "power" to push the gases out...
you can use the manifold both inlet and exhaust to help promote and remove the gases better - the out going gases from one cylinder help with the gases exiting from another - thats why there are 4-1 and 4-2-1 manifolds and are variuos lengths and shapes
buts its all a compromise to achieve the best results
hi all,had my Y pipe mapped in this afternoon at RS Tuning,car was not running well after fitting it and after one run on the rollers paul said the car was running very lean,he was quite shocked by how far the Y pipe had thrown the fuelling out,at this point my heart was in my mouth,after a few runs and some tweaking though the car started to sound alot healthier,car spent an hour and a half on the rollers and as you can see by my graph its made a pretty big difference mid range,there is virtually no flat spot what so ever which i'm very happy with,the car drives and pulls really well right through the rev range,paul did say i might want to put a new set of plugs in as it was running so lean they may be damaged and cause a misfire,had no misfires in the drive home but i think i'll change them for piece of mind,still getting nice pops and cracks every gear change and thankfully the seriuosly loud cracks have toned done,think these may have been caused by the fuelling issues,anyway here's the results,