hey guys got a highly worked brand new motor running 10:1 comp, 3500rpm-7000rpm cam, port polish, xf falcon 67mm throttle body ( i groung out my original plenum and bolted it on with a few modifications.) and aftermarket ecu, deleted balance shafts, deleted maf sensor and air intake, i have a pod directly on tb. i have extractors and high flow cat lukey muffler etc. the car has wicked power for a magna and beats ss commies off the line but there is more potential there im sure of it. it struggles to get over 6000rpm and make any power even with the cam. i think there are 2 weak points in the car... 1. the exhaust is press bent and the muffler i am told is too small for the setup im running. and 2. the plenum chamber may be too small. i am wondering after reading an article on here if i would experience any significant gains by getting a custom plenum made, or if the exhaust will even make that much difference. any ideas or suggestions would be appreciated...

Nice, wat kinda k/w and 1/4 times you get ?

How big an exhaust is currently on the car?
I wouldn't mind seeing this car in the flesh, sounds like a real sleeper :badgrin: .

With that amount of work done to the engine I'm assuming you're going for top-end power right? If so then a custom intake manifold and plenum chamber would definately make a difference. Especially since it sounds like you're running the stock stuff.

How stock is the exhaust setup? Cos a decent set of extractors along with a mandrel bent 2.5/3 exhaust system would also make a difference. Really, it all depends on how much you can do yourself and how much you're willing to spend.

says u already have highflow muffler and extractors. just curious, what brand of extractors or are they custom? as for exhaust really depends on what else your planning for the car, stock is 2" on the 4cylinder. If your planning on something with heaps more balls then yeh its worth a mandrel bent but if your not going to do heaps more then just a 2.5" press bent is more than enough.

lukey extractors and 2.25" high flow cat and 2.25" back.
been doin some thinking and seems like i could pick up a fair bit on the intake side of things coz the 67mm tb is bigger than the plenum so the plenum is restricting it a bit.

i want your motor. i'd defenatly look at you intake, and mabey better extractors and a larger pipe, as high rev motors like larger pipes.

Have a look at the link on this post. It's got everything on how to make a tuned intake, runner length, plenum chamber size etc.
http://www.aussiemagna.com/forums/showthread.php?p=531855#post531855

this has happened to the turbo magnas aswell, they tend to stop creating power near the high rpm range, it may just be the engine and the way it has been made, even the performance mechanics were baffeled, i am speaking about the 2.6 astron.

this has happened to the turbo magnas aswell, they tend to stop creating power near the high rpm range, it may just be the engine and the way it has been made, even the performance mechanics were baffeled, i am speaking about the 2.6 astron.
Was it you having a problem with the injector duty cycle VIP? If it was, did you get it sorted?