Finally got it fixtured into the flow bench, we were able to test our ported/polished/teflon'd y-pipe against a OEM stock y-pipe, sorry we didnt have one ported/polished but not coated available for testing.

We first tried to flow the new ypipe at 28in of flow as thats where we tested our manifolds, isuue arose that the machine could not keep up. Remember our manifold testing was for ONE manifold and this ypipe feeds BOTH of them. We finally decided to flow them both at 20in of flow as the machine has a capacity of 648cfm and we wanted to stay under that for accuracy. so short answer is they flow a hell of a lot!
Stock y-pipe flowed 599cfm @ 20in
Needswings y-pipe flowed 632cfm @ 20in
So we picked up an increase of 32cfm at that low airflow. i suspect that the gains would increase at a rising rate as airflow and pressure increases but that would require an even more expensive flow bench and more expensive flow time.

Now to the question, which now flows better? the manifolds or the y-pipe? how about they both flow very efficently and can handle more then we are able to throw at them at this point

 

I am not sure if i read you correctly . The so called Y pipe on my srt6 (stock) is a plastic square box, kinda ,, what pipe are you flow checking and calling it stock,? thanks jim

 

bump for answers.

 

no it's the aluminum y piece that your manifolds connect to with rubber couplings. It's back beneath the throttle body.

 

It is this one:

 

which gets turned into this one..
http://www.needswings.com/Product.as...7-bde87b6d2092

 

Thanks now i know whitch u r talking about, but from now on we should call it the intake y pipe ,,,and the manifold y pipe, it is like calling a intake a intake on a 1969 anything yet call a intake on say, a crossfire and you get a tube going to the throttle body called a intake, now we are clear. jim