Let's have an exhausting discussion

[74 challenge]

What don't you like about the 3" system?

Too large for a 318, loss of power. Would have done a 2.5.

[Chryco Psycho]

Neil

I am guessing that "high RPM race build" means > 7k rpms eh?

B

Yes

[Chryco Psycho]

The Term Back pressure is thrown around a lot , but is wrong , you really do not want back pressure but you do need & want velocity , if the system is too big the exhaust will lose speed inside the system this will hurt the scavenging / vacuum to draw out the next exhaust pulse , on a small block 2 .25 is often better , 2.5 for the big block

[Racer57]

The Term Back pressure is thrown around a lot , but is wrong , you really do not want back pressure but you do need & want velocity , if the system is too big the exhaust will lose speed inside the system this will hurt the scavenging / vacuum to draw out the next exhaust pulse , on a small block 2 .25 is often better , 2.5 for the big block

Its so refreshing to see that other people understand the difference. 

But, as much as I understand the purpose of collectors and equal length head pipes and even anti-reversion cones commonly used on 2-1 headers, could you please explain (if you know) why none of that applies to NHRA Top Fuel ?  Is it a matter of just too much volume and any thing else would restrict it ?

[Strawdawg]

Forced aspiration pushes the exhaust out so no scavenging is needed... Main thing is no back pressure to work against the blower.

[Racer57]

Forced aspiration pushes the exhaust out so no scavenging is needed... Main thing is no back pressure to work against the blower.

DUH !

[73restomod]

I picked my mufflers based of a thorough chassis dyno comparison in (yipes) a fast fords article. I will see if I can get a link here shortly.

http://www.mustangandfords.com/parts/m5lp-0212-ford-mustang-muffler-comparison-test/

yeah it's done on fords, but it's a thorough article, and if you take the time to read the dyno chart the Borla Pro-XS's really shinned through out the RPM's.

[HP_Cuda]

Wow I'm impressed with Magnaflows ability to stay up with the top numbers and stay quieter at 2k and WOT.

Have to look into those!

B