Exhaust gurus. Headers and high flow 3" twin into standard rear can?

[hjtrbo]

Hey all,

Currently have a Harrop pro extreme header back system on a VF LSA setup. 1-7/8" long tubes into 3" per side all the way back, 100 cell cats, straight through centre and rear mufflers.
Wondering if there will be any performance loss if I went backwards a little and retro fitted the HSV rear cans. Thinking the gas is colder and has less volume at the back of the car so might be able to get away with it. Any gurus out there that know how this will go? Reason is just to tame the noise down but still want it to go hard. Still have bimodals active on the Harrop system.

 

[lmoengnr]

Don't think you'd lose too much with the bimodals closed.
Probably on a par with valves open.
Have you been shaking your neighbors house on cold starts?

 

[07GTS]

dosnt make much of a difference back there unless ur pushing big power, on boost i was using the stock rear mufflers for ages to keep noise down and ran fine made good power

 

[hjtrbo]

dosnt make much of a difference back there unless ur pushing big power, on boost i was using the stock rear mufflers for ages to keep noise down and ran fine made good power

Good to know. What was the sound like? Comfortable when cruising but still loud when you got up it?

Have you been shaking your neighbors house on cold starts?

Lol, I know inside our house with the Mrs working from home she gets shitty. She sits on a spot where the reverb is quite nasty

 

[Not_An_Abba_Fan]

Anything forced induction will be fine, the exhaust is just there to keep it quiet. The SC will overcome any flow restriction in the rear mufflers.

Tell the missus to change spots.

 

[07GTS]

Good to know. What was the sound like? Comfortable when cruising but still loud when you got up it?

stays good when cruising almost like factory but just that extra note that isnt in your ear which is good, then still sounds good under WOT

 

[RevNev]

Any gurus out there that know how this will go?

An LSA engine's in the 1 7/8 primary twin 3" area, but you'd really need to dyno the car to see if it loses power. The stock rear mufflers neck down to 2.25" and that's a dramatic flow reduction from 3". Mate of mine's got an LSA with 1 7/8, 100 cell cats and a twin 3" Redback system, it's bloody loud outside and droney inside, not real nice on a GTS.