std exhaust power issues

[TuxMan]

just looking at engine bay last night trying to work out if there is anymore easy power to be had and the one area i have not looked at are the std exhaust ,seem to remember someone telling me that they resrict enough to cost 30bhp !!!! anyone done any mods to release a bit more power .
Have already matched manifolds to head !!!

[ultimaCZ]

maybe not really related, but I was surprised to see that my LS7 made actually more power on the dyno with cats than without. Thought the cats would restrict the flow, but its opposite...

[bluesatin]

I remember Andy (Andygt) did some work on his canam years back and found 30 bhp on the dyno from the exhausts

[TuxMan]

sounds good !!! how do i find 30BHP !!!Andy ????

[Stig]

TuxMan said:

sounds good !!! how do i find 30BHP !!!Andy ????

Didn't Andy have a balance pipe installed?

[TuxMan]

Stig, do you mean a balance pipe between the boxes?or headers

arn,t the headers all supposed to be the same length ?

[andygtt]

I dyno'd the headers back to back with less restrictive ones and on a genuine 490bhp they robbed 30bhp... it will be more on more powerful engines and almost nothing on some less powerful ones.

Basically with you 400bhp engine (is my memory right?) you probably wont gain anything.

BTW 30bhp was in the rev range it only lost 10bhp peak!

[TuxMan]

Andy so what is the easyist way to improve the std headers ????

[Stig]

TuxMan said:

Andy so what is the easyist way to improve the std headers ????

Ceramic coating! 'nowt to do with restiction, but will help your under canopy temps (and therefore probably the intake chage temps).

[bluesatin]

Stig - also the coating helps draw the exhaust gas out better due to higher temp.

[TuxMan]

Stig , done that already ,have fitted a cold air pickup system that draws air from the side pod ,ecu has a temp probe in the top of the airbox ,works well have seen underbonnet temps of 50degrees with inlet temps of 20 !!! engine feels alot better on hot days !!