Akrapovic Dyno with valve open or closed ?

[hot-j]

Anyone know if when the valve is open, does the Akrapovic exhaust make more power?

[Piets94]

I'm not certain about Akra per se, but with the HMS exhaust (which is a very similar valved design), I made 7 rwkw more with the valve OPEN, all at the top end.

Depending on which exhaust tip the dyno operator puts their sniffer probe, you may get an inaccurate AFR reading too because of the valve. Log at the same time to confirm.

[hot-j]

Originally Posted by Piets94

I'm not certain about Akra per se, but with the HMS exhaust (which is a very similar valved design), I made 7 rwkw more with the valve OPEN, all at the top end.

Depending on which exhaust tip the dyno operator puts their sniffer probe, you may get an inaccurate AFR reading too because of the valve. Log at the same time to confirm.

Will do, thanks for the tip.

[The Wind Breezes]

Why don't you double down on the dyno runs and answer the question for us?

[hot-j]

It'll be a couple of weeks before I do... just trying to prepare best I can.

[Piets94]

Originally Posted by hot-j

Will do, thanks for the tip.

Was there a pun there??!
Interested in the results when you get them.

[Tinsta]

Would have thought the open valve would give the higher figure, as the gases would have the least restrictive path to travel.

I've noticed the 2 outer pipes certainly have more choked/black soot than the 2 inner pipes.

[martymil]

I'm running the akra with the wireless kit with upgraded rb turbos on 98 ron fuel

closed 340.4 rwk
open 351rwk

+/- a couple of rwk in dyno variance

Haven't tried it with straight e85 yet but I guess the the difference could be bigger.