PierreTT

Very good question. I hope somebody have some answers/facts.

I just went out in the garage and did the mod... 5 minutes per sides. Very easy, not lift or special tools needed.
Still have not plugged the inlet though...
I'll try the car tomorrow and report back.

ONEOFEW

None that I can detect, it too far down the path to really make any difference. I bet if one starts changing to high flow cats, or delete the side mufflers it will be noticeable.

joshdunn87

Even if the flaps are open, under a certain RPM I don't feel that the sound really comes alive until around 3,000. Kinda nice if you are trying to be quite in the neighborhood early in the morning.

drechsler

Lines plugged and non-valved side delete. Symphony unleashed. If there is any loss of performance it is not evident seat-of-the-pants.

911dev

One of the valve tubes on mine came loose on its own. I immediately felt the difference. It was likely not secured correctly at the factory. I quickly corrected the issue and immediately felt an increase in low-mid torque.

ipse dixit

Yes.

PierreTT

For those who cares... Back from road test
I like it and cannot (from butt dyno) feel any difference about low end torque... I'd like to see some dyno charts comparing both, if they exist.

Just need to find a better way to plug the inlets so no dirt gets in the valves. Now it is "ghetto duct tape" mode plugged...

FourT6and2

Dyno charts exist. Do a search. Obsessed Garage did a bunch of dyno runs a while back.

ONEOFEW

this is how I have mine plugged, any auto part store will have these plugs in verity of sizes.

Buddhamonk

NVRANUF

Hi Pierre, how are you enjoying the GT3? Getting much seat time in your Radical?

Here are what the rubber vacuum caps look like, they are similar to what I used. They are available at Canadian Tire, Napa or any automotive store.

PierreTT

OneoFew & Peter,
Thanks for the tips.
Enjoying every minute spent in the 3 Peter, like you I would guess!
Radical is also epic. Injury kinda made me miss June but I'm jumping back on the horse in 10 days! :-)

As for Dyno charts, it is raining today here so I'll look into it. Hard to judge impact, from Butt Dyno at least but if there is a real low end torque loss, I may revert the mod...

PierreTT

Buddhamonk
Thanks for making my life easier!!

Bottom Line, my butt dyno is not that bad... :-)

fskof

erik_plus8

If there is a performance difference between open and closed exhaust flaps, it has to be to the advantage of open flaps. A lower static back pressure can never be a bad thing for volumetric efficiency and scavenging, rather the opposite. And add to that, I think the flaps are probably anyway too far downstream to have an meaningful effect on the dynamics of the gas exchange.