Hello guys, thanks for having me in this forum. I recently bought my si with 4k miles on it and I swapped out the stock exhaust for an Invidia R400 (Invidia Gemini Cat-Back w/ Ti Burnt Tips | 2017+ Honda Civic Si Coupe).
Before, My idle rpm (warm engine) was about 600prm, and my cruising speed of 60mph was about 2100-2200rpm. After the exhaust swap, my idle rpm is 750, and my 60mph is 2500 rpm. I'm wondering if I have an exhaust leak somewhere, or they messed up somewhere installing it (I went to a muffler shop to have them replace it for me, too scared to do it myself since I will probably mess it up lol). I don't think having a new performance exhaust will increase my rpm overall though, but I'm not very sure.
Next mod: I already bought the PRL Motorsports"Cobra" Cold Air Intake Street for 2017+ Honda Civic Si and would have the professionals install it for me as well. Only doing these mods for now to avoid voiding my warranty haha.
Thanks for the help!
I've changed many full cat-back systems on many of my cars in the past, 4,6, and 8 cylinder engines. I've never seen higher rpms in any of my cars after the install. I watched an install video on this exhaust. It's 3 bolts/nuts at the down pipe and some exhaust hangers to remove the old. A few more bolts/nuts as the new system is 3 pieces, but there's nothing electrical underneath the Civic to mess with. And even in the after install, idle didn't sound any different that before (rpm's wise).
I might have just been reading wrong in the first place. Thanks!
Yeah your RPM's should not be affected at all by a new exhaust system. Are you sure your pre-modification reading was correct?
