Ok here is my setup, motor is half bridged with a single 35r setup. My current exhaust is a midpipe and n1 style muffler. I'm in debate of putting a high flow cat on and keeping my current muffler for a few reasons. First off my setup flows so efficient that it overboost. I upgraded the wastegate from a 48 to a 60mm to try to solve this issue, but had some success but not enough. Using the tailpipe silencer created enough back pressure to obtain and hold my Target boost. I really like the exhaust but don't like dealing with the tailpipe silencer kinda stupid looking. But without it it spikes hard and is way too loud for me which is another reason why I'm thinking of going this route. But here is my big question how much HP am I looking at sacrificing doin this route. I'm also debating on maybe just kicking the n1 to the curb and using a full muffler like a apexi world sport ii or tanabe medallion and keep the midpipe. Which would be a better choice? A high flow cat and n1 muffler or a midpipe and a more restrictive muffler?I understand that the motor is bridged, I love the brap and will know it will always be noisy, I just want to kick it down a few notches in noise without losing to many pony's. Any facts and opinions would be great.

 

What boost are you running? seems strange that a 60mm gate couldn't control it.
what about a mid pipe with a muffler instead of a cat?

 

I mentioned that as an option above. I'm running 14lbs. I'm debating on what way to go.

 

sorry im new to this but wouldnt a boost controller solve an overboost problem?

 

Boost controllers allow u to go beyond the wastegate spring rate not beneath it.

 

i'd put a big muffler in the mid pipe. it will help with the noise, and it should help a little with the boost creep too

 

Why not try some sort of restrictor plate in the exhaust?

 

Do you have a picture of your turbo manifold? With a 60mm wastegate and a well designed manifold you should be able to control a 35r.

 

How is your vacum line set up from the wastegate?

 

What turbine housing are you using and what spring is in your wastegate, is it re routed or dumped to atmosphere? I also think you should be able to run 1bar on a 35r without creep as long as you have a quality manifold and a properly setup wastegate with boost signal sourced at or near the compressor outlet.

 

This.

It would allow you to keep your free flowing setup with minimal changes or losses in flow. A smaller diameter exhaust gasket is usually used. It is the easiest solution before changing out to an expensive high flow cat.