Hey guys. Im looking at exhaust to put on an 06 Evo 9 MR and being new to the turbo would (came fro mthe supercharged world) i want to know is it really true that you get a hell of alot more power going turboback rather than catback? I herd turbobacks throw codes because of the sensor being taken out? I could be way off but If i decide to go catback am i still llooking for a nice hp gain? thanks.

 

YES, TBE power will be much greater than a cat back, and a test pipe instead of a high flow cat will yield more power because there is less resistance. Another option is a cutout downpipe like QTP makes.

 

The Turbobacks throw a code because you use a Hi Flo Cat or Test Pipe which in turn flows more air than stock. That will throw the CEL code for the Rear O2 sensor. You can buy a Electronic Cel fix to splice into your wires or you can buy a Mechanical Cel fix and screw onto your O2 Sensor (or Spark Plug Anti Foulers). The Electronic tricks the ECU and the Mechanical pulls the O2 sensor out of the TP/HFC and slows the air down going into the O2 Sensor.

Also this question will pop up later because it always does. "Where do I put the Rear O2 Sensor because the new TP/HFC do not have an O2 bung?" (Some Don't have them some will) You can put the O2 Sensor into the IP Pipe where the VIII's put theirs.

 

Don't all cars make more power with a full exhaust rather than a cat-back? I mean even if you have an S/C or N/A car, the stock downpipe and stock cat are going to rob you of power for sure.

Anyway, you'll get about double the power with a full TBE than you will with a cat-back on an Evo. The code is not a problem - it's a $5-20 fix that we all have to do.

 

It depends on where you want your power. Some restriction on the exhaust side will give you a quicker turbo spool so for 1/8 mi or short bursts between twisties, you might have better all-around performance keeping a smaller diameter pipe or going HFC instead of test pipe. Most are just looking at peak HP in 3rd or 4th at WOT which depending on the track, you might not get a chance to get to the top of 4th.

 

By no means is that true. The less backpressure we have, the quicker we spool and the more power we make. Neither a smaller DP nor a hi-flow cat will perform better than a straight pipe and bigger downpipe anywhere in the powerband. It's a myth that we need backpressure to help spool. The truth is we perform best with NO backpressure. That's why people run open downpipe whenever possible, and it is not just for top-end power - it helps spoolup, torque, mid-range, and top-end power.

 

This is def. true for turbo and supercharged cars. As far as naturally aspirated goes....some backpressure does amount to some added torque and power usually on the bottom end. With the EVO a dump/cut out would realistically be the best at the track

 

+1 for last 2 posts

go for the full TBE with cat delete

 

Yes, but we were only talking about the Evo. EV06MR specifically referenced turbo spool, and that's what I was refuting.

 

TBE is the way to go, there are ways to fool the o2 sensor and prevent the CEL issue.

 

Beyond a shadow a doubt, go TBE; more power increase and more aggressive sound.

 

Would a TBE with a high flow cat still pass emissions?

 

TBE all day son... and twice on sunday!!

 

Usually, but not always. Emissions tests are different all over the country. You'd have to ask people in your area if they have passed your local emissions, because other states do it differently.

 

there are some HFC's out there that say they will pass even California's emmissions, which are higher than the rest of the country... I have a Helix HFC that will supposedly pass, but i havent had to get emmssions testing yet... I replaced it with a test pipe when I installed my O2 housing for a true TBE since it should flow a bit better than a HFC, but I'm hanging onto the HFC to slap on just for emmssions testing