Dual-mode track and street pipes
 

Thought someone might be interested in my custom exhaust.

It is a turbo with a 3" all the way through (including dump pipe and overpipe) with just a high-flow cat and no mufflers. An exhaust bypass cuts this out for 'street' mode and exits via the other exhaust tip which is 2.5" and has a muffler.

An aftermarket ECU allows one dash switch to both open the valve and set a new ECU map. It goes in for dyno tuning next week - we think we'll get a few more degrees of ignition timing with the open pipes. Let's test the theory and see if it actually makes more power.

Cat is installed such that it can be removed relatively easily.

Video of the bypass valve testing here

Take my money and sell me one...:thumbsup:

I wonder how did you made ecu tune also actuate straight exit exhaust valve?

Very nicely done. In for the test results.

Nice man. I wish there were more valved options for this car. I may need to have something made as well.

There are several valve options, if one searches, that can be welded in. Electric or mechanical wire actuated. IIRC i've seen here another one or two similar setups on this forum. But actuated by ECU tune sounds something new.

Thoughtful solution and it appears to be well executed! I'd like to hear the difference via a test video...

I’ll be second in line!

Clean!

Looks pretty cool. Why does the valve open past 90 degrees? It seems like 90 would be best.

It does open to 90 degrees. The camera angle makes it look weird.

It makes a large difference in volume but i haven't rev’d it past 3500 yet - still has a NA map. Goes for dyno next week - I'll report back then together with any differences in HP a video with the valve open and closed.

That is the easy part. The MoTeC ECU is very configurable. A 10 position Driver Rotary Switch enables Auxiliary Output to switch to ground which then then operates a relay to drive the servo motor of the valve.

That one Driver Rotary Switch can operate several software options at once. for example:


Switch Pos Ex Valve Rev Limit Timing
Pos 1 - Valet Closed 3500 Map 1
Pos 2 - Daily Closed 7000 Map 1
Pos 3 - Track Open 7500 Map 2


I can even operate outputs based on GPS position. One track I got to has a restrictive noise limit. I'm thinking of programming the ECU to close the valve as the car approaches the Decibel meter and then opening it back up when I'm further away.

It's only really limited by your imagination - it could open based on engine RPM, throttle position etc etc.

I would love to have a dual mode exhaust for everyday driving and track/autox days... most options are too expensive or custom. And here's the perfect spot for that switch...https://d2o2wp2jhq0iwx.cloudfront.ne...t-1024x768.jpg

I can't wait to hear how yours turns out!

Impressive! Interested to see the vid & result as well