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Hi, I've been part of HPA for a long time but had completely forgotten this amazing resource for all car related questions. This may be a very broad question related to exhaust cutouts but, can anyone share how big the benefits of Open vs Closed you've seen on your builds. I'm trying to determine if it's worth it or not on a Diesel with an already straight pipe with a muffler.
It's a 5.9 24V Cummins, twin turbos in series (oem factory up top, S475 on the bottom with a 5" downpipe). As it sits today they downpipe goes from 5" to a 4" reducer to a 4" exhaust all the way. I'm thinking on a 5" electric cut out right at the dump pipe.
I know it may possibly come down to a "buy it, install it, dyno it and log it" but it's always interesting to see what other's experiences.
Thanks in advance!
PD: Hopefully this was the right forum place to post this.
A good idea to see how likely you are to see improvement would be to measure the backpressure you're currently seeing post turbo. The higher the back pressure is, the more gain you'll see from bypassing your exhaust system.
Andre, you are right but is there a way to relate back pressure to approximate gains from a cut out?
ie does 2psi of back pressure yield a 3% loss in efficiency?
second point is what are reasonable amounts of back pressure after the turbo?
Thank you Andre. I've been looking for an effective way of measuring the back pressure and have read many mixed reviews. Most of the tooling I find is used for catalytic converter diagnosis on OEM platforms. Would that work with an exhaust stream this big (5")?