Thor Forums

[gmtech16450yz]

Originally Posted by Jgbram

What’s your thoughts on exhaust modifications, like a Banks system vs engine tuning.

Again, another EXCELLENT question! Short answer is proper tuning makes 10 times the difference any exhaust mods would.

Funny you should ask this too, since I spent the last few days modifying the exhaust on my Vegas. My goals were NOT power though. My main goal was to move the exhaust from the right side exit to the left. Too many times when leaving the door open while letting the engine warm up and picking up leveling blocks, securing rig for travel, etc, I would get in the coach and it would smell like exhaust inside. Hard for it not to when the exhaust exits about 5 feet from the door! I also wanted to have the exhaust exit in front of the rear axle, eliminating the added hardware going past the airbags, suspension, etc.

What I ended up doing worked out really sweet, I'm re-using the stock pipe and bends to go over the driveshaft and out the left side. I've ended up cutting about 5 feet of pipe out of the system, and it's much cleaner and better supported. The sound is a titch louder, which is fine since these stock systems are super quiet.

There are two big issues with changing exhaust on these V10's. First is they sound horrible when you can actually hear them! The second is the rpm range where these engines run in this application is 90% of the time between 2k-2.5k. You don't need a very big exhaust system for that rpm, and going bigger on pipe diameter/headpipe diameters can actually hurt power. Not because of the "engines need backpressure" myth, which is total bs btw, it's because you lose scavenging and you also lose exhaust gas temperature. Let the exhaust hang around in huge pipes too long and it will cool and be much harder to push out the entire system. The ideal exhaust is one that keeps the flow/scavenging moving and keeps the gasses hot all the way to the end. The stock Ford V10 exhaust does a decent job of doing that, at least at the rpm's we run at most of the time. Will headers and a huge freeflowing exhaust result in more high rpm power? Usually. But unless you're running your motorhome WOT at 5k rpm all day, it's a compromise that isn't worth the cost and losses elsewhere in the power range.

Proper tuning on the other hand can result in power and efficiency gains EVERYWHERE in the load/rpm range. There are no losses in optimizing engine calibrations. There can be noticeable losses in changing exhaust systems.