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NASCAR-Style X-Pipe Exhaust Explained

4:47
30:04
73.9K views

At 4:47 in

Dr. Gas's NASCAR Inspired Mustangs: $1,400 Shelby GT350 & Fastback Track Car

What happens here

Boyd reveals that the Sledgehammer car features a NASCAR-style X-pipe exhaust system. He explains that the X-pipe addresses issues in the firing order, where exhaust pulses from cylinders that fire consecutively fight each other. The X-pipe allows for a smooth flow, improving engine efficiency. He then shows an example of a similar system (painted copper) installed on a vehicle, detailing how the exhaust transitions from a 3-inch round pipe to a 3.5-inch ovalized pipe for clearance, then back to 3-inch, and finally uses Borela mufflers as resonators to control sound without creating performance-robbing backpressure.

Goal: Explain the design and performance benefits of the NASCAR-style X-pipe exhaust system.

Tools and materials

  • Borela Mufflers Borela — Acting as resonators to reduce sound, High-Temp Copper Paint Forest Coatings

What they say

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the car up, because there's a NASCAR-style system here that I'll show you. Is this a solid roller camshaft or hydraulic? Mechanical? Oh yes, you'll like it. The only real Ford parts in this car are the sheet metal. I see the radiator support. It looks like I've seen this before. Sheet metal. Only sheet metal. We use alcohol in it. It runs on ethanol, E85. We don't want to gas you here , so If you could feel it. barely touched the gas on it. Just Oh, yes. You see, it's like a small No mass flywheel. Very lively. Yes, he drives the same way . The reaction to gas is simply amazing . This door weighs about 16 kg? This door weighs almost nothing . I can even feel the play in the curtains just by lifting them. I bet that door weighs 10 pounds at most. So, did it have custom throttle bodies when you got it, or did you... Yeah, we ended up replacing the intake manifold, the cylinder heads, and had to sand everything down because there were vacuum leaks. And by the way, here's some of what we talked about earlier. Here is our firing order. This is the firing order of the 351 Windsor, which if the numbering was the same would match the LS, but the ones next to it , first and third, here they are. Therefore, these two fight each other in the collector. I painted this with copper heat resistant paint. It's from Forest Coatings, and it's a little scratched. This is actually from the trailer, right here. But here's mine, here's the first thing here. My X-shaped pipe. It eliminates that impulsive situation we talked about earlier. And so from here the flow moves smoothly here. Now here's another trick we use to muffle the sound. These are Borla mufflers that I use as resonators. I don't think they're anything special, but they're straightforward. In fact, the core size, you see, there is an adapter here. It expands to 3 and a half. 3 and a half passes here. And then we narrow it down to three again. By the way, let's go back up here . The collector here is for three. And then I make the transition right here. You see, this detail right here—we're moving to the oval. And that's the standard NASCAR size: 2 and a half one way and 4 the other. And this was measured as we discussed earlier to get a nice distribution. And then the resonators allow the exhaust, because they increase the size a little, the flow slows down . The speed slows down a bit here, and I'm quite far from the engine, so what's happening behind, the engine doesn't even feel or care about. So the exhaust…

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