Just thinking ahead a bit.. The frame on the 39 Poncho is nearing completion. Is there any reasoning involved in where to locate the mufflers? Any preference in closer to the engine or further rearward? I’ll be running either 2.25” or 2.5” dual exhaust and can locate the mufflers pretty much centered front to rear.. OR .. just ahead of the rear axle. Now is the time to over think the simple sh!t.
Although it boils down to the style of muffler and where they will fit, a few considerations as far as muffler location- since the mufflers are usually larger in diameter, they may be closer to the floor pan and transfer heat. The exhaust gases expanding in the muffler can cause a low frequency hum (some call it a rumble) that may raise noise level in the passenger compartment. I would opt just ahead of the front axle. 2.5" could be too big depending on your motor build. Crossover pipe? I put SS short mufflers on my 53, with 2-3/8" pipes. Big mistake. Noisy.
Almost all modern vehicles have mufflers at the very back. I don’t know if that is for performance, noise, or because the fuel tanks are ahead of the rear axle.
It would be nice if there was a 5 day return policy on mufflers after installed. For sound , With pretty much all top Brands its a gamble what Your's may sound like compared to some one you know using same Muffler, I have several rides , on one I put a set of XR1 @ Idle & light cruise it sounds like a Farm tractor , 650 hp range @ Wot sounds correct . Pipe/ muffler dual 2-1/2 good for 500-600 Quality made. Thrush & Turbo usually sound good on Stock to mid H -Rs
Thanks. The engine will be a very mild build. Maybe 300 hp max. Definitely leaning toward 2.25” exhaust.
Muffler can go anywhere. They seem to last longer away from the engine and before the axle. Corvette's had them all the way at the back in the quarters and they rotted out because they didn't get hot enough to burn off the condensation in short hops around town. Camaros stuck theirs between the axle and the gas tank which seemed to work well (one muffler, dual inlet/dual outlet). I typically place them behind the driver and infront of the axle. Lots of room there to tuck them up and route the pipes.
what mufflers are you going to run? if not sure, there are a number of sound comparison videos online. of course, what sounds good on one ride may not get same results on another. 2.25" plenty for your motor. no matter what you run place as close as possible to rear axle. still need to place interior insulation from firewall to through trunk.
short bend tubing, from the mufflers exiting in front of the wheel. Hello, I had the option of doing plenty of different exhaust routings when I got a set of long Corvette tubular mufflers. The mufflers fit perfectly under our 1958 Impala. But, the muffler shop owner gave us too many options for exhaust routing. So, he laid them out and we chose the short elbow bend units first. Now, the chrome tips would come out in front of the rear wheel. That looked great like a modified Altered Coupe, yet it was perfectly legal for street use at the time. So, for a week, I drove around with that set up. The Corvette mufflers by them selves were like having open exhaust. The short curved pieces gave it a little more of a quiet sound, but still rumbled. Which was ok for show. But, the sound was too loud inside and the fumes started coming in when we opened all of the windows. (now, all exhaust ends cannot be in front of the rear wheel. DMV rules) The next ones we were offered at the muffler shop were the "above the rear axle" and out to the side, in back of the rear wheel. Now, it was definitely quieter, but we could still hear the sound all of the time. The sound was pretty good as we drove down the street and anytime we drove into the drive-in restaurant parking lots, it was definitely a “head turner.” But again, it was loud all of the time and we still could get fumes when all of the windows were down, especially during the summer time cruises. So, one last choice was offered to us. Impressive and legal at the drags in the Stock car class. All open outlets had to be closed, so the shorter pipes behind the wheel supposedly gave us an advantage. YRMV Jnaki Since the over the rear axle pipes were already in place, the muffler guy modified the side ways pipe and made it go straight out of the back, under the rear bumper and had new chrome tips. Like Goldilocks, it was just right. Still sounding great, but now, at cruising speed and certain rpms moving slowly or medium speeds, it was quiet. So, a cruise into foreign drive-in restaurant lots was a sleeper sound. I could make it rumble with the longer pipes out of the back, but it was fun when folks asked if I had a bigger modified motor under the hood. Or, as we drove all over So Cal, the sound was just perfect for conversations inside with and without the windows up or down. So, I would recommend the over the axle and straight out of the back under the rear bumper as the final set up for fun sounds and no fumes. As far as performance, the exhaust over the axle is just as good as any exhaust outlet open, straight down from the header pipes. The time at Lion’s Dragstrip were in the .02 to .03 difference. (15:02 versus 15:03, usually, depending on a good start.) With the Corvette mufflers and rear exit pipes, 14.68 but, I had on the real Bruce Slicks for traction off of the line…) The Corvette mufflers qualified in the stock class due to it being on the Chevy dealer’s parts list and anyone could buy them stock. (no actual header pipe systems were allowed) thanks, @themoose ...
Exhaust gases cool as they travel down the pipe, resulting in less volume. Since the muffler is a restriction, the farther back from the engine the muffler is, the less back pressure is created due to the cooling and contraction of the gases. This can also mean the system will be quieter with the mufflers farther back. The actual HP changes due to the location of the muffler is related to the backpressure created. A restrictive muffler located close to the engine is going to drop the HP more than the same muffler located farther from the engine. The location of a free flowing muffler will have less effect.
The Jalopy Journal
