Yes, I did a lot of searching before asking this question. My question is the reverse of what most people are asking. I am not the original owner of my truck in the States. A previous owner replaced the exhaust and muffler with a Cherry Bomb glass pack and straight pipe. I have since had work done to the engine (replaced belts, water pump, distributor, sparkplugs & wires, and more...) and the truck is running like a champ. I work in the middle of the day, so warming the truck up in the late morning/early afternoon hasn't been a problem, BUT I am switching to an early morning shift and I don't want my neighbors to hate me (anymore than they already do ), so I was thinking of replacing the loud glass pack with an actual muffler. My question is: Will replacing a glass pack with a muffler affect my performance and will I need to have the truck re-tuned? Any suggestions on a performance yet mellow muffler is also appreciated. Thanks in advance.
I can't speak confidently for the Carry; however, I have worked on a lot of carbureted motorcycles and small engine things. A change to the exhaust is likely to impact the way that air flows through the engine, and particularly in the development of back pressure waves. If you're lucky, it can be negligible and you won't notice any ill effects. On some small bikes, it's required a complete readjustment of the fuel-air mixture, idle speed, and all that fun stuff.
Wire Fox, yeah...you're confirming pretty much what I was/am thinking. I'm NOT a mechanic of any sort, so any change is both time and $$$. The good news is that my neighbors haven't gotten a signed petition to remove me, yet.
> Will replacing a glass pack with a muffler affect my performance and will I need to have the truck re-tuned? It might improve performance. An exhaust that flows too free stands to not properly scavenge the exhaust. I have gone too big on some engines and had to go back smaller, I pretty much avoid cherry bombs and straight pipes or glass packs now on any vehicle. Another mechanic gave me "free" cherry bomb glass packs off a Saturn for my small 4x4. It actually hurt my performance enough that I went to Summit and bought the quietest 2" muffler I could find and tried to get a straight shot out the back of the vehicle without twisting around the rear axle as much as possible. 660 ccs is fairly small and too large an exhaust and you stand a chance of burning valves and such. Besides the seat of the pants feel when letting out the clutch and it not stalling, if you track your MPG, that will usually tell you how effective the exhaust upgrade was. The factory flywheel and exhaust were designed to operate together to give you the torque and response you need to pull a load. The thing I really dislike about a loud exhaust, besides not being able to hear google maps, is it can mask a problem that you should be able to hear, that you do not find out about until the part totally fails. Such as a bad alternator, hissing of a bad vacuum brake booster, bad idler pulley, or rear end whine. I like to put on a flanged exhaust system so I can easily change out a muffler or cat. converter when they rust out or get damaged. Though you would be better off leaving that to an exhaust shop since it ifs fairly easy to burn through exhaust pipe MIG welding with flux. If you ditch the complete factory exhaust and go all performance and gain 2-3% over stock, what will that provide, an extra 1 to 1.5 HP? On my rolling pieces of rust, I have found a good free flowing LARGE air cleaner with a clean filter delivers the best ROI. I have had real measurable MPG increases with that of 1/2 - 1 MPG depending on the vehicle.
I really appreciate your thoughtful and detailed response. I use my little truck as a daily driver (that wasn't the original plan, but it is way too much fun to drive) and my commute is brutal. I literally drive 75' from my driveway, then drop 200' in 1/8th of a mile, then from a dead stop have to climb 250' in less than a mile. You would think the return trip of climbing 200' in an 1/8th of a mile would be worse, but I have momentum that carries me more than half-way up the hill. All that to say that I need all the performance I can pull from the little truck every single day. The little guy has never faltered and has been rock steady on the temperature - planted firmly in the middle of the gauge. I would like to quiet the truck down, I'm not young and don't look to draw attention to myself, but I'm afraid of changing anything for fear of upsetting the balance that has been working so far. All your points are excellent and I completely understand them, I just need to decide if I take the chance to change the exhaust flow. A neighbor's complaint would definitely tip the balance. BTW, on a Dodge Ram 1500, years ago, I changed the exhaust and air filter to make it more free flowing. The truck sounded great, nice and deep throaty sound, but when it climbed a hill it overheated, which is what I believe you were referring to above with the comment about burning valves from deviating from the engine's designed operation. The fact that my little truck doesn't fluctuate at all with regard to temperature once warmed up, do you think that shows that it is working well with the current exhaust system? Again, thanks for your input and thoughts, I really do appreciate your input.
