Re: Current resonator opinions Reply #20 – July 01, 2019, 04:46:47 pm Quote from: craneman – July 01, 2019, 04:13:20 pmWere these gas engines with special exhaust? That would make sense. Our muffler cans from the factory would pretty much eliminate that issue. The diesel truck drivers put on straight pipes and were legal but sure are a problem with a Jacobs brakeThe 40s were all diesels, American Eagles, Dreams, and Traditions. Quote Selected
Re: Current resonator opinions Reply #21 – July 01, 2019, 06:26:23 pm I wondered about that backpressure thing. Maybe it's time to add that resonator. But then there is the log truck example so ?? Quote Selected
Re: Current resonator opinions Reply #22 – July 01, 2019, 07:38:11 pm Quote from: Jack Lewis – July 01, 2019, 04:06:13 pmIn the late 90's when California Hwy Patrol tried to get any motor home over 40 feet off the hwy we had inventory that was 4-5 inches over the 40 ft limit. Fleetwood tried to shorten the exhaust by those inches and was stopped by the engine mfg saying they needed that precise length. They said it needed a precise amount of back pressure from this length according to the eng mfg to run properly. I never knew if this was true or not. They said the mfg would not honor the long engine warranty if they modified the length. My rv has the replaced resonator and have wondered if this makes the engine run hotter or different from it's original design.It might make a difference if it's a full mechanical engine. Just like going full airflow on a carbureted petrol engine and not increasing the fuel flow. It can lead to a too lean condition. Electronic injection however will compensate. Manufacturers are odd ducks though. Just look at the flat towing situations where there was a 180 change on OK for towing to no towing with no mechanical change. Quote Selected
Re: Current resonator opinions Reply #23 – July 02, 2019, 10:28:46 am The turbo creates all the back pressure you need with straight pipes. Quote Selected
Re: Current resonator opinions Reply #24 – July 02, 2019, 11:04:46 am Let me get this right, pressurizing the intake creates exhaust back pressure ?? Quote Selected
Re: Current resonator opinions Reply #25 – July 02, 2019, 11:09:14 am Quote from: Olde English – July 02, 2019, 11:04:46 amLet me get this right, pressurizing the intake creates exhaust back pressure ??Naturally. You are compressing the air and feeding it to the intake so the exhaust has to spin the hot side of the turbo and it can't do that for free. Has to be a little back pressure created but it cuts a lot of the noise compared to a straight pipe.Pierce Quote Selected
Re: Current resonator opinions Reply #26 – July 02, 2019, 11:21:00 am Perhaps look at it a slightly different way.The turbo wheel in the EXHAUST has restriction for the exhaust-- certainly more than if it weren't there. Quote Selected
Re: Current resonator opinions Reply #27 – July 02, 2019, 11:24:01 am To clarify a little more,the turbo has 2 wheels,an intake and a exhaust. Quote Selected
Re: Current resonator opinions Reply #28 – July 02, 2019, 02:16:52 pm Seems like a free flowing exhaust will create a larger exhaust pressure differential before and after the turbo, thus increasing turbo efficiency, right? Always heard less back pressure on diesel the better at least on older diesels. Quote Selected
Re: Current resonator opinions Reply #29 – July 02, 2019, 02:21:31 pm Quote from: Chuck Pearson – July 02, 2019, 02:16:52 pmSeems like a free flowing exhaust will create a larger exhaust pressure differential before and after the turbo, thus increasing turbo efficiency, right? Always heard less back pressure on diesel the better at least on older diesels.The same for gas engines. The purpose of headers was to create a venturi effect with the primaries to scavenge the exhaust. Quote Selected
Re: Current resonator opinions Reply #30 – July 02, 2019, 02:45:19 pm Quote from: craneman – July 02, 2019, 02:21:31 pmThe same for gas engines. The purpose of headers was to create a venturi effect with the primaries to scavenge the exhaust. With the exception being two stroke bikes and the large expansion chamber required. Guess it's from the lack of valves and exhaust cycle.... Quote Selected
Re: Current resonator opinions Reply #31 – July 02, 2019, 04:18:37 pm The less restricted any hot high speed gas flow is before and after the turbo. The more of it's energy can be transferred to spinning the turbo. My (now gone) 2014 Mercedes 4 cylinder 2 liter Diesel had two small turbos to help with Turbo lag. That little 2 liter Diesel diesel had 208HP @ 369 Lb/Ft. and returned over 40 MPG. It had a max output of 104HP/184Lb/Ft per liter to our M11's 40HP/131Lb/Ft per liter. Pretty impressive little diesel that Mercedes had. That's like our M11 having 1144HP@ 2024Lb/Ft torque. It would be death to the Allison transmission. Quote Selected
Re: Current resonator opinions Reply #32 – July 02, 2019, 06:26:17 pm I just put the Jones big one on...problem is I did two things at once...I discovered the Economy mode on the trans..so I do the exhaust and love the sound..yeah it's beefy..but it is nice...now this is my performance gains I think I feel...I now drive in E mode..and this last 300 mile round trip..I set cruise at 65 and it held it's speed uphill better...now I'm confused...was it E mode or exhaust upgrade. It might be both..it just seems to pull better. It seems that before it would fall quickly to 60 then 55..but now 65 all the way up... Quote Selected
Re: Current resonator opinions Reply #33 – July 02, 2019, 06:42:37 pm Mike, Just put it back in the performance mode and use the ole butt dyno to compare with the old muffler. Post up some videos with sound. And for those about to change. Perhaps some before/after videos. You tube has proven useless for comparisons. Quote Selected
Re: Current resonator opinions Reply #34 – July 02, 2019, 08:22:26 pm Slash cut exhaust tip will reduce velocity pressure losses also due to exit area sqaure inches that's why the big rigs have a slash tip or slashed elbow. If you look at your exhaust cfm flow on the Donaldson site engine charts. At full load hp you may have a 300 mph leaf blower eating up 3+ hp based on velocity pressure alone, let alone the lousy fitting coefficient of a straight abrupt exit. Quote Selected
Re: Current resonator opinions Reply #35 – July 02, 2019, 11:14:17 pm I just found the Ft. Knox of muffler information with cut aways, dozens of photos, etc. Everyone owns me a beer for this one and no cheap stuff.Techtips - Exhaust Systems: Mufflers and Catalytic Converter GuidePierce Quote Selected
Re: Current resonator opinions Reply #36 – July 03, 2019, 08:42:37 am Thanks, Pierce. Nice primer on muffler types. Brings back good memories of playing around with various mufflers on old cars.I had a 1969 Camaro Z28 that was ordered from the factory with dual chambered exhaust pipes. No mufflers - just straight through dimpled pipes - and it was street legal. Produced a beautiful sound from the little 302 cu in engine. Was considered by many to be one of the best sounding factory exhaust systems of the day.One thing to watch for when selecting resonators for your coach: check the I.D. of the inside tube. In some cases, the inside pipe is smaller than the connection stubs on the ends. If you are paying for a 5" in & out resonator, be sure it is 5" all the way through. Quote Selected
Re: Current resonator opinions Reply #37 – July 03, 2019, 09:21:32 am Quote from: Pierce & Gaylie Stewart – July 02, 2019, 11:09:14 amNaturally. You are compressing the air and feeding it to the intake so the exhaust has to spin the hot side of the turbo and it can't do that for free. Has to be a little back pressure created but it cuts a lot of the noise compared to a straight pipe.PierceTANSTAAFL, or for you non Heinlein readers, there ain't no such thing as a free lunch. But there is thermodynamics. Turbo chargers recover energy from the waste heat. Here's a picture showing the temperature difference between exhaust in and exhaust out of a turbosupercharger. Quote Selected
Re: Current resonator opinions Reply #38 – July 03, 2019, 10:07:02 am Quote from: Old Toolmaker – July 03, 2019, 09:21:32 amTANSTAAFL, or for you non Heinlein readers, there ain't no such thing as a free lunch. But there is thermodynamics. Turbo chargers recover energy from the waste heat. Here's a picture showing the temperature difference between exhaust in and exhaust out of a turbosupercharger.That's also why you install the EGT probe a maximum of 6 inches from an exhaust port. Otherwise, the reading will have to be corrected or it will give a false sense of security.My 2-cycle articles have made me a stranger in a strange land so not that illustrated. P Quote Selected
Re: Current resonator opinions Reply #39 – July 03, 2019, 11:06:14 am Quote from: Pierce & Gaylie Stewart – July 03, 2019, 10:07:02 amThat's also why you install the EGT probe a maximum of 6 inches from an exhaust port. Otherwise, the reading will have to be corrected or it will give a false sense of security.My 2-cycle articles have made me a stranger in a strange land so not that illustrated. P I'm glad I didn't know about Foretravel using the Detroit 2-strokes. I might have stretched the budget into purchasing something I can't afford, just so that I could live with one of those engines. I like the idea of a uniflow engine, not to mention recovering some of the waste energy with a turbo charger. And the sound! On the long road to the SIATA Spring, we passed on a V-12 Jaguar, once again because of the sound. We used to own a 1964 MK X, an all original car that I rebuilt the engine on after I finished the XK-120 for a friend. Beer is a gateway drug. "Art, you like projects. How would you like to put my XK-120 back together again?" "Oh, yeah, did I tell you I took it apart 12 years ago?" said Don Jesseman.Don Jesseman playing the great room at Councilor Burton's home.Don Jesseman on the Piano - YouTube Quote Selected
Topic: Current resonator opinions