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Update! Newbie needs exhaust help... did I make an expensive mistake?
Being a newbie, I'm not sure if this is the correct forum to post in, but please move if needed. I just installed full 2 1/2 dual exhaust (no h pipe) on the 68 Cutlass. stock 350 2 barrel, 2 speed. The drone is unbearable. I tried 2 diff mufflers. The installer insists an H pipe will not help. I got a second opinion, and this very experience builder took one look at it and said the exhaust was very large for a stock 350. He said it was like driving a school bus. He was exactly right. He suggested 2 1/4 max, with h pipe and flo pro muffs. He said he guarantees there will be no drone. I asked if he could try to save what I have, and he said not possible. I think what he says makes sense. Any opinions would be appreciated. Sorry to lose the money I just put in, but the car cannot be driven as is. Thanks
Ron
Last edited by Ron68; September 30th, 2018 at 09:51 AM.
Every driver has a different ear for exhaust loudness and tone, I would say 2 " pipe would be more than enough with a decent Turbo style muffler for a stock 350 2bbl 2-speed
If your kicking around the idea of more performance down the road, than 2 1/4 would be the way to go.
Many guys like the tone of the Dynomax mufflers on the street .
Good luck with your decision!
Eric .
The installer recommended the system. He did many kit installs for me with no problems. I asked for a good sounding quiet exhaust. We tried thrush welded and dynomax turbo. I have an appointment next Thursday at the other shop. He comes very highly recommended for the classic stuff. I will definitely report back with the results. I appreciate the responses.
I'd do something other than cutting it out...that sounds crazy.
mine has h pipe and dynomax...very little drone.
my dads car same flowmaster delta 2 no drone.
it has stock manifolds. I'm expecting it to stop the drone. I made sure this time to be clear as to what I wanted. He promises there will be no drone. He seems very confident that I will be happy with the result.
Go put the H pipe in it before you scrap the system you just paid a lot of money for. You have good mufflers and I don't think a 2 1/4 inch system is going to sound that different. I agree you only needed a 2 inch system with your current engine. If that doesn't work to suite you then change the tailpipes to 2 inch.
Go put the H pipe in it before you scrap the system you just paid a lot of money for. You have good mufflers and I don't think a 2 1/4 inch system is going to sound that different. I agree you only needed a 2 inch system with your current engine. If that doesn't work to suite you then change the tailpipes to 2 inch.
This sounds like a common sense way to proceed -- what do you have to lose? It can't cost that much to fab up an H-pipe for the existing 2 1/2" system, so why not give it a try? If it doesn't help, you can always go back to Plan A and replace the entire exhaust.
I totally understand what you guys are saying. There's a little more to the story. Unfortunately the guy who installed the current system seems to be taking it personally that I am not happy with it. Both he and I are frustrated about the situation. He spent at least 12 hours on this job (he broke the manifold studs 5 times), and does not even believe there is a problem (stating that I'm too old). He even refused to come for a test drive until I really pleaded with him. During the test drive, we had to yell at each other. He said that he thought it was acceptable. I offered to pay extra for an h pipe, and he flat out refuses as he knows for a fact that it will not help. I don't want to destroy the relationship, as he is very fair with pricing for the easy stuff. I would rather go to someone who has more experience. I don't like throwing away money, but I just want it done right. The new installer is one of those guys that has a little shop with no advertising, and is always busy. He had a couple exotics in his shop when I went to see him. I have a lot more faith in him. Maybe we can save the mufflers...
This should have been your first clue to find someone else...
(stating that I'm too old).
And this should have been the second...
I don't want to destroy the relationship,
I'm pretty sure he has already done that.
Maybe we can save the mufflers...
Again, the mufflers are likely the problem. Keep the pipes, get Walker Dynomax Turbos (if you want a musclecar sound) or Walker QuietFlow (if you want stealth).
WHICH "Dynomax"? Super Turbos? Ultraflo? Big difference. If these really are the Super Turbos, then all I can suggest is changing to the Walker QuietFlows. I've got Super Turbos and 2.5" pipes on pretty much everything I own, and they don't drone. I'll add that I just turned 60 this year, so I'm sensitive to the noise also. Of course, my wife accuses me of having hearing problems.
I have the Dyno Super Turbos on them now. Made absolutely no difference as far as the droning. I don't think the mufflers alone are the issue. I will talk to the guy and see if he wants to try a fix first, but I don't want a pieced together hack job. None of the pipes line up well, and I want it to look as good as the rest of the car. I know you guys are making suggestions to help save me $$$, but at this point I don't think I want to save this system. I can always keep this setup if I want to go to a 455 down the road..
Last edited by Ron68; September 21st, 2018 at 02:28 PM.
I just went through this with the Series 2 in my G body. Have someone else or yourself make sure it is sealed correctly at the manifolds. A leak there will make it extremely loud. It took me several tries loosening, moving around, and retightening to get the y-pipe sealed up. Also. check your y-pipe blockoff.
I think the guy that put the system on crapped all over you. I would probably tell him something small children should not hear. Maybe you should just buy something like a Pypes system that is make to fit your car.
I had my exhaust system replaced a couple months ago. The engine is a 350 4 barrel, originally two, otherwise stock. The pipes are 2.5" with H pipe and Xcellerator mufflers, No appreciable drone. I do get some at low RPM's when I shift into gear or sometimes while stopped at a light. regular driving at all speeds on or off the highway, no drone.
I had a 72 Cutlass convertible that I converted to duals with generic turbos from the muffler shop. Initially had no H pipe and it had a significant drone. Took it back and they installed the H pipe and it was drone long gone. It is your car so do what you want. I sure the heck would spend the money on the H pipe but it sounds like your mind is made up.
Last edited by redoldsman; September 21st, 2018 at 04:01 PM.
I run a 2 inch Midas system on my Chevy. No crossover at all, I believe it's called "custom duals" lol, with Raven Flowmasters. Holding up ok after 16 years, small tick leak. They're a little loud but I don't mind them. I'll restore it with Gardner some day.
Thanks Guys,
There is full factory sound deadening in the car. I want to try the h pipe as well. I guess I can try to find a local shop to put one in, (all we have around here is a Midas, but I know they will charge a small fortune) but I'm concerned that I'm throwing good money after bad. I'm going through the frustration stage, where I just want it done right. The guy who installed the system really is a good guy, and wasn't trying to pull one over on me. I have used him for years for small fixes and complete kit installs. Never had an issue with his work. Just never used him to bend a full system from scratch. He is truly saddened that I am not happy with it. The new system will cost me just over $680 CAD (around $500 USD), if I buy a kit, it will end up being more. Believe me, I don't like to burn money, but I think that 2 1/2 inch may be more than I need. Maybe I am too old! I just want it quiet. I have other cars for the go fast part. I want no drone what so ever, not even a little! If that means going back to factory sized exhaust, then I'm all for it. After having many toy cars, I have learned that the time I enjoy most is being behind the wheel. If the car isn't comfortable to drive, then I won't drive it. I will let you guys know how it turns out. I call this a lesson learned. Hopefully my experience can help others. Thanks everyone.
Some exhaust guys build you what they think you will like, I'm sure the guy that built the system, didn't do it just to make you unhappy and waist your $$.
No point in throwing more money into a system your not happy with, especially when your frustrated to the point where nothing could change the outcome in the mind set.
I think a 2" system will bring back some lost torque in your 350 for starters , a set of mild turbo's should keep it sounding really nice without the drone, no need for an H or X pipe to get in the way of things either.
$680.00 CAD is a decent price to make you happy, while eliminating the continuous frustration of having to cut , weld and piece pipes that will end up looking butchered, unless the guy is a wicked at pipe swaging and welding a tight seam.
This is a good thread for many guys new to the hobby, a good read through and once an update is revealed , it will save others time nailing down what they want in an exhaust for cruising and enjoyment
I hope you get the sound your after this time!
Eric
Last edited by 76olds; September 22nd, 2018 at 10:32 AM.
Eric, I totally agree with you on the 2' system but disagree on the H pipe. I am basing that on experience with the 72 Cutlass I had. Just my experience.
I think before cutting up a brand new exhaust system I’d ask for some of your car buddies for advice, maybe even a ride and listen. No point replacing mufflers with new that you may not like any better.
Hey Folks,
Just wanted to update the post as promised. Just got back from the new install. I just wanted to share some pics of before and after...
Those pics were what I started with. These next ones are the first attempt...
These last pics are of the current setup...
I really like the way he tucked in the exhaust compared to the first install. I don't like the pipes sticking out the rear down low and out. I much prefer the cleaner look of the factory style.... This lower pic is how the first system looked compared to the new one above...
I did this install to get rid of the annoying drone the car had in the first setup. The new install is far nicer to look at, but did it solve the drone problem? Not really...
The drone is still there... A little better, but still very offensive. It is completely quiet at highway speeds and idle, but still very present during normal city driving. The installer is very confused and upset. We went thru the entire car looking for any place the drone could be hiding in. We checked every tranny/motor mount and clamp. I even went as far as pulling up the back seat and installing sound deadening material where I thought the sound was resonating from above the mufflers... pics below front start to finish showing original sound mat.
The installer is not happy and said he will continue to work with the system until we get this figured out. I started doing a ton of research and found lots of information online dealing with this very common problem. Two identical cars with exactly the same setup in every way can still sound very different. The installer asked me to come back this week to show me a car he just did identical to mine with no drone whatsoever. Then I came across some info that I really understood. Frequency. I tinker with electrics quite a bit, and have some basic knowledge about using equal opposing frequencies to cancel each other out. It also works with sound waves. I am now in the process of finding the offending frequency, and will design a 1/4 wave J pipe to see if it helps. There is a formula to calculate it. Or I can see if I can find an over the counter resonators to achieve the same effect. I will definitely update the post as to how it turns out. I would like to hear from anyone that has used resonators with success, and their placement in the system. Thanks.
Location: Edmonton, AB. And "I am Can 'eh' jun - eh"
Posts: 24,525
I put resonators on my 72 Cutlass S when I converted it to dual exhaust - for exactly the same reasons you have; drone at highway speed. I also have an H pipe about where yours is. The resonators make a big difference but still allows the exhaust to sound throaty at idle. My resonators are located in front of the exhaust tips. They're almost invisible from the side or from behind.
I have a 67 CS convertible. When I first replaced the stock 330 with a C headed 455 the exhaust was built around that configuration. The exhaust starts with Pypes down pipes to a Borla X cross over. The mufflers are Hooker Aero-chambers to Flowmaster mandrel bend ‘over-axles’ to Classic Chambered Exhaust short Powerstick as resonators all in 2.5” In 1967 they came from the factory with resonators at the exhaust tip and I wanted to stick to that theme. With this set up and X-pipe I still had drone. After install at the exhaust tips the drone went away. My goal was a performance exhaust but quiet enough when the top is down.
I used a stainless rolled slash cut tip.
Here's what I see - the shop apparently only wants to use the new style hangers. Those are much stiffer than OEM and will transfer more vibration into the floor pans. I would STRONGLY recommend ditching those hangers and using OEM style. I also again suggest 21" Dynomax super turbos... I have NEVER had a droning problem in an A-body car with Dynomax mufflers and OEM hangers (and 2.5" pipes).
Thanks for responses and the pics guys.
I will definitely consider the resonators at the tail pipes. From the research I've done, some people have had some success helping with the drone, others have not been so lucky.
Joe - I understand what you are trying to get at with the mounts, but I'm not convinced the real problem is vibration thru the mounts. Vibration is one thing, but drone is another. I had the original mounts on the single factory exhaust and the drone was still there. I'm pretty sure the dronemaster muffler didn't help.
I used my sound meter to find the offending frequency. It maxes out right about 132Hz. It seems to be a very common problem. I will be going back to the shop this week to fabricate a 1/4 wave resonator like J pipe tuning stub that will run along side the middle exhaust pipes. I don't just want to lessen the drone, I want to eliminate it. It has been used very successfully in many applications, and by various auto manufactures to completely eliminate any drone in their performance exhaust systems. Using the formula, you should be able to tune the pipe length to pinpoint and cancel out the offending frequency. I know I'm a bit OCD about this, but I will not give up until I'm satisfied. Will let you guys know the outcome...
Last edited by Ron68; October 1st, 2018 at 09:50 AM.
I've read most of this thread, and I'm running the dreaded Flowmaster mufflers (pn 42441) on a stock 9:1 350. Only change to the motor is a Holley carb. 2.25 smash bent pipes with no H pipe (cut it out like 10 years ago) that I bent and installed WAYY back in '99. I'd really like to hear your sound cause I've got no drone. I'd like it to be louder on the freeway lol. One difference from your car is I'm using the OE style hangers.......there may be something to that!
Actually, I will be installing a Holley in the next few days. 2 barrel of course. I won't get suckered into going 4 barrel. Did it before, and found very little benefit unless you build the rest to match. 2 barrels have that nice low end push.
Just in case you guys think I'm crazy and have no idea what I'm talking about, I can give a bit of background as far as my experience working on cars. I have personally owned and worked on over 30 cars during the last 30 years. I built my first BB chevy at 17 years old. I can fix nearly anything, not just cars. I know what exhaust drone is, and how it can drive you nuts. This drone is the most annoying I have ever heard in any of my cars. When 2 different exhaust guys are stumped, it's obviously not just in my mind. I'm not looking for silent exhaust, as I rather like the low rumble. Just want the drone gone. I am really shocked that no one here has had this issue on their A body. There are tons of discussions on other forums regarding this same issue. I have a friend waiting for me to come up with something to help him having the same issue on his 68 GTO (he has the pypes system). I'm very confident that I will solve this issue. I will do the calculations and have the guy bend it up and install. If I still had my hoist, I would do it myself.
I hope you get the drone taken care of Ron , I don't think anyone here is challenging your experience working on cars . I really think most guys just hear things differently.
Each of us have a different ear for what sounds like a good exhaust , then age comes into play haha.
I hope you get things straightened away soon with your exhaust.
I can't say I have read a thread such as this , however ... I'm sure this will come to mind prior to the next exhaust install for some.
Also , I'm sure this will help any new guys coming into the hobby, wondering how to dial in an exhaust system for Zero Drone !
Interesting thread without a doubt, I'm still following along, looking forward to the final outcome .
All the best!
Eric
September 20th, 2018, 05:22 PM
Update! Newbie needs exhaust help... did I make an expensive mistake?
). He even refused to come for a test drive until I really pleaded with him. During the test drive, we had to yell at each other. He said that he thought it was acceptable. I offered to pay extra for an h pipe, and he flat out refuses as he knows for a fact that it will not help. I don't want to destroy the relationship, as he is very fair with pricing for the easy stuff. I would rather go to someone who has more experience. I don't like throwing away money, but I just want it done right. The new installer is one of those guys that has a little shop with no advertising, and is always busy. He had a couple exotics in his shop when I went to see him. I have a lot more faith in him. Maybe we can save the mufflers...
and have no idea what I'm talking about, I can give a bit of background as far as my experience working on cars. I have personally owned and worked on over 30 cars during the last 30 years. I built my first BB chevy at 17 years old. I can fix nearly anything, not just cars. I know what exhaust drone is, and how it can drive you nuts. This drone is the most annoying I have ever heard in any of my cars. When 2 different exhaust guys are stumped, it's obviously not just in my mind. I'm not looking for silent exhaust, as I rather like the low rumble. Just want the drone gone. I am really shocked that no one here has had this issue on their A body. There are tons of discussions on other forums regarding this same issue. I have a friend waiting for me to come up with something to help him having the same issue on his 68 GTO (he has the pypes system). I'm very confident that I will solve this issue. I will do the calculations and have the guy bend it up and install. If I still had my hoist, I would do it myself.
