I know posts about exhaust sound fixes are annoying but I don't have the time or money to experiment. My specifics:
I have a 1999 Z24 with the polished aluminum AEM short ram intake and the Mangnaflow dual catback system #15762. I have no other engine mods. Since it is a dual, there is more surface area under the car and it resonates into the passenger compartment a lot. I like the sound over 2500 RPM. Under 2500 it starts to get really low pitched. If I step on the gas and open the throttle up under 2000 RPM it sounds like the whole car is full of subwoofers... a horrible droning noise. Because of this I have been driving my car in the higher RPMs to bring the pitch up to a more tolerable level. However, I don't have great gas mileage and it is much louder outside the car when I force myself to drive like this.
Here's a pic of the exhaust layout
http://www.magnaflow.com/02product/parts/15762.jpg
Here's the install PDF
http://www.magnaflow.com/07techtips/pdfs/15762.pdf
What would you recommend doing to the exhaust to eliminate the loud droning noise below 2.5-3k RPMs while still getting the kick at higher engine speeds?
Thanks in advance
- Ken
'99 Z24, Manual
my friend put the 18" resonator that magnaflow used to sell on his and it sounds 100% better
unfortunalty they do not sell the 18" anymore , only have 14" last time i was on the site
I checked and it doesn't look like they make resonators at all anymore. I heard about the magnapacks a while ago but they are discontinued.
'99 Z24, Manual
check magnaflow distributors... some still have em...
esle get the largest thing you can fit under there from wherever... i have a 30 incher, so i know that fits for a fact.
Quote:
What would you recommend doing to the exhaust to eliminate the loud droning noise below 2.5-3k RPMs while still getting the kick at higher engine speeds?
Like they said get a resonator. I have a dual exhaust setup and really it's not that bad of a sound. Have you tried driving in those low rpms but in a higher gear? It might be quieter....
www.kronosperformance.com / 732-742-8837
Just to double-check... will a resonator eliminate more of the low-pitch sounds or does it reduce the total sound (at all wavelengths) more equally?
'99 Z24, Manual
Ken Rushia wrote:Just to double-check... will a resonator eliminate more of the low-pitch sounds or does it reduce the total sound (at all wavelengths) more equally?
the resonator eliminates the buzzing, reduces total sound, and creates a lower pitch.
I was a retard, and now I'm permanently banned.
Sounds like a resonator isn't what I want then. It's the low (<200 Hz) sounds that I want to eliminate.
'99 Z24, Manual
A resonator will get rid of the droning to a large degree, and clean up the sound while lowering the overall volume of your exhaust, if you don't want it real quiet, get a shorter one, but get at least a 12-14" to make it worthwhile.
15.3 @ 89.97mph, 14's on the way?
For Sale:
'01 SFGT springs $50CAN
Getrag '00-'02 2.4 8000kms $800
No event I don't want it high pitched. I just don't want it low pitched. It seriously sounds like 3000 watts of out of control sufwoofers when I open up the throttle at lower RPMS... like when I go up a hill at 55 MPH I need to downshift to 4th or 3rd gear or my head will explode. Ironically it is much louder outside the car at the higher RPMS. Somehow the low tone resonates through the car while the higher tone gets shot out the back end.
I'll look at the resonator options a bit more... I just don't want to pay someone to mod it and have it still suck and have my $$$ exhaust ruined.
'99 Z24, Manual
it sounds like your complaining about the droaning vibration sound , thats what the resonator will knock out of the system as well as alot of the beeezz in a tin can sound when cold
largest you can find then.....
also with dual exhausts... you might like the look, but two mufflers is just asking for the deep tones... not sure if you are more performance or looks oriented, but if possible ditch the duals and that alone will cut sound down.... your call...
other than that... the larger the resonator, the more overall sound absorption.
if it is resonating inside the cab, your tail pipes may not extend quite far enough past the bumper [ just my .02]
035spdecotec johnson wrote:if it is resonating inside the cab, your tail pipes may not extend quite far enough past the bumper [ just my .02]
I really doubt that's the problem, just my opinion.
15.3 @ 89.97mph, 14's on the way?
For Sale:
'01 SFGT springs $50CAN
Getrag '00-'02 2.4 8000kms $800
Ken,
Let me give you my experience.
This was done last Friday up untill this Monday
On Friday I did my cat back exhaust with Dynomax Super turbo part # 17733 & 17748, Dynomax’s resonator 28-inches long #24214, 2.5in mandrel piping all around (I'm S/Ced) with GM quad S/S tips.
After it was done, I cranked up the car and the exhaust's tone sounded exquisite. Outside it had a excellent sound (TY big I-4). Rev it up and it sounded like a Lotus Elise. I drive it about 5 min out with windows down and notice the exhaust the tone is getting louder (bass note). I roll up my windows thinking it would get better (quieter on the inside) and the bass tone was droning on the inside as I gently accelerate. After 20 min of driving, I got extremely tired and worried. I made a bad mistake. This was by no mean what I wanted. It was to much, my Monsoon radio which normally is strong, sounded weak with these mufflers. My mirror vibrated and when I went out with people I had to raise my voice to be heard.
Not only that, I immediately felt a tremendous torque loss, top-end was not improved either. Took it on the highway, the muffler quiet down a bit, (not stock quiet) but it did not drone. To top it off, my gas mileage dropped tremendously with one tank I did 190 city miles when I normally do 230 city miles (full to 1/4 tank left).
All in all I screwed up big time!!!!
What I did on late Monday was install back my stock mufflers while still retaining the Dynomax glasspack, all the 2.5in mandrel pipes and GM quad tips. I started it up and once again total quietness (similar to a Saab’s Ecopower I-4 tone), but get this, the huge resonator made the tone sound absolutely perfect for me, it was a little louder then stock too (few decibels). It always sounded nice stock, but this time it sounded meaner, a girl stopped me at the beach and told me my car sounded nice
. Best of all my Torque and HP felt wayyy better then when I had the Dynomax mufflers or when I had my stock piping aswell. My gas mileage is back to normal, as I write this, I dunno if it improve over stock but, yet... .
Best of all, I am not going crazy with the drone.
According to 4 exhaust shops, resonators all it does is remove the raspyness, it will not reduce the noise. You will get a little bit more of a base note, but the drone will remain, that is if you have muffler that is loud.
I did my research, and I everywhere I heard that the Dynomax super turbo is the quietest around. Magnaflow is more bassier. So I took Dynomax, boy was everyone wrong. I thought it was just a few decibels over stock, wrong more like a lot lol.
Hey it was costly mistake, the exhaust shop and I did cried when we took the Dynomaxs off, but it was either my wallet ($$) or my sanity. I chose sanity.
Later on I will put it on the dyno again, to see how much I gained. I know right now I am better then stock and wayyy better then with the Dynomax muffler.
I'll keep you all updated.
Sorry it was so long, but just sharing my costly experience.
>>>For Sale? Clicky!<<<
-----The orginal Mr.Goodwrench on the JBO since 11/99-----
well on my experience....
i dont have drone, even when letting off the gas and at highway speeds.
my pipe size is 2.25 throughout.
i run
1 30 inch magnaflow XL powerpack as a resonator
1 5x8 oval magnaflow muffler
1 20 inch magnaflow resontaor 4 inch round universal.
you can not hear my exhaust at idle, you can not really hear it on acceleration.... you do however hear the engine and intake, but no exhaust. plenty of my friends locally have gotten fix it tickets, and i prob would have two.
i;ve went through 7 total exhaust setups in less than 6 years trying this and that.
the more packing materials used, the more sound absorption there will be. pipe size also have ALOT to do with the sound of something.
i dont like the whole drone/downshifting noise deal some live for, especially on manuals.
sure it draws attention to your car, and its fast and furious like, but where i grew up, the only thing that was to make the noise was the engine itself. so never really caught onto the fad.
just my experience as well. also back when i was learning about pipe sizes, i did dyno higher with 2.25 over 2.5.... might have only been 2-3 HP, but velocity plays a large deal in exhaust making power.
also to note, at one point and time, and recently at that, i had the entire REAR section of the exhaust welded to the frame. literally i was told when lester finished, to come hang on it. it supported over 300lbs with me and lester pulling on it. then i had an extremely low amount of sound transfered to the cabin if any through all the gears.....
now i have 2 of those points 5 points on hangers....
usually the softer the mounting point, the less vibes that are transfered. however with as much packing all three of my mufflers have, there still really isnt much difference.
i;ve just always been taught extremely loud cars and like fighters who brag too much...the majority dont have the power to back it up
Thanks for the stories guys. My car had stock exhaust with a magnaflow round muffler when I bought it. It sounded okay but I never had a stock exhaust so I don't know if it was better. It rusted out though and the pipe split in two and fell off on the road. I did a lot of research myself and wanted something stainless so I wouldn't have this rust through again. Magnaflow is what I went with because I heard a lot of good things about them and I could get a system shipped next day. I got the Magnaflow dual system because it looks better. I knew a single had more power but I thought it was only like 5-7 HP difference. Sadly my full stainless exhaust is already covered in rust
definately not what I expected.
I'm going to dynamat the entire car first and see if that helps. That brings me to another question: is there any kind of heat resistant sound insulation I can wrap the exhaust pipes in? I want to try other things before I start tearing apart my exhaust that cost me $760 and a lot of sweat to get.
In the meantime, I'm still interested in hearing what other people have been happy with for exhaust systems on the 2.4L... and especially any advice from people with the same Magnaflow dual and what they did to fix the problem.
- Ken
'99 Z24, Manual
only one thing.... i;d refrain from wrapping the pipes for your location....
NH....salt snow ice.... unless the pipes are coated, or stainless steel for sure, wrapping in a NH north north east winter can produce rotted pipes quicker.
singles dont necessarily have more power, but for the purpose of exhaust are more efficient. these cars only need one exhaust exit. 2 and 3 exits are for show. but your choice.
look at designengineering.com or their stuff on summit, DEI, or thermo-tec or thermocool...
all have padded insulating material thats heat reflective.
