RPM resonance. Front hood, dash?

[gvr4ever]

My car is close to damn near sorted. I have a 2200 RPM resonance that I just can't find.

Anyone else have this problem? I suspect it could be the newer exhaust, but near the same time, a lightweight ACT flywheel was installed and a Greddy 6 puck clutch.

A worn rear hood mount that had play was replaced and the front rubber bumpers are currently adjusted tight. No obvious play.
I really want to find and deal with the issue, but I just can't find the source.

 

[gvr4ever]

I suspect it is the new CM exhaust. Not sure why the older 2.5" exhaust didn't have the same issue, but different material, thickness, whatever. Next step is a resonator. Anyone have suggestions? I went from a oldsckool Magnaus exhaust and didn't have this issue. but when changed to a CM exhaust. I had the largest muffler installed available, from the 3" exhaust with stock looking dual tips. Overall, it has a good sound and doesn't drone, but I'm getting a very obvious resonance it the 2200 PRM range.

Anyone else running a CM exhaust experiencing the same thing?

 

[ggsxkid]

Yes, I have the exact system 3" with dual tips. I'm just chalking it up to the regular "mods have trade offs" mindset. If I'm not mistaken I get a nice vibration/shake in the rear view around that rpm as well. But I also have the boostin fab rear engine mount, and roll stop/crossmember and I noticed even more vibration with that as well obviously haha.

 

[gvr4ever]

Mods do have trade offs. I just set all my AGXs to the softest setting and I like it better. Still a firmer ride, but a little more road friendly. As far as the vibrations, I really don't like it. Kind of makes the car sound broken, when it's not. Just wondering if a pass through resonator in the stock location would take care of the issue. Even if I can fix the resonating issue, I still have a chatty puck clutch, but I'll just deal with that because I have a lighter clutch pedal compared to any performance street clutch I've tried. Gobs of space on the floor too.

 

[turbomister2]

Mods do have trade offs. I just set all my AGXs to the softest setting and I like it better. Still a firmer ride, but a little more road friendly. As far as the vibrations, I really don't like it. Kind of makes the car sound broken, when it's not. Just wondering if a pass through resonator in the stock location would take care of the issue. Even if I can fix the resonating issue, I still have a chatty puck clutch, but I'll just deal with that because I have a lighter clutch pedal compared to any performance street clutch I've tried. Gobs of space on the floor too.

I have to agree with you, my car rattles like no tomorrow and I always say “I should’ve just left the car alone it was such a nice ride “ especially at a light I feel like everyone can hear my “broken” car😂

 

[ggsxkid]

I have to agree with you, my car rattles like no tomorrow and I always say “I should’ve just left the car alone it was such a nice ride “ especially at a light I feel like everyone can hear my “broken” car😂

Man all of this is the truth. My car was stock when I bought it and not half bad lol.

 

[gvr4ever]

Stock Galant VR4s did have a quality ride to them for sure. My only complaint, would be the stock IC. Heat soak city after one decent run in the summer. I personally always thought the stock suspension was too soft and rode too high.
I'm sure high end coilovers would offer a better ride than H&R springs and AGX shocks, but I just couldn't justify spending that much for a road toy car. As is, it feels closer to how an early 2000s WRX could handle, compared to the original boat suspension.

I'm going to work with a local exhaust shop this week and discuss resonator install cost. I'll report back if I go for it, and if it works.

 

[turbomister2]

Yeah I actually sold my coilovers to keep my agx so I had a comfortable ride

 

[gvr4ever]

Yeah I actually sold my coilovers to keep my agx so I had a comfortable ride

Do you not like the AGXs? Now that I have them on the softest setting with H&R springs, I'm liking them more. Still have to watch out for pot holes and bad road bumps, but they feel more road compliant on the softest setting.

 

[gvr4ever]

I don't want to come across that modding is bad, just that it can have street after effects. For me, I'm willing to deal with a chatty Cathy clutch, but I'm currently unhappy with the RPM resonance. Everything is a trade off. I fully enjoy the upgraded power and more modern tight suspension over stock. I don't regret modding my car at all. Stock might be comfy, but slow compared to today's standards of fast. 20psi makes a great street 4G63 toy. As long as you aren't chasing 1/4 mile times and just enjoying what the car can do, mods are good, when done right.

 

[turbomister2]

Do you not like the AGXs? Now that I have them on the softest setting with H&R springs, I'm liking them more. Still have to watch out for pot holes and bad road bumps, but they feel more road compliant on the softest setting.

I love them. It’s the closest thing to a stock ride quality but added performance benefits. No body roll or pushing out on turns when I get the opportunity to drive the car on the roads with out traffic

 

[ggsxkid]

I don't want to come across that modding is bad, just that it can have street after effects. For me, I'm willing to deal with a chatty Cathy clutch, but I'm currently unhappy with the RPM resonance. Everything is a trade off. I fully enjoy the upgraded power and more modern tight suspension over stock. I don't regret modding my car at all. Stock might be comfy, but slow compared to today's standards of fast. 20psi makes a great street 4G63 toy. As long as you aren't chasing 1/4 mile times and just enjoying what the car can do, mods are good, when done right.

All good I totally understand. I'm at stock boost level right now. But 20 psi and some light suspension work is all I plan for mine as well. OEM + if you will. I feel like with today's current issue for drivetrain parts it's the best way to enjoy these cars.

 

[gvr4ever]

All good I totally understand. I'm at stock boost level right now. But 20 psi and some light suspension work is all I plan for mine as well. OEM + if you will. I feel like with today's current issue for drivetrain parts it's the best way to enjoy these cars.

That is a very realistic goal. As long as you don't plan on clutch dumps, high RPM aggressive gears slams, I'd dare say that can be done reliable(ish), depending on the build and supporting mods. The engine short block can take it for sure. Head might need some work depending on your RPM goals. I had mine rebuilt mine about 5 years ago. Just reseated valves, new valve stem seals. Currently no dirty exhaust, stock RPMs, just runs clean...

 

[gvr4ever]

I didn't make it to the exhaust shop this week. Got smacked with life and ran out of time. Planning on going next week.

 

[gvr4ever]

Update: Went to the local exhaust shop, that I trust and it must be an annual vacation or something. They are closed to the 12th. My car was stored for about 2.5 months for winter and I'm really looking forward to getting a resonator installed.

 

[gvr4ever]

Local exhaust shop wouldn't even order a stainless steel resonator, much less properly weld with stainless steel. My mechanic can, but it might take awhile to get in.

 

[ggsxkid]

Local exhaust shop wouldn't even order a stainless steel resonator, much less properly weld with stainless steel. My mechanic can, but it might take awhile to get in.

That's a bummer! I was really curious too. As time has gone on with my exhaust I'm more like an old man. Kinda wish it was quieter.

 

[gvr4ever]

That's a bummer! I was really curious too. As time has gone on with my exhaust I'm more like an old man. Kinda wish it was quieter.

Ya, I'm getting annoyed, but I'll keep looking. I'm older and in the same place. I want a quiet exhaust. Not only to get it in the same place as a normal old school luxury sports sedan, but also to be a true sleeper that doesn't draw attention. The wheels are stock with 205-55-15 performance tires, and the exhaust tips look stock enough. Just got to make it sound closer to stock.

 

[gvr4ever]

I called Circle City Speed Shop out of Brownsburg today. They can do the work, but it will probably cost $300 (2 hours labor) plus the part. They have no problem with me ordering whatever I want.

I was looking at this one. https://www.summitracing.com/parts/vpe-1793

Wanted it installed where the stock resonator heat shield is. Anyone have any suggestions on a different one? I really don't know much about resonators.

Last exhaust was a Mofugas 2.5" exhaust and it droned at highway speeds, but not in town. Now I have in town resonating issues and I don't have a drone problem, but annoying sounds right where I need to cruse at.

 

[slugsgomoo]

To get rid of a specific RPM drone, you're better off adding a Helmholtz resonator than a straight resonator