I've got a 78 280Z that I'd like to quiet the exhaust down on. Here is the current setup:

Stock engine

MSA header

2.5" pipe

28" glasspack next drive shaft

Small turbo muffler at rear

Right now I get a loud resonance at around 2000RPM. I added the glasspack this winter hoping it would quiet it down, and it did, but not nearly enough.

I'd be willing to go back to the exhaust manifold if needed, but I would like it to breath almost as good as it does now (pretty decent high RPM power).

I'd rather not go to a stock setup, but I just might.

What are others running? What is the best combination that will keep the sound level down, but not choke the exhaust flow.

Any suggestions appreciated.

I built a custom dual exhaust. I have a header from Clifford InLine 6 Performance (I think it is the same as the old Nissan Comp header from the 70's) 3 into 2 configuration. Dual 2" pipes with two 4" round Magnaflow stainless mufflers in the drive shaft tunnel, and 2 small oval Magnaflow mufflers in the back (stacked), finished with dual stainless 2 1/4" tips. It looks really nice, and is actually not loud. The problem is it doesn't sound very good. It flows very good though.

Previously I had the same header, with dual 1 3/4" pipes and nothing in the tunnel with 2 small and 2 large glasspacks (1 for each pipe) in the back, finished with Ansa type exhaust tips. This used to sound very good, but over the years, it seemed to get louder, to the point where it was too loud. It was also quite restrictive as evidence by an inability to hit 6000 RPM in 4th gear with this exhaust vs. the one I mentioned above.

Anyway, I'm very interested to hear what others have. Also, if any of you can make a sound file of what you have for us to listen to, that would be awesome!

Garrett

For one thing, you say you have a glass pack, and there can be one of your problems....

The longer it is in use, the more the fiberglass packing burns up and it continuously will get louder and louder....

You might try one of the Turbo mufflers with the baffles, such as Flowmaster, Dynomax and some of the others are selling today, they have no glass packing to burn out ever so the tone should stay pretty even over the life of the muffler.

You say you have a small Turbo muffler, is it oval or round? Does it have more than one chamber?

One of these days, I'll find out how a Flowmaster 2 1/2 in, 3 chamber with 2 1/2 inch pipes and a 2 1/2 in bullet style race muffler for a resonator sounds.....Gotta get the car back together first...:stupid:

My 280Z sounds awesome from outside the car, and quiet over 3k RPM. Anything below 2500RPM resonates badley in the passenger compartment.

Pete

Thats good info. but what are you running? you dident say ! I am in a quandry myself over this same issue. I plan to install the header and 21/2" piping that I have but I dont want the car to sound like a Honda buzz bomb, I am looking for a deep sound and at crusing speed , 3grand , I want to be able to hold a conversation and not be hollering. I have been looking at the Dynomax also Flowmaster however it seems the latter is louder. I am also leaning to a glass pack behind the header as a resinater if this the way to go. I am looking into a super-trap, but in the past on big V-8s I dont like the funny sound . I have never heard one on a L-series engine. I am open to all suggestions. Thanks Gary:classic:

ive got a 2/1/2 inch system with a single resonator after the extractors and a glasspack straight through muffler at the tail. this is way too loud, big time 2000rpm resonance, difficult to hold a conversation. ill be putting on a proper muffler in the tail with baffles.

:classic: I am so glad that this was brought up and I hope others will add to the discussion with a few solutions to the resonance problem .:sick:

I've got 2.25" with single Lukey muffler at the tail and mine sounds great

But then again I'm one of those "young" people who like to have to turn up the stereo full-bull just to hear it over the exhaust note

At idle he sounds fairly lopey (compared to newer engines) and at 1000 he sounds smooth and nice. At 2000 if you are pushing any petrol in, it will resonate pretty badly (to the extent where you think you might be in a 4-cylinder! :tapemouth ) and then when you reach 2500 it's very quiet. 3000 he's loud and throaty and 4000 he's screaming and wanting more. 5000 he starts to feel a bit breathless and I don't make a habit of going that far, let alone beyond......

I can't talk on the highway, but I say if you want a quiet car get a Merc (that's Mercedes for you yanks, not Mercury)

I am running 2.5 pipe off a H&M Header set into a Hot Dog (read reasonator) just behind the gearbox and on to a glasspack at the rear.

I got some reasonance problems in the last few months when I changed the glasspack at the rear. I even got the glasspack swapped off and a diffrent brand fitted the reasonance stayed. This all happened on a system I have had no problems with for years. I took it back to the shop for checks, for leaks and body clearance checks. My reasonance was at low RPM. I serviced the air flow meter and everything returned to normal no reasonance (perfect).

"Sometimes we have to look out side the circle"

my 2cents

Good luck

Steve :classic:

Here is what a Rebello 3L sounds like through a 3" exhaust with only a Supertrapp.

The owner is a good freind, and wears ear plugs on long trips.....

MP3 sound file

Thanks for the clip! About 10 years ago, I did the same thing as your friend with my Datsun 510. I ran a 2 liter L-20B motor with a header and 2 1/2" exhaust all the way back with a single turbo muffler. My girlfriend and I both used ear plugs for long trips, but most of the time I drove without them. I definitely lost some hearing because of this. My ears ring all of the time- though it has gotten less noticeable over the years.

I encourage you to tell your friend about this. Losing hearing is not fun.

G