I could have posted this in the exhaust section, but this is specifically for the sedans.

A lot of people assert that the most restrictive part of the stock sedan exhaust is the muffler. Some people say that messing around with the stock muffler will show a loss of low-end torque. But do we really *know*?

So, I want to find out. I've got the week after christmas off, and I'm thinking about taking my car to the dyno. I plan on doing set of three baseline pulls, then removing the rear muffler, then another 3 pulls. I will include full charts for analysis afterwards. *If*

A set of pulls costs $55. Two sets will be $110. However, if I do the two sets back-to-back, I'm pretty sure the manager of the shop will give me a moderate break; say $100 for both sets. I'll pay for the first set, but I'm looking for donations for the second set.

So, I need roughly $50 in donations. I highly doubt anyone will fork up the money, but I figured I'd try it out. So what do you get for your donation? The "warm-fuzzy" feeling for helping out the community.

And here's your chance to backup your opinions, or at least find out if your guestimates are correct or not.

If all you have to say is something like "don't bother; you'll gain 10hp", or "don't bother; you'll lose 10hp", or "don't bother; driving without mufflers is illegal", please don't waste my time. This is our opportunity to find out just how restrictive the stock muffler may, or may not, actually be. Granted, we're not doing a comparison to an aftermarket muffler, or catback exhaust, but this would be scientific enough.

Plus, if I actually do this, the whole thing will be on video for those interested.

 

I know its not much but I will be first to throw in $5 for the cause. I would love to see how this turns out.

Jamey

 

I'm curious enough to fork out $5 also. As long as Paypal is ok.

 

From what I've read the stock muffler is a good one. It's got a variable baffle system which helps maintain torque at all rpms.
No doubt it can be improved on like most OEM parts, but the stock one isn't so bad.
C.

 

I think I'm more interested in how restrictive the stock muffler is as compared with a non variable muffler; not necessarily no muffler at all. But I realize that would add even more cost to the experiment

 

The stock muffler is actually really good and I disagree that it's a bottleneck in the sedan exhaust. The variable capacity design is the same one used originally on the Skyline GTR. BMW and Benz have been using these variable capacity mufflers for years too. Over at Maxima.org guys have done numerous exhaust tests with VQ30 and VQ35 Maximas:

1) Remove everything from behind the y-pipe: result was a significant loss in low/midrage power and a minimal gain above 5000rpms.

2) Remove the OEM variable capacity muffler (OEM on 00-03 Maximas): result was less power from 3000-5000rpms and a 2hp gain above 6000rpms and retarded exhaust noise. I even tried this with my 96 Maxima. Yeah, loud.

3) Remove the OEM variable capacity muffler and replace with a high flow HKS/Greddy/etc muffler: Result was no change in measurable power.

Over the years with my VQ Maxima, I ran the stock muffler, a high dollar HKS muffler, and finally an 02 Maxima muffler. With the HKS muffler, I saw no difference in 1/4 ET/MPH or dyno power over the super quiet stock muffler. When I installed the 02 muffler, the exhaust had a sweet yet somewhat throaty idle and WOT noise espeically when the valve opened around 3500-4000rpms. I don't know if it was the muffler, but my car always ran it's quickest ET/MPHs with no other changes. I never dynoed with the muffler, so I'll never know.

I love the design of the OEM G sedan muffler. I think it gives the best of both worlds. With that said, I'll probably be getting the Borla TD in the future so that means bye bye OEM muffler. It's give and take

 

And???? Where's the contribution???

 

I would fork up some dough if you were comparing it to an aftermarket muffler. Since nobody is going to drive thier car w/o a muffler, who cares. Even if you do gain some HP w/o the muffler on, that dosnt prove that the stock muffler sucks. It just proves that no muffler at all is better, wich isnt going to help out most of us.

 

what he said....what are you going to put on after you cut the oem section out? If you are going to dyno, I would dyno stock, then replace the cat back and dyno that. At least you will see some gains then hopefully. With just replacing the rear section - I wouldnt expect any gains except in volume.

 

I agree....not sure why you're comparing stock muffler vs. no muffler at all, as you wouldn't drive it w/ out a muffler. I too think it would be more worth testing stock exhaust VS aftermarket (one that claims it is less restrictive and reduces backpressure).....just my $0.02.

 

The 05 + design is comparable to the Coupe ones, they are more smaller compare to the 03-04 ones when i took mine out!!!

 

I agree with those saying it's not worth the effort. There will probably be some kind of gain w/o the stock muffler but that doesn't answer any questions. You would still not know if any aftermarket muffler can do any better.

 

that actually can solve the myth even tho he doesnt have an aftermarket muffler to comapre with.

By running without any muffler, he will get an upper bound of the amount of improvement an aftermarket muffler can bring to a G (Mind you that a reduce in backpressure will mostly only help HP but not torque, so if you get say 5hp in 6k to 7k rpm range from running without a muffler.. this can translate to an upper bound for the amount of HP an aftermarket muffler can yield)

All in all, this test is NOT useless

 

I have heard and read that the stock muffler is pretty good. It was suggested to change out the stock cats to high-flow cats to get better exhaust flow.

 

From what i recall, i think the Y-pipe is the most restrictive, the resonator are quite large