Why don't my aftermarket mufflers roar after 3000RPM?

[johnnxiv]

Recorded with Samsung S5. These are 2 x universal mufflers. This is an automatic car.
It roars from 2000 to 2900RPM, but after 3000RPM, it quiets down and only produce raspy engine's sound.
Everything else is stock(ORM). Please use earphones for best sound quality.

Why there is no sound after 3000RPM? bad mufflers?

When I press hard on the gas, my car shifts gears at higher than normal (3500)RPM, like 5000 or 6000RPM.
Will my transmission goes out soon? is it normal?

 

[obi_waynne]

You are experiencing kick down, the car will assume you want max performance when your foot is flat on the floor so will hold on to the revs for longer to give the extra performance. Otherwise at part throttle you will be in a best economy mode compromise when the gears change.

Engine noise is often lower after 3000rpm, the pulses from the engine are quicker and merge into one, most mufflers and exhausts cope really well with deadening the sound at the mid to upper end of the rev range. Mufflers are there to deaden the sound not enhance it or make it boom.

 

[HDi fun]

Your tachometer is red-lined at around 6200rpm therefore changing up at 6000 will not cause problems. The only caveat is to avoid high load and high revs until the engine is fully warmed up. Basically, drive conservatively for the first twenty minutes or so.

Most automatics have very good part throttle kickdown now so you can very easily control gearchange points with your right foot alone.

Nothing to worry about, and welcome to Torque Cars btw.

 

[obi_waynne]

Good advice there HDI.

Some automatics are clever enough to allow the engine to warm up! The M3 is a good example of a nannying car, it won't let you push it hard on a cold engine!

 

[HDi fun]

Many do adopt a different change pattern during warm up. But full kickdown will give you full power regardless. Simply for safety reasons.

 

[johnnxiv]

What can I do now to make my car roars louder after 3000RPM? delete the premuffler?

 

[HDi fun]

You could but you this, paradoxically, could lead to reduced performance. Plus, you need to considered both Federal and FL State regulations relating to vehicle roadworthiness. It's quite common for there to be rules concerning excessive noise. Defining excessive is very difficult, there's no reliable way to measure sound level. This is covered here in the UK with our annual MoT roadworthiness test by the phrase 'in the tester's opinion'.

Personally I want my car as quiet as possible but I do understand that some people don't share my preferences.

 

[johnnxiv]

I understand exactly what you mean. My car is an automatic so it changes gears at 3500-4500RPM. This mean even if I have loud exhaust, my car wont be that loud compare to a MT car which shifts at 6000RPM.

Can you tell me how to make my car roars louder after 3000RPM? delete the premuffler?

 

[HDi fun]

I think we've already covered that. It's difficult to know what kind of roar you are seeking. It's like trying to describe the colour green to someone who has been blind from birth.

You're never going to get the buzz and bark of, let's say for example, a tuned V6, from an inline 4.

You can rip out all the mufflers but I think you'll find that the ones nearer to the engine (premufflers) also play host to the catalytic converters. Removing those will almost definitely render you in contravention of the law.

Strangely I find noisy fast cars less offensive than noisy slow ones - the fast car snarls for 5 seconds and by then it's well off into the distance and annoying someone else

 

[obi_waynne]

Fitting a cherry bomb silencer to the rear will give the car a deep throaty roar if that's the sort of thing you like! Larger bore pipes make a deeper sound (generally speaking) but you'll probably lose bottom end power if that is fitted.

Removing the first expansion box may help a little but it is the rear box that does most of the silencing work in the exhaust.

 

[TCJBOLDIE]

Some cars will never sound nice ( to my ear anyway ) no matter what type of system you throw at it .
For example compare a 4G63 against a SR20 that sounds like a truck IMO

 

[johnnxiv]

If you guys have watched my video above. You guys can hear I have a quiet deep tone from 2000-2900RPM, right?

The only thing I want is to make it continues to roar past 3000RPM. I dont want it to be super loud and get fix it tickets.
I just want a deep deep tone from far away.(you know what I'm talking about)

 

[HDi fun]

The problem is that I don't know what you're talking about. It's like trying to describe green to a .... you know the rest - read my previous post(s).

All exhausts are acoustically designed, generally to minimise noise whilst allowing desireable gas-flow characteristics.

Accoustically engineered exhausts that produce a 'pleasing' sound (on the likes of BMW's M car range and Porsche's Boxster are very expensive to design).

All I can suggest is that you set aside a large budget to keep swapping out and replacing exhaust components until you get the noise you want. Bear in mind that you might never achieve the desired result.

 

[obi_waynne]

There is a simple fact that the higher an engines RPM the higher the pitch of the exhaust. Pulse frequencies come into play here, more pulses = higher frequency. The exhaust has been designed to cut noise at over 3000 rpm as well or long journeys will become booming and noisy.

Some exhausts have a flap which opens at a set RPM range to allow a higher flow. This sort of setup might help create the effect you want but any larger exhaust pipe will deepen the sound.

 

[Aerial Andy944]

I think a trip to your local custom exhaust specialist is in order. He'll be able to explain what will fit best on your particular model/setup. Similar question was on another recent thread here and flaps in exhaust was suggested, closed on part throttle for quiet running then open on full throttle. I had them on my Nismo exhaust fitte to my old Skyline and they worked very well. The RB26 engine is known to be very loud anyway, your engine will react different so as Waynne says, trial fitment may be in order

 

[VahagnZ]

Recorded with Samsung S5. These are 2 x universal mufflers. This is an automatic car.
It roars from 2000 to 2900RPM, but after 3000RPM, it quiets down and only produce raspy engine's sound.
Everything else is stock(ORM). Please use earphones for best sound quality.

Why there is no sound after 3000RPM? bad mufflers?

When I press hard on the gas, my car shifts gears at higher than normal (3500)RPM, like 5000 or 6000RPM.
Will my transmission goes out soon? is it normal?

Hello I think I have the same problem. Recently I also have put flowmaster 40 series delta flow muffler on my BMW E92. And have the same problem sound is perfect and increasing during 800-3000 RPM but the sound does not change in the same way after 3000 RPM. What is the reason. Did you find a solution to the problem?