Quietest 4" exhaust - and options to make it quieter?

I've a feeling that the Tanabe 3" on my car might well be the weak point on my car now - and will be a bottleneck when upping the power. Now, I know I can easily buy a 4" exhaust, but I don't want the noise/drone from such a system.

So, what I'm asking is what is the quietest 4" system that is currently available? I've read the dB Register to see what's what, but I've no reference for my Tanabe Medallion Touring. I don't want much louder than that, as I want a car that the missus and I can enjoy when I'm not flooring it. One other thing, it must have the Tanabe/Stock straight tailpipe.

I've also thought about the Sound Performance Exhaust Cut Out - and having a 4" version placed early in the exhaust to open at 10psi. Giving me a 4" unsilenced exhaust on full-throttle. When it's closed, it'll be a nice 3" quiet exhaust after that. I can even have a cat welded in to make it easier to MOT.

All input/thoughts/suggestions welcome.

Get a big back box, mine is so quiet with the big box on, swap between them, im just in the process of modding my system so i can use the big box again if i want to be quiet.

That's certainly something to consider.

Do the boxes sap much power, Jamie, or do they just dampen the noise?

To me they always feel faster with loud, free flowing exhausts, the single big back box dont feel bad though, keep with a system that is nice and straight, avoid anything that bends about a lot.

To me they always feel faster with loud, free flowing exhausts, the single big back box dont feel bad though, keep with a system that is nice and straight, avoid anything that bends about a lot.

Cheers Mr P

As far as I've researched, 4" exhausts will flow enough for 1200+ whp - so if you aren't aiming for that kind of power, a few restrictions in the form of silencers/boxes will be fine. So far, my chopped up Blitz Nur (3.25 cat back) has coped with over 800 but is still stupid loud at idle. I'm considering a big silencer in the midpipe (and tailpipe if necessary), and new cat back section potentially.

The only viable alternative is the electronic exhaust cutout (if bypassing the remainder of the exhaust straight to air) or the electronic variable exhaust (if retaining the exhaust but want noise reduction under boost threshold).

You could either get a 4" exhaust custom made to your spec or buy an off the shelf one and add an additional silencer to the mid pipe if it's too loud.

I've just ordered a SS Jetex 3" silencer that I'm getting welded onto the mid pipe of my Blitz NUR R (MR2) which I'm hoping will tame the sound level.

As far as I've researched, 4" exhausts will flow enough for 1200+ whp - so if you aren't aiming for that kind of power, a few restrictions in the form of silencers/boxes will be fine. So far, my chopped up Blitz Nur (3.25 cat back) has coped with over 800 but is still stupid loud at idle. I'm considering a big silencer in the midpipe (and tailpipe if necessary), and new cat back section potentially.

 

The only viable alternative is the electronic exhaust cutout (if bypassing the remainder of the exhaust straight to air) or the electronic variable exhaust (if retaining the exhaust but want noise reduction under boost threshold).

I think I might well look for a 4" system, with as many silencers in as possible

You could either get a 4" exhaust custom made to your spec or buy an off the shelf one and add an additional silencer to the mid pipe if it's too loud.

 

I've just ordered a SS Jetex 3" silencer that I'm getting welded onto the mid pipe of my Blitz NUR R (MR2) which I'm hoping will tame the sound level.

I'll see what the traders can offer, failing that, Jetex will be on the look-up list.

How about a 4" or 5" 100 cell sports cat welded in, should quiet it down and make it easier to MOT as well

How about a 4" or 5" 100 cell sports cat welded in, should quiet it down and make it easier to MOT as well

That's part of what I thought, Wez. In conjunction with a SP Cutout (link in first post). Quiet for the drive around town/cruising on the motorway - then LOUD when needed

That's part of what I thought, Wez. In conjunction with a SP Cutout (link in first post). Quiet for the drive around town/cruising on the motorway - then LOUD when needed

Sounds like a plan to me

If using the SP bypass you could even go for a 3" sports cat to keep it neat, the extra back pressure may even help/improve torque off boost

That's an idea, and certainly something for me to look at after the Dragonball.

Keeping the Tanabe does appeal, I do like the look of it. Adding a cat will only help with noise and legality. My MOT tester isn't getting any younger!

The SP unit looks good but isnt it a tad expensive for basically a throttle plate and wastegate actuator

How about a 4" or 5" 100 cell sports cat welded in, should quiet it down and make it easier to MOT as well

This is basically the system I have now - a removeable midpipe section with a cat or catless pipe. Difference in response and power is huge, but may simply be that the current system cannot flow sufficient with a restriction - an issue which should disappear with a 4" exhaust.

The SP unit looks good but isnt it a tad expensive for basically a throttle plate and wastegate actuator

Yep, but there's not many issues with the SP one, versus the QTP one. I guess you get what you pay for!

I have an active 4" valve in mine and it does help with the drone but I would still like a mouse mode.. Keep looking at those divert back boxes.

I don't see where you could find room for a midbox on a 4" system. The ex is already to lowest point on the car.

I'm actually thinking about a 3" - used to have one on my old car and I liked it a lot.

iirc didn't whifbitz early 4" systems come in twin-box form?

iirc didn't whifbitz early 4" systems come in twin-box form?

Yea, still too loud for me though.

I have an active 4" valve in mine and it does help with the drone but I would still like a mouse mode.. Keep looking at those divert back boxes.

 

I don't see where you could find room for a midbox on a 4" system. The ex is already to lowest point on the car.

 

I'm actually thinking about a 3" - used to have one on my old car and I liked it a lot.

All I can think of, is somewhere on the downpipe?

Yea, still too loud for me though.

Yup, it was louder than the hks ti i took off.

I think the under car silencers are a waste of time on a 4" system, the box's are so small they make next to no difference, huge back box is whats needed, cut out like above would be nice for when you want to make some noise.

hmmm.... not sure...

like jamie says...

the idea of a box is to have lots of room and damping, so you need quite a space -

also DP will be insanely hot, not sure how a mo in there would cope.. certainly be a bigger heat source near the engine (which is not ideal) Wrapping is to keep the heat in and get it further back to radiate out?

I had a MASSIVE custom back box put on mine and it is a lot better but the drone remains..

Ideally I would like a 2" silenced pipe alongside the main and the just have the valve switch the two..

What is your side pipe there??

Of course, another high expense option is to reconstruct the stock system with a twin 2.5" or 3" silenced midpipe section, post-dump pipe, that rejoins near the back box. A mate back home has this, and I'll post up a pic if I can find one.

EDIT: it's this thread here on SF.com.au http://www.supraforums.com.au/forum/mkiv-discussion/40963-challenge-build-quiet-600rwhp-capable-exhaust-90db.html

http://img516.imageshack.us/img516/9869/exhaustms6.jpg

whoa!!

that is pipework! it's a rather inelegant solution, looks like I'd have it off on the first speed bump too...

wonder how much quieter it is..?

I just did the math (assuming I am right)

area of 4" = 39.43 sq inch

area of 3" = 22.18 sq inch

area of 2" = 9.85 sq inch

so to get the same circular surface area as a 4" system you would have to use nearly 2x 3" systems..

My mid pipe has cracks, corrosion and damage (BL 4" pipe) :-(

may be forced into doing something...

Of course, another high expense option is to reconstruct the stock system with a twin 2.5" or 3" silenced midpipe section, post-dump pipe, that rejoins near the back box. A mate back home has this, and I'll post up a pic if I can find one.

 

EDIT: it's this thread here on SF.com.au http://www.supraforums.com.au/forum/mkiv-discussion/40963-challenge-build-quiet-600rwhp-capable-exhaust-90db.html

 

http://img516.imageshack.us/img516/9869/exhaustms6.jpg

Im liking that, I had a twin box on the black car and it was pretty quiet could have fitted another small box in there.

Of course, another high expense option is to reconstruct the stock system with a twin 2.5" or 3" silenced midpipe section, post-dump pipe, that rejoins near the back box. A mate back home has this, and I'll post up a pic if I can find one.

 

EDIT: it's this thread here on SF.com.au http://www.supraforums.com.au/forum/mkiv-discussion/40963-challenge-build-quiet-600rwhp-capable-exhaust-90db.html

 

http://img516.imageshack.us/img516/9869/exhaustms6.jpg

Very nice but I bet it weighs a ton, something similar in titanium would be nice