Gtr Rear Muffler Options

[portaz]

Might look into it as mine is pretty loud, what was the cost of muffler?

[SiR_RB]

Call Kevin on 0448 139 302

[portaz]

Ta will do

[mattie4270]

Any vids mate?

[butterfly effect]

I was recently told that it is common practice with some japanese high performance aftermarket exhausts including those intended for nissan gtr's to fit restrictors or stepdowns as they are called in the mufflers to obviously reduce noise levels. That will be achieved but unfortunately at the expense of flow capacity as is being found out when performance modifications are carried out on the engines. I will soon make available a rear muffler and resonator , both round , mild steel , 3.5" bore size at a reasonable price. I now have access to s.s. 3.5" perforated tubes which I imported. These mufflers will have a deeper , quieter sound and max flow. They are painted charcoal grey. I never intended to make shiny , look at me mufflers just something that does the job efficiently.

[scotty nm35]

Mild steel will rust out in no time. Why not use stainless, the materials would cost bugger all extra, the main cost is in labour... And then I might actually be interested in buying some.

[discopotato03]

I'm interested to hear about the maximum size of mufflers that will fit under R32s and R33s . I had my R33 (GTST) measured recently and it has a Nismo Jasma I assume 3" cat back ATM . I wanted mufflers at least as large but I'm not sure anyone does a 5 x 10 x 16 for the mid one .

It's interesting that Kevin did an 18 x 7 round rear one because David Buschur in the US used a Magnaflow 14 x 7 round on his quiet "diff back" for Evo Lancers .

I was told a 6 x 11 x 20 oval would go in the back of my R33 though I'd rather try a 7 x 18-20 round if it can fit . If Kevin can do the same size as the middle Nizmo one - or better - I'd like two mufflers please . There is limited space between the upper side of the mid muffler and the tailshaft so it's a bit of a juggle .

One other thing is where the cats located . If it could be moved further forward a third resonator could possibly go where the cat was and quieten things down even further . I mention this because the Americans sometimes fit another muffler where the cat was and run catless which is risky on the street . They reckon a 6 x 14 Magnaflow round in the cats location makes a noticeable difference with the 7 x 14 round at the back .

Just yesterday I read a long thread on Evom.net about a bloke that wanted a factory standard sounding Evo with a 3' aftermarket exhaust . The closest he got was with a Dynomax VT , valve technology ? , muffler with a lightly spring loaded valve in the back of it . It worked well but the valve rattled badly at idle partically on engines with big cams in them .

Anyway quiet free flowing mufflers for Skylines in 3-3 1/2" would be great , cheers Adrian .

[SiR_RB]

I think that 18x7 round was for me, could of fit a 20" long in there I rekon...

I'm gonna measure the biggest muffler that can fit under my 32 gtr and let Kevin know, might be interested in throwing another AES mid muffler under and see how quiet we can get it (even now everyone is amazed how quiet it is)

[asps91]

Get a magnaflow

[r32-25t]

Mild steel will rust out in no time. Why not use stainless, the materials would cost bugger all extra, the main cost is in labour... And then I might actually be interested in buying some.

who told you that? My car has the same mild steel exhaust I bought it with 11 years ago

[asps91]

Mild steel will rust out in no time. Why not use stainless, the materials would cost bugger all extra, the main cost is in labour... And then I might actually be interested in buying some.

I custom built my own exhuast system from the 4inch dump pipe back into a 3.5 inch straight through into a magnaflow rear muffler. I chose to go mild steel as in total it would cost me $450 vs $750ish (including the muffler). The price difference i would personally say is not in the labour but the material.

Mild steel will last many years. My first car which was a 1994 toyota supra is still getting around with the same mild steel exhuast and that was almost 8 years ago, i bumped into the owner a few weeks ago.

[discopotato03]

I will ring Kevin in a few days because I'm curious to know if two of his larger mufflers can silence a 3 1/2 system on a GTS25T with a GT3076R . Dump to cat is already 3.5 just need the rest . By quiet I mean REAL quiet and no drone . Steel is fine too .

Cheers Adrian .

[scotty nm35]

who told you that? My car has the same mild steel exhaust I bought it with 11 years ago

Coated I bet, they rust out from the inside anyway. Try fabricating a bare steel system without a coating on the inside and see how long it lasts. You would need to factor in the coating costs to compare them properly. E85 will limit it's life even more.

I don't need other people to tell me anything btw, I remove so many rusty shitty mild systems and replace them with my custom stainless, the piles of old pipes are leaving stains on my concrete. Do you want some? You are welcome to them.

Your choice at the end of the day, I hate seeing rusty shit under my car. I guess if your ride is devaluing to nothing then a few hunge is not worth wasting on it.

[butterfly effect]

The rear muffler 3.5"bore, no stepdowns, for the gtr 32 I think can be 500 mm long and 7" diam. Flat spun ends are preferable rather than a cone version because the muffler contains more packer but a combination can be used if prefered. Not too sure yet about max resonator specs. It will be interesting to db the result. I expect it to be good. Even with a 3.5" exhaust it would be preferable to go to 4" from turbo to 3.5" resonator. The exhaust flow rate will increase by an unknown but reasonable amount. Could be better than expected. The dreaded drone can always be a problem with big systems on low , cruise mode. It is a bit of a lottery. Most times you win but sometimes not. Acoustics is a complicated science.Helmholz tubes can eliminate them. My stage 3 active exhaust kit destroys them.

[scotty nm35]

Acoustics is a complicated science.Helmholz tubes can eliminate them. My stage 3 active exhaust kit destroys them.

Agreed.

The Japs love using Helmholtz chambers, and they work very well from my experiences with them, but they need to be tuned to the frequency you want to remove, which can add a fair amount of R+D to a custom exhaust.

I think the active exhaust is a much better option, especially if Vac actuated. Unfortunately no-one wants to spend that kind of coin, and good quality vac operated valves aren't cheap.

Here is my attempt, made from scratch.

[wolverine]

The Stagea has a 3" straight through system with a regular oval mid muffler and a monster 18" x 13"x 12" rear can.

Uber quiet and no tricks. The rear of the Stagea gives you the room to go larger but the lesson is the same on the R33.....stick the biggest cans you can fit.

[wolverine]

The Stagea has a 3" straight through system with a regular oval mid muffler and a monster 18" x 8" x 12" rear can.

Uber quiet and no tricks. The rear of the Stagea gives you the room to go larger but the lesson is the same on the R33.....stick the biggest cans you can fit.

Slight correction ^^

[discopotato03]

Someone above mentioned 500mm which is about 19.6" and that's about what can fit with a tightish radius bend into it . Depth wise will probably depend on how low your car is and how likely it is to get hit or torn off . Somewhere around the 7-7.5" is probably about it height wise and maybe 11" wide . Stageas obviously have long range tank space for the rear can ...

A .

[butterfly effect]

I can supply rear muffler 3.5" bore , 7" diam. 500 mm long almost flat spun ends or with exit coned end , mild steel, externally tigged , 409 s.s. perforated tube with expansion joint to prevent fatigue , quiet deeper sound, $400. Same specs but 3" bore $380. Don't have dimensions for resonator yet. It will be something like 5" diam and 400 mm long.There will be power robbing stepdowns. This package will work well. If 500 mm long proves to be a difficult to fit I will come back to 480 mm. Time will tell.

[butterfly effect]

Woops.There will be NO power robbing stepdowns.