Who Does A High Flow Exhaust In 4 Inch Or 90mm

[BU5TER]

hahaha thats cool I half thought I was wrong

[Ronin 09]

are there any centre muffles/resonators in that system marcus, or just the rear can?

It's got some excuse for a 'resonator' behind the cat... if the pipe is 3.75", the 'resonator' is 4.1" round and about 10" long.

So, more or less just the rear can

[R31Nismoid]

you only did 109db?

I had 115 with mine or there abouts for my EPA... and i dont think mine was as loud as yours was...

interesting

[NXTIME]

2 x 2.5" pipes have 75% the flow of one 4" pipe.

2 x 2.75" pipes have 95% the flow of one 4" pipe

2 x 3" pipes have 110% the flow of one 4" pipe

[JimX]

You can work out how much flow you'll get almost exactly with some simple maths. Multiply the radius (1/2 diameter) by Pi to get the area which equates to how much it'll flow. For example:

 Exhaust		   Area		(x2)
diameter"		  sq"
 2.5			 4.91		9.82
 2.75			5.94	   11.88
 3			   7.07	   14.14
 3.5			 9.62	   19.24
 4			  12.57	   25.14 (ha!)

So as Nxtime showed above, 2x2.5" exhaust has nowhere near the flow of 1x4" pipe.

[BU5TER]

Thanks guys thats great info

[saliya]

Hey,

I had one custom made by a friend with stainless everything for my R32 GTR. It was around $1500 in materials,

and $400 for 2 x 3" catco stainless cats. He said that he'd do the same thing for someone else for $4k.

Dual 3" off the standard dumps, through cats, to 4" through a 4" resonator and a 4" muffler.

He had to fabricate the resonator and the muffler because we couldn't find anything big enough at the time

and 105dB @ 3700 was too loud for the coppers. It's 95dB @ 3700 now (which is still too loud, but I don't get

pulled over anymore).

Then I lowered it as per the SK GB recommended settings. 355mm/345mm centre-guard (I think!); I think it's now too low.

The resonator touches the ground where there are lumps in the road. I would pull the resonator out and just put a bit

of 4" pipe back there, but...

I'm considering selling it to pay for the new exhaust that will be required for my new T04Z. PM me if you're interested;

I'll take a photo of it (it's off the car at the moment) and put it in the relevant for-sale section. I'm thinking of getting something

in an oval section to get the flow without the clearance issues...

Regards,

Saliya

[GTR-80Y]

Brett mate get urself to a place called tonys exhaust or mufflers out at moorebank rd. Got some 4inch work done there, was on the hoist next to a mac truck gettin a 6inch exhaust stack done.

[benm]

I believe Autostyle take all their cars to www.bestmufflers.com whom gives a guarantee (to within 5%) of the db output before any work begins. I was talking to the owner of a 500rwkw R32 GTR owner on friday nite whom got his work done their and it didnt appear to go over about 88db.

[J_Red33]

Hey guys, I'm interested to know, what kind of power are you all looking at putting out with a 3.5 to 4 inch system??

I'm only looking at putting a 3 inch on my 33 GTS-T at the moment as it'll be the car's first major mod, but I am looking to eventually have 300 to 400 rwKW's once I've spent a lot more elsewhere.

I am interested to know as I'm not sure whether to got a cheaper bolt on system for now & then buy a custom 3.5 inch one later when I'm ready. Otherwise if all I need for this kind of power is a 3 inch system, I'll go custom now.

Any input would be appreciated. Cheers

Edited April 16, 2006 by Electro

[paulr33]

exhaust is the last of your worries. buy the mods to suit your current target, then worry about the future when it comes. 300rwkw is a about a 12k exercise

[GTR-80Y]

Mate the prices of a good jap system are so damn low now. I was shocked to find aussie best don't do anything bigger than 3 inch.....they sent me down the road to tonys cos they couldn't work on the existing jap system i had.

[Craved]

i was talking to my exhaust guy, and most aus shops dont really stock 3.5" piping.. its a shame really..

even worse was my old Kakimoto running 3.25 " .. very hard to find a resonator in that size .

going to have to look into a twin 3" system in mine once the rb30 goes in, single now is way too loud, but brand new so i'll try and squeeze another 3" down under there aswell

[rb26s13]

4 grand for an exhaust system.. haha maybe i should charge people more than wat i do...

either way

4inch mandrel bends = 50 bux each retail is 75 bux from memory?

3 meters of 4inch stainless = i cant member thinking 200 to 250

4inch straight thru cannon = 300 bux (magnaflow i think it is that made mine)

5inch body'd cat 4inch in and out = 300? i think

flanges cost i think 15-20 bux each.. cant remember

so.. roughly 1150 for all materials needed add another 300 for a flat 4inch straight thru muffler for under the car if ya want the 2 mufflers.. than prolly 350-400 to tig weld together and mount.. not all that expensive for a custom 4inch cat back including cat if ya ask me..

making a cat back for a car takes f*ck all time.. longest part of it all would be welding it all if ya ask me..