Jump to content
SAU Community

Recommended Posts

Hey all.

So I've got a completely stock r33 s2, and want to build it up as a bit of a sleeper. Really stock looking on the outside, but with a bit of a punch under the bonnet. Nothing too crazy, maybe would like to push up to 200kw over time.

The aim of the game is to have the car 100% legal, or as legal as is humanly possible. I got a Just Jap return pipe intercooler put on which uses the standard intercooler pipes and did not require the cutting of the body etc. First mod= legal. A dyno run after the installation revealed that the car has 145kw at the wheels.

The other day I chuck a high flow k&n panel filter in the standard air box. Noticibly smoother accelleration etc. Second mod= Legal.

Now it comes time for the exhaust. The car needs to be under the legal db limit.

I bought a second hand 3 inch dump pipe from the forums, ready to bolt on.

I also bought a second hand 3 inch cat back exhaust, minus the end muffler. The system is designed to bolt up to the cat and can accomodate an aftermarket muffler, and has a flange, so that the standard muffler can be bolted on as well (for when the EPA bites you in teh ass presumably. The idea is to not get to this point however). Both of these parts appear to be mild steel, not stainless.

So now, to recap, I need a 3 inch high flow cat and an end muffler to complete the system. (If anyone is selling any of these items btw, let me know)

My question is. What sort of muffler should I have put on that will flow well, yet ensure that the system falls within the legal db limit? Please also keep in mind that I would like the muffler to look as stock as possible- I guess that rules out cannons etc.

Does anyone have any suggestions? Also, does anyone have any idea how much of an increase in power this should net me? Any tips etc, let me hear them as I am relatively new to the scene and am keen to learn.

Cheers.

Link to comment
https://www.sau.com.au/forums/topic/250355-building-my-exhaust/
Share on other sites

Going 3" straight through you will be pushing it for legal db's!

Your best shot would be to talk to a good exhaust shop (some have a db meter handy), but i would recomend fitting a resinator of some sort

^^ you couldn't be more wrong. Easy to get a 3" legal. I have a 3.5" - 92dB, ended up with under 90.

And resonators do not work, so another piece of bad advice in afraid.

You need two decent sized mufflers. Simple as that.

A panel filter isn't illegal. You're using the stock airbox, that's all that matters.

So you cant use a pod filter in Australia? thats gotta suck

Australia's laws are so tight ass compared to New Zealand, I have to hand it to our 3rd world approach to things, lets me gets away with a straight through exhaust and ground clearance that turns me into a grader on any gravel road.

So you cant use a pod filter in Australia? thats gotta suck

Australia's laws are so tight ass compared to New Zealand, I have to hand it to our 3rd world approach to things, lets me gets away with a straight through exhaust and ground clearance that turns me into a grader on any gravel road.

Our exhaust law still states that it has to be under 95db :blush:

oh i see

damn aye

in regards to the exhaust but i have a 3 inch turbo back with high flow cat and rear resonator + cannon and atm mines losing boost pressure up higher in the revs so im only pulling 170 on the dyno instead of about 200 which my tuner reakons i should be seeing

so yeh I'll have to see if its the exhaust doing this but i suspect its the problem

boost is on the intake side, you cannot loose boost from an exhaust, as boost does not exist on the exhaust side

I think the poster about losing boost wasn't referring to losing it out the exhaust, more so eluding to the fact the exhaust might be a large restriction causing a drop in flow, causing a loss of boost.

As to a legal exhaust:

You will want a 3" exhaust, with a 3" high flow cat, a 5" bodied mid muffler, with some decent length, and then you will want as large of a rear muffler as you can fit.

I would also say to put the twin tips on the exhaust, and have them painted black.

I run a 5" mid, and a 7" end muffler (Cannon style) except they're not stainless, and not all shiney, and the whole exhaust, when looking at it from the back any more then 2 metres away, and it looks invisible, matched with a nice and quiet exhaust note, no issues there with the plod.

My mufflers are also 650 and 550mm long respectively. You want LENGTH AND DIAMETER for a good muffler. And yes, mine are both straight through and are custom built.

i had a 3inch exhuast on my 33 s2 with a hot dog as the centre muffler (needed the ground clearance)

and a full size muffler out the back and the db meter hit 89.5 on back off (wich is ur loudest figure)

and was given a certificate to state that the exhuast was legal in every way

just one thing to know....your front mount is not 'legal' in the true sense of the term...its only legal if you pass a free emisions test at the RTA in botany or penrith...

SORRY but my comments are for NSW...

Orig poster = Vic

Vic = the laws being discussed/applied here.

Can people from other states please refrain from posting about legalities if they do not know Victorian law?

All it does is confuse the issue for people reading at present, and then later on if they search and find this thread.

R31, It'd be handy if we actually knew the person was from vic.

Nothing in the post states location, and the only way we can assume he's in Vic, is being a Vic club member, and hey, they could have moved or anything since becoming a member.

Maybe get the board admin to show everyones state at least...

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • As discussed in the previous post, the bushes in the 110 needed replacing. I took this opportunity to replace the castor bushes, the front lower control arm, lower the car and get the alignment dialled in with new tyres. I took it down to Alignment Motorsports on the GC to get this work done and also get more out of the Shockworks as I felt like I wasn't getting the full use out of them.  To cut a very long story short, it ended up being the case the passenger side castor arm wouldn't accept the brand new bush as the sleeve had worn badly enough to the point you could push the new bush in by hand and completely through. Trying a pair of TRD bushes didn't fix the issue either (I had originally gone with Hardrace bushes). We needed to urgently source another castor arm, and thankfully this was sourced and the guys at the shop worked on my car until 7pm on a Saturday to get everything done. The car rides a lot nicer now with the suspension dialled in properly. Lowered the car a little as well to suit the lower profile front tyres, and just bring the car down generally. Eternally thankful for the guys down at the shop to get the car sorted, we both pulled big favours from our contacts to get it done on the Saturday.  Also plugged in the new Stedi foglights into the S15, and even from a quick test in the garage I'm keen to see how they look out on the road. I had some concerns about the length of the LED body and whether it'd fit in the foglight housing but it's fine.  I've got a small window coming up next month where I'll likely get a little paint work done on the 110 to remove the rear wing, add a boot wing and roof wing, get the side skirt fixed up and colour match the little panel on the tail lights so that I can install some badges that I've kept in storage. I'm also tempted to put in a new pair of headlights on the 110.  Until then, here's some more pictures from Easter this year. 
    • I would put a fuel pressure gauge between the filter and the fuel rail, see if it's maintaining good fuel pressure at idle going up to the point when it stalls. Do you see any strange behavior in commanded fuel leading up to the point when it stalls? You might have to start going through the service manual and doing a long list of sensor tests if it's not the fuel system for whatever reason.
    • Hi,  Just joined the forum so I could share my "fix" of this problem. Might be of use to someone. Had the same hunting at idle issue on my V36 with VQ35HR engine after swapping the engine because the original one got overheated.  While changing the engine I made the mistake of cleaning the throttle bodies and tried all the tricks i could find to do a throttle relearn with no luck. Gave in and took it to a shop and they couldn't sort it. Then took it to my local Nissan dealership and they couldn't get it to idle properly. They said I'd need to replace the throttle bodies and the ecu probably costing more than the car is worth. So I had the idea of replacing the carbon I cleaned out with a thin layer of super glue and it's back to normal idle now. Bit rough but saved the car from the wreckers 🤣
    • After my last update, I went ahead with cleaning and restoring the entire fuel system. This included removing the tank and cleaning it with the Beyond Balistics solution, power washing it multiple times, drying it thoroughly, rinsing with IPA, drying again with heat gun and compressed air. Also, cleaning out the lines, fuel rail, and replacing the fuel pump with an OEM-style one. During the cleaning process, I replaced several hoses - including the breather hose on the fuel tank, which turned out to be the cause of the earlier fuel leak. This is what the old fuel filter looked like: Fuel tank before cleaning: Dirty Fuel Tank.mp4   Fuel tank after cleaning (some staining remains): Clean Fuel Tank.mp4 Both the OEM 270cc and new DeatschWerks 550cc injectors were cleaned professionally by a shop. Before reassembling everything, I tested the fuel flow by running the pump output into a container at the fuel filter location - flow looked good. I then fitted the new fuel filter and reassembled the rest of the system. Fuel Flow Test.mp4 Test 1 - 550cc injectors Ran the new fuel pump with its supplied diagonal strainer (different from OEM’s flat strainer) and my 550cc injectors using the same resized-injector map I had successfully used before. At first, it idled roughly and stalled when I applied throttle. Checked the spark plugs and found that they were fouled with carbon (likely from the earlier overly rich running when the injectors were clogged). After cleaning the plugs, the car started fine. However, it would only idle for 30–60 seconds before stalling, and while driving it would feel like a “fuel cut” after a few seconds - though it wouldn’t fully stall. Test 2 – Strainer swap Suspecting the diagonal strainer might not be reaching the tank bottom, I swapped it for the original flat strainer and filled the tank with ~45L of fuel. The issue persisted exactly the same. Test 3 – OEM injectors To eliminate tuning variables, I reinstalled the OEM 270cc injectors and reverted to the original map. Cleaned the spark plugs again just in-case. The stalling and “fuel cut” still remained.   At this stage, I suspect an intermittent power or connection fault at the fuel pump hanger, caused during the cleaning process. This has led me to look into getting Frenchy’s fuel hanger and replacing the unit entirely. TL;DR: Cleaned and restored the fuel system (tank, lines, rail, pump). Tested 550cc injectors with the same resized-injector map as before, but the car stalls at idle and experiences what feels like “fuel cut” after a few seconds of driving. Swapped back to OEM injectors with original map to rule out tuning, but the issue persists. Now suspecting an intermittent power or connection fault at the fuel pump hanger, possibly cause by the cleaning process.  
×
×
  • Create New...