Exhaust size

[chris240]

fellas

well I finally managed to fit my extractors last weekend...Ive got the 2" system running upto halfway along the car which terminates at a 2" hotdog muffler ....I will be getting the remainder of the new exhaust bent-up and attached to a new muffler within the nextweek for me to install.. question is , do I maintain 2" right-thru to the end or do I go for 2.25" ?

The motor is basically stock L24..also any recommendations for type & brand of rear muffler.

(Im thinking 2" system...)

[gav240z]

I'm thinking there isn't much point increasing diameter if the rest of the system is only 2". Unless you are planning on going larger in the future of course.

 

I'd probably ask the exhaust shop for their recommendation. Make sure they don't give you a tacky looking exhaust tip! .

[matt drago]

I just got my exhaust done.  I've got the HM Headers on it and thought that it was 2.25", but it terminated to 2".  The exhaust guy that I went to, as soon as he saw it, said "I'll cut the 2" pipe off back to the dual pipe section and open it up to 2.25" all the way, put in a small hot dog and sports muffler".

 

Everyone that I talked to told me to do this setup and the exhaust guy suggested it to me as well before I could tell him what I wanted.

 

And it sounds sooo sweet.

 

Shame that you have already got the 2" dog on.  But I agree with Gav, I don't see the benefit of opening up the pipe once you have already constricted the flow.  See what your exhaust guy says.

[modular9]

Most people i know err on the side of the 2 1/4 system. Purely because it has "room" for more mods done to the engine. I too have a stock l24 but the plans for it are to open up the breathing a little more so I too will be following matt's example . Anyway the 2.25 exhaust seems to be the sweet spot.

 

Gav : I am going for a love heart exhaust tip and at the same time get a tow ring welded on and putting a plush toy on the ring. Should match my 24 inch wheels , tuck and roll hilighter green leather interior and ground effect led's 

 

blingricerZowner !

[Zedman240®]

For a stock L24, 2" is fine but as everyone have said if you plan on any other mods later, go for the 2 1/4 or 2 1/2" system. I don't really like "hot dogs" in a system. You are better off having a straight through pipe! The ones with the perforations sticking out into the flow are the most restrictive.. If you hate that "barky" note then the best thing to install is the biggest resonator you can fit under the car near the extractors. The trick is to get the hot gases to expand slowly, usually the biggest resonator you can fit does the best job. On my car I have a twin 2" system (the exhaust place didn't listen to me) joining to one just after the 90' bend after the diff. I'm upset coz the muffler place used 2 hotdogs in the system. When I have more $$$ I'll fix that asap! Although I'm getting good results power wise and had no EPA notices, something must be right.

[chris240]

hmmmm seems like 2 1/4 " might be the way to go...I adopted the hotdog as it was already on the system I bought. I was thinking to have a twin pipe muffler (same as late 80s skylines) ...and then I came to my senses. 

[Brabham]

What are the thoughts on a 2-3" straight through on a mild L26? What are the power/ backpressure benefits/drawbacks and what is it likely to sound like? Thanks.

[Toecutter]

Lose alot of bottom end, exessively loud, way too much resonation at 100km/hr or 2500ish rpm depending on gearing. I did'nt have straight through but just a large resonator in the middle so straight through would have been a bigger nightmare. It was crap to drive, sounded too loud to the point it was annoying and resonated like crazy on the freeway. I ended going with 2.25" with hotdog and "turbo flow" muffler. Tough sound with good drivability.

 

Sulio

[Lynton]

The exhaust shop has recommended to me a 2.25 pipe from my extractors back on my 2+2 and it will be fitted next week, so from what I am reading that seems to be the go so I am happy!! I have also asked for a nice quality chrome tip not some crappy thing.

Lynton

[Zedman240®]

What are the thoughts on a 2-3" straight through on a mild L26? What are the power/ backpressure benefits/drawbacks and what is it likely to sound like? Thanks.

 

If you go to a 3" system on a L26, unless the engine is going to spend most of its time revving around 5-7000 rpm, it will be a waste of money. Best results would be from a 2-1/4 mandrel bent system. Fit a large cylindrical resonator roughly were the gearbox sits and a larger truck resonator at the back (which is almost straight through) and you will have a free flowing quiet system that won't attract attention (from the cunstibulary) but have a nice healthy deep roar with no barky noise coming off the accelerator.

I remember when I went to an exhaust place asking for a specific system like the one above, and the fitters were trying to convince me to install a hotdog in the middle. After about half a dozen attempts to convince me, while I was firmly demanding a resonator I picked out from their racks, they listened to what I wanted. I remember their words; "if its too loud don't blames us!". So they told me to come back in an hour. When I arrived back, I found one of the installers, with my car off the hoist and engine running, giving the car a small rev over and over. He said to me " I can't believe how quiet it is!"

I told him, I know what I wanted because I've had that same system in previous cars and it works very well!

 

[Brabham]

What is the function of the hotdog and the resonator specifically (aside from cutting down noise and vibration) to me it always seemed that running all these silencers was a bit excessive

[zed240au]

id have to agree with 2.25 system what i had on my old l26 with hm headers and it sounded great made noticable difference to power as well

went with exhaust shop recomendation just small middle pipe and muffler at rear with 2.5" outlet

though id get quieter muffler if i did it today 20 years ago i just luved the 96 decibels

 

mick

[Zedman240®]

To me a hotdog is just an expensive pipe joiner. The trick is to let the hot exhaust gases expand slowly; that will get rid of the noise. I have a book here on exhaust systems and it has whole chapters dedicated on the way sound waves travel through pipes. A resonator does nothing to slow down the gases passing through it, its there mainly for the gases to expand slowly, cooling and making less noise out the back. The ones I used where about 12cm in diameter and when you see through it, you see nothing but holes in the side. From memory they are packed with fibreglass. The ones with the bits of metal sticking out into the gas flow are the worst. If I can get some pics of everything I'll post them up.

[620Z]

I can tell you 2.25 would be ideal for your application. No smaller. Having gone through about 5 different exhaust systems I can tell you that whilst loud sounds good for a while. It will drive you crazy in the long run. Do not run straight through pipes unless you want to end up deaf on a long drive. I used to have small resonators on my twin 2.5" exhaust system with straight through mufflers. Was way too loud. Short trips it was great but after 6 months it was too loud on extended drives to the point where I didn't enjoy it. I have now settled on much longer resonators and gotten different mufflers which lose little power. Now the car runs way quieter. Lots of people comment on how quiet it is. But at 5-7,000 rpm (because of the diametre) it does get loud and allows good flow. But chugging around town the car sounds almost normal. So the same theory would apply to a single 2.25 system. Smaller than that and I bet you will go bigger a year or so down the track.

[RBZ 260]

ive noticed that if u use japanese branded mufflers the sound is absolutely sweet without resonating its butt off. though they usualy use one big resonator (muffler style) followed by a decent size muffler at the back. very quiet with nice bite on the end. other brand but it is $$$ is Remus. sound brilliant.

 

on NA applications you shouldnt use straight through design. way too loud. on turbo bigger the better and no baffles.

 

also stainless steel pipes makes the car sound different and less resonance not to mention longer lasting.

 

since you have 2" prob there is no point going to 2.25" unless u going to change the front end again down the track. it wouldnt hurt maybe just little bit louder.

 

on my 240z i got extractors 2.25 with press bent 2.25 pipes with one small muffler with (not straight through) way loud. though sounds tuff when pedal is mashed down. being press bent the diameter is more close to 2" on the bends.definetly needs another resonator or small muffler.

 

 

[Zedman240®]

When I was saying about my straight through resonators before, I never mentioned they were quiet as and never gave an annoying droning note on the freeway or that annoying barking note coming off the pedal. I remember going through random breath test stations without even a second look at the car when I left. I'm sure if it sounded too loud they wouldnt've wasted a second to stop and book me...

[Spartan Warrior]

A follow up and pictures would be great once you have had it fitted, cheers

 

Darwin 2 + 2

[chris240]

Aaaanyway, back to the original posting, last weekend I fitted 2" straight thru with an oval shape rear muffler..sound is pretty good.

For the Canberra guys I can really recommend Neil at fyshwick exhaust 2/129 Newcastle street. 

[datsfreak]

I just got a new exhaust 3 days ago- replace my knackered 2 1/4 system with a 2 1/2.

He cut it off at the extractors at the 2 1/2 point.

 

The guy at the shop trialed it with a single "3 flow" at the back BUT he said it sounded crap.

 

So he put on a offset straight thru at the back and hot dog in the middle.

It sounds very good now - at least with my  stockish  l24 thats a everyday car.

 

Its amazing how wonderful our old L6's sound revving out thru gears.