Truenotch

Muffler Tech

Recommended Posts

Have made them out of a bit of everything over the years, inc pink bats i pinched from my oldies ceiling.     But yeh, the above is a good idea for the .. above reasons.  
Have used straight chop strand fiberglass on a lot of them. they do burn out after awhile but not as fast as you would think. closer to the engine, the faster it will happen.    the stainless wool around the perf first is a good idea.   different sizes and shapes will be better at shutting up different tones.   don't ask me what size does what because i don't know.  but its the reason why its good to use at least 2 different size/ shaped mufflers in same system.

for the ls1  3" will be fine if its stock.     The time to ignore the above chart, is on na engine with big cams and overlap.

Edit: yet another top fail

  • Like 2

Share this post


Link to post
Share on other sites

Bigger is better. Less exhaust pressure. Better spool.  Less manifold pressure, less heat build up and less likely to knock.  

Not saying 2.5 wont work. But i would be going 3"  

  • Like 3

Share this post


Link to post
Share on other sites
53 minutes ago, kpr said:

But i would be going 3"  

I'm glad nothing's changed since this thread started in 2013. 

3" is king. 

  • Like 7
  • Haha 1

Share this post


Link to post
Share on other sites
On 07/10/2019 at 13:17, Ashkellybarr said:

Think 2.5” would be to small for a 2.4L turbo with 10:1 comp and high rpm?

TBH with that setup id even be looking at 3.5"  for at least the front section

does depend how much hps and rpms you are talking though. and how much you value the free hps  and quicker spool less backpressure nets you.

  • Like 1

Share this post


Link to post
Share on other sites

Sweet I’ve got 3” straight of the turbo for the down pipe, reduces into 2.5 just past the bottom of the fire wall. Hard case fuel and brake lines are on the inside of that chassis rail.

might need to relocate them while its all a part..

Share this post


Link to post
Share on other sites

Quietly sporty system to suit '70s Pommie four banger with 100-120bhp - 2" pipes big enough, with a couple of Coby-style mufflers, or a two-box at the front and a resonator at the back?

Share this post


Link to post
Share on other sites

The table on the previous page has peaked my interest, my pos racecar runs a stock b18cr which when new was probably good to a touch under 200 flywheel hp. It currently has a thin walled 2 1/4 stainless exhaust system... I could go and make a new system but it would be heavier and I'm 50:50 as to whether there would be any benefit. (based on 185hp listed for me 2 1/4 system) 

Ideally a quick dyno session of a 3 inch side pipe vs the current full system would answer my question i guess. But i'm not really excited about spending monies on this thing. 

 

  • Like 1

Share this post


Link to post
Share on other sites

I think its basically a fact that all hondas go harder with a 3" zaust? Just have to put up with the noise.

You can probably dig through the dead forums and find a million dynos on honda shit (with dead pic links :pale:). You definitely can for K20/24 every combo of parts has been tested if you look.

  • Like 1

Share this post


Link to post
Share on other sites

Looks like the baffle is broken in my starlet's muffler. I pulled the back half of the exhaust off of the car because it sounded like there was a stone rattling around in the rear muffler. It seems to be something similar in length to the muffler itself, so I guess it is the baffle.

What should I do? (It's a stainless exhaust system if that influences any opinions.. I also want the car to be quiet)

Share this post


Link to post
Share on other sites

Stainless? That's not stock. 

Put a mild steel muffler in.  It'll be fine. 

What pipe dimensions, etc? Three quarter inch for the massive powerhouse K-series? 

  • Like 2

Share this post


Link to post
Share on other sites

Been wondering how much weight difference there is for different pipe dias. 

So from 2.5" OD (63mm) to a 3" (76) with the thicker walls theres about 2kg difference

Capture.PNG.39c90f88b9e441a26bec0c309c70187b.PNG

In order for 2kg to pay itself off in terms of power/weight you only need to gain the tiniest fraction of power, like, 1hp and it's worth it
 

  • Like 2

Share this post


Link to post
Share on other sites
19 hours ago, ajg193 said:

What should I do? (It's a stainless exhaust system if that influences any opinions.. I also want the car to be quiet)

Grab new muffler from Autobend, zap it on and good to go.

Share this post


Link to post
Share on other sites
11 hours ago, Roman said:

Been wondering how much weight difference there is for different pipe dias. 

So from 2.5" OD (63mm) to a 3" (76) with the thicker walls theres about 2kg difference

Capture.PNG.39c90f88b9e441a26bec0c309c70187b.PNG

In order for 2kg to pay itself off in terms of power/weight you only need to gain the tiniest fraction of power, like, 1hp and it's worth it
 

   

 

 

 

OD: 76mm    Wall 2mm       2.5m  =  3.14kg  pir2

halve your weight  double your power and   prepare to weld it back together when it falls apart   :  Aluminium

  • Like 3
  • Haha 1

Share this post


Link to post
Share on other sites

3AU 1500cc. I had a front pipe bent up a while back in 1.5" to carry on from the existing 1.5" pipe. Charts say 80HP would be max for that size (I won't make that I don't imagine). Am I better off starting the lot again and upsizing the pipe, or will 1.5" be sweet? Looking to buy a combo bend setup, reso and muffler, some straight pipe, prices of which won't vary much between diameters I don't imagine. Easier to stick with 1.5", but if that will be shooting myself in the foot a bit, i'll upsize it. TIA

Share this post


Link to post
Share on other sites

Certainly won't be doing that haha. Sweet thanks for that, will add on to what I have then, don't want loud noises. Just not keen on keeping the current system and finding out after five minutes of running it's full of holes.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.