45 replies to this topic

[LXCHEV]

Damn, you guys are making me want Hooker mufflers so bad!!!! But I'm trying to shut it up!!!! lol. Maybe I'll have to have several exhaust systems made

82911 - Are your Hookers the aero-chamber ones or a different style?

Liam - yep the Dynomax are definintely at the top of my list, but I would love to try out all 4 of those!!!! I need an exhaust sponsor! I'm hoping Struggler or someone can enlighten us as to where we can buy the Dynomax's in Australia (if there's even a supplier).... maybe he ordered his direct from the states... By the way, it's funny we are both chasing the exact same thing - less putt putt and more deepness in the note!

[Struggler]

I'm hoping Struggler or someone can enlighten us as to where we can buy the Dynomax's in Australia (if there's even a supplier)....

Brett, you should be able to get them at any exhaust outlet, they are a very big supplier !

Pick up the Yellow Pages and let your fingers do the walking !!!

[Struggler]

How big are the truck mufflers you are talking about Struggler?  Is it the length or the width that makes the difference to quietness?

Just the volume. Beware though as some have a large internal baffle blocking direct flow. You want to be able to hold it up and look straight thru at the full diameter of the pipe for which it was intended. The truck mufflers I am setting up now are 24" long, 8" in diameter. On my old 454 HQ I used 2 at 36" long, 10" diameter. They fitted under the boot where the fuel tank used to be. It was one of the quietest cars at the track, yet still ran 9.5's with the exhaust on.

This raises another point.... to get the best (read biggest) volume you can use a larger diameter muffler than your system, and have the pipe flared up to suit. For example you can fit a 3.5" truck muffler in your 3" system. This will give greater flow and less restriction than fitting a 3" muffler. Remember to reduce the pipe size back down after the muffler though...... you DONT want the rice look. Having a tail pipe that is too large makes the exhaust too noisy (as the ricers demonstrate). Remember, as the exhaust gets further from the engine it cools and slows down, therefore the diameter of pipe required is less. Fitting smaller tailpipes is a great way to knock the noise down. Also run at least 8" of tailpipe from the muffler to the atmosphere, any less will also create too much noise.

[LXCHEV]

Thanks again guys!

[LXCHEV]

Ok first round results are in. I bought myself a sound level meter, should be accurate enough to give decent ball-park readings. It has 2 settings - 'A' weighting and 'C' weighting. I'm not sure what official EPA meters use, but from what I've read, I believe 'A' is for measuring noise, 'C' is more for music etc.

Anyway, on the 'A' setting, my car is 90dB at idle, 98dB at 2,000 and ramps up to about 106dB at approx 3300/3400rpm. (From memory this is the rpm tested at for a V8 in Victoria). If I change the meter to 'C' weighting, these readings go slightly higher again by another few dB.

So it looks like I need to remove approx 10dB. Changing to triple-pass mufflers will be very interesting to see the exact change. Will keep you posted.....

[LXCHEV]

Liam, yeah mate we will have to test your car on the meter for sure! Anytime dude!

As for the 3/4 throttle thing, nope, it's definitely a fixed RPM in Vic (different RPM for 4cyl, 6cyl, 8cyl, rotarys etc). I've been through it twice before with my car (once with the 6, once with the V8). Also Deb's EH too. Every time they had a set RPM level to test at. (The figures are available somewhere, I just can't remember where). I'll have to dig out my old paperwork and see what I can find there.

[Tiny]

In NSW they test 4 cyls at 3000Rpm, V8s at 3500Rpm and roataries at 4000 Rpm.

With a limit of 96 DB @ 3500Rpm i think i'm going to be pushing it uphill to get there!

Will let you know though i'm getting an engineer to sus the car out next week hopefully!

Cheers

[LhMusL]

Digging this up
How did you go in the end brett???????????

[LXCHEV]

Wow this is an old topic!

Luke I am actually still running the same mufflers. We had played around with the system a little bit - by fitting twin 10" hotdogs (resonators) into it (before the mufflers), and running twin 2.5" tailpipes, the note settled down a little bit to what it was originally (still loud, but not insane loud).

I still want to change mufflers at some stage (away from these interference/expansion chamber ones)... I was planning to go for the Dynomax Super Turbo triple flows as suggested by Struggler. I just can't justify the cash yet to change something that isn't broken! I keep getting comments about how good the car sounds, so for now these mufflers will stay a bit longer.

Liam did end up changing his mufflers - hopefully he will give us his thoughts and comments.

[LXCHEV]

PS. Keep us updated Herne.