Quiet down!

[Bill Waters]

I am beginning to accept the fact that I will have to have some type of noise reduction plan to run on certain tracks in my area. Having searched these pages, there are a number of good discussions. However, most discussions focus on the tactic of changing the side pipe exit so that the noise is directed downward, but I don't think that will suffice for all situations.

I presume that the Challenge car side pipes are without any form of internal muffling. However, the standard roadster side pipes should, including the optional stainless ones - basically a glass-pack style straight through design, of course.

Does anyone know:
1. what the db reading of a standard, unmuffled Challenge car side pipe is at WOT?
2. what performance reduction the muffled FFR side pipes cause?

Thanks,

Bill

[David Hodgkins]

ttt for the racers out there...

[mhoward1]

Believe it or not, I have yet to be dinged, and this included Road Atlanta.

It will say it was much quieter before the headers. The OEM headers actually reduce quite a bit of noise with out a huge penalty in flow.

[Mark Dougherty]

challenge cars use the stock ffr side pipes

[Mark Dougherty]

many things determine DB readings
lower compression gives lower readings
vice versa

[Bill Waters]

That's good news, Marty. I'll have to say, some of the cars that run at Road Atlanta are ear-splitting, so I'll bet I'll be OK there. I am also a member of a club track (Atlanta Motorsports Park), where db restrictions are in the 90s. Our club has neighbors, so I'm thinking the noise rules will be enforced.

I just took delivery of my BBK equal length headers.....

Mark - are the stock pipes then muffled like glass-packs?

Thanks, guys.

[wallace18]

If you need a set of stock side pipes I have a brand new set in the box. PM me if interested. I'll make you a deal on them.

[Gordon Levy]

What you will end up with is probably 2 sets of pipes. One with a very quiet muffler and the other stock or open. The other option is make the side pipe a slip on and have a few different inserts for different tracks with noise restrictions.

[GoDadGo]

I've used the Dynatech Cone Inserts in a 3" diameter, 20" long collector on another car.
It took the edge off the open header exhaust note; however, I cannot tell you how much it helped or hurt the overall performance because the car was never run on a dyno.
Overall E.T.'s stayed the same with a loss of 1 or 2 MPH on the big end, but improved on 60' times a tenth or two with the 1/8 mile MPH being virtually unchanged.
383 SBC / 1980 Camaro Z-28 / 3,600 Pound Car / 3.73 Ring & Pinion Ratio

[Bill Waters]

Thanks, Gordon. But clarify something for me. I am under the impression that the stock side pipe is muffled with a glass pack - type configuration (i.e., with 'glass packing along the walls of the side pipe held in place by a slotted metal shroud). Is that true? If so, what would you do to create more muffling? Or do the stock ones have a less effective type of muffling?

edit: I just read on the FFR Web site that the stainless side pipes are glass-packed; what about the regular, mild steel ones?

edit: And thanks, GoDadGo; your post pooped up the instant I responded to Gordon. That's very useful information; thanks

[Mark Dougherty]

yes
the stock pipes are a large glass pack
there is a thread on the forum about a much quieter glass pack to replace the FFR unit
if you need someone to weld them in for you let me know
we can mock them up on a car and do it for you

[Bill Waters]

OK; thanks, Mark. I'll see how the stock ones do and go from there.

Bill

[avgjoe]

Don't forget to read the rules or check with a series director.

Our cars are pretty low/deep toned(?) compared to a straight pipe rotary (OMG, jab a pen in my ear to make the noise stop!). Most of us have not had a problem but I know it can be a track/regime specific problem.

[Bill Waters]

avgjoe - I'm sure you're right. I want to be able to at least show a good-faith effort at rules compliance, especially with my club track and its neighbors. I also agree with you about the rotaries! Absolutely piercing.

Thanks