[Spridgets] 1275 with headers exhaust?

Fri Jun 29 16:29:53 MDT 2018

Here in the UK noise has become a bigger issue over the last decade + (that
I've been a scrutineer (tech official)). A turned down pipe outlet or a
turned outside track rather than inside track doesn't fool us.  Nor does
under declaring the rpm limit for testing, or rigging the tacho to under
read rpm.  Several tracks have sophisticated sound metering equipment that
not only identified a noisy car but takes a photo of it (while racing on
the track) with the decibel reading imposed on the photo. Some even
automatically send that data to the local council/authority.

However, noisy cars don't necessarily make more power.  Yes, there is a
weight penalty on having an exhaust silencer fitted but any good quality
silencer on a racing A-series engine won't rob power.  If you're interested
in exhaust add-on parts, like the Super trap product - read what David
Vizard has to say about them. In recent years they have become increasingly
scarce in UK motorsport, and that's not just because they often parted
company with the exhaust system pipe.

UK Noise limits vary but 98 to 103, and occasionally 105 are typical.

Regards

Daniel

On Thu, Jun 28, 2018 at 3:23 AM, crusaderchuck55 at aol.com via Spridgets <
spridgets at autox.team.net> wrote:

> Considering I'm better known for racing my 1960 saab 93F , I'm very aware
> of decibels.   Kinda explains why I have my own meter?  LOL!
>
> We encountered ( a number of years ago) a huge amount of prejudice towards
> the saab and rotary powered RX7's with the Pennsylvania hillclimb
> association.  After a few events the individuals objecting to our alleged
> offensive noise .....backed off significantly!   Why you ask??   It was
> determined the MAC's, MGB's and spridgets were producing high enough levels
> that they should have been protested , not our saab nor the mazdas.
> Rotarys & 2 strokes have piercing high pitches, but not near the SCCA
> maximum allowed Db limits.  And I'm aware of troubling road and lime rock
> with restrictions.    I did add a turn down to attempt to be kind to our
> starting line workers at hillclimbs but it had no bearing on our Db
> readings.  Chuck
>
>
> Sent from my LG Mobile
>
>
> ------ Original message------
>
> *From: *Bob Spruck
>
> *Date: *Wed, Jun 27, 2018 9:21 PM
>
> *To: *spridgets at autox.team.net;crusaderchuck55 at aol.com;
>
> *Subject:*Re: [Spridgets] 1275 with headers exhaust?
>
>
> FYI - One thing to consider is noise limits at the tracks you plan to race
> at. I race at Road Atlanta which has none but the limit at Roebling Road is
> 104 decibels for vintage cars. I am also a Tech Inspector for VDCA and warn
> new drivers of the consequences of too loud exhaust. They send you home!
> Most drivers have designed a swiveling, down-turned tailpipe extension that
> can be pointed away from the meter at the sound station. Some drivers have
> had to install a muffler (what heresy!). A friend in a Turner had to back
> off at a point about 1/3 down the front straight, where the sound meter
> was. Really impacted his racing and happiness (and safety). The
> neighborhood monitors impose LARGE fines to the track for those over the
> limit.
>
> Just sayin'.
>
> Bob Spruck
>
> On 6/27/2018 6:00 PM, Rick Fisk via Spridgets wrote:
>
> This was on my car when I bought it a few months ago.  No pipe at all
> under the car!
>
> [image: image1.JPG]
>
> Sent from my keyboard
>
> On Jun 27, 2018, at 4:10 PM, crusaderchuck55 at aol.com via Spridgets <
> spridgets at autox.team.net> wrote:
>
> Here's a question!   Ignore what size header collector..ok?  Ignore the
> fact all available mufflers only come in a certain size!
>
> What diameter pipe would you run from front to back and why.  I'm building
> an exhaust for Frank's race car project.  I'm making an oval pipe for front
> to rear ( or possibly a side pipe! A custom made side exit header is coming
> my way and might end up on the car!).   I've heard a lot of 1&3/4", 1&7/8"
> and 2" suggestions.   Ok what's going to work for a tad of back pressure
> and outright breathing if I create a chambered pipe ( like corvette 1960's
> had) .   I can fabricate any specific area in an oval as far as the end
> area equaling a round pipe.
>
> So, what are the collective thoughts?
>
> Share away!
>
> I'm not putting a round pipe under this car!   Also I'm not going through
> the tunnel.  Also for those of you who have had dyno time,  the length is
> important to dial in max torque at a specific RPM range.
>
> So?  What cha think?
>
> Chuck
>
> Flogging away on Frank's race car!!
> Sent from my LG Mobile
>
> ------------------------
>
> spridgets at autox.team.net
>
> Donate: http://www.team.net/donate.html
> Suggested annual donation: $12.75
>
> Archive: http://www.team.net/pipermail/spridgets
>
> Unsubscribe/Manage: http://autox.team.net/mailman/
> options/spridgets/refisk at chartermi.net
>
>
>
> ------------------------spridgets at autox.team.netDonate: http://www.team.net/donate.htmlSuggested annual donation: $12.75Archive: http://www.team.net/pipermail/spridgetsUnsubscribe/Manage: http://autox.team.net/mailman/options/spridgets/raspruck@gmail.com
>
>
>
> ------------------------
>
> spridgets at autox.team.net
>
> Donate: http://www.team.net/donate.html
> Suggested annual donation: $12.75
>
> Archive: http://www.team.net/pipermail/spridgets
>
> Unsubscribe/Manage: http://autox.team.net/mailman/
> options/spridgets/weslake1330 at gmail.com
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://autox.team.net/pipermail/spridgets/attachments/20180629/1a99e151/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 1530151942066.png
Type: image/png
Size: 240630 bytes
Desc: not available
URL: <http://autox.team.net/pipermail/spridgets/attachments/20180629/1a99e151/attachment.png>