Tweety and Sylvester, Two RX7s are better than one!

[spirit r]

Three Rx7s are better than two! You are the FB King now James.
I like that elford rear wing most!

[spirit r]

Any chance to get some detail pics of Sylvester's stainless steal exhaust? I think about open my racing beat muffler and restore the inside getting it a little more quiet after 30 years now. I read something about your muffler you get the option to refill it very easy.

[gt_james]

Hi Thomas,

here's the exhaust on Sylvester, I essentially copied the racing beat system.



chinese racing beat copy header, 2" stainless 304 tube, the exhaust builder did go over some of the welds, but overall quality was good for a chinese copy part.



header back system was custom work by Martin Kerr at tubeworx to racing beat style layout. These pre silencers are SS wool packed, but not repackable.



Over axle and merge at around 120", into 3" tail section



Custom rear box, repackable. This is 8" round, the big clamp at the front of the box lets you slide it off to repack.



Overall I'm pleased with the system, seams to flow well, no dyno results. Keeps it down to 99dB. I think the presilencers should have been made repackable as well really, but it was a balance between cost and performance, and the presilencers are harder to repack.

On my race car I will be doing the same sort of thing, but instead of the pre silencers, the mid pipe will be un silenced, to help with scavenging, as the pre silencers do reduce the effectiveness, and it will help with ground clearance. I will stick with a rapackable back box, hopefully this will keep the 12Abp down to 105db. If needed I will add another box below the rear bumper across the car, will look a bit ugly but needs must.

[gt_james]

In terms off silencer packing, the best for reducing the sound is fibreglass, but this will burn out extremely quickly, and wont even last a qualifying session.

Stainless wool is longer lasting, but still burns out quickly. My silencer is a few rolls of stainless wool, then the outer layer is glass. Its normal to repack the silencers between race meetings, but you want it to reasonably last qualy and a couple of races.

If you don't want to pack regularly use lava rock from aquariums. Its heavy, doesn't silence as well, but it wont burn. Needed for longer races, and probably good for a road car as a fit and forget silencing packing.

[spirit r]

Thanks for sharing your very interesting experience!

Did you what racing beat take in there old mufflers cause i found a very special package resistant at 1000C degree.
Not shure lava rock from my barbeque grill or aquarium will help to be quiet on bad streets

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[gt_james]

Racing beat uses SS wool. Some ceramic packing material works, but mostly its no better than fibreglass. No idea if what you posted is the good stuff or not.

[gt_james]

More important to put the biggest (outer diameter and length) silencer on than what material is in it IMO, especially for a repackable one as you can try a few different materials.

[gt_james]

Just had a look and Racing beat say their ceramic wool is rated at 2000c, I imagine the 1000c rated stuff you posted will not be an improvement over SS wool, but obviously the only way to know is to try it.

[spirit r]

Just had a look and Racing beat say their ceramic wool is rated at 2000c, I imagine the 1000c rated stuff you posted will not be an improvement over SS wool, but obviously the only way to know is to try it.

2000` F = 1000`C

so more then 1000`C are even better then the racing beat ceramic wool.

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[spirit r]

Hi James,
i wanted to restore my old racing beat muffler cause the new muffler sucks.
Can you post some pics from the inside and a soundfile of your repackable muffler please?