Are there cheaper alternatives to the RB pre-silencers? For those that have the pre-silencers are there actually little holes internally along the length of piping? Are they packed with stainless steel or lava rock or something? I will probably buy a racing beat road race header but I'd like to fab the rest of my exhaust. It will be used on a peripheral port 12a so it has to quiet things down a good bit. I have some nice thick walled 3" diameter mild steel piping that I was thinking I could use to make pre-silencers...depending on their composition. Could I run a 2" pipe through the 3", pack it with something, and weld flanges around the end that fit over the 2" pipe and block off the 3"?

I'm just looking for ideas here.

 

buy a cherry bomb
cut it open take the fiberglass out and put
stainless steel packing in re weld it and BAM, you got a ghetto cheap presilencer

-greg

 

Sweet burnout pic!!!!!!!!!!!!!! ill think about that presilencer idea.

 

I will definitely look in to that. Is this something you have done before or seen done perhaps? Do I just use regular steel wool? Will it quiet things down approximately the same as a RB pre-silencer would?

 

I bought the bonez presilencer, from rx7.com, I think it was, $150 delivered with the installation hardware. It's a straight pipe with an expanded middle section that has lots of small (1/4") holes opening from the pipe into the expanded part, but the pipe itself is completely open.

The unit is of very good quality and a perfect replacement for the three cats in the 84/85 12A cars, very easy to install. I had it in in about two hours, most of that time spent getting the car up on jacks.

I think it is worth paying a bit more to get a proven unit that is a simple bolt on, rather than spending time and effort fabricating something that's a pain to put in and probably won't work as well. I had cherry bombs on my '38 chevy pickup, retrofitted with a corvette engine and hurst shifter, which seems about right for cherry bombs. RX-7s deserve better.

The cat back system on my 85 GSL is some generic american unit, probably midaz or something, not installed by me. Still with the presilencer this system produces a great sound, not too loud and not at all tinny, a nice throaty note kind of like my MGB. Also got a nice power boost, an excellent return for a couple hour's work.

I'm hoping the generic muffler will rust out or blow up, like they say cheap exhaust systems on rotaries tend to do. Then I can put on a stock or racing beat muffler, but so far the american tin can is holding up well.

Ray

 

Hey

I paid 50.00 for a used RB pre-silencer.....wiped it off and it was brand new........will last forever........cant beat RB's product.......look for a used one.....save some money.....Stick with the best.....

 

......use lots of periods.......