Datsun Roadster Forum-311s.org

What muffler are some of you using out there? I've been running straight pipe so far, but last time at Roebling I was right up against the 106 limit. I'd like to run some other tracks that are a little more restrictive on dB, so I will need to come up with a muffler plan. I'm still finishing up the car, but I hope to be able to run 2.5" exhaust since a PO had increased the openings in the frame. Worst case will be 2.25". Thanks.

2.25" or 2.5" inlet to 4.5" outlet SuperTrapp with number of plates and open vs. closed end affecting tuning and dB.

McDowell car had a muffler. Because Dave was tiny, he was able to cut out the outside floor on the drivers side and build a box over it, and the muffler was between the seat and the door. That did not function for me. I needed the space, so the box and the muffler were removed, and we went to straight pipe.

I believe it was some sort of Magnaflow.

Vest car did not come with a muffler, we have not run one.

Burns stainless make race mufflers pricy but good quality

Thanks everyone. Hadn't thought of the Supertrapp. Worth some more research.

Hi Al,

I have one on the 2000. I think it may be a Burns but I can't remember. It's narrow and fits in the space between the rocker and frame as that's where my exhaust runs. Exit is in front of the rear wheel.

Mike

I definitely suggest researching the SuperTrapp mufflers before you purchase, most of my reading suggests a performance reduction with them...

With a SuperTrapp, the number of plates (up to 12) and open vs. closed end affect both tuning and dB.

The Mazda 13B crowd is where the SuperTrapp first got its reputation of augmenting power (if done right, from intake to SuperTrapp) and getting under dB limits.

My new exhaust manifold design will be tested on the dyno in several weeks.

Running a 3 inch straight through flowmaster (has about a 4 inch round case) that fits in space between frame and rocker. Stainless steel and the cheapest thing on my header exhaust. Sound good but a little loud. Have not run it a lot yet but seems to work.

Is that a BRE-style over- and under-frame header?

I've got a 2.5" straight through 12" 'muffler' between the X frame exiting in front of the rear tyre and its under 95dba, which is our usual race limit in Oz, didn't seem to impact power materially between engine and chassis dyno readings

In answer to RWMann- yes it is a under over frame header type exhaust. Looks like car had one previously (supports between rocker and frame modified to make room for exhaust) but pipes to collector and the collector back was missing. So had to get most recreated since header pipes where cut at the frame. Had a local shop use a Speedway mustang 1 5/8 header kit to cut and weld pipes and collector and then added a flowmaster tube muffler and stainless 45 degree tailpipe. Seems to fit ok. But will know when use it more.

Still trying to figure out if the car has any prior race history since it seems fairly well set up and race paint scheme does not seem all that recent and shows some racing scars.

I think those are the longest primaries on any header I've ever seen on a roadster.
Would love to see a dyno sheet from that engine.