Datsun Roadster Forum-311s.org

Hi Elvin. Do we have a part number on the resonator or the muffler

I have a Borla I'll sell at cost. Don't care for the fit. pm or email jt

A tiny bit OT but it relates...

Anybody been to the Two Stroke Extravaganza that takes place near Sylmar or Santa Clarita? At noon, everyone starts up thier two strokes and revs thier engines.. “Smoke out at Noon!” its announced. Oil, smoke, un burnt fuel everywhere in a public park.. not sure how they get away with something like that.

It was really cool to be able to see each bike in action. Some really rare race bikes are demo as well, exotic four cylinder smokers, and some oddities. Somebody usually get carried away and does a burn out or two.

“Datsuns...start your engines!!!”

Revisiting.....

Both alvin's old and new systems do not route over the rear axle. Looks very clean plus more direct route. Is over the rear axle necessary, or was this because of Alvin's non-stock engine and suspension?



Is a resonator necessary? What about moving the muffler back behind the rear axle where the resonator normally resides, which would eliminate the heat and noise directly under the driver? If possible, does eliminating the resonator change the muffler requirements?

Thanks,

One issue when having a pipe under the axle is that, if you jack up the car on the body, the axle can drop down and rest on the exhaust. Does on mine, so I try to lift the car by the diff. I have a Dynomax turbo with a monza tip. It's a nice rumble that's not too loud and never raspy. My carbs can be louder.

ppeters914 wrote: ↑Tue Jul 05, 2022 6:09 pm Revisiting.....

Both alvin's old and new systems do not route over the rear axle. Looks very clean plus more direct route. Is over the rear axle necessary, or was this because of Alvin's non-stock engine and suspension?



Is a resonator necessary? What about moving the muffler back behind the rear axle where the resonator normally resides, which would eliminate the heat and noise directly under the driver? If possible, does eliminating the resonator change the muffler requirements?

Thanks,

Hi Pete,
The exhaust was routed under axle because of the 4-link suspension. It's designed to have clearance at full droop.
I've seen it routed under axle on a few stock-suspension roadsters as well.

A resonator is not necessary. The area where the stock resonator resides is between the leaf spring and fuel tank. A standard, oval-style muffler will not fit in this space laying flat. I've seen a few mounted vertically like on an S30.

Gregs672000 wrote: ↑Tue Jul 05, 2022 10:40 pm One issue when having a pipe under the axle is that, if you jack up the car on the body, the axle can drop down and rest on the exhaust. Does on mine, so I try to lift the car by the diff. I have a Dynomax turbo with a monza tip. It's a nice rumble that's not too loud and never raspy. My carbs can be louder.

Hi Greg,

Do you have just the Dynamic muffler or a resonator, too? Pics?

Alvin wrote: ↑Tue Jul 05, 2022 11:59 pm

ppeters914 wrote: ↑Tue Jul 05, 2022 6:09 pm Revisiting.....

Both alvin's old and new systems do not route over the rear axle. Looks very clean plus more direct route. Is over the rear axle necessary, or was this because of Alvin's non-stock engine and suspension?



Is a resonator necessary? What about moving the muffler back behind the rear axle where the resonator normally resides, which would eliminate the heat and noise directly under the driver? If possible, does eliminating the resonator change the muffler requirements?

Thanks,

Hi Pete,
The exhaust was routed under axle because of the 4-link suspension. It's designed to have clearance at full droop.
I've seen it routed under axle on a few stock-suspension roadsters as well.

A resonator is not necessary. The area where the stock resonator resides is between the leaf spring and fuel tank. A standard, oval-style muffler will not fit in this space laying flat. I've seen a few mounted vertically like on an S30.

Hi Alvin,

Why did you a add a resonator? Are you still happy with this setup, or would you do something different?

I run a very small Flowmaster straight through muffler on my 2000. When I had the exhaust system built I had a flange installed just aft of the axle. Then I had two tips made, one with a resonator and one without. I initially started with the non resonator tip, and while it sounded good it also had a lot of popping and crackling on deceleration. I figured that was going to get me in trouble with the neighbors as well as the police. The resonator tip got rid of 95% of the popping and slightly mellowed the sound. Quality of sound is subjective, so going by what somebody else did without hearing it first is somewhat of a crapshoot.

Pete, I don't have any pics at the moment, but the routing is pretty much what you see with Alvin's, just not as nice (not SS or mandrel bent). The Monza tip is a single and is a small glass pack. I think it makes an important sound difference. As I recall it's 2.25 through the frame (frame holes widened) and 2.5 after, non stock mounts and the flex pipe was moved to the middle of the X instead of just past the header due to the mounting choices made (size is probably overkill, but it doesn't vibrate). I REALLY like the sound... it's a deep rumble for a 4 cylinder. It only pops when my fuel settings are too lean on deceleration, and matches up well with the induction sound. I am comfortable driving through camp grounds etc because it's not obnoxious, and does not get raspy at WOT. I would not call it quiet, but it's a pleasant sound.

A few pictures of under-axle exhaust routing:
viewtopic.php?p=202206#p202206

Mine is just a stock 3-main R16 w/ SU's and header (brand unknown). Except for the header, the system that came w/ the car was basically I-just-bought-a-welder crappy welds and old school Cherry Bomb-style mufflers. The piping and mufflers went to metal recycling.

A little rumble and not raspy (IMO the Datsun equivalent to crappy VW) w/o setting off alarms, campers, and neighbors is exactly what I'm looking for. I figure adding a flex pipe and using 1-3/4 or 1-7/8 piping should be adequate. Just need to decide on muffler and resonator (or maybe no resonator).