Datsun Roadster Forum-311s.org

Pulled my '67 2000 (#1001) out of the garage to test fit the new center exit pipes....






Plenty of clearance!




Routing:

I personally wouldn't want the duals directly under the tank.

Alvin's model make it look possible. If you take out the resonator it looks like the tank could shift sideways about an inch to give enough room to run pipes against the floor, around the tank and then back out the center. That would work well with a center inlet, outlet at both ends sort of muffler that might be hidden behind the diff.
Thinking of my 300ZX, there is very little room anywhere. The heat shields on the exhause clear the pipe by less than 1/4" and have about the same clearance to the body.
Dan

Ha! hell yeah Alvin, that is great. This visual got me thinking that utilizing the space between the tank and rear bumper, could also be an option. It wouldnt look exactly like the two straight pipes out the back but depending on measurements, I could retrofit a style of muffler like these. Has this been done?

I'll do some measuring when I get home to see how much room there is and how much of the canister you'd end up seeing.

Yeah I know, my skills in "Paint" are unreal.

This is what I thought could work

Thanks Alvin for the complement on the systems! Many folks on the forum have my SS system in either stock 1 ¾ or 2”. They are very high flow and provide the original roadster look with an easy installation factory mounting. I can even do a “below the rear axle” pipe option for the very lowest in restriction. (Isn’t really necessary with the precision formed pipes)

Here are my thoughts:

First on maximum performance – that is what the BRE system was really about and routing it down the center tunnel and straight out the back makes sense on a Z with 3 cylinders/pipe and minimal bends along the way. Down the tunnel is the least restrictive, nearly straight route. That method isn’t really practical in a roadster since you really don’t want the exhaust running below the frame (especially if the car is lowered). (Z’s and 510’s don’t have frames)

Concerning pipe routing, I agree with Sid about not running the pipes under the tank . Just from a practical perspective, it isn’t a very good idea, because:

1. If you wanted to drop the tank (pretty common exercise with roadsters), you would have to remove the rear exhaust, which would be a pain, so that’s not really a step forward.
2. You would need a mount to hang down in front of the tank to support the pipes, can be done, just but not very convenient location.
3. The pipes would be right at the fattest part of the rear axle, so there isn’t much space there for bends and routing.
4. Shocks, hydraulics, fuel lines and brake linkage are all inconvenient for this route.
5. Heat shields and all that jazz for the tank and just the fact that the pipes would be so low and easy to damage both the pipes and possibly the the gas tank.
6. I’m not saying it could not be done, it just doesn’t seem to be a good way to go for these reasons and more.

So if the “BRE Look” is really what you want, here is what I’d suggest:

Run the pipe/muffler in the standard route with 2” rear pipe. Use all the factory mounting points so the system doesn’t rattle on the frame.

Use a SS rear resonator (without the megaphone) in the factory position next to the tank.

After the rear resonator can, hang a 90 degree mandrel bend in 2 or 2 1/8” from the rear-most exhaust mount and run it under the rear frame member. (It could be painted black so you don’t see much of it.) It would not need to hang down any lower than the regular exhaust exit, so it would not be below the tank level. That is good for clearance reasons.

Have two polished 316 SS pipes come off that pipe running under the frame. (They could be at almost any spacing apart)
The right pipe could also exit with a mandrel bend for high flow. The right side would need support as well.

Pretty sure I can build all this as a bolt-on if desired.

You might need some extended mounts for the reverse lights so you don’t cook them.

Personally I would not try force fitting some aftermarket muffler behind the tank for both flow, fitment, weight, and mounting reasons.


Hope this helps! LMK if anyone wants a prototype built.
jt

Form was following function on the Z exhaust. Because of the IRS, there was nowhere else to route the pipes but under the stationary pumpkin what with all the control arms flopping around back there.

I love the look on the roadster and would probably do it the way JT describes it above.

JT, this is some really good info. Thank you for the insight. Your idea sounds like the best option.. Just so I can have a visual. Is this design similar to what you are talking about? Obviously different car and different side, but concept wise this looks to be what you are describing.

Yep, same general concept, different execution, hangers etc. j

JT68 wrote:Yep, same general concept, different execution, hangers etc. j

I think this would look real good, especially if the horizontal pipe leading to the tips were blacked out. You think this is something that you could design and build, bolt in? As for the additional hanger, the rear cross bar of the frame could be utilized, right?

I would have to come up with something for the reverse lights. even if I moved them further apart, I dont think it would look very "clean" with them, too much going on.

I found this picture, with the top reflectors converted to reverse lights. This could be an option, seems like a pretty simple modification.

Does anyone know if this car belongs to a member on the forum? I'd be interested to see how the dual exhaust was configured underneath.

DatsunRoadster2000 wrote:
Does anyone know if this car belongs to a member on the forum? I'd be interested to see how the dual exhaust was configured underneath.

...but that is not "BRE Style"!

DatsunRoadster2000 wrote:

JT68 wrote:Yep, same general concept, different execution, hangers etc. j

I think this would look real good, especially if the horizontal pipe leading to the tips were blacked out. You think this is something that you could design and build, bolt in? As for the additional hanger, the rear cross bar of the frame could be utilized, right?

I would have to come up with something for the reverse lights. even if I moved them further apart, I dont think it would look very "clean" with them, too much going on.

Absolutely, glad to do it.

Just tell me what pipe size you want to meet up with (or I build all those pipes too), what size and spacing between the two rear pipes , and how far beyond the bumper to protrude. I can build it pretty inexepensive as a prototype and we can go from there.

The backup light won't be a big deal certainly, probably just use 1 not 2 - like the earlier cars and just position it in a reasonable spot (maybe just a simple bracket mod) not a big deal.

send me a pm and we can figure out the details. I can put it on a 2L to show you photos etc. jt

I'll do a proto with 2" pipe with similar spacing to what Alvin posted on the silver model and post some photos. jt

Alvin wrote:

DatsunRoadster2000 wrote:
Does anyone know if this car belongs to a member on the forum? I'd be interested to see how the dual exhaust was configured underneath.

...but that is not "BRE Style"!

I know I know! I was mostly using that picture to show an option for what to do with the reverse lights. Dont see dual exhausts like that on our cars often so just curious!

Using JT's idea, I can make the spacing on the pipes far enough apart to where it would emulate the BRE style, without having to go through the complications of the gas tank clearance and heat shield etc.

Seems like a much better approach than serpentining up, around,in front/and under the tank and axle.

Could also do just one reverse light in the center (there is a captive bolt we can utilize) There are lots of visually decent ways to address the light detail...

I think it could be kinda cool if you want to get away from the stock megaphone look - which is of course, classic Datsun Roadster.

Only thing I don't like about it is the idea of getting close to the hot pipes after a long drive if you need to get in the trunk. Could be a burner.

From that perspective , keeping the pipes over to the sides and not protruding out very far is mo - betta. I'll set it up like Alvin showed, just for fun.

Truth be told though, the stock routing with a 2" megaphone WOULD flow better just because is a straight shot after the axle. The difference may be academic however for must engines. jt