Would an inline muffler with 1 inlet and 2 outlets work well as a y-pipe?

 

I don't see any reason it wouldn't.

However, make sure that it can handle the heat. The exhaust temperatures off a rotary are SIGNIFICANTLY higher than a piston engine, and it's not unheard of for people to literally melt muffler insides, or burn through cheap mufflers in a matter of days or weeks.

If you can find a good quality heavy duty muffler that can take the heat, it should work fine.

-=Russ=-

 

It would work fine, but I wouldn't do it unless I knew exactly what the inside of the muffler looked like. There are good dual-to-single mufflers and there are bad ones. At least with a Y-pipe you can clearly see if it's a good one or not.

 

This is how it looks like if it will help

 

what brand is it? the magna flo mufflers can take the heat.

 

that is a magnaflow design

 

bump

 

Effectiveness isn't going to be your problem...nor is heat. You're just simply not going to fit the thing under the car unless you mount it in the cat area, and even then I don't think you're going to have room.

 

so if i choose to use a hi flow cat, there won't be enough room for any kind of inline muffler?

 

Not in the exhaust routing.

 

do you need a muffler or could i run just straight pipe (86fc 13bn/a)

 

Not and keep your 6-ports.

 

Yah with an '86 you'd either have to wire your 5-6 ports open and lose all sorts of low end power, or get the rb exhaust which still creates backpressure to open your ports.

 

dont put it in the location of the stock ypipe, you're gonna see sparks every time you hit a crack in the road....

 

... or wire up an RPM switch and low pressure air compressor, or use the air pump, or one of many other options to open the ports without the rather unreliable exhaust backpressure method.

-=Russ=-

 

Rather unreliable?

 

I can say that the RPM switch and low pressure air pump setup works great. I'd never do it any other way.

 

Exhaust backpressure is less reliable when exhaust system mods are done, and even when it works perfectly it is less predictable than an RPM switch.

Instead of screwing with making sure backpressure is proper, just put the ports on an RPM switch & air source. Heck, if you want, you can tie the starter signal in to flip them open during starting just like the RX-8 uses to make sure they stay free.

-=Russ=-

 

...or you could remove the sleeves and actuators all together and not lose anything noticeable.

(I don't consider a 4hp loss below 4000rpm "noticeable")

 

Have you driven the car in this state directly after driving it with working ports?

Right now my ports are on a switch, because I haven't gotten around to building an RPM switch (and I seldom take it over 4k RPM unless I'm merging onto highways, so it's easy enough to just tap the switch before launching up an onramp).

The difference between the ports open & closed at low RPM (sub-3k) is VERY noticeable. On a track car, it may not matter, but for a car that is driven with a significant amount of time below 4k RPM, you will notice a significant difference.

4hp is significant if the engine is only making 30hp or so at that particular RPM.

-=Russ=-

 

Yes. Do some searching. This has been discussed and proven. The power loss down-low is minimal. If you suddenly lose your abillity to cruise at low RPM, you have other problems.

 

Fine, call it whatever you want. The car drives fine with the ports open, but there is what I could consider a noticeable lack of torque with them open.

-=Russ=-

 

No, it's been claimed by some, and refuted by others. Nobody has ever posted any real proof either way, despite the fact that is only takes two dyno runs (ports closed then ports open) to come up with some pretty conclusive evidence.

 

I found one quite a while back searching for random crap in this section...there was no "before" run, but there were plenty of other graphs to compare to. Showed that there was similar power up top, and a 2~6hp drop everywhere below 4200rpm.

I don't see that kind of drop as "destroying low rpm driveabillity".

but you're right, without back to back dynos it's kind of a moot argument, and I've never seen back to back dynos. I'd love to do one myself...maybe the next project car will be another FC...

 

A line welded on the header first bend and looking straight into the port works effectly on opening your aux ports. I used a compression type fitting and used brake line which then went to standard silicon vac line to the port actuators when I ran true duals. Worked great, no switches, no air pumps etc.

~Mike..........