exahust port size

[stuart wizy]

pic on left is std port pic on right opened out port on fc rotor housings
should i go bigger on my exahust ports for a full bridge port engine?

[JayDee]

For a bridge i would go bigger, down aswell as up, make sure you put the taper back on the edge of the port like on the standard one.
Have you gone outwards at all?

Jason

[stuart wizy]

im quite close to breaking through the steel insert looking from inside the rotor housing, ive gone up and down and sideways but i didnt want to go through the steel insert where is meets the housing face, thought it might be a bit weak

[stuart wizy]

am i right in thinking increase the square area of the exaust port the same as the increase in square area on side housings (bridges)?

[JayDee]

You dont want to port the steel insert, just polish it up only port the aluminium. The port will stay the same size where the steel insert starts.

[stuart wizy]

cheers for that info mate, much appreciated

[JayDee]

I personally dont, as the exhaust port has a less restrictive path to flow. What are your plans for the car? What turbo are you using? How much boost? etc depends on the size of the port

am i right in thinking increase the square area of the exaust port the same as the increase in square area on side housings (bridges)?

[stuart wizy]

as much power as possible for drag and track use
3mm atkins seals solid corner seals full bridge 100mm thick large front mount all ic pipng no less than 70mm with 120mm straight inlet all made from ali 1.5 wall tube
t51r turbo
dont have ecu or large injectors yet
going to make injector rails up when engines run in
the port on pick was milled out on cnc miller with long series end mill
ive done a program for milling the bridge slot out with a small slot drill as well
the exaust port could be made into a bore if i wanted any size, i dont no anything about ports on rotarys though!

[bnaellis]

Sounds like a very nice project you have going on there. Open up the exhaust
port more & make sure you have a very unrestricted exhaust system. you want as little backpressure as possible.

[Carl]

The important thing with the exhaust port is to keep the gas speed up as much as possible all the way to the turbo.
Yes it should be opened up,and there are a few way\'s that people do this,but you don\'t have to go to mad with them like you would on a naturally apsirated engine.
Keep the inserts,they aid heat transfer to the exhaust manifold.
The reason that you do not need to open the exhaust to the same area as the inlets is because the exhaust is a Perpheral port,which means it has a great deal longer duration than the inlet ports which are side ports,and also that the gas pressure in the exhaust is very high when the exhaust port opens so the gas escapes much more readily than the inlet charge enters the engine.Along with that the turbo is not only driven by the exhaust gas,but also helps to keep the gas moving as the pressure drops through the cycle.
Regards
Carl

[DRAGON]

Dont listen to that Jaydee, he is non-member scum!!

[stuart wizy]

if i remove the steel inserts and open the ports more, how close can i go to the water channels safely ?
ie-  what you look at on the pic looks like a slot now, will become a bore but there wont be much material left between the bore and the water jakets that run above and below the port.
could i just bore right through and make a round stainless insert as big in diamater as poss and press it in? this would break through water jackets so they would have to be blocked of.
ive got a dud housing that im gonna try on first to see what happens, also im thinking of trying a j port  on the side housings with custom made exaust manifold with pipes the same dia as new round exhaust ports to get huge flow out to turbine :3gears-lh
ive herd 600 ponys plus is possible at the wheels with this set up
by the way if this engine is proved good in my fc weve got a tubular chasis drawing of a funny car rated at 5000 brake from the states that my mate has started building in work,
ive just got to convince him to try rotary instead of chevy
the potential here is huge with weight reduction between rotary and chevy

[bnaellis]

if i remove the steel inserts and open the ports more, how close can i go to the water channels safely ?
ie-  what you look at on the pic looks like a slot now, will become a bore but there wont be much material left between the bore and the water jakets that run above and below the port.
could i just bore right through and make a round stainless insert as big in diamater as poss and press it in? this would break through water jackets so they would have to be blocked of.
ive got a dud housing that im gonna try on first to see what happens, also im thinking of trying a j port  on the side housings with custom made exaust manifold with pipes the same dia as new round exhaust ports to get huge flow out to turbine :3gears-lh
ive herd 600 ponys plus is possible at the wheels with this set up
by the way if this engine is proved good in my fc weve got a tubular chasis drawing of a funny car rated at 5000 brake from the states that my mate has started building in work,
ive just got to convince him to try rotary instead of chevy
the potential here is huge with weight reduction between rotary and chevy

You can port the exhaust ports really big without removing the inserts.
As Carl the inserts help with heat transfer, so they serve a goof purpose.
If you want to run big boost then it may be worth while going massive on the exhaust ports but if you only want to run like 1.5 there is no need for them to be so huge taht you will want to remove the inserts.
I machined inserts so they are thinner and also bent the ends so the do not protrude in the way of exhaust gas flow.
I have really huge exhaust ports.

[stuart wizy]

i wanna max t51r out on this engine, its not going on the road its just a project to get maximum power on the strip and track
with what ive spent so far compared to a race spec small block engine you wouldnt believe.
my mate spent 7 grand having a small block built in  the states for his drag car
nostalgia drag racing in this country is all about chevy, but i think the potential for a 3 or 4 rotor engine or even 13b on a frame chasis is enormous

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For £8K Ross has a 4 rotor engine ready to rumble.