If one has access you a flow bench would it be possible to flow the irons and housings?? Maybe you would have to make an adapter for it. How about flowing the UIM and LIM to see which truly flows better? Just wondering.

 

http://www.pineappleracing.com/TechLinks.html

 

Yes, check out Yawpower flow bench info.

Just remember there may be more complex relationships through out the engine than just maximum flow potential and I imagine that is the kind of thing you were thinking of when you talk of flowing irons and housings together at a bench.

For example I imagine you could port your primaries and secondaries so the each one flows very well, but when assembled they blow right at each other and cause a flow restriction.

Or perhaps you could port them so they flow very well, but as the rotor shrouds the port the flow goes to crap or you lose the dynamic intake effects from opening/closing are reduced so a tuned intake has less effect.

Or you could decide to port your primary smaller even though it will hurt primary flow in order to give it a high velocity and direction that will put a "siphon" on the larger 2ndary and increase the 2ndary flow and chamber fill as well as accelerating the rate of velocity increase in the 2ndary flow and having better low end power.

On the exhaust possibly you could cut a port that flows very well, but does not block the reversion wave back into the engine well and hurts dynamic flow and chokes out the benifits of your overlap.

In the relationship of intake to exhaust ovlerlap it gets even more complex especially with turbo and manifold lengths.

More overlap may put more raw fuel into the exhaust and spool the turbo faster despite the "common" wisdom that overlap will hurt the lowend power.

But maybe it is not getting a lot of overlap for this, but getting the intake pressure to exhaust pressure equalization (and therefore gas interchange) when the exhaust is hottest at the port right when exhaust opens (so less overlap than bridge port and more than stock) so the fuel burns most completely.

Or perhaps there is the relationship of exhaust pressure to intake pressure so that if you are "blowing down" your exhaust port pressure just as the intake opens and before rotor chamber volume increases the shape of the rotor tip to intake port creates a "siphon" (in relative boost pressure to exhaust pressure terms) to aid in initiation of intake flow into exhaust.

You can think up a bunch of what ifs and ways to test the theories by putting a rotor and e-shaft in an iron and housing and rotating it around w/ a piece of plexiglass w/ ports drawn on it.

 

http://www.pineappleracing.com/TechLinks.html

Jedi mind trick. Have a long conversation w/ Rob sometime or even just look at products he has developed...

 

THanks for the links interesting stuff!

 

Not sure I completely buy Rob's arguaments on this. Yes there is more to power production than the flow numbers off a bench, but that's true in the piston world as well. I suspect its more that, over a number of engines he has come up with ports that work for him.

For my point of view I would love to have time to play with a flow bench and see what can be discovered. Sterling is going though this at the moment and will hopefully be able to shed some light on things.

 

My friend and porting man Mikael has a flow bench for testing side housings and rotor housings. He first made it back in 1997 and back then it was most street and bridge port flowing. Example: A stock FD secondary port flows 80 cfm@10" With a good stage 1 port it flows 92 cfm. A small bridgeport flows 102-104 cfm. The last years we have concentrated to gain as much air flow as possible from the PP inlet ports they flow from 220 cfm@10" with 42 mm idia to up to 298 cfm with a 49 mm idia. Note the 42 mm PP port is D-shaped while the 49 mm is rectangular. We use a Flowquick to measure the flow and a big 380V suction motor. It's also a great tool when you shall improve the flow of the intake manifolds, the stock one's always decrease flow which is bad hp wise! Therefore Mikael makes his own tapered inlet manifolds with butterflies or slide for maximum hp and torque. So i think flowing the inlets and outltets of the rotary is a must if you shall develop ports and gain good flow and velocity. Maybe i can come up with some pics of Mikaels homemade flowbench!?

 

Did you see the UIM and LIM were ported too? Did you see a BIG difference between the porting? How much were they flowing before and after?

 

Mikael shall port 2 Monster street with UIM and LIM ported to. I shall check the difference in flow before and after. Will come back with some numbers!

 

Hey Lasse,

Good to finally hear someone who has some solid figures etc with a flow bench, that would be great if you could share some pics of Mikael's flow bench and some more figures

cheers

Lance

 

Hey yeah i have lots of pic's on cd but i am a little bit lazy loading them up here but i will do my best (slide manifold i know!) Oh i can bring some exhaust figures to! Stock FC,FD 125 cfm@10" which is 209@28" (Multiply by 1.67) With our monsterstreetport exhaust (4mm earlier opening and about5- 6mm later closening 160 cfm@10" Last mod is to take out the steel sleeve and split it that is enlarge it, then it flows 176 cfm!

 

Paul Yaw inspired me to build my own flowbench. It is a great tool for porting rotaries. Pineapples explanation of how they aren't useful is a copout for not owning one or knowing how to use one. That's an excuse and excuses aren't results. He says that you can't judge a ports potential by just slapping an iron on a flowbench and seeing how much it flows as is. Um, duh? You don't just slap a cylinder head on a flowbench with no valves in it and flow it like that either. On piston engines, you need to compare flowrates at certain valve lifts. You get alot more info on how the air flows at different openings than just at full open. The rotary is no different. You have to have a rotor housing and a rotor in place as well. You take different readings with the ports in different stages of opening and closings. This is useful info. Just having a port that flows alot with no rotor or housing isn't very useful info but it does tell you a little. Then you also need to flow the manifold you intend to use. If it flows only a certain amount, there isn't much point in making a much larger port that flows more. When you port an engine with a flowbench as an assistant, you also can benefit from a velocity probe to see where the best gains are coming from. I use a very crude but useful tool. I have welding rods with different sized steel ***** attached to the end. While the plate is on the bench, I can take these and insert them into the airflow and move them around to see how the readings change. Sometimes you'll find a spot in the port where putting this in the airstream doesn't do anything or at least not as much. You don't really want to waste alot of time and make these areas larger. There's no point. Fix what needs fixing and leave the rest alone. Sometimes things work differently than you would logically think they do too. It's actually harder to guess the best shape than everyone thinks it is. Using port templates only tells you how big something is on the surface. It's what;s underneath that really counts. A flowbench is an absolutely useful tool.

As Paul Yaw's article says, do you want the person porting your engine measuring or guessing?

 

I must say that i fully agree what Rotarygod has explain about flow testing becausse Mikael does exactly the same on side housings. On PP inlet we have an adapter that bolts to the rotorhousing which he can slide from fully closed to fully open PP port. Interesting to see that also Rotarygod uses the welding rod with steel ball, that is also a very useful tool when Mikael develops our ports. You can actally see it on the FlowQuick if flow increase or decrease when using this simple tool!