6-Port Power

[NoDOHC]

Has anyone here exceeded 200 WHp with a 6-port rotary?

They are SO much more common than 4-port rotaries that I am tempted to build one for power.

The biggest issues that I see are:
Not large enough ports to breathe with 6PI closed
Too late of intake port closing with 6PI open
Runners too small on LIM
Runners too small on UIM
Impossible to port UIM due to complicated geometry.

I am looking at some Metal-ceramic compound that I may be able to fill the upper part of the 6PI in with, allowing more advantageous port timing. I could then convert the secondary and auxiliary ports to a single port and run a 4-port manifold.

I could also build a custom intake manifold for the 6PI (possibly using the factory LIM, as it can be modified to flow pretty well). This would allow the 6PI to remain intact (giving better low end dynamic compression ratio).

[PercentSevenC]

Hyper4mance2K did 190.5 WHP on a 6-port with Y-casting center iron. Smoothed port runners but stock timing. He did this with 90 PSI compression and a 48 IDA. With a rebuild, some more porting, and a bigger carb, we're certain he could break 200.

[C. Ludwig]

We've done 182 on a stock long block engine on a Dyno Dynamics dyno. The SCCA EP guys are knocking down 240+ on street ported engines.

[NoDOHC]

240+ WHp is very good, What type of dyno is that on?

Did they run the stock Intake manifold?

Did you have the stock intake manifold on the 182 WHp engine?

I think I can break 200 WHp with a 6-port, but I would have to rev to about 8200-8500 rpm to do it. I can't get any torque out of them because of the terribly late intake port closing. To make power at 8500 rpm, the first thing I need to do is fix my ignition issue. Maybe next year I will get an E8. (It is amazing that this year is almost over).

The only way to get 200+ WHp that I can see is with a ported stock LIM and a custom UIM. I am thinking that I can cut the flange off an S4 6-port UIM and weld some short runners going to a custom plenum to that.

I see promise in the LIM design. I can't see how I could ever get enough air to make 240+ WHp through that terrible UIM (S4 is a little easier to port than S5, but still nearly impossible).

How does a dyno dynamics Dyno compare to a Mustang Dyno? The dyno right near my house is a Mustang, so that is where I would be getting the numbers.

[C. Ludwig]

The 182 was an SCCA ITS car, so by the rule book everything must be stock from the entrance of the airflow meter to the exit of the exhaust port, with the exception of having the 6 port sleeves and their actuators removed, which is allowed. The Dyno Dynamics dynos typically read around 15% lower than Dynojets. I'm skeptical of that number at the lower end of the scale though. Typically a good ITS car will put down 175-180 on a Dynojet. This particular car has been proven on track to be a bit of freak and is certainly at the pointy end of the class. I wouldn't be surprised to see 190 on a Dynojet but 200+ on stock ports is just hard to believe.

The ITS car makes about 138 lb/ft peak at around 6200 rpm. Peak power is around 7700. It has 120+ lb/ft from 4000 - 7700. Not sure what you consider "low end" but you're not going to find a rotary that makes power below 4000 and has any kind of high end power.

Kahren (look him up on the the club and nopistons) did a tad over 200 with a street ported 6 port a while back.

The SCCA EP cars run through 42mm carbs or, if they want to run fuel injection, through the stock manifold. Not sure if the 6 port is required or if they're allowed to use 4 port irons. I do know some guys have hogged out the 6 port into a single port like you're talking about. Paul Yaw had some images of one he was working on on his website a while back but the website is down. He also had a street port, 4 port NA engine that put down around 240 on the website.

Keep in mind to make this kind of power you're looking at spinning the engine in excess of 8500 rpm which puts you into a whole new realm of needed work and components to make the engine live. The assembly should be properly balanced, the rotors clearanced, properly clearanced bearings, and some sort of lightweight, non-ferrous apex seal (carbon or ceramic). A scatter shield would be a great idea as well.

[Silver86]

i like this thread...


subscribed.

[NoDOHC]

I agree for longevity, an engine should be balanced, but I have yet to run into balancing issues with any rotary engine. Even my s4 4-port with 300 grams removed from either rotor (and no other balancing performed) pulls smooth to 9,000 rpm. (In fact, that was how I talked the dyno guys into letting me run to 8,000 rpm was by laying my hand on the engine as I revved it to 9,000 rpm to show how smooth it was.)

The ITS car makes about 138 lb/ft peak at around 6200 rpm. Peak power is around 7700. It has 120+ lb/ft from 4000 - 7700. Not sure what you consider "low end" but you're not going to find a rotary that makes power below 4000 and has any kind of high end power.

This is interesting as my 4-port made 160 Wlb-ft at 6100 RPM and 216 WHp at 7500 rpm. (I still contend that this is limited by ignition and compression ratio). The curves are similar, only the 6-port is 15% lower. This 138 WLb-ft is the problem. If I could get 160 Wlb-ft out of that like I can out of my 4-port, I would have no trouble with the 200 WHp goal. That late intake port close is KILLING me. Even 120 Wlb-ft past 4,000 is not that good, as my 4-port makes that at 2500.

Reading this has almost convinced me to port the primaries and the lower port of the 6PI and fill the top port with iron-ceramic. I think I could make as much power at considerably lower revs (I'm talking 7,000 rpm territory) if I could get rid of the late port close caused by the 6PI.

I don't intend to rev this engine to 10,000 rpm, as it will have stock s4 internals (I will stop at 9,000). I do intend to make 200 WHp, but to do that - I need more torque. To get more torque, I need to have better VE. To do that, I can't force 28% of my intake charge back out into the intake manifold.

The 182 was an SCCA ITS car, so by the rule book everything must be stock from the entrance of the airflow meter to the exit of the exhaust port, with the exception of having the 6 port sleeves and their actuators removed, which is allowed. The Dyno Dynamics dynos typically read around 15% lower than Dynojets. I'm skeptical of that number at the lower end of the scale though. Typically a good ITS car will put down 175-180 on a Dynojet. This particular car has been proven on track to be a bit of freak and is certainly at the pointy end of the class. I wouldn't be surprised to see 190 on a Dynojet but 200+ on stock ports is just hard to believe.

I completely agree. I made 155 WHp with my stock s4 6-port and I was happy with that. Thankfully, I am not limiting myself to SCCA rules, or I would be in trouble. The big issue is that I am not running against Dynojet numbers, I must make 200 WHp on a Mustang Dyno. (Which is somewhere near 210 WHp on a dynojet).

Right now I think I will try:

Porting:
Porting the Primary port to max-effort (without changing timing, gaining port area by crowding the Oil control rings).
Porting the secondary port (the lower one) to max-effort (modifying port to max out against bottom of 6PI port and crowding the oil control rings).
Removing 6PI port from the equation altogether.

Manifold:
Matching port cross-section in LIM
Filling portion of manifold that fed 6PI with aluminum-ceramic.
Manufacturing custom UIM

I will post some porting ideas/sketches up tomorrow for discussion.

[NoDOHC]

Maybe I should rethink my goals, if I do all of that, I will not have a 6-port

I will revisit this later. I have thinking to do.

[Whizbang]

i think we should revive the na power thread

[NoDOHC]

Ok, so I want some thoughts and opinions.

I have two tracks this could take.

Track A:
I do a buildup that basically shows how to make a 6-port block into a 4-port block that will make 200 WHp. (Which I am very confident that I can do, but what am I really proving?)

Track B:
I attempt to do a common-sense minimal street port of a 6-port iron and still leave it a 6-port (with functional sleeves and all) and see if I can get 200 WHp out of it by using a manifold like Gravity Fed shows on his buildup thread.

What do you think?

EDIT: There is no hurry for this, as I will not likely be doing anything with this for quite some time.

[Whizbang]

well the intake manifold with a function aux ports would require some custom work surely, but if you can get it to work, it would optimize the low end.

[RX200013B]

make a different intake manifold to choice, but make it like the euro manifold with throttle plates the base next to the block and make a curved piece to make the flow better in the aux ports. also you are going to gain surface area!

[NoDOHC]

This development is intended above all to be a budget build.

I will list the tool and component expenses when I do it.

Although I have the necessary tools to manufacture a custom intake, I doubt that may people reading this thread have those features.

The total cost of the build should come up considerably under $500.00, including the purchase of the 6-port engine.

I will probably modify a stock LIM and a stock s4 UIM for the build (forget modifying the s5 manifold).

I really don't know if this can be done, but I want to try.

If this development can be done, there will be a cheap, cookie-cutter formula for 200WHp out of a very common and readily available 6-port rotary. This is my goal.

I will probably have to open the block for 200 WHp, but if I could get 185 WHp without it, it would be more useful.

I really want to do this all with the stock ECU, but I am afraid that I can't see how that would work.

As I said before, I have a 4-port engine already, the 6-port development would be for the rotary community, not for myself (200 WHp is old news for a 4-port).

[rotaryracer]

This is interesting. I was running an early model 13b 4pt in my 83 race car. DynoJet read 177bhp @ 8000 w/ 127lbs torq @ 4500. 48 IDA Weber dawn draft. I picked up a 4pt Renisis hoping to get 200bhp w/side draft Mikuni. Unfotunately we broke our race motor before we completed the intake for the Mikuni. We have a couple 13b 6pt motors. Found a side draft intake @ R.B. for a $150. Not in the budget yet. Borrowed a 6pt intake and an Edlebrock carb jetted for a v-8. Wondering what kind of hp numbers to expect. From what I see here, should be close to race motor. Don't want to rev 8000 with a stock motor tho. Porting is not in the budget with race motor rebuild. Plan on using 6pt motor as backup until race motor is ready.

[NoDOHC]

I think that 200 bHp is easily doable out of a 6-port. This thread is talking about 200 WHp (which is more like 240-250 bhp). I got 155 WHp out of a bone stock 6-port (mechanically stock anyway) with 190,000+ miles, this is almost 200 bhp (about 190).

I see you mentioned Dynojet, was this dynoed at the wheels, or the flywheel?

177 WHp is good out of an '83 4-port. 177 bHp is average.

I have only seen carbs on 12A rotaries, and have never attempted to make additional power with them. Fuel injection is so much easier to tune precisely (although initial startup is much easier with the carb).