Is porting for power a myth?

Any form of normally aspirated power mods.
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Re: Is porting for power a myth?

Post by RobinPZ72 » Sun Nov 11, 2018 12:17 pm

Yeah I'll probably sink a 1m square heavy plate in concrete and use it to anchor it from that! This is a pipe dream though!!!

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Re: Is porting for power a myth?

Post by 13Black » Sun Nov 11, 2018 12:20 pm

Hook it up to a genny plugged into the mains and a smart meter.
Convert from kW to HP and 'free' leccy while you science.

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Re: Is porting for power a myth?

Post by ChrisHolmes » Sun Nov 11, 2018 12:40 pm

Gas flowing of piston engine cylinder heads has been a vital process in understanding the air flow through the ports and past the valves into the cylinder and I wonder how much flow bench work has been done on the rotary engine.
A tad more complex to set up given that the "valves" opening and closing the ports in a Renesis are dirty great 4218gm triangular lumps which don't move in a linear motion and also the inlet manifold contains valves which dependent on RPM open and close varying the tract length in order to time the energy pulses to be high pressure as the port opens, so lots more variables to consider!
Is there a fluid dynamics specialist out there amongst our members or their friends who wants a little project?
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Re: Is porting for power a myth?

Post by Conan » Sun Nov 11, 2018 12:47 pm

RobinPZ72 wrote:
Sun Nov 11, 2018 11:23 am
Anyhoo i was thinking of making a test bench and fanny around with porting etc. Probably not a dyno as such, but using just the brains then do some number crunching! A bit of fun and if it goes bang whoops and move on!
I did suggest once that someone used the front end of a car with the wings cut away etc to use as a test bed for their experimentation.
This lets you drop an engine in taking only minutes to check experiments and bedding in but you can't measure HP ( you just need a bit of space )
They went and bought a hub dyno though :)
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Re: Is porting for power a myth?

Post by PeteH » Sun Nov 11, 2018 1:30 pm

13Black wrote:
Sun Nov 11, 2018 12:20 pm
Hook it up to a genny plugged into the mains and a smart meter.
Convert from kW to HP and 'free' leccy while you science.

Call me 13Eddison.
It would make 720 amps at domestic voltage, requiring a one inch diameter cable. Sounds doable. :thumleft:

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Re: Is porting for power a myth?

Post by 13Black » Sun Nov 11, 2018 1:33 pm

Might have a fuse for that. Lemme just check my spanner drawer.
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Re: Is porting for power a myth?

Post by RobinPZ72 » Sun Nov 11, 2018 1:56 pm

Now we're thinking!

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Re: Is porting for power a myth?

Post by ChrisHolmes » Sun Nov 11, 2018 2:09 pm

We may have mythed the point of thith thread!
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Re: Is porting for power a myth?

Post by warpc0il » Sun Nov 11, 2018 2:19 pm

Building a test stand to hold and provide fuel, coolant etc to take a running engine isn't that difficult, if you just want to prove that it runs.

However, as others have suggested, loading that engine and measuring the power output is a whole different challenge.

Early engine test rigs used to use a paddle turning within a water tank to provide the load, where the increase in water temperature would be the indication of power produced but real-time measurements need something a lot more dynamic, like a big flywheel and a calibrated brake...
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Re: Is porting for power a myth?

Post by 13Black » Sun Nov 11, 2018 3:00 pm

Heck even Chambers made a little engine test rig to 'prove' that their engines worked before shipping it to customers :lol: it's just the few thousand miles afterwards that problems seem to rear their head...
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Re: Is porting for power a myth?

Post by RobinPZ72 » Sun Nov 11, 2018 3:22 pm

Aye there's lots of see it's working just fine people out there and it's only once things are nice a loose they go pop! It's also a lot to do with the operator not quite adhering to a running in procedures and when it breaks it the engine builders fault off course!

They'll always be failures out there that know one can predict!

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Re: Is porting for power a myth?

Post by 13Black » Sun Nov 11, 2018 3:28 pm

I think I could have predicted some of their failures better than a random number generated would have :lol:
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Re: Is porting for power a myth?

Post by RobinPZ72 » Sun Nov 11, 2018 4:13 pm

Oh not the best then!!!!!!!!

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Re: Is porting for power a myth?

Post by Conan » Sun Nov 11, 2018 4:31 pm

RobinPZ72 wrote:
Sun Nov 11, 2018 4:13 pm
Oh not the best then!!!!!!!!
There is some suggestion that overseas customers were sent engines from scrap cars rather than rebuilt units that failed within minutes.
I cannot verify that myself personally of course.
Pete

PS: And in the spirit of this thread I don't think they were ported ;)
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Re: Is porting for power a myth?

Post by RobinPZ72 » Sun Nov 11, 2018 4:59 pm

It's kind of why I do most things myself! I know it's tuff to make small business work and it's so easy to say f**kit and do what others do and cash in!

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Re: Is porting for power a myth?

Post by ChrisHolmes » Sun Nov 11, 2018 6:36 pm

https://www.rx8club.com/attachments/ser ... t-port.jpg

Here you go, porting does work over the pond!!!!
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Re: Is porting for power a myth?

Post by RobinPZ72 » Sun Nov 11, 2018 8:23 pm

Interesting they worked on the intake manafold. This has nothing to do RX8, but I got the best gains on my FZR 1000Exup R by removing material on the intakes. 146bhp was funny as hell as there was a fully loaded Ducati could only get 136bhp!

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Re: Is porting for power a myth?

Post by PeteH » Sun Nov 11, 2018 8:33 pm

So they got the "traditional" 15% by doing everything they could think of (before bridgeporting really became a thing on RX8s). The cost of that spec, including the required rebuild, would be something north of £5k.

Again, I'm not saying porting or tuning is worth nothing. Just that we should have realistic expectations.

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Re: Is porting for power a myth?

Post by Conan » Sun Nov 11, 2018 8:46 pm

I don’t think they even got to the 15% mark
I also think the majority was probably the exhaust system and mapping rather than the porting.
As PeteH says the porting is a minimal gain. (Not saying people shouldn’t do it though) :)
Pete

PS: There is a thread somewhere about intake tract porting
Last edited by Conan on Sun Nov 11, 2018 9:38 pm, edited 1 time in total.
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Re: Is porting for power a myth?

Post by RobinPZ72 » Sun Nov 11, 2018 9:35 pm

Yeah not sure how much, but the REC development of the exhaust port could be a good gain as there's a horrible vert and step back which would cause vortexes that maybe undesirable!

Ps I'm still peeing into the wind, so crap could come out too.

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Re: Is porting for power a myth?

Post by ChrisHolmes » Sun Nov 11, 2018 10:22 pm

RobinPZ72 wrote:
Sun Nov 11, 2018 9:35 pm
Ps I'm still peeing into the wind, so crap could come out too.
With that result you may need a doctor
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RobinPZ72 (Sun Nov 11, 2018 10:54 pm)
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Re: Is porting for power a myth?

Post by 13Black » Sun Nov 11, 2018 10:37 pm

Already been through that phase, Chris?! :o
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Re: Is porting for power a myth?

Post by carnut1974 » Mon Nov 12, 2018 5:53 am

An interesting discussion.
The basics I take from this are there is not much to gain if you own a 231.
However larger potential if you own a 192.

I find a lot of the details discussed later on are very deep and technical, but not enough specifics on whether each member is being specific on their gains - regarding what engine they have done the modification to ie; 192 or 231.
Could we be more specific when discussing our experiences or gains?

Personally from research it appears through this and the US owners group if you own a 231 - the only potential positive small gains are with a reputable sports cat and Japspeed mid and rear exhaust. Which assists the breathing exhale.
Upgrade to optimum igniting coils. But as I understand that's about it for bolt on mods for a reasonable cost.

Bridge porting a 231 seems pointless from my reading unless you want to rev the nuts off it all the time at the loss of low end comfortable driving. As stock the 231 seems to drive a nice mix from low end revs - cruising to high end racing through the gears. But I do hate the stock exhaust systems. Much prefer the Japspeed throb. 🙂👌
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Re: Is porting for power a myth?

Post by 350matt » Mon Nov 12, 2018 7:48 am

I think the reason for the lack of detail is that we simply don't have more hard data to add.

The point of Pete's post was to highlight that porting on its own doesn't seem to do much and the only positive evidence for doing so is that racing beat graph , which is 'polluted' by them adding an exhaust too
bridge porting should give a more reasonable gain but once again we're yet to see an A condition B condition test where just that mod is tested in isolation


I had to port mine as I found all the sharp turns rather offensive but as to how much better they made the engine I cannot say
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Re: Is porting for power a myth?

Post by kopite72 » Mon Nov 12, 2018 8:49 am

Tbh to say that Porting doesn't do much is unfair. It may not add a whole heap of power but it totally transforms the car from what is a decent drive in to a superb drive.

As I've said previously Porting makes the car come alive, the difference between a ported and a non ported car is night and day really
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