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I've probably milked this for long enough now so here goes .
Technical details :
It's bridgeported and has small peripheral exhaust ports ................. so there is a **** ton of overlap but relatively small ports. Not terribly exciting but should make a difference.
Will start by venting the PPs to atmosphere (not as noisy as you might think because they open so much later than the side ports) and using the wastegate to control when that happens.
I discussed small peripheral ports with a very skillful mechanic some years ago, he had no experience with rotary, but suggested a knife like port that was adjusted with RPM on 2 stroke engines. I do not have the fabrication skills, and he sadly died, so did not go further. I assumed that it was difficult to make, but as he said "they make it work on high stress 2 stroke".
I discussed small peripheral ports with a very skillful mechanic some years ago, he had no experience with rotary, but suggested a knife like port that was adjusted with RPM on 2 stroke engines. I do not have the fabrication skills, and he sadly died, so did not go further. I assumed that it was difficult to make, but as he said "they make it work on high stress 2 stroke".
Interesting ...keeping them from seizing up would be a challenge.
I've probably milked this for long enough now so here goes .
Technical details :
It's bridgeported and has small peripheral exhaust ports ................. so there is a **** ton of overlap but relatively small ports. Not terribly exciting but should make a difference.
Will start by venting the PPs to atmosphere (not as noisy as you might think because they open so much later than the side ports) and using the wastegate to control when that happens.
So in the meantime, the PPs are just pushing out against the waste gate?
So in the meantime, the PPs are just pushing out against the waste gate?
Actually , my fabricator couldn't make me the mini manifold i needed to fit the WG due to everyone wanting their rides ready for 'Rotary Reunion'. So at the moment I've just got some galvanised pipe fittings with a plug on the end.
My biggest challenge atm is how to test it because without the wastegate i have to open the ports manually and as mentioned ...engine will barely run below 2500 with them open ...
Actually , my fabricator couldn't make me the mini manifold i needed to fit the WG due to everyone wanting their rides ready for 'Rotary Reunion'. So at the moment I've just got some galvanised pipe fittings with a plug on the end.
My biggest challenge atm is how to test it because without the wastegate i have to open the ports manually and as mentioned ...engine will barely run below 2500 with them open ...
Could you use an electronic exhaust cutout valve to control that in the mean time? Would be up to you to determine when it would work or not without the need of pulling over and opening them Manually
Could you use an electronic exhaust cutout valve to control that in the mean time? Would be up to you to determine when it would work or not without the need of pulling over and opening them Manually
Either way ...I still need plumbing to the valve ...so no better off.
Update time ............... I managed to do some runs with the PPs open . Had to drive out to remote location , drive car onto ramps , remove the plugs from the pp pipes the do the runs ,put the plugs back for the drive back into town . Was a bit of a pia but at least I got a test done.
Initial results compared to strong stock engine (the one that dynoed at 220whp):
up to 3600rpm ...same power
3600-6000 ..... lost power
6000-7000.......same
7000-9000 .......small gain
That was a few days ago and since then I've done some tweaking with ssv timing which got back most of the lost power so currently:
up to 4500...same power
4500-6000...lost power
6000-7000...same power
7000-9000...small gain
Plan on doing some testing with vdi and apv timing (along with work out the pp open timing) to try and improve power band some more with the goal of minimising the mid range loss and maximising the gains in high rpm range.
Overall ...fat lady hasn't broken into song ..... but.............. nothing to get excited about.... yet.
Re the stock engine I pulled out . The porting appears to be unmolested so I think we can safely call it a 'stock' Renesis.
It does have the best compression and vacuum of any engine I've ever tested though so it's as good as it gets.
Also : I dynoed another rx8 (on the same dyno )last week. This was a raced prepped rx8 with full 3" exhaust and good engine (not rebuilt) . It dynoed at 206whp, which is the same as another raced prepped rx8 (with freash rebuild) engine I did last year on same dyno.
So ...it's still a bit of a puzzle as to why mine got such a good number . One thing that came to mind though .............. I do have very thin (comparatively) oil in the gearbox ....................... Kevin ?????
Update time ............... I managed to do some runs with the PPs open . Had to drive out to remote location , drive car onto ramps , remove the plugs from the pp pipes the do the runs ,put the plugs back for the drive back into town . Was a bit of a pia but at least I got a test done.
Initial results compared to strong stock engine (the one that dynoed at 220whp):
up to 3600rpm ...same power
3600-6000 ..... lost power
6000-7000.......same
7000-9000 .......small gain
That was a few days ago and since then I've done some tweaking with ssv timing which got back most of the lost power so currently:
up to 4500...same power
4500-6000...lost power
6000-7000...same power
7000-9000...small gain
Plan on doing some testing with vdi and apv timing (along with work out the pp open timing) to try and improve power band some more with the goal of minimising the mid range loss and maximising the gains in high rpm range.
Overall ...fat lady hasn't broken into song ..... but.............. nothing to get excited about.... yet.
Great work! Where do you find the motivation and courage? I'm deeply impressed.
My idea for a PP was not to increase NA power, but to increase the potential and reliability when adding FI. For a turbo setup, it must redefine the definition of plumbing nightmare, but for a supercharger setup, its another story. Regarding reliability part, idea was that it would relive the side exhaust port, and thereby take away the worst punishment.
Great work! Where do you find the motivation and courage? I'm deeply impressed.
My idea for a PP was not to increase NA power, but to increase the potential and reliability when adding FI. For a turbo setup, it must redefine the definition of plumbing nightmare, but for a supercharger setup, its another story. Regarding reliability part, idea was that it would relive the side exhaust port, and thereby take away the worst punishment.
Thanks
You are probably correct on all that. I did briefly consider making this an FI setup also but decided the power level on my stock renesis turbo was ample and if I wanted more, the next step was an REW . There doesn't seem to be much point going higher on a hybrid Renesis because it's never going to spool as well or make the power as easily as an REW can.
At sub 400 levels though ...it's frickin' awesome and ,for a street car, there is no point fitting an REW to achieve a sub 400 output.
Well my thinking is that the ports aren't big enough to allow the bridgeports to clear out the exhaust carryover.
So I'm working on getting as much flow as possible through them .
If you're getting the same baseline power, but without mods that would actually take advantage of overlap, that's pretty promising, right?
You mean like scavenging headers etc ?
I'm going to vent the PPs to atmosphere initially which is way more scavenging than anything that could be done with headers........... I think.
I am seeing maybe 10-15 extra g/s flow up top with pps open right now . With what i'm doing opening up the port exit inserts etc, I might be able to do better than that ...fingers xd
Watching this with interest,as always.
If nobody tries this stuff, then all of us learn less. Good for you. Thanks for the effort, and keeping us all up to date.
For the "strong" engine, what compression numbers did you see? Just curious.
The Redline MT-LV is of course the game changer. I knew it all along. :
Watching this with interest,as always.
If nobody tries this stuff, then all of us learn less. Good for you. Thanks for the effort, and keeping us all up to date.
For the "strong" engine, what compression numbers did you see? Just curious.
The Redline MT-LV is of course the game changer. I knew it all along. :
Thanks Kevin .
Compression was around 115-120psi from memory and vacuum was -20psi . Vever seen that much vacuum on that gauge before ...it's normally below 19.
Re the oil ..... it must be worth a few horses .....but certainly not 15! Maybe 5 on a good day ..
02-02-2020, 04:27 PM
