Major HP Engine update
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Major HP Engine update
Hello rotary gods,
All in short. I red this https://www.rx7club.com/naturally-as...ybrid-1121187/
Sadly that was exactly my idea to go Hybrid engine (rx7 S5 rotors and housings with all other from Renesis , the siamese /center housing exhaust is closed) turbocharged with HX-55 turbo. I already have engine ready only needs welding exhaust. Then tune the ECU ( RX-8).
My question is is it worth it to continue or i wont see much power from this engine/setup?
All in short. I red this https://www.rx7club.com/naturally-as...ybrid-1121187/
Sadly that was exactly my idea to go Hybrid engine (rx7 S5 rotors and housings with all other from Renesis , the siamese /center housing exhaust is closed) turbocharged with HX-55 turbo. I already have engine ready only needs welding exhaust. Then tune the ECU ( RX-8).
My question is is it worth it to continue or i wont see much power from this engine/setup?
this is well discussed on RX8Club and as I stated there numerous times it’s a waste of time and money over an REW engine. You can’t just close off the side ports and with them there are open the exhaust is split up into too many streams each contributing inefficiency losses. Then there’s the whole Renesis durability issue for those parts. Numerous people ballyhooed it up and then disappeared. The only decent results I ever saw were from Kyle Mohan and they were not anything special imo. It just adds a lot of effort (5 exhaust ports in a 2-rotor space) and a lot of cost with a negative overall payback imo. Unless just being different is more special to you than actual performance.
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this is well discussed on RX8Club and as I stated there numerous times it’s a waste of time and money over an REW engine. You can’t just close off the side ports and with them there are open the exhaust is split up into too many streams each contributing inefficiency losses. Then there’s the whole Renesis durability issue for those parts. Numerous people ballyhooed it up and then disappeared. The only decent results I ever saw were from Kyle Mohan and they were not anything special imo. It just adds a lot of effort (5 exhaust ports in a 2-rotor space) and a lot of cost with a negative overall payback imo. Unless just being different is more special to you than actual performance.
1. Spliting exhaust streams. You have a point about having 1 large pp exhaust port per rotor is better than having pp and side port. But overal flow is i think better. If you have standard pp and side port (not ported).
I did not port any ports on this engine since i am tryng to run minimum overlap.
What i observed is that pp exhaust opens first then the side port opens. Means there will be nice impulse to turbo. Once the pp exhaust port does not flow enough then gases will start leave over side port after main inpulse. Keep in mind my turbo is dual scroll so thats why each rotor downpipe is separated. Since siamese exhaust port would allow gases traveling from 1 rotor to another i closed it( block has been welded).
Now for exhausts to travel back to another rotor would mean to return back from turbo exhaust side low pressure zone to high pressure zone of downpipe of second rotor. In praxis only possible if turbo downpipe does not flow enough.
2. About durability issues.
What i know is that rx8 apex seals are not good for boosted aplications and rotors are high compression which contributes to knock.
I am runing low compreasion rx7 rotors. With 2 piece apexseals with 1 piece corner seals and standard side seals.
My housing have been machined for rubber seals since this engine had rubber in irons.
But when it comes to rotating assembly. I have no knowledge about weaker shaft, shaft bearings which came from rx8 engine i ma case.
I used rx7 oilpump with rx7 oil pressure regulator since it runs higher pressure and is larger.
Correct me if i am wrong. I am open to learn something new.
Also when it comes to financial side of things. I am from central EU. It is impossible here to get REW engine i was trying and trying to find one for years. Then i found broken rx7 FC turbo engine. From this one i salvaged all the goodies.
Now i had from older scania truck hx55 turbo.
Thats why i go this setup.
I was just in fear of not being able to do any substantial hp (400 whp at least). Bu now i came to think it trough. Its still best idea for me when i compare price and power benefits.
Last edited by Remuron; Jun 19, 2020 at 07:31 AM.
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Sorry but i think you totally missunderstand it. You have pressure in chamber as rotor moves it opens PP exhaust. Gases escape trough PP port. Then as rotor moves more it starts to open Side Exhaust. In this case most of gases already escaped trough PP port but now they have possibility to go also trough side port. Once there will be boost and lots of gases need to leave trough PP port maybe it would not be able to flow enough. In this case gases will have also ability to go trough side port.
if all you want is 400 hp you can get that out of a Renesis without too much difficulty. I’m not saying you won’t make that or it won’t run, it won’t have any benefit and will actually cause more harm imo. You’re dealing with pressurized flow and varying timing between the peri and side exhaust ports. Your view on how it will work is too simple and not accounting for the dynamic realities revolving around six exhaust ports having 5 exhaust pipes on a 2 rotor engine.
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if all you want is 400 hp you can get that out of a Renesis without too much difficulty. I’m not saying you won’t make that or it won’t run, it won’t have any benefit and will actually cause more harm imo. You’re dealing with pressurized flow and varying timing between the peri and side exhaust ports. Your view on how it will work is too simple and not accounting for the dynamic realities revolving around six exhaust ports having 5 exhaust pipes on a 2 rotor engine.
I will be tommorow moving the engine. So i can still dissamble it.
Should i close side exhaust ports and leave only PP exhaust? I dont want to use FC engine blocks if not necesary.
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you're making too many assumptions, just two quick examples because I’m not interested in wasting my time on a known fail:
what happens if instead of exhaust gases flowing out as the side ports open later exhaust gases circle around and come back in there instead?
furthermore, unlike an REW where when the peri exhaust opens and the pulse goes out a single pipe to the turbo inlet where is it going on your contraption? Due to the Renesis centerplate siamese exhaust port you can’t separate the exhaust stream between the two rotors and you instead have multiple pipes with increased overall volume you’re trying to pressurize.
Sorry, you’re just not thinking it through thoroughly. I can tell you that nearly nobody has figured out just what the siamese exhaust port situation creates.
trust me, I know you’re going to do it anyway, just like was already posted.
what happens if instead of exhaust gases flowing out as the side ports open later exhaust gases circle around and come back in there instead?
furthermore, unlike an REW where when the peri exhaust opens and the pulse goes out a single pipe to the turbo inlet where is it going on your contraption? Due to the Renesis centerplate siamese exhaust port you can’t separate the exhaust stream between the two rotors and you instead have multiple pipes with increased overall volume you’re trying to pressurize.
Sorry, you’re just not thinking it through thoroughly. I can tell you that nearly nobody has figured out just what the siamese exhaust port situation creates.
trust me, I know you’re going to do it anyway, just like was already posted.
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Joined: Mar 2017
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you're making too many assumptions, just two quick examples because I’m not interested in wasting my time on a known fail:
what happens if instead of exhaust gases flowing out as the side ports open later exhaust gases circle around and come back in there instead?
furthermore, unlike an REW where when the peri exhaust opens and the pulse goes out a single pipe to the turbo inlet where is it going on your contraption? Due to the Renesis centerplate siamese exhaust port you can’t separate the exhaust stream between the two rotors and you instead have multiple pipes with increased overall volume you’re trying to pressurize.
Sorry, you’re just not thinking it through thoroughly. I can tell you that nearly nobody has figured out just what the siamese exhaust port situation creates.
trust me, I know you’re going to do it anyway, just like was already posted.
what happens if instead of exhaust gases flowing out as the side ports open later exhaust gases circle around and come back in there instead?
furthermore, unlike an REW where when the peri exhaust opens and the pulse goes out a single pipe to the turbo inlet where is it going on your contraption? Due to the Renesis centerplate siamese exhaust port you can’t separate the exhaust stream between the two rotors and you instead have multiple pipes with increased overall volume you’re trying to pressurize.
Sorry, you’re just not thinking it through thoroughly. I can tell you that nearly nobody has figured out just what the siamese exhaust port situation creates.
trust me, I know you’re going to do it anyway, just like was already posted.
My siamese is from begingng closed on port side. Block has been welded. No noving gases between chambers because of that.
Please read before you make another accusations.
Thread Starter
Newbie
Joined: Mar 2017
Posts: 6
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you're making too many assumptions, just two quick examples because I’m not interested in wasting my time on a known fail:
what happens if instead of exhaust gases flowing out as the side ports open later exhaust gases circle around and come back in there instead?
furthermore, unlike an REW where when the peri exhaust opens and the pulse goes out a single pipe to the turbo inlet where is it going on your contraption? Due to the Renesis centerplate siamese exhaust port you can’t separate the exhaust stream between the two rotors and you instead have multiple pipes with increased overall volume you’re trying to pressurize.
Sorry, you’re just not thinking it through thoroughly. I can tell you that nearly nobody has figured out just what the siamese exhaust port situation creates.
trust me, I know you’re going to do it anyway, just like was already posted.
what happens if instead of exhaust gases flowing out as the side ports open later exhaust gases circle around and come back in there instead?
furthermore, unlike an REW where when the peri exhaust opens and the pulse goes out a single pipe to the turbo inlet where is it going on your contraption? Due to the Renesis centerplate siamese exhaust port you can’t separate the exhaust stream between the two rotors and you instead have multiple pipes with increased overall volume you’re trying to pressurize.
Sorry, you’re just not thinking it through thoroughly. I can tell you that nearly nobody has figured out just what the siamese exhaust port situation creates.
trust me, I know you’re going to do it anyway, just like was already posted.
My siamese is from begining closed on port side. Block has been welded. No moving gases between chambers because of that.
Please read before you make another accusations.
this information existed from the beginning, but was often overlooked
the details matter about why a Renesis and previous 13B engines are similar, but not the same and can’t be treated the same in many regards
https://www.rx8club.com/series-i-maj...5/#post4927322
https://www.rx8club.com/series-i-maj...6/#post4927399
and no; it wasn’t the OP I was laughing at, but the conundrum faced whenever attempting to explain the situation. I suppose welding off the ports might work if the plates don’t warp, or crack, or one of the four welded pieces comes loose and takes out the motor. I don’t see it as a practical solution after studying it many years, but maybe he’ll prove me wrong on that point. However the overlap issue still exists and is not so easily addressed.
.
the details matter about why a Renesis and previous 13B engines are similar, but not the same and can’t be treated the same in many regards
https://www.rx8club.com/series-i-maj...5/#post4927322
https://www.rx8club.com/series-i-maj...6/#post4927399
and no; it wasn’t the OP I was laughing at, but the conundrum faced whenever attempting to explain the situation. I suppose welding off the ports might work if the plates don’t warp, or crack, or one of the four welded pieces comes loose and takes out the motor. I don’t see it as a practical solution after studying it many years, but maybe he’ll prove me wrong on that point. However the overlap issue still exists and is not so easily addressed.
.
Last edited by TeamRX8; Sep 11, 2020 at 02:37 AM.
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