Brettus 20B Renesis Hybrid thread
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10-19-2020, 08:33 AM
#28
FYI, Defined's ITB semi-PP made 476 WHP.
CLR has a full PP making 486 WHP
I would personally take the 10hp less for more drivability.
As far as a 20b renesis, if I was going to do it... I would have to insist on 6 port base design, and all 9 ports staged like the factory renesis, and probably semi pport setup similar to what Defined did with their setup where the p-ports have a slide throttle to close them off at the housing until they're needed. Also, the thick iron would have to be 100% port matched to the stock renesis porting. Exhaust setup would be the big unknown for me, so not going to get into the theory crafting in all that nonsense. you guys do that enough hahaha.
I'm kinda with team though... after you go through that whole laundry list of things there's just no point, as nothing really justifies the cost. Event an original 20b will cost you 6k for a # - C series block. D blocks are 15k used now. 3k for the rebuild kit, the eshaft will most likely be bent limiting you in RPM range (Defined number required 10k rpm, and CLR did it at 8.5k), labor, etc. You're taking a 10-15k engine just to start, and that's an off the shelf engine, and stock. i would imagine this hybrid could easily cost you 20~25k in just the engine. gets hard to justify those numbers for under 500WHP. I know I'll be well over 30k into my 20b swap alone. I'm at least 15k into the block already, and I don't even have it in my hands yet. With a D block I would be pushing 21k into the block alone already. I fully expect the # - C blocks to come up to the D block price over the next few years. New OE thick irons from mazda are 6k, and new eshafts are 9k. The prices are getting scary. I only paid 2k for my first 20b....
If you have the cash to burn, give it a try... would be interesting to see results.
CLR has a full PP making 486 WHP
I would personally take the 10hp less for more drivability.
As far as a 20b renesis, if I was going to do it... I would have to insist on 6 port base design, and all 9 ports staged like the factory renesis, and probably semi pport setup similar to what Defined did with their setup where the p-ports have a slide throttle to close them off at the housing until they're needed. Also, the thick iron would have to be 100% port matched to the stock renesis porting. Exhaust setup would be the big unknown for me, so not going to get into the theory crafting in all that nonsense. you guys do that enough hahaha.
I'm kinda with team though... after you go through that whole laundry list of things there's just no point, as nothing really justifies the cost. Event an original 20b will cost you 6k for a # - C series block. D blocks are 15k used now. 3k for the rebuild kit, the eshaft will most likely be bent limiting you in RPM range (Defined number required 10k rpm, and CLR did it at 8.5k), labor, etc. You're taking a 10-15k engine just to start, and that's an off the shelf engine, and stock. i would imagine this hybrid could easily cost you 20~25k in just the engine. gets hard to justify those numbers for under 500WHP. I know I'll be well over 30k into my 20b swap alone. I'm at least 15k into the block already, and I don't even have it in my hands yet. With a D block I would be pushing 21k into the block alone already. I fully expect the # - C blocks to come up to the D block price over the next few years. New OE thick irons from mazda are 6k, and new eshafts are 9k. The prices are getting scary. I only paid 2k for my first 20b....
If you have the cash to burn, give it a try... would be interesting to see results.
10-19-2020, 01:36 PM
#29
I have had a quote to build the engine for around (edit) 10k $NZ ($6600US) using mostly parts I already own. I also have a mock up of the lim and the uim which have cost me just time and 0$ so far. They will require some machining and welding to complete ... not a whole lot.
I've said it should make 320-350whp, be very streetable and even relatively economical to run and I stand behind that statement 100%.
I see it more as a cool alternative to a turbo Renesis rather than trying to duplicate what a semi or full pp 20b can do. That's because power will be in that sweet spot where the existing drivetrain can manage it without destroying itself.
However ...I have not pulled the trigger on the project yet . My biggest concerns are around the costs of modifying the chassis to accept the engine .
Not to mention ...... I already have a well sorted fast spooling 400whp turbo Renesis plus a very strong N/A 6 port sitting in the gge so I'm struggling to find a good reason to do it.
I've said it should make 320-350whp, be very streetable and even relatively economical to run and I stand behind that statement 100%.
I see it more as a cool alternative to a turbo Renesis rather than trying to duplicate what a semi or full pp 20b can do. That's because power will be in that sweet spot where the existing drivetrain can manage it without destroying itself.
However ...I have not pulled the trigger on the project yet . My biggest concerns are around the costs of modifying the chassis to accept the engine .
Not to mention ...... I already have a well sorted fast spooling 400whp turbo Renesis plus a very strong N/A 6 port sitting in the gge so I'm struggling to find a good reason to do it.
Last edited by Brettus; 10-19-2020 at 06:52 PM.
10-19-2020, 03:53 PM
#30
Throw out backseats and make a mid engine 4 rotor RX8?:D
10-19-2020, 06:42 PM
#33
Re the subframe .......... I don't know ...my engine builder seems to think it wont be hard to do along with a power steering setup ... I'm a bit nervous about that aspect TBH.
10-20-2020, 04:37 AM
#35
These guys : Rotary Parts | Precision Engeneering
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Brettus (10-20-2020)
10-23-2020, 05:17 PM
#39
10-23-2020, 06:39 PM
#40
Putting a LiFe battery under the hood isn't the end of the world either, and removes the weight instead of adding weight with heavy cabling and moving weight around. Some people fight it to the end of the earth but I'm curious how many of them do so because of experience..
10-23-2020, 08:31 PM
#42
That's less than half of one person ... and it mostly down low .
10-25-2020, 01:08 AM
#44
Yes, you guys posting about inertia effects of battery location, or added cable weight of moving a battery that doesn't like heat exposure to the trunk for that protection, and other such nonsense.
My extra-length battery cables added maybe 2 lbs if that to my 10 lbs of battery and mount weight, which has a 1000+ CCA capacity, and it was all routed down low on the passenger/RH side to help offset the usual driver/LH side weight bias, but let’s not fuss over the particulars like your car not cranking on a regular day or flooding on a cold 32*F day and other such nonsense because the battery is too small/low in capacity or on it’s way out due to excessive heat exposure. Which I’ve dealt with all those things since 2006 except fortunately never flooded because I was fortunate to have a battery jumper box on standby. Trust me, some extra weight for some extra protection is worth the hassle and inconvenience of every time that happened in the past before I finally wised up and paid the price to do it right. I obsess about weight as much or more that anyone, but do also appreciate and understand the give and take nature of it; cut it where you can, concede it where you must.
otherwise the weight addition Brett mentioned is expected and not really the issue. If you understand the subject at hand then the issue is more about the engine management mods, custom internal engine mods, custom intake, custom engine brackets/mounts, custom subframe mods, custom exhaust manifold, custom fuel system mods, and so on in total, yet is still supposedly economical. It’s still basically a full engine swap, which in other threads is proposed as the opposite of economical by the same person without all those same consideration or to a lesser degree. Of course I can speculate on multiple scenarios and assess how it could possibly have good fuel economy and hit the projected whp target, but would prefer to wait and see what Brett specifically proposes to accomplish such a lofty goal.
not that any common sense should prevail ... because some of the commentary represents the wild @ss speculation Brett speaks out against, but then he also doesn’t fully appreciate the difference between those kind of comments and someone who may have the experience to wield it properly and make accurate assessments. Then again he assumes what is known without having any clear understanding to the sources of the knowledge based on what may or may not be posted on the forum. I share plenty in due time, but not necessarily everything for my own good reasons. The recent 4-port ported thread discussion as one of many such examples.
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My extra-length battery cables added maybe 2 lbs if that to my 10 lbs of battery and mount weight, which has a 1000+ CCA capacity, and it was all routed down low on the passenger/RH side to help offset the usual driver/LH side weight bias, but let’s not fuss over the particulars like your car not cranking on a regular day or flooding on a cold 32*F day and other such nonsense because the battery is too small/low in capacity or on it’s way out due to excessive heat exposure. Which I’ve dealt with all those things since 2006 except fortunately never flooded because I was fortunate to have a battery jumper box on standby. Trust me, some extra weight for some extra protection is worth the hassle and inconvenience of every time that happened in the past before I finally wised up and paid the price to do it right. I obsess about weight as much or more that anyone, but do also appreciate and understand the give and take nature of it; cut it where you can, concede it where you must.
otherwise the weight addition Brett mentioned is expected and not really the issue. If you understand the subject at hand then the issue is more about the engine management mods, custom internal engine mods, custom intake, custom engine brackets/mounts, custom subframe mods, custom exhaust manifold, custom fuel system mods, and so on in total, yet is still supposedly economical. It’s still basically a full engine swap, which in other threads is proposed as the opposite of economical by the same person without all those same consideration or to a lesser degree. Of course I can speculate on multiple scenarios and assess how it could possibly have good fuel economy and hit the projected whp target, but would prefer to wait and see what Brett specifically proposes to accomplish such a lofty goal.
not that any common sense should prevail ... because some of the commentary represents the wild @ss speculation Brett speaks out against, but then he also doesn’t fully appreciate the difference between those kind of comments and someone who may have the experience to wield it properly and make accurate assessments. Then again he assumes what is known without having any clear understanding to the sources of the knowledge based on what may or may not be posted on the forum. I share plenty in due time, but not necessarily everything for my own good reasons. The recent 4-port ported thread discussion as one of many such examples.
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Last edited by TeamRX8; 10-25-2020 at 01:12 AM.
10-25-2020, 01:21 PM
#45
When I say 'economical swap' I mean that as a relative term, as in ; by comparison to a traditional 20b. Same goes for fuel economy.
And yes I do realise all that needs to be done ..... I would have just done it by now and not procrastinated for so long otherwise.
And yes I do realise all that needs to be done ..... I would have just done it by now and not procrastinated for so long otherwise.
10-25-2020, 01:22 PM
#46
I don't discredit your experience or choice. I do know, however, that at least some lightweight starter LiFe batteries can handle years of track use in an Rx8. Maybe these cars that use them (mine included) are not stock cars nor do they see climate extremes or daily use, but that doesn't discredit them all together.
10-25-2020, 05:07 PM
#47
Without getting into specifics of how this will be achieved (shouldn't be too hard to guess) I may as well divulge the basics of the engine setup proposed. It's kinda looking like I wont do it anyway so may as well discuss the merits or otherwise of such a setup.
Here it is:
2/3rds Renesis 6 port with full s-dias .................1/3rd semi pp intake (staged) with pp exhaust . No Siamese ports.
Obviously it will require ability to tune each rotor separately but if that can be done .... it should meet or beat the whp goal no problem while still being fuel efficient (for a 20b)
Here it is:
2/3rds Renesis 6 port with full s-dias .................1/3rd semi pp intake (staged) with pp exhaust . No Siamese ports.
Obviously it will require ability to tune each rotor separately but if that can be done .... it should meet or beat the whp goal no problem while still being fuel efficient (for a 20b)
Last edited by Brettus; 10-25-2020 at 05:20 PM.
03-08-2021, 12:42 AM
#48
I like the way u think, and thx for linking me to this thread.
@TeamRX8, just because a 3-rotor Renesis is cost-prohibitive or not worth the $ doesn't mean it shouldn't be done. I'd argue that just having the data/results from such a build would be worth the endeavor. Sure, you can make heaps more power w/ a typical turbo 20B, but that's already been done many times the world over. Don't you want to see something new, especially w/ Renesis parts? I've only seen 1 example thus far of a 3-rotor Renny. Honestly, this is the kind of build where cost should more or less be disregarded. This is basically "dream car/build" territory. You don't skimp out on builds like this.
Anyway, my take on a "20B-MSP" would be to forgo the turbo that most 3-rotor builds include. I'd prefer a 3-rotor Renny to be either N/A or centrifugally S/C. Now, hear me out... the goal shouldn't be absolute maximum HP. That can be achieved via a traditional 20B or 26B build. Imo, I'd love to have a motor w/ the feel of a Renesis, but simply larger. Basically, it should rev sky high w/ a torque curve that just keeps on giving.
Does this mean you'd essentially be using center plates w/ blocked off exhaust ports? (Or REW center plates?) What are your thoughts on center bearing mod on a short-shaft setup? I've always wondered how that'd work w/o a "thick" center plate. Btw, why are you no longer pursuing such a build?
P.S. I really wish aluminum/billet Renesis plates were a thing...
@TeamRX8, just because a 3-rotor Renesis is cost-prohibitive or not worth the $ doesn't mean it shouldn't be done. I'd argue that just having the data/results from such a build would be worth the endeavor. Sure, you can make heaps more power w/ a typical turbo 20B, but that's already been done many times the world over. Don't you want to see something new, especially w/ Renesis parts? I've only seen 1 example thus far of a 3-rotor Renny. Honestly, this is the kind of build where cost should more or less be disregarded. This is basically "dream car/build" territory. You don't skimp out on builds like this.
Anyway, my take on a "20B-MSP" would be to forgo the turbo that most 3-rotor builds include. I'd prefer a 3-rotor Renny to be either N/A or centrifugally S/C. Now, hear me out... the goal shouldn't be absolute maximum HP. That can be achieved via a traditional 20B or 26B build. Imo, I'd love to have a motor w/ the feel of a Renesis, but simply larger. Basically, it should rev sky high w/ a torque curve that just keeps on giving.
P.S. I really wish aluminum/billet Renesis plates were a thing...
Last edited by Staf00; 03-08-2021 at 01:09 AM.
03-08-2021, 01:37 AM
#49
I
Does this mean you'd essentially be using center plates w/ blocked off exhaust ports? (Or REW center plates?) What are your thoughts on center bearing mod on a short-shaft setup? I've always wondered how that'd work w/o a "thick" center plate. Btw, why are you no longer pursuing such a build?
Does this mean you'd essentially be using center plates w/ blocked off exhaust ports? (Or REW center plates?) What are your thoughts on center bearing mod on a short-shaft setup? I've always wondered how that'd work w/o a "thick" center plate. Btw, why are you no longer pursuing such a build?
We have a firm here that does the center bearing mod. How good it is ...
I decided to pursue the turbo manifold instead because it worked so well. The 3 rotor project would be a huge undertaking and I wasn't ready to go down that rabbithole.
