Is there a viable option out there to replace the Renesis with ANYTHING else? These are selling for pennies and it's an awesome chassis that is begging for a simple swap. Somebody has to have solved the Canbus riddle, right?
Hint hint. I'd love a fly and drive to Colorado for a Flyin RX-8.
A 13b fits really well, costs less than any swap kits.
I'm wishing for more like a reliable 180-200hp 4 cylinder that can be "plugged and played"!
Just buy a miata, they are cheap now too.
I have a RX8, it was $500, but won't start. I also have a mazda KL V6 and thought of putting that in it.
If you have the skills anything is possible. If looking for easy, don't engine swap a RX8.
In reply to nimblemotorsports :
Even a 13B Turbo can be made to fit. The ECU may have a hiccup or three, though.
I'd have thought that these would be fantastic for Honda K-swaps.
The Duratec-4 lineup is probably your best bet given that the RX-8 is literally a bigger Miata
May i suggest a gm 60 degree v6? Theyre a RIOT in the miata.
Why wouldn't you do a 2.5 something something-Tec swap? It fits into an NC Miata, so it will fit an RX-8. As far as electrons, why couldn't you swap over an NC brain box? Why does the RX need to know it's an RX?
Isn't the RX-8 just a slightly bigger NC?
I looked at this a lot too.
Apparently there is lots of suspension stuff both front and rear that can be a hassle.
For example, the steering components are centrally located and have to move for most engines other than wankels (as I understand). And now you've just created all sorts of bumpsteer and akerman issues for yourself. I think there are LS swap companies, and they make remedies for all this stuff, but it adds cost and complexity.
Also, the diff is mounted to the trans, so if you're not using the stock trans, you need to solve that problem (again, not insurmountable, but adds cost and complexity).
How about an electric motor mounted at the rear diff and a bunch of batteries in the engine compartment?
We’ve done LS swaps on the sister NC, so that’s obviously possible. I know the subframes interchange, so an MZR 2.5 would be cake. You’d have to come up with a PPF, but that’s pretty easy.
triumph7 said:How about an electric motor mounted at the rear diff and a bunch of batteries in the engine compartment?
This is honestly easier. The best way to do it too. If youre going to gut the car, set it up for decades to come. $500 chassis. $2,500 to make it a sloth with no range. $10,000 to make it a Tesla.
theoretically speaking, You could put the electric motor up front, giving you all sorts of room for batteries in the back and rear seat area. You then have the choice of direct drive, or mated to the transmission for a torque multiplier (no clutch take offs or stops!)
Putting electric motors in back means you'll be engineering the rear suspension for the rest of your life.
_ said:triumph7 said:$2,500 to make it a sloth with no range. $10,000 to make it a Tesla.
OK, what's the recipe for that? It seems like quality DIY high-performance EVs always rack up the big bucks.
OHSCrifle said:I'm wishing for more like a reliable 180-200hp 4 cylinder that can be "plugged and played"!
So.... a Japanese import Renesis?
I'm 6'-5" so Miata isn't the answer.
Keith: what is a PPF?
No interest in a wankel.. awful fuel economy when they're running well. Rather solve several problems not perpetuate them.
PPF = Power Plant Frame. It's a beam which ties the transmission to the differential. It reduces drivetrain fore/aft motion. All generations of miata have one, as do the RX-8 and FD. Mazdas with a PPF don't have a transmission mount.
I'm 6'5" and own a NA (aftermarket seat) and would own an ND if my spouse would permit it.
In reply to Snrub :
It's more beautiful than that. The PPF does more than stop pitching motion of the differential, it also ensures that the entirety of the drivetrain fiorces are resolved either internally to the PPF or at the front and rear subframes, which means the chassis can be lighter, and there is no drivetrain NVH getting transferred directly to the center tunnel from a diff mount or trans mount.
Chevy started doing it on the Corvette toward the end of the C3's life, and C4s all had one, too. Which brings me to my point... has anyone swapped into a PPF type vehicle using Corvette transmissions, or differential too I guess, so they could try to use a PPF type device instead of making a trans mount and diff mount?
Kreb said:_ said:triumph7 said:$2,500 to make it a sloth with no range. $10,000 to make it a Tesla.
OK, what's the recipe for that? It seems like quality DIY high-performance EVs always rack up the big bucks.
There was some discussion in another thread (albeit fwd) that Nissan Leafs were a nice self-contained unit... but that Ford battery packs were 'cheap on the ground', and better state of charge compared to the leaf packs which see 'hard duty' thanks to being 'aircooled'
edit: also, I'm pretty sure this Leaf/Ford combination would require some kind of new motor controller, but I'm not sure what/which
Kreb said:_ said:triumph7 said:$2,500 to make it a sloth with no range. $10,000 to make it a Tesla.
OK, what's the recipe for that? It seems like quality DIY high-performance EVs always rack up the big bucks.
Quite a lot, but the possibilities are getting kinda awesome.
Per SpinningMagnet's work on the Endless Sphere forums we can get a good idea of the sizes of several battery types, but also figure out which ones are liquid cooled. While a fun daily driver can get away with an air-cooled battery, LEAF cells have shown that liquid cooling/heat maintenance is necessary for long battery life and stable discharge rates- considering the trans tunnel and small spaces you're dealing with in an RX-8 I would bank on small Chevy Spark cells- "Inwo"s comment in that thread shows they are comparable to the LEAF cells in size. Volt cells also come in a range of sizes, and if you can find them (and if research supports this) the ZERO motorcycle battery is supposedly pretty baller as well.
The final two that could work would be the Tesla cells made for the Smart FourTwo which can also be liquid cooled, but I know of only one build that uses them in an offroad FJ40. The other is the current BMOC- the LG Chem packs for the Chrysler Pacifica. At 6x8 inches they could fit, and their discharge rate is WILD, to the point where EVWest is using them in their EV drift BMW.
For a motor you've got quite a few options, though it all depends on your controller and inverter which I don't fully understand. I DO know however, that a drift or drag race EV would likely want brushless DC and everything else would want to go AC. BLDC are wild- super high efficiencies similar to AC, they *have* to generate more power the more electrons you push down their throats- but it comes at risks of flare out events and few are liquid cooled. You also have AC options- but they are expensive including the Tesla motors, though I don't know what the over/under is on separating one from the diff housing and you're limitied to the X/S units as the 3s hasn't yet been hacked. There's also promise in the next few years of Axial Flux which might be the new Raven motors, though your only options there are the Lynch/Agni motors right now which are rare and pretty wild.
End result? Your "cheapest" one that you'd be happy with woudl easily hit $10K even with proper research and that's using a BLDC motor overvolted with no regen. Even spending slightly more could easily get you an AC motor or one actually built for sport/vehicle use instead of a Wumbo-ed forklift drive, so it absolutely becomes an issue of cost- but naturally it's a question of wether you want a fun daily driver EV or a drift machine.
Since we've gone this far- does anyone have measurements of an RX-8 for swaps? We might as well make a full plan at this rate.
sleepyhead the buffalo said:Kreb said:_ said:triumph7 said:$2,500 to make it a sloth with no range. $10,000 to make it a Tesla.
OK, what's the recipe for that? It seems like quality DIY high-performance EVs always rack up the big bucks.
There was some discussion in another thread (albeit fwd) that Nissan Leafs were a nice self-contained unit... but that Ford battery packs were 'cheap on the ground', and better state of charge compared to the leaf packs which see 'hard duty' thanks to being 'aircooled'
edit: also, I'm pretty sure this Leaf/Ford combination would require some kind of new motor controller, but I'm not sure what/which
There's tons of motor controllers on the market- a battery is a battery, and motors follow physics first, software second.
3.0l with a manual out of a lincoln?
If you would like to see a RX8 chassis and hear my ramblings.
As an update, I ended up removing just the suspension for my GT6 project and chopped the rest up for recycling.
The GT6 will have an Audi Transaxle fitted to the rear suspension. I think I have pics of that somewhere in here.
The RX8 is a great chassis let down by an engine that is more trouble than it's worth. Don't get me wrong I love rotaries and had a blast driving mine with the stock engine, but longevity, and power are definitely lacking with the Renesis. There's quite a few swaps that've been done, the ones I know of: Mazda (KL, MZ, 20B, 13B) GM (LS, LT, LFX, LF4, 350) Honda (K, J, F) Toyota (JZ, UZ) Nissan (SR, RB, VQ, VH) Mercedes (M113) BMW (S50) Isuzu (6V) Cummins (6BT) Ford (Coyote, 300 I6) Mitsubishi (4G63) VAG (1.8T) and a few electric conversions
LS is the easiest right now since it is the most supported with kits and documentation.
I started my swap back in 2014 and it took me about 2 years to finish, but that's when there weren't that many finished swaps and the knowledge base was limited. Much easier to do them now.
I used the V8Roadsters kit, and I was one of the beta testers for the kit. So refining it was a big part of the time sink, but V8R was really helpful along the way. The beta kit was essentially the NC subframe kit slightly modified, driveshaft and rear end mount kit. I used a GMPP crate LS3 with a GTO T56 and Ford 8.8 I pulled out of a Lincoln Mark VIII and swapped a 31 spline lsd to the use the axles in the kit.
I ended up having to do my own radiator mounting, figure out the wiring and mount for the GM Drive by Wire pedal, air conditioning, and exhaust. Steering rack was swapped from electric to modified hydraulic unit from a NC miata, as it puts the rack in the stock position. Had a bit of a headache with the front sway bar as the early V8R subframe wouldn't work with the stock RX8 bar, it interfered with the crank pulley and ac belt tensioner, and they didn't have a solution yet. I ended up getting a thicker bar made with slightly longer arms and spaced it down 3/8" and used shorter end links, but still had issues with the ac tensioner. Fixed that by using an OEM CTS-V stretch to fit AC belt and ditched the tensioner all together, still had to clearance the ac bracket a bit. They fixed all that in subsequent kits.
To get ABS working you have to use a base model ABS unit. The DSC/ABS unit requires too many inputs from the engine that are no longer present. Base ABS unit is self contained, but needs to have the harness modified to fit the new plug. An ABS module, DSC or base, must be retained as it supplies the speed signal to the dash unless using the V8R CANBUS unit.
The unit needs to be relocated and new lines run to clear the head
To get the dash working there are a couple options.
First option retain the RX8 ECU and harness, fit a crank trigger wheel and sensor and add the coolant and oil pressure switch to the swapped engine. If you use a kit that retains the stock electric rack you'll have to do this anyway.
Second option is run a canbus module. When I started my swap there was only one module available from a guy in England. I ended up getting the last one, as he went out of business about a month after I bought it. Long story short, it didn't work well. It turned off all the dash warning lights, but the tach bounced around like a sugared up 7 year old. I did get the guy who sold it to help me troubleshoot, which involved a round trip of the unit back to England, but the problem persisted. It's a shame as this would have been a great solution for all swaps as it pulled all of it's signals for the dash from standalone sensors so you weren't tied to the CAN protocol of the swap ECU. Fortunately someone on a FB group for RX8 swaps brought his unit to market right when this was going down, and I bought an early unit. Fixed the tach, but had issues with the warning lights, the speedometer would occasionally stop working, and the odometer no longer worked. There was some movement toward a second gen unit, but then he seems to have dropped off the face of the earth. V8R had been working on a unit since before I started my swap, but wasn't ready to deploy it. I finally convinced them to let me test it after all this. After working through some issues with GM's obsession of minor undocumented changes inside ECU families that completely change compatibility of their CAN outputs, the dash works flawlessly. The guy who developed the module for V8R is an awesome guy, and working with him was actually a lot of fun.
From what I can tell the V8R unit is the only one on the market currently. There are a few people that pop up from time to time saying they are developing a unit, but nothing material yet.
This turned out more long winded than I intended, but the short of it is RX8 swaps aren't too difficult as most of complications have been identified and solved. However, don't expect to spend $500 on a blown RX8 and expect to have a running swap for a few thousand more. All the little things that have to be solved add up in time and cost. I went way overkill and over-engineered some things, and spent a lot more for than I could have because I didn't want to cut corners and end up with a janky swap. I wanted a car with as few compromises as possible. Totally worth it to me though, finally has an engine that compliments the chassis. It's a sleeper as I did a very quite exhaust and externally it looks stock other than the wheels. Surprised quite a few people who thought it was just another RX8.
Here's some links to swap companies
V8R https://v8roadsters.com/mazda-rx8-parts-upgrades/ (LS based) can work with most engines if you get a cradle without mounts and make your own
LS1 RX8 https://www.ls1rx8.com/ (LS, JZ, Coyote) uses the stock cradle, can use as a base for other engines
Keisler Automation https://www.keislerautomation.com/ Complete LFX kit
Ronin Speedworks http://www.roninspeedworks.net 8.8 IRS kit
CX Racing https://www.cxracing.com/engine-swap-kit-mazda-rx-8 budget LS 13B
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