SCCA Street Modified RX-8
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Responding to DCT8s PM here since I like to keep all this stuff out in the open.
Camshafts are a set of Kelfords that used to be sold by Dynotronics under their "Integral 1.5" name. They are a relatively mild cam. Idle is like stock but they make a lot more power up top than stock. Valve springs are Supertech. Stock retainers, stock valves, no head porting or even port work.
I am running ARP studs. Lots of people in the MZR/Duratec/Ecoboost/DISI world think they are weaker than the factory bolts. I don't believe that to be the case, I think the issues people have with them are because they don't torque them properly. They are fussy to get torqued correctly. I like them because the factory head bolts are not re-usable once torqued, and I had the head off the engine several times during the build. If I weren't going for the power level I have, I would have just used stock bolts. Bottom end is stock other than having the crank balanced, removing the gear for the balance shafts, and keying the snout. Stock bolts holding the mains. Oil pan is a custom baffled deal.
Pistons are Supertechs, I think they're not sold anymore. They are around 10.5-10.7:1 static CR.
I rev the motor to 7600. Probably higher than I should but it gives me the MPH I want with the gearing I want.
Camshafts are a set of Kelfords that used to be sold by Dynotronics under their "Integral 1.5" name. They are a relatively mild cam. Idle is like stock but they make a lot more power up top than stock. Valve springs are Supertech. Stock retainers, stock valves, no head porting or even port work.
I am running ARP studs. Lots of people in the MZR/Duratec/Ecoboost/DISI world think they are weaker than the factory bolts. I don't believe that to be the case, I think the issues people have with them are because they don't torque them properly. They are fussy to get torqued correctly. I like them because the factory head bolts are not re-usable once torqued, and I had the head off the engine several times during the build. If I weren't going for the power level I have, I would have just used stock bolts. Bottom end is stock other than having the crank balanced, removing the gear for the balance shafts, and keying the snout. Stock bolts holding the mains. Oil pan is a custom baffled deal.
Pistons are Supertechs, I think they're not sold anymore. They are around 10.5-10.7:1 static CR.
I rev the motor to 7600. Probably higher than I should but it gives me the MPH I want with the gearing I want.
I've learned a lot from reading your thread, so thank you for documenting everything.
Do you know what the limit of the stock cast 2.5 crank is? I'm planning on running forged pistons/rods, but I don't want to swap the crank if I don't have too.
What power level do you currently run the car at and what do you think it could make and still be reliable?
I'd like to make around 500whp with my 2.5 swapped NC Miata. It's a time attack track car.
It's getting a BMW ZF 5 speed synchro box and I'll probably swap to the 8.8 rear as well since I can run the RX8 rear subframe and utilize the Ronin kit like you did.
Not sure what the cost comparison is, but the Keisler Camaro diff swap doesn’t require any welding. I suspect it actually is the weight savings diff swap since it has the rear mounting ears integrally machined on the rear cover from aluminum billet along with a bolt-on aluminum front nose mount. They also have a bolt-on trans brace that’s pretty slick. You can pick and choose parts as they’ll sell you anything separate from the kit options.
I bought some of those parts for a Nissan CD009 trans conversion and my intention to delete the PPF but retain the OE rear diff with it.
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I bought some of those parts for a Nissan CD009 trans conversion and my intention to delete the PPF but retain the OE rear diff with it.
Last edited by TeamRX8; Jun 27, 2021 at 08:50 AM.
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Not sure what the cost comparison is, but the Keisler Camaro diff swap doesn’t require any welding. I suspect it actually is the weight savings diff swap since it has the rear mounting ears integrally machined on the rear cover from aluminum billet along with a bolt-on aluminum front nose mount. They also have a bolt-on trans brace that’s pretty slick. You can pick and choose parts as they’ll sell you anything separate from the kit options.
I bought some of those parts for a Nissan CD009 trans conversion that deletes the PPF but retains the OE rear diff
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I bought some of those parts for a Nissan CD009 trans conversion that deletes the PPF but retains the OE rear diff
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It’s all in the same vein it seems to me, but will try to get that measurement for you.
I had forgotten to include the video link for the Keisler Camaro diff install and added it to my earlier post above.
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I had forgotten to include the video link for the Keisler Camaro diff install and added it to my earlier post above.
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That diff install can't really get any easier. Thanks for the link!
Wow! You've built quite the car! I found your build thread by searching for 2.5 engine builds.
I've learned a lot from reading your thread, so thank you for documenting everything.
Do you know what the limit of the stock cast 2.5 crank is? I'm planning on running forged pistons/rods, but I don't want to swap the crank if I don't have too.
What power level do you currently run the car at and what do you think it could make and still be reliable?
I'd like to make around 500whp with my 2.5 swapped NC Miata. It's a time attack track car.
It's getting a BMW ZF 5 speed synchro box and I'll probably swap to the 8.8 rear as well since I can run the RX8 rear subframe and utilize the Ronin kit like you did.
I've learned a lot from reading your thread, so thank you for documenting everything.
Do you know what the limit of the stock cast 2.5 crank is? I'm planning on running forged pistons/rods, but I don't want to swap the crank if I don't have too.
What power level do you currently run the car at and what do you think it could make and still be reliable?
I'd like to make around 500whp with my 2.5 swapped NC Miata. It's a time attack track car.
It's getting a BMW ZF 5 speed synchro box and I'll probably swap to the 8.8 rear as well since I can run the RX8 rear subframe and utilize the Ronin kit like you did.
If the 8,000 RPM rev limit is a hard requirement I'd probably build one of the short-stroke hybrid engines based on the Ecoboost crankshaft.
I like the Keisler diff setup quite a bit. It came around after I had already bought the 8.8 setup. No regrets, though, I pulled the 8.8 this weekend in prep for the Giken install and was no sweat to get out. But the Camaro diff is a nice option and Andrew makes great parts (he is also really responsive and active in the community).
Last edited by John V; Jun 28, 2021 at 06:40 AM.
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I've always thought the Ronin front mount was way overbuilt. The ears take the majority of the twisting forces, the front mount only has to resist an upward compression force. The Ronin kit looks beefy enough to jack the whole car up from.
Though it is interesting that Ford went from a single front mount ear through '05 to a dual front mount in '06-'10. It'd be interesting to know the behind the scenes details on that one.
Ronin charges $839 for just the diff mount kit (no axles). If that's anywhere near what Keisler is charging for the billet CNC diff cover and front mount, then kudos to Ronin for the margin they're capturing on their laser cut flat steel weldments.
Though it is interesting that Ford went from a single front mount ear through '05 to a dual front mount in '06-'10. It'd be interesting to know the behind the scenes details on that one.
Ronin charges $839 for just the diff mount kit (no axles). If that's anywhere near what Keisler is charging for the billet CNC diff cover and front mount, then kudos to Ronin for the margin they're capturing on their laser cut flat steel weldments.
Interesting you mention that, I do jack the rear end from the pumpkin 
I like overbuilt when it comes to drivetrain stuff. I was blowing up the diff on my BMW about once a year and that **** got old. The other nice thing about the 8.8 is that they are absolutely everywhere, and cheap. I've yet to come across a pick 'n pull yard that doesn't have an IRS Explorer in it.
I like overbuilt when it comes to drivetrain stuff. I was blowing up the diff on my BMW about once a year and that **** got old. The other nice thing about the 8.8 is that they are absolutely everywhere, and cheap. I've yet to come across a pick 'n pull yard that doesn't have an IRS Explorer in it.
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Did your 330 have forced induction? I busted two front diff mount bolts on my E36 before I finally drilled it out and tapped it for the larger 14mm bolt. No issues with the bolt since then. But the first time I let a friend co-drive it, he made a particularly violent 1-2 shift and snapped off one of the ears on the cover.
The pick 'n pull near me is pretty sparse on the newer or cooler cars - I've never seen a post-2000 Mustang or any Camaro at all, but they always have plenty of Explorers. $57 for my diff from a 2010.
The pick 'n pull near me is pretty sparse on the newer or cooler cars - I've never seen a post-2000 Mustang or any Camaro at all, but they always have plenty of Explorers. $57 for my diff from a 2010.
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Thanks again for the help John. This thread is a wealth of info.
I'm curious about your traction control setup. I know you're running the non-dsc RX8 abs unit.
That's the unit I'm planning on running. Are you able to split the abs wheel speed sensor signal and feed the signal into the abs unit and into the ECU for wheel speed?
I'm curious about your traction control setup. I know you're running the non-dsc RX8 abs unit.
That's the unit I'm planning on running. Are you able to split the abs wheel speed sensor signal and feed the signal into the abs unit and into the ECU for wheel speed?
I'm not sure what you're asking. My car, an '05 Base, was non-DSC from the factory. The ABS unit in those cars only needs four wheel-speed sensors and a 12V power source to operate. However it does communicate with the factory ECU via the CANbus; the wheel speeds are sent on individual CAN addresses to the ECU. I run a Haltech ECU in place of the factory unit, and it is set up to communicate on the factory Mazda CANbus so the gauges work (among other things). The Haltech is therefore directly reading the individual wheel speeds and it has built-in traction control options that work very well once set up.
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I'm not sure what you're asking. My car, an '05 Base, was non-DSC from the factory. The ABS unit in those cars only needs four wheel-speed sensors and a 12V power source to operate. However it does communicate with the factory ECU via the CANbus; the wheel speeds are sent on individual CAN addresses to the ECU. I run a Haltech ECU in place of the factory unit, and it is set up to communicate on the factory Mazda CANbus so the gauges work (among other things). The Haltech is therefore directly reading the individual wheel speeds and it has built-in traction control options that work very well once set up.
I get now that you're getting the wheel speeds via CAN. My car is not going to communicate via CAN. I have no factory wiring in my car at all and I'm building my own very minimal harness.
I'm going to running the non-dsc unit as a standalone. I would still like to feed a front and rear wheel speed into my standalone ECU as well and it would great if I could do that with the existing abs wheel speed sensors.
I'm wondering if I can just tap into the signal wire that goes from the wheel speed sensor to the abs pump. Then take that tapped wire and run it into an input on my ecu. Hopefully that makes sense. Basically just one wheel speed sensor but having it send a signal to the abs pump and to the ecu.
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I was able to do that on my BMW - the wheel speed sensors are shared between the factory ABS module and the Megasquirt. No issues with it, but I think results could vary based on the electrical qualities of the sensor, ABS module, and whatever you're using to process the signal on your end.
I finally found a Sumitomo RX8 non-dsc abs for my car. I've been looking for a few weeks now.
I get now that you're getting the wheel speeds via CAN. My car is not going to communicate via CAN. I have no factory wiring in my car at all and I'm building my own very minimal harness.
I'm going to running the non-dsc unit as a standalone. I would still like to feed a front and rear wheel speed into my standalone ECU as well and it would great if I could do that with the existing abs wheel speed sensors.
I'm wondering if I can just tap into the signal wire that goes from the wheel speed sensor to the abs pump. Then take that tapped wire and run it into an input on my ecu. Hopefully that makes sense. Basically just one wheel speed sensor but having it send a signal to the abs pump and to the ecu.
I get now that you're getting the wheel speeds via CAN. My car is not going to communicate via CAN. I have no factory wiring in my car at all and I'm building my own very minimal harness.
I'm going to running the non-dsc unit as a standalone. I would still like to feed a front and rear wheel speed into my standalone ECU as well and it would great if I could do that with the existing abs wheel speed sensors.
I'm wondering if I can just tap into the signal wire that goes from the wheel speed sensor to the abs pump. Then take that tapped wire and run it into an input on my ecu. Hopefully that makes sense. Basically just one wheel speed sensor but having it send a signal to the abs pump and to the ecu.
There are quite a few wiring differences between the non-DSC and DSC ABS units.
https://www.rotaryheads.com/PDF/RX8/13Electrical.pdf
Page 122 is for the non-DSC unit.
Pages 124-126 are for the DSC unit.
https://www.rotaryheads.com/PDF/RX8/13Electrical.pdf
Page 122 is for the non-DSC unit.
Pages 124-126 are for the DSC unit.
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Ok sounds good. All of the posts I've been reading have mentioned different lines and different wiring between the two.
According to that wiring diagram, I will need the 8 wheel speed sensor wires, two CAN wires to my ECU, three power wires, and two grounds.
Maybe John can chime in and confirm that's how he wired his unit.
Thanks again guys! I really appreciate the help!
According to that wiring diagram, I will need the 8 wheel speed sensor wires, two CAN wires to my ECU, three power wires, and two grounds.
Maybe John can chime in and confirm that's how he wired his unit.
Thanks again guys! I really appreciate the help!
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Thanks for getting me straight on that. The equivalent DSC module info was posted in a different part of the service manual that I wasn’t familiar with since my car doesn’t have DSC. It would have been obvious had I compared the plugs on the wiring diagrams. What was posted is all that was needed for the non-dsc module wiring pinout though.
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