Fb rx7 renesis
07-11-14, 03:23 PM
#1
Can Post Only in New Member Section
Thread Starter
Join Date: Mar 2013
Posts: 2
Likes: 0
Received 0 Likes
on
0 Posts
Fb rx7 renesis
So I have a 84fb and just got a renesis that I am rebuilding at the moment. I want to know if anyone can help me figure out how to get the renesis in the fb. I've seen people have it on YouTube so I know it is possible, but haven't had any luck with finding a build thread or anything of that nature. Thanks in advance.
07-11-14, 05:58 PM
#2
Retired Moderator, RIP
iTrader: (142)
Join Date: Sep 2005
Location: Smiths Falls.(near Ottawa!.Mapquest IT!)
Posts: 25,581
Likes: 0
Received 131 Likes
on
114 Posts
Maybe because It's not easy,but if it has been done it is ON this Forum.
Search other engine conversions and 1st Gen specific or Build threads.
Search other engine conversions and 1st Gen specific or Build threads.
07-11-14, 07:52 PM
#3
This sounds like an interesting swap, though the electronics might be a bit challenging.
If you're familiar with how a rotary engine is assembled, what I'm about to say will make much more sense. Aaron Cake has an excellent video on youtube detailing how one is assembled.
To the best of my knowledge, most of the parts forward of the Front Iron would have to be N304 parts from a GSL-SE. The Front Cover is absolutely going to have to be a GSL-SE one in order to mount the engine to the chassis.
For quick reference, I'll be using the following part number prefixes to denote items as follows. These are the actual part number prefixes Mazda uses for Engine and ECU-related parts.
N304: 84-85 GSL-SE
N326:: 86-88 Non-turbo
N3A1: 93-95 Twin turbo
N3H1: 04-08 RX-8
Please keep in mind that going from a N3H1 Front Cover to a N304 one means replacing essentially everything connected to the Front Cover. This includes but isn't limited to the following items listed off the top of my head
Water Pump & Housing: RX8's housing is integrated into front cover, all prior are separate. N304 should do the trick
Distributor/Crank Angle Sensor: The RX8 did away with the traditional setup that Mazda used on all prior rotaries. If you want to use a distributor, a N304 GSL-SE one is what you'd need. If you want electronic ignition, a FC Crank Angle Sensor will fit in the N304 Front Cover with no fuss. I'd use the CAS if it were me.
Oil Metering Pump: Not sure what the best way is here, gut feeling says a N326 one will make happy. It's mechanically linked to the throttle, unlike all later ones being electronically controlled by the ECU.
Fuel system: Simplest way I know would be to keep the RX8 injectors and rails, while using a GSL-SE tank assembly and a FD fuel pump on the GSL-SE sender
Electronics: This is where things get complicated. You can't use a N304 ECU as it can't compensate for the much higher compression ratio (10.5:1 vs 9.4:1), nor can it control the RX8's six fuel injectors (GSL-SE only has two). I am not sure if the RX-8's ECU can be used or not, due to the Crank Angle Sensor being from a FC. Also, all 89+ ECUs go into Limp Mode if their matching Oil Metering Pumps are not used. There's bound to be a workaround to keep a bone-stock 89+ ECU 'alive' when using a Pre-89 OMP though, I just can't think of it at the moment. If all else fails, a Standalone EMS such as the Haltech or MegaSquirt products can be used, but they are an expensive, yet universal solution.
Clutch, Flywheel & Transmission: RX-8 uses the 86+ Turbo flywheel and clutch setup, requiring the transmission, starter and flywheel/clutch all match accordingly. Simplest way would be to get an aftermarket flywheel and suitable uprated clutch intended for a GSL-SE. This will keep everything related to the transmission as bone stock GSL-SE stuff, saving a lot of headaches in trying to cobble together different parts.
Let me reiterate that this isn't an exhaustive list, it should only serve as a basic guideline on what you'd be getting into with the swap.
If you're familiar with how a rotary engine is assembled, what I'm about to say will make much more sense. Aaron Cake has an excellent video on youtube detailing how one is assembled.
To the best of my knowledge, most of the parts forward of the Front Iron would have to be N304 parts from a GSL-SE. The Front Cover is absolutely going to have to be a GSL-SE one in order to mount the engine to the chassis.
For quick reference, I'll be using the following part number prefixes to denote items as follows. These are the actual part number prefixes Mazda uses for Engine and ECU-related parts.
N304: 84-85 GSL-SE
N326:: 86-88 Non-turbo
N3A1: 93-95 Twin turbo
N3H1: 04-08 RX-8
Please keep in mind that going from a N3H1 Front Cover to a N304 one means replacing essentially everything connected to the Front Cover. This includes but isn't limited to the following items listed off the top of my head
Water Pump & Housing: RX8's housing is integrated into front cover, all prior are separate. N304 should do the trick
Distributor/Crank Angle Sensor: The RX8 did away with the traditional setup that Mazda used on all prior rotaries. If you want to use a distributor, a N304 GSL-SE one is what you'd need. If you want electronic ignition, a FC Crank Angle Sensor will fit in the N304 Front Cover with no fuss. I'd use the CAS if it were me.
Oil Metering Pump: Not sure what the best way is here, gut feeling says a N326 one will make happy. It's mechanically linked to the throttle, unlike all later ones being electronically controlled by the ECU.
Fuel system: Simplest way I know would be to keep the RX8 injectors and rails, while using a GSL-SE tank assembly and a FD fuel pump on the GSL-SE sender
Electronics: This is where things get complicated. You can't use a N304 ECU as it can't compensate for the much higher compression ratio (10.5:1 vs 9.4:1), nor can it control the RX8's six fuel injectors (GSL-SE only has two). I am not sure if the RX-8's ECU can be used or not, due to the Crank Angle Sensor being from a FC. Also, all 89+ ECUs go into Limp Mode if their matching Oil Metering Pumps are not used. There's bound to be a workaround to keep a bone-stock 89+ ECU 'alive' when using a Pre-89 OMP though, I just can't think of it at the moment. If all else fails, a Standalone EMS such as the Haltech or MegaSquirt products can be used, but they are an expensive, yet universal solution.
Clutch, Flywheel & Transmission: RX-8 uses the 86+ Turbo flywheel and clutch setup, requiring the transmission, starter and flywheel/clutch all match accordingly. Simplest way would be to get an aftermarket flywheel and suitable uprated clutch intended for a GSL-SE. This will keep everything related to the transmission as bone stock GSL-SE stuff, saving a lot of headaches in trying to cobble together different parts.
Let me reiterate that this isn't an exhaustive list, it should only serve as a basic guideline on what you'd be getting into with the swap.
07-11-14, 10:15 PM
#4
gonna have to fab up your own engine mounts on this one. and thats the easiest part.
07-11-14, 11:13 PM
#5
If all 3 N3H1 RX-8 irons are thicker, how is it possible to use a RX8 eccentric shaft in a prior 13B? IIRC, every 13B E-shaft is the same length
Even if the N3H1 RX8 front iron is a bit different in depth, it APPEARS that a GSL-SE would bolt right on. Add in the 12A to 13B adapter bracket from Mazdatrix, then it's a matter of seeing where the engine mount holes line up when the transmission is bolted in place
07-12-14, 12:16 AM
#6
) so i can only speculate at the moment that the MSP front cover might be a little thinner than the older 13B. from my rough measurements, the intermediate and rear housings are both the same as the older 13B.
Thread
Thread Starter
Forum
Replies
Last Post