Bumjubeo

Hey,

So I'm undecided on what to do and coming to the Internet for help

I've got a s4 n/a and I'm decided if I want to rebuild or swap a renesis. I do want to keep it n/a because that's just what I want. If given the option would you swap to renesis or just do rebuild on the s4 with s5 rotors and aggressive porting?

Looking between a t2 and renesis engine, it looks like I can get a JDM renesis for cheaper than a JDM t2 right now, but a rebuild is still probably cheaper right?

Budget for this is about $5k, so that probably rules out the renesis but again just looking for opinions and I'm open to ideas.

mazdaverx713b

iTrader: (91)

If you want more power, just do a TII swap. A Renesis will require a lot more fabricating. The Renesis is a great engine if maintained properly and does make a nice amount of power but for the cost, it may be easier to do a TII swap.

rx7b13

I agree, and with the t2 swap, I'd go with a stand alone ecu, since you are going to have to change wiring harnesses anyways. Also have you put any though into the drivetrain? NA and T2 drivetrains are different, from the input shaft back to the diff. Mazdatrix makes a t2 trans to NA diff, so you dont have to swap the rearend over to a t2 diff.

j9fd3s

iTrader: (3)

the Rx8 is 3000lbs and 230hp and its so/so. the thing that Mazda wanted was 2400lbs with 225hp, and THAT would be pretty awesome.

so a 13B-MSP in an FC, if you can drop a few LB's has potential to be really cool.

the bad news is that you would be the first to do it, so all the stupid mounts, and brackets and wiring, you need to be able to make/figure out on your own.

Natey

iTrader: (19)

I agree on everything but the Renesis being a great engine.
TII all the way.

Dak

This one is tough mainly because of your budget as any JDM TII is probably going to need to be rebuilt. That said from everything I've read on here I think it is a better base to start with. If you want to stay N/A I'd still use the TII as my base and do a large street port. The 4 ports once ported make better power so I hear. Port match your S4 N/A intake to the TII block and run it with a standalone which you were gonna have to have to use to run the Renesis anyway. Also the price difference in engines is offset buy all the custom fab work you would have had to get done to install the Renesis. The best base engines are the 13B-RE or 13B-REW but they are more expensive and the RE is getting hard to find, but there are some somewhat bolt in solutions on the market for them. Here is an old thread of mine that might interest you. I wish I had went 4 port back then if I could have.

https://www.rx7club.com/naturally-as...-port-1093755/

Eydes2Rotor

iTrader: (3)

As an owner of an S5 NA and a renesis swap (WIP) FB, I would go for the renesis! You aren't the first to do it( ), but it's definitely a cool/uncommon swap. Anybody who's ever driven a well running 6 port RX-8 will tell you how exhilarating they are. Now imagine the same power in a 200-400 lb lighter chassis! Renesis swaps are cool, I'm really surprised that they aren't more common. There's far better access to renesis parts(as opposed to earlier engines where new parts aren't even available anymore, and probably never will be again) they are relatively cheap and very reliable with the right upkeep. Hell, you might be able to get away with running the engine on the stock RX-8 PCM. That's what I'm doing. The mounts will be pretty easy as both engines mount around the same spot, and the FC bay has more room than the FE. Besides that everything is pretty similar. You can hook up the renesis to the stock drivetrain by using an RX8 rear flywheel counterweight with an FC lightweight flywheel and clutch (ask me how I know, FB is the same kinda thing.) The plumbing should be extremely easy! Just use the stock FC oil cooler and make AN lines to it, then just sort out radiator hoses and engine bay side fuel lines into the RX8 rail. This is a much easier swap than my FB is because the FC chassis is already setup much more suited to an EFI engine. If you need any advice or resources if you decide to go that direction, let me know :-)

Bumjubeo

THanks everyone!

Given my budget I think the T2 swap may be the easiest for now. Looking through all the other threads I was thinking an REW swap may not be off the table either.

Keeping the stock twins, which I've read will fit, and doing a PowerFC and either the Angel or Motive (I'm partial to the Angel mounting bracket) may allow me to keep it under $5k hoping I can get a full setup imported that doesnt need an immediate rebuild (This is probably going to be the most improbably part)

I've got a connection for a T2 trans, which I know i would want to upgrade to since the S4 NA trans probably wont handle the REW power very well, ooorrrr I do the FD transmission with the trans mounting adapter/kit from RHDJapan....

Just going over the parts list in my head I think I'm well over my budget......maybe a T2 swap is just the right ticket unless I can increase my budget....

Dak

The REW probably has the best stock ports if you wanted to stay n/a and can swing it budget wise.
I used to want a PowerFC myself but lately I've been thinking about the Haltech Elite series. Depending on the model prices are similar once you buy all the adapters you need for the PowerFC plus its a more modern ECU as well.