Engine swap possibilities in an FD? (other than a V8)
 

Hello,

I am a huge petrolhead, big fan of the RX-7. My dream is to own an FD. I think it is the best looking Japanese car of the ‘90s, and possibly one of the best-looking cars of all time. :tear:

The biggest downfall of the RX-7, however, seems to be the long-term reliability of the engine, especially when pushing it hard.

A part from the V8, I wonder if there are any possible swaps out there to make it a reliable car for the track and daily driving.

i.e.: EJ25 (STi motor), SR20DET, RB20DET, another 6 cylinder etc..


Let’s say all I have to start with is an FD shell and I plan on changing everything. Is it at all cost-effective?

Keep in mind I am not an irrational tuner trying to achieve ridiculous hp numbers. I am simply aiming for a reliable 350hp max. Key word here is reliable.

Maybe just rebuilding and maintaining the TT rotary will be more cost effective than doing a swap, I don’t know.

you can get a 350hp rotary reliable, get full exhaust, intake and tune it with a piggy-back, like the Peter Farrell Purple box. The purple box claims 360Hp on the "stage 3" setting. And that stock block. Theres other combo to get that HP.

Main factor for reliability is TUNING.

Hai

As a sub-question, why is the LS1 swap so popular? Doesn't this bother RX rotary purists?

you have no idea what youre talking about. The PFS purple box is great for light modding but nowhere near reliable for 360rwhp. If you want a reliable 350hp rx7 youre gonna need a single and a PFC or even nicer EMS.

as for engine transplants there is no simple choice. The most well documented comversions are the 20b and the 350. Aside from that there has been one 2jz. The renesis sucks. There is no cheap-ass honda engine transplant. either stick with the 13b or get a different car.

the 2jz and the sr20 are too tall. the rb and ej are probably too wide.

those that go LS1 are either superficial turds who just want the body styling and dont care for the soul of the car or former rotary purists who are now disillusioned with its reliability.

Like I said, I'm a huge car-fan and I agree that the engine is a huge part of a car's soul. Swapping the FD's techie, japanese rotary for american muscle is sorta unsettling. I'm still not sure what I think of it.

I'm not one who is interested in quarter-mile times nor winning highway runs. I do however want a reliable daily-driver and good-handling track-car.

Is a stock LS1 for me?

I'm still unsure about the whole concept. Don't think Id betray the car. :confused:


:confused:

LS1 is likely the best option. It fits amazingly well, HP is right at your requirement with little mods. Huge aftermarket support for the motor and many have done the conversion, no turbo to deal with so plumbing, tuning, etc are all easier.

Nay sayers preach 1 of 2 sermons.

#1. The rotary is the "spirit" of the car.
#2. It will kill the handling.

Well #2 is BS, I've auto-xed a LS1 car and it handled great at the same event I drove my 93 R1. You'll add about 40-60lbs to the front of a stock FD (not modded FD, could be as much as 120lbs LS1 vs modded rotary).

#1, well you can't argue facts there so don't try:).

I've never-ever been so confused in my life. I love the RX-7. I love muscle cars but...... ???

Purely factual question (considering I'm aiming for a reliable 350hp):

A stock LS1 will weigh how much more than the stock rotary + turbos + piping + FMIC ?

why would the rb be too wide?

I would just stick with the rotary. Start with a new engine with a small street port, add full exhaust, intake, intercooler, PFC with a nice rich tune, and 12 psi and you'll have somewhere around 300-320 rwhp, which is about 350 flywheel hp.

This setup will be relatively reliable and very fun to drive and track. There is no reason stock FD's shouldn't last 100k before a rebuild. Owners just neglect maintaining it correctly and this is what causes the problems.

I think if I was given a brand new stock FD with the knowledge I have now, I could get it to last AT LEAST 100k miles before needing to be rebuilt.

Remember, not all 7's are as unreliable as people say. If you treat it right, it will treat you right.

turbo V6, two banks, two headers, two turbos WIDE

try turbo inline 6, one bank, one header, one turbo (unless its an rb26)

ABOUT 40-60lbs more than a STOCK FD.

Consider a stock FD has cats, large battery, airpump, twin turbos, light flywheel, etc that can all be removed and/or replaced with lighter pieces. A modded FD, with single turbo, full exhaust, no emissions, no AC, light flywheel could probably weigh 70-80lbs less than stock. So the total weight difference comparing apples to apples (LS1 conversion w/no cats, AC, emissions, etc) could be 110-140lbs heavier for the LS1 car.

I've personally seen a 2500lb FD, it is likely no LS1 car will be that light without serious cutting.

did you see my quote of you? you referred to the rb i asnwered.

any inline 6 is too tall, any turbo v6 is too wide, any boxer style engine is too wide. one of the rotary engines main advantages is that it can be place real low and real narrow and real light. there is no, none, any, ever engine that will fit in an fd like the 13b without major modification. its not a honda.

How pathetic are you guys that think cars have souls? It's almost as sad as those peta freaks. Wait, the things they are fighting for actually do have souls. It must suck to be a bigger loser than those peta kids. Huh?

Ignore my last post. I dont have time to argue on the internet. However, I wonder why you inquire about these engines "i.e.: EJ25 (STi motor), SR20DET, RB20DET, another 6 cylinder etc..". Is it any better since it came from a japanees car? The ls1 appears to meat your requirements. There is a wealth of information and its tried and true. It will save you a ton of headaches. Mike

The 13B-rew is not exactly light, with the turbo assembly(s), the oil coolers, intercoolers, and other accessories not needed with a piston engine like the LS1. Also, the crankshaft in the LS1 sits lower than the eccentric shaft in the 13B which helps lower the center of gravity, keeping the engine balanced. In fact, thanks to the high eccentric shaft, the transmission has enough room for the massive T56 transmision that goes well with the LS1.

The beauty of the LS1 is the reliable power it makes. 300 whp is very possible from an unmodded engine, as well as 300-350wtq! That makes a huge difference, especially when pulling away from a corner.

Oh and if by betraying the car, you mean replacing an unreliable, inefficient engine with another engine that is very reliable, gets 25-28 mpg, has torque, cheap to run, doesn't sacrifice handling, has improved drivability, where do I sign up to betray my car?

I don't think you understand what I am trying to say. THE RB IS AN INLINE 6, NOT A V6!