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-   -   Thoughts on a V6 or 4cyl Engine Swap? (https://www.rx7club.com/build-threads-292/thoughts-v6-4cyl-engine-swap-1040310/)

Hannibal King 07-09-13 09:59 PM

Thoughts on a V6 or 4cyl Engine Swap?
 
About to purchase a FD shell, & was curious if a v6 or even possibly a 4 cyl swap in a FD would be smart. I know you guys are going to say a v8.

But I'm looking for something that I could lightly tune to get a little power but a dependable FD.

& also something that won't break the bank entirely.

I had a though of a 240sx engine, maybe a s2000 engine? I don't know.

Ideas?

*The only reason is I had a FD before & within the first week of having it, it only having 30k miles, the apex seals went. Just not excited to have another rotary but LOVE the FD*

Rxmfn7 07-09-13 10:15 PM

LS swaps are so well documented and there are so many off the shelf, bolt in parts available for the swap that when doing it for the sake of dependability and "not breaking the bank", it really is silly to even consider anything else.

limepro 07-09-13 10:21 PM

Get a Miata, convertible FD 4cyl, there you go.

TwinCharged RX7 07-09-13 10:23 PM

OP is just plain dumb. Breaking an engine by driving it 30 miles without providing any detail on what caused it is probably because he doesn't know what caused it so now he wants to go around talking about how unreliable the engine is.

Dumb people always place the blame on the engine and not the driver/mechanic/tuner

jacobcartmill 07-09-13 10:28 PM

i'm guessing that you're going to want ~400whp if you're going to do all this work, and i'd venture to say that any 400whp 4 cylinder is going to be less reliable than a 400whp 2 rotor. the 4 cyl would be a little easier to tune though, if tuning is a factor for you.

don't want 400whp? only 300? drop a rebuilt REW in the car and get a powerFC and intercooler and make 300whp forever.

so let's talk V6. which V6? a VQ35? doesn't make enough power, too wide and tall. VQ38? too wide and tall. a single cam domestic V6? they're all old and they suck. an I6? 2jz? too long and too tall. RB26? too long, too tall, and too expensive. a quad cam V8? way too wide and tall.


and really, my post was bordering blatant disregard for you being a total n00b and blowing apex seals in your newly acquired FD. was the car setup correctly? was it tuned? was it modded? apex seals don't generally "just go."
it's pretty easy to blow a boosted piston engine too (you probably already knew that though).

Hannibal King 07-09-13 10:43 PM


Originally Posted by TwinCharged RX7 (Post 11516379)
OP is just plain dumb. Breaking an engine by driving it 30 miles without providing any detail on what caused it is probably because he doesn't know what caused it so now he wants to go around talking about how unreliable the engine is.

Dumb people always place the blame on the engine and not the driver/mechanic/tuner

Yes, I am new to this territory. You never asked a question?

Nah, your just fuckin smart aren't ya? :nod:

LuvingMy93FD 07-10-13 01:12 AM

You have to think where you are posting lol...This is an rx7 forum so it will be a bit biased toward someone putting a non rotor motor. Also google is your friend, you should be able to find rx7 builds with 2jz's, sr20's, 4age's, v8's...I originally bought my fd to swap an LS and then decided just to keep the rotary, I don't see any point in putting a 4 cyl or V6 in it. Any car can be reliable, all depends on the owner. When I bought my rx7 I read up on it before I did, and I planned to assume the responsibility of the extra care it needs to make it reliable. To answer your question I don't think it's smart to want to put a 4cyl or v6, go rotary, v8, or just don't buy the FD shell at all. This is my opinion, so in the end do what you want, it's your money.

Hannibal King 07-10-13 12:45 PM


Originally Posted by LuvingMy93FD (Post 11516486)
You have to think where you are posting lol...This is an rx7 forum so it will be a bit biased toward someone putting a non rotor motor. Also google is your friend, you should be able to find rx7 builds with 2jz's, sr20's, 4age's, v8's...I originally bought my fd to swap an LS and then decided just to keep the rotary, I don't see any point in putting a 4 cyl or V6 in it. Any car can be reliable, all depends on the owner. When I bought my rx7 I read up on it before I did, and I planned to assume the responsibility of the extra care it needs to make it reliable. To answer your question I don't think it's smart to want to put a 4cyl or v6, go rotary, v8, or just don't buy the FD shell at all. This is my opinion, so in the end do what you want, it's your money.

Very good point, I suppose I shouldn't let one bad engine ruin it for me. Dont get me wrong I love the rotary, just the dependability worries me.

TwinCharged RX7 07-10-13 01:09 PM

If you build it right, and tune it right it will be plenty reliablie. And don't take what I said the wrong way, I don't care what engine you put in it, its your car. Just don't go complaining about how unreliable the old engine was when, at the end of the day, the cause of the engine failure probably had nothing to do with the fact that it's a rotary.

czwalga00gt 07-10-13 01:30 PM


Originally Posted by TwinCharged RX7 (Post 11516836)
If you build it right, and tune it right it will be plenty reliablie. And don't take what I said the wrong way, I don't care what engine you put in it, its your car. Just don't go complaining about how unreliable the old engine was when, at the end of the day, the cause of the engine failure probably had nothing to do with the fact that it's a rotary.



Apex seals went, pretty sure that's rotary specific. :scratch:


LS1 v8 swap if you dont want the rotary, cheap, lots of power don't mess around with some random 4cyl. Itll be more reliable than rotary, despite what some may say. Mine was on the 3rd engine at 120k; only thing done too it was reliability mods. Really I think they are hit an miss, which could be the quality of the builder, but i'd always be worried bad things would happen.

Make the choice either rotary or ls1; obviously i'm for the ls1 others rotary; but on both sides of the fence I think we'd agree than anything other than those 2 would be a stupid choice.

Hannibal King 07-10-13 06:12 PM

True, I'd like to do a ls1. Just need to learn more about the swap. Found a shell for $3700 so that will be my start.

SA3R 07-10-13 11:41 PM

You want dependability?

Leave the REW stock. No PFC, no high boost, nothing. Showroom stock. 255hp or thereabouts. Drive it every day. It will not give you any trouble.

My car is stock. It is driven every single day of its life, and in 30,000km of daily driving, guess whats broken? Nothing. Absolutely nothing. No dramas, nothing. Guess how much engine repair costs me per year? $0.00. Keep a good 20W50 or similar mineral oil in it, stock, change the coolant when required, and that is it.

A 4 cylinder FD or a V6 sounds like a disaster. You want to stress a 4cyl to make 300hp and then you want it to be reliable? Thats contradictory. Just leave the stock REW in there and get the power and reliability you want.
If you are new to the game, then the worst thing you can do is build a rotary and just throw random "go-fast" bits on it, and expect to go fast with no problems.

And as a side note, do you realize how ungodly expensive the S2000 4 cylinder engines are to upgrade and maintain? Or how stressed and peaky they are already? Not a good combination.

What happens if you do put some sort of odd 4 cylinder in the car (lets go with the Honda) and then 6 months down the track, it gives trouble. It does a head gasket, or it burns an exhaust valve . Are you going to come back and say the FD is unreliable still? Reliability in a car with an engine transplant or extra horsepower is not going to be the same as a Honda Civic or a Subaru.

Hannibal King 07-11-13 12:37 AM


Originally Posted by SA3R (Post 11517358)
You want dependability?

Leave the REW stock. No PFC, no high boost, nothing. Showroom stock. 255hp or thereabouts. Drive it every day. It will not give you any trouble.

My car is stock. It is driven every single day of its life, and in 30,000km of daily driving, guess whats broken? Nothing. Absolutely nothing. No dramas, nothing. Guess how much engine repair costs me per year? $0.00. Keep a good 20W50 or similar mineral oil in it, stock, change the coolant when required, and that is it.

A 4 cylinder FD or a V6 sounds like a disaster. You want to stress a 4cyl to make 300hp and then you want it to be reliable? Thats contradictory. Just leave the stock REW in there and get the power and reliability you want.
If you are new to the game, then the worst thing you can do is build a rotary and just throw random "go-fast" bits on it, and expect to go fast with no problems.

And as a side note, do you realize how ungodly expensive the S2000 4 cylinder engines are to upgrade and maintain? Or how stressed and peaky they are already? Not a good combination.

What happens if you do put some sort of odd 4 cylinder in the car (lets go with the Honda) and then 6 months down the track, it gives trouble. It does a head gasket, or it burns an exhaust valve . Are you going to come back and say the FD is unreliable still? Reliability in a car with an engine transplant or extra horsepower is not going to be the same as a Honda Civic or a Subaru.

Never said i wanted "300" horsepower. I'm happy with the factory 255. I'm glad that your rotary has treated you well and you treated it well in return. But very commonly and quite obvious the rotary engine is not a 100k mile engine. Argue that all you want, but look at the countless people who managed their stock engines properly but also replaced them 3 times in 100k miles.

As I said, good for you that your rotary hasn't shit out on you. As I know this is a rotary forum, so not many will agree with me. But I was asking to see if anyone has attempted these swaps. Not "hey this is what I'm going to do".

Its called asking questions, but maybe some people just come right out of the vagina a genius I suppose.


Oh & this:

Originally Posted by SA3R (Post 11517358)
Are you going to come back and say the FD is unreliable still?

Let's see, if i replace the engine with a Honda engine & it blows..... "Omg guys this FD engine is a piece of shit"
Yeah thats exactly what im going to do, blame the FD for a engine that didn't even come with it.
Did I do that in my case? No I didn't, please read my post before replying with noob remarks like this.

Hannibal King 07-11-13 12:39 AM

Oh and my FD was bone stock and I was the second owner, the previous owner was a friend who babied that car, and the apex seals went out in 30k miles. Yep, real dependable.

ZE Power MX6 07-11-13 01:11 AM

Too lazy to go back and read but did you ever explain why the apex seal went? This argument is pointless without the root cause.


Originally Posted by czwalga00gt (Post 11516855)
Apex seals went, pretty sure that's rotary specific. :scratch

But the reason it went is probably not...

Whizbang 07-11-13 08:23 AM

Owning an FD is kinda like having unprotected sex with your ex-wife.

Anywho, The LS swaps are easy and for the price well worth it. Your run of the mill popular 5 cylinder engines will nearly cost as much for likely less performance value. And still require a lot of figuring and beer-induced engineering. Whereas the LS has a simple kit, anything you want has been done etc.

alternatively, you can spend lots of money on a rotary for the car to last an unknown number of miles. I love na rotaries, but turbo ones leave a lot to be desired.

Grinch 07-13-13 09:48 PM

S2k swaps cost a decent amount. But with head studs and valve spring and good ems you could boost to 500hp easy. Long as a good tuner it will last a long time as long not beat to crap day after day. Or could do a k24(tsx) with mild head build and get around 275-300na reliable. But for price of ether best bet would be to go ls. I had k series and they are not cheap, ether are s2k. I debated about a ls or rebuilding the 13b, which I end up doing just to stay true to te rx7.

Dliverance 07-14-13 01:13 AM

Miata 1.8 then boost the living shit out of it.

Starfox07 07-14-13 02:38 PM

I've always felt that the FD needs an n/a engine. So naturally a 3 or 4 rotor n/a is most appealing.

However, a flat six (Subaru or Porsche) might be pretty cool. They sound *nearly* as good as a 3 rotor, and actually have better induction noise, IMO.


Me personally, I would skip the FD and just buy a Boxster S or a 996 C2. More commonly available, far more reliable, and just as good to drive. Not as sexy nor rare, but sexy and rare is a mute point when it's not running. Then again, I'm happy with 250hp, most people on here are not.


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