13B-REW to LS1 Perspective
 

The 13B-REW engine has a bad reputation which I consider to be unreasonable.
The engine itself is good, but Mazda grossly un-engineered three supportive support systems.
(1) The radiator was too small considering the power of the engine.
(2) The IC was also too small considering engine power.
(3) ECU programming was negligent as the cooling fans would not work unless the engine reached 221F and emergency /high speed fan usage
(thermoswitch) was at 226F. Combined this with poor mechanic training/service, and the poor reputation was formed.

Upgrade the radiator and IC, and put in a Apexi PFC with properly adjusted fans, and the engine is reliable. Consider that this engine was producing about 225 whp from 2.6L.

The LS1 (5.7L) family of engines produce between about 305 to 350 hp in 2001. The LS6 version made 385 to 405 hp. Theses were flywheel, not whp.

If the Chevy 5.7L engine had produced the same hp per liter as the stock 13B-REW, it would have produced 493whp. My friend's LS1 with reworked heads, headers, mild cam upgrade, FAST intake manifold and TB, with 4" cold intake; produces 444whp. Still 49hp short of equivalency.

Now consider the above upgraded 13B at about 15psi boost produces 350whp and was still reliable. To match power per liter, the LS1 would need to make 761whp.

Mine and many single turbo 13B-REW are easily making about 400 whp with stock or close to stock ports. Again the LS1 would have to make 877 whp to match power per liter.

Given this perception, our little engine is amazing! If the Chevys had produced equivalent power during the same time frame, I wonder how reliable they would have been.

I tend to agree, although the LSX engines are definitely impressive.

I think you need to add "unreliable turbo control system" to your list. :) The sequential system is great, but after 12+ years and lots of miles the vacuum hoses and solenoids really start to break down.

You definitely make some good points and I agree that these little engines are impressive.

One thing you didn't take into consideration, is HP vs long block weight. That would be an interesting comparison, since there is so much shit strapped to the little 13b keg.

BTW, can someone give me a link to that thread explaining the 13B's displacement and why it is 2.6L? I'd like to read through that again.

I wonder about this. I wonder if the real limitation....the real outer edge of the envelope....isn't the coolant passages on the hot side of the engine block on the 13B-REW? Even with a larger radiator, with some setups under certain conditions, aren't you going to get localized hot spots?

Good comparison, funny thing though is that when people talk about vacuum lines and wiring harness getting old and brittle please remember that this is a 12+year old car and that any other car would probably be about the same.

Why would you compare HP per liter though against an engine that has 5 times the displacement?

People go to LSx because they dont NEED alot of HP to get moving. They can do a STOCK lsx drop in and be faster than their rotary with bolt ons. And be 100x more reliable to.

Its a simple thought out decision. Would i want a smaller displacement engine cranking out about 1/2 what an LSx would make STOCK or have a higher displacement engine, leave it stock and kick ass or do minor bolt ons and really destroy people on the road?

Although you have alot of good points, the comparison in trying to favor the rotary based on HP per liter alone seems like a kick to the shin. Although it makes sense, it doesnt pertain as to why people shouldnt do the LSx swap.

Most people dont do it because they wanna stay true to teh rotary. I thought about it countless times in the past but i wanna keep the rotary. As much as having a v8 in a light car like the FD. In the end, the bottom line is, you're still driving a japanese car with a v8. Hence why theres alot of them for sale. Moreso than rotary FD's.

I got a 12 year old POS civic hatch back. Harness isn't brittle or unraveling at all.

Although you point out the many good points on the REW, you forget that the REW can't make good mpg or reliability that a LSx can. Although cermet housings and ceramic cermet tipped seals look promising...

There really isnt too many lsx fd's for sale, and the ones that are for sale usually do not have AC/ PS. I also beg to differ on the people selling them because it is still a japanese car with a v8...

OH NOES MODS PLEASE MOVE THIS THREAD TO THE OTHER ENGINE CONVERSION IMMEDIATELY! HOW DARE YOU BRING UP LSX ENGINES IN THIS SECTION!

In all seriousness, you can get a .049 model airplane engine for $10 that makes 450hp/l, for the rotary to match it, the rotary engine would need 1170hp!!!111!!! ZMOG that means rotary engines are worthless right!?

No, what it actually means is your argument is retarded. Whatever, if it makes you feel better....

If you want a V8, buy a Z06, you will have a better turn-key package, better resale and support, and your insurance will actually pay you for it if you run down a telephone pole or get your car stolen.

Z06 not "original" enough for you? Go with the Factory 5 GTM Supercar. Will beat the pants off pretty much anything out there including $200K+ macines and no one has one (as compared to a Z06).

http://www.factoryfive.com/gtmhome.html

A proper running fd will get 25mpg which is roughly equivalent to a Vette. With a large single and supporting mods of course fuel economy declines.

While the Radiator and IC leave a lot to be desired I think it is the AST, FPD, and fact that the fans dont run high speed until 108c for emissions purposes that give the fd such a bad name. That high of temps is just a recipe for disaster. Still the best all around performing car for the dollar though, unless the c5 vettes drop much more.:)

The discussion started with specific out and has moved to hp/weight. Also consider the different in throttle response. With a Corvette engine there is no lag between your foot going down and the advertised output coming up. You can't appreciate the difference that makes until you drive a light car with a big motor.

lol are you kidding? 25mpg? if you want to do an stock to stock comparison that wouldn't even be possible. Then we can talk about ls1 in fd comparison then we can talk about making the rew the same hp as the stock ls1 comparison.

sorry but low mpg is the nature of the beast. esp since its fi.

LOL doubt it on the 25mpg.

Most FD guys are barely seeing 20, and thats highway.

Jeez even the LS7 is rated at 26mpg highway, and thats a 7 LITER ENGINE!

my fd did 240something when i dynoed it in 99, and gets 23mpg on the freeway.
for an UNTOUCHED 100k mile rew i think thats not bad.

I disagree with your hp/L logic, it's classic ricer benchracing. I recommend hp/engine size (not displacement), or hp to engine weight. even better torque/size or torque/weight.

Also, for any given turbocharged engine a naturally aspirated engine making the same horsepower will probably have more space under the curve.

My FD EASILY got 28mpg on the highway, and that was with some full throttle runs when I got bored. But I was running an open exhaust system (no cats), which helped I'm sure. It was certainly not as refined as a new vette from the factory.

Sorry i dont believe it.

How can you make better MPG than what was once tested over 14 years ago?

And you're going full throttle too at times? LOL

25mpg ill sorta believe but not really but 28mpg? LOL unless you were in neutral and using a draft of other cars to get your going, then ill believe it.

i got 25 mpg when my FD was bone stock.
got to Buffalo on a single tank of gas from CT.

28 tho... with WOT runs? sorry but i dont see it >.>

as for the ACTUAL post...

i think the LSX series of engines are impressive, but personally, i dont think they're meant for our cars.

The Rotary was SPECIFICALLY chosen for our cars. When they went to redesign the RX-7, the project manager was told he could choose any engine he wanted to use, and he stuck with the rotary.

Ill always be a fan of the Rotary in the RX-7's

I agree, I always mention all of the above to people claim the 13B-rew is an unreliable engine.

Simple things the car is just as good as any other if not more reliable especially under stress!

PFC
IC
Koyo
Cat-Back
Downpipe
Silicon Hose Techs
Intake

Boost Gauge

94 window switch ;)

You will be making over 265rwhp, having fun and daily driving with decent mpg with out a care...

If you want a V8, buy a corvette, quit putting it in our cars...

As for power, I like that this 1.3 makes 255 bhp. I can't deny that the LSx engines make good power stock, but in the end, I prefer the rotary. I don't care for MPG, I don't care for the higher hp, I like the rotary because it's two triangles...

funny you said "our" cars as if you owned a fd lol, go figure...

and i checked on the 3rd gen forsale forum, i presently see about 4-5 lsx fd's forsale...and about 15 or so rotary fd's for sale...so where are u gettin this "so many v8 rx7s forsale" lol happens

Im talking about the ratio of LSx swapped FD's over rotary.

Example.

5 LSx FD's out of say, 10 of the forum, thats 50% of them for sale.

AS oppose to 15 rotary FD's out of how many on the forum? 300?

Not exact figures but just showing you i was talking about ratio.

Almost half, maybe even more FDs that are already LS swapped, are for sale.

Maybe instead of just going by what all those "amazing steve kan" tuned FD's are getting you should learn more..... I've tuned a ton of 400rwhp+ that get 21-25 mpg.

-J

Ill keep the rotary motor in mine even though i could have had at least 2 lsx motors for the money i have in the motor i have. I have driven an lsx fd and it had a lot of torque but i like mine better, and its faster anyway.:)

It seems to me there are a variety of people that own fd's, purest that want low miles bone stock, road race guys, 1/4 mile racers, show cars, and full out hard core drag cars, so it seem theres an fd for everyone even those that want 8 pistons!

Im just happy to get 20 mpg with almost 500 h/p and not feel like its going to quit on me. Drive to the track run 10.8's come home in cruise with the ac on.

I even got invited to join the supra midwest meet and have picts on there forum the fd's been good for me.

Just have fun and enjoy!:icon_tup: