13B-REW to LS1 Perspective

[cewrx7r1]

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.

[0110-M-P]

Very good call Chuck. I am tired of people saying, "nice car, but I wish they were more reliable." It seems I have to go into a 30-minute explanation every time to backup my claims that they are reliable with little effort.

[SPICcnmFD]

+1, If their is a 13b that has been drove hard and still ticking it's mine, and I'm still gradually tuning and upping the boost on it from time to time. It does get taken great care of maintenance wise though.

[David Jerome]

Although the IC and Radiator arent teh best I dont see them as real problems.

Mazda waiting for 108c for the fans to hit full speed, the AST, and the FPD are the 3 things I think that gave the FD such a bad name. Everyone always makes comments about how unreliable the rotary is, however, when I drive an fd engine failure is the last thing I am worried about. It is all the accessories on the engine that lead to engine failure that scares me. You would be blown away by how many fds I buy and customer fds that show up with leaking FPDs. Its shocking.

[josh18_2k]

hp/l is a ludicrous argument. it seriously belongs with the honda fanbois, and i would expect better from a website 'above the standards of rx7club.' people often whine when v8 defenders bring gas mileage into the mix, but at least thats a useful measurement. sure gas mileage is back burner in a sports car, but hp/l affects absolutely nothing in the real world.
if anything, power/weight (of the engine) would be a much more appropriate scale.
as for actual power output, the perspective thing goes both ways. if you're talking big numbers (600+), it may very well be cheaper/easier with a rotary. in a daily driven street car, anything over ~350 in a car this light is pretty much useless considering wheelspin does not accelerate a car. while LS1's make an advertised 305-340 fwhp, the fact is they all put down over 300whp through stock manifolds/cats (custom exhaust/intake obviously- its a swap). a mild cam with headers can make 400whp and pass smog. stock LS1's can take a 150 shot without drama, if you're into that sorta thing. more power than anyone needs in a DD, however fun it may be. and who can argue with torque?
for a sports car that sees mainly street use, i see zero downside to an LS1 vs a rotary, other than initial cost, and rotary pride (not saying thats a bad thing!). the fact is, you gain an extra gear (gas mileage- sorry i went there), dont gain any weight (some lose weight), and have a car that will really move at any rpm in any gear.
if you're going big, rotary is prolly where its at. there are def some 13b's making huge power out there, relatively reliable, thanks to quality parts and a knowledgable tuner.

(i happen to be a v8 owner, but have zero disrespect towards rotaries. they definately have the potential, but just arent for everyone.)

[djmtsu]

My FC gets phenomenal MPG (30 to and from DGRR) with no emissions, full exhaust and intake with an FCD. So no, I am not making 400+hp, but it is more than the 18 year old stock suspension can handle right now.

I like LS1's and all, but consider the price of rebuilding. Pop a rotary and you might be out a housing, a rotor (or both) and a turbine wheel (maybe). Throw a rod in a V8 and tally up that bill.

Cost effective rebuilds is what keeps me rotary.

[cewrx7r1]

hp/l is a ludicrous argument.

By your idea of reality, it is fair to have a 150lb boxer go against a 329lb boxer and say it is even-steven/ok?

The next time some guy beats you silly in his 1000CC+ super bike, let's hear you say it was an even match.

[Heeley]

By your idea of reality, it is fair to have a 150lb boxer go against a 329lb boxer and say it is even-steven/ok?

The next time some guy beaks you silly in his 1000CC+ super bike, let's hear you say it was an even match.

I think what he's getting at is that there's not really any such thing as 'fair' when talking about engines. In the end it doesn't matter whether a fight's fair or not, just who wins, honestly.
I agree, power/unit of displacement isn't really a useful argument. To me, it's a term that manufacturers and magazines use to pimp their products, and tell us what a wonderful feat of engineering our cars are. It doesn't have much use in the real world. No matter how you rationalize the hp/L argument, what matters is specific output. That, and whether or not you like the characteristics of the rotary, and if you're prepared to put up with the quirks or not.
I am. That's why my car's currently under rebuild. The hp/L argument does work though as a rationalization for a rebuild though.

[a7xh7]

its more like 2 runners, one is 200lbs and 5'8, the other is 6'2 but is lighter 180lbs. one has a longer stride, one has stronger leg musculature. when looking at leg speed one takes 3 strides to the other's 2 1/2. one dominates the 400m, the other prefers a 100m. there are a lot of differences but they are both runners.

today they race a 250m, most people probably care who finishes first. but maybe im more impressed at the competitor that finishes 4/100th second slow but find out he's blind.

hope that made some sense. lol

[busted7]

No was it suposed to?:confused:LOL

[My5ABaby]

I think it all comes down to preference. If you want a unique engine that is a thrill to drive, revs high, and makes the inner child scream, the 13B is your engine. If you want an engine that makes little children cry because their big wheels don't match up and that puts down phenomenal power, get an LS#.

Although the IC and Radiator arent teh best I dont see them as real problems.

Mazda waiting for 108c for the fans to hit full speed, the AST, and the FPD are the 3 things I think that gave the FD such a bad name. Everyone always makes comments about how unreliable the rotary is, however, when I drive an fd engine failure is the last thing I am worried about. It is all the accessories on the engine that lead to engine failure that scares me. You would be blown away by how many fds I buy and customer fds that show up with leaking FPDs. Its shocking.
Agreed. One of the main problems with rotaries is all the shit that's strapped to them. I've never had a problem with my engine (granted it's an N/A FC), but rather all the 8 jillion things needed on the engine.

if you're going big, rotary is prolly where its at. there are def some 13b's making huge power out there, relatively reliable, thanks to quality parts and a knowledgable tuner.
I'm going to have to disagree with that part of your post, and only that part since the rest is pretty much spot on.

Regardless of what people may try to argue, there's no replacement for displacement (at least Wankel rotary vs. piston). People argue that you can turbo a 13B and have it make just as much HP as an LS#. Sure... you can... you can also take the same turbo (or something comparable) and put it on the LS# and blow the 13B away.

[cewrx7r1]

Many of you are missing the point of the comparison, and you have let your emotions overide your reasoning capacity.

Yes a 400hp LS1 will outlast a 400hp rotary. The idea was what if they both made the same hp/L then how would they compare. We are talking about engine stress. Would a 877whp LS1 in a vette fair as well as for a dayly driver?

[josh18_2k]

nitro RC engines make over 850hp/l. funny cars make 975hp/l. are they comparable to a production engine? how about each other? hp/l makes zero difference (performance wise) in the real world, unless of course displacement is fixed (sanctioned racing).
what matters is how much power makes its way to the wheels (peak and under the curve), and how much the car weighs (among other things).
Many of you are missing the point of the comparison, and you have let your emotions overide your reasoning capacity.

Yes a 400hp LS1 will outlast a 400hp rotary. The idea was what if they both made the same hp/L then how would they compare. We are talking about engine stress. Would a 877whp LS1 in a vette fair as well as for a dayly driver?
seems to me that 'which will last longer' IS the reasonable argument, and 'which can make more hp/l' is driven by emotion.
we all know both engines can make tons of power. what matters to many is peace of mind. no one likes a blown engine, and FD owners are often driving around waiting for theirs to pop. sure there are reliable rotaries out there, but it really only comes with the right combination of parts and a good tuner. not everyone has access to a dyno, much less a knowledgable rotary tuner. LS1 owners can get mail order tunes for about any setup. twin turbo LS1 guys should probably be hitting the dyno..

btw- heres 1100hp on 93 octane with a 2 year 24k mile waranty (way expensive tho.. err)
http://www.corvettefever.com/featuredvehicles/153_0308_lingenfelter_twin_turbo_c5_corvette/index.html

[85rx-7gsl-se]

Blah Blah Blah...Josh, we know you are diehard V8 guy and we have diehard rotorheads on here. HP/L may mean nothin in the real world, but it is a figure many in the engineering community love to spout off and is often linked to the engine perceived efficiency. For example, the ITR Honda engines are hailed for there engineering brilliance with excellent HP/L numbers....

BTW Josh, ultimate HP/L in my oppinion....Mid 80s Turbo F1 engines. 1500hp outta 1.5l engines designed to last and entire F1 race :D

[josh18_2k]

im not a diehard v8 fan. i often stand up for v8s in rx7 forums because some people are grossly misinformed, but i totally understand the desire to keep a rotary in an rx7.
i'm only really bothered when people talk down to someone for doing a swap. thats just disrespectful (thankfully i havnt seen any of that on this site). the hp/l thing also annoys me, probably about as much as you guys hate hearing gas mileage argument.
not trying to start a fight, just offering the other side to a thread about perspective.

[SPICcnmFD]

Many of you are missing the point of the comparison, and you have let your emotions overide your reasoning capacity.

Yes a 400hp LS1 will outlast a 400hp rotary. The idea was what if they both made the same hp/L then how would they compare. We are talking about engine stress. Would a 877whp LS1 in a vette fair as well as for a dayly driver?

I still think everyone is missing your point.

hp/l IS a valid argument from a physics stand point. Is it how the public looks at hp, no, but it is a valid argument when it comes to reliability and how much stress an engine will take. A 400hp LS1 is not near as stressed as a rotory, 2.0l I-4, 3.0l v-6 etc. So an equally powerd LS1 is more reliable. All CW is saying is, would a 877whp LS1 be as or more reliable than a 400hp rotary?? It's not how much power you can make or is a rotary better than an LS1. You could use a 5.0 ford or a 5.9 chrysler in the same argument, he's not attacking LS1s, they are just the typical swap.

[Smokey]

BTW Josh, ultimate HP/L in my oppinion....Mid 80s Turbo F1 engines. 1500hp outta 1.5l engines designed to last and entire F1 race :D
technically that was only in qualifying trim. They tuned them back to a much more conservative number for the races...still ultimately impressive though.

I think that the LS1 FD makes great sense as a street car. You can get in, turn the key and not even think about it.

In my opinion though the LSx is not a good choice for a track car. While you don't gain much weight (compared to a similarly equipped 13b i.e. a/c and p/s) the weight is carried farther forward and higher in the vehicle. You also have to work around bump steer issues from moving the steering rack. There are absolutely work arounds for this and plenty of people tracking LS1 FDs, but I would compare those efforts to the same as having a turbo rotary street car....concessions need to be made.

[85rx-7gsl-se]

^Yeah, thats is good to know that was just qualifying trim. The thing is, did they use the same motor for the race? If so, thats still more impressive than top fuel cars that get one burnout and pass per rebuild :(

[P71]

^Yeah, thats is good to know that was just qualifying trim. The thing is, did they use the same motor for the race? If so, thats still more impressive than top fuel cars that get one burnout and pass per rebuild :(

Top Fuel engines are also over 8,000HP. That's 16HP/CI (a 1,440HP 13B then...). They also run on liquid T-N-T. Most cars keep the same short block the entire race and only replace gaskets/bearings (due to MASSIVE amounts of pressure/stress). Each piston/cylinder makes over 1,000HP on it's own. Think about it...

As for the "original" argument...

First, let me say that I'm a car/engine lover. I have a 13B, a 302 Ford, a 2.3T Ford, and a 401 AMC in the garage on stands, and drive a 12A, a 4.6L SOHC Ford, and a 3800 Series II GM V6. For those of you counting, that means I have at least one rotary, 4-cylinder, V-6, V-8, and at least one OHC and pushrod, and 3 carburetors and 4 types of fuel injection along with some turbochargers for good measure.

OK, so now that you see that I am truley un-biased, let me lay down some facts. As a 3-year member of the Clevite Engine Builder's Guild, I can professionally say that HP/L is bunk (notice I used HP/CI in the Top Fuel statement). The CI-to-Liters conversion is not regulated and so you end up with "off" numbers (5.0L Ford 302CI is really 4.9L, 4.9L Chevy is 305CI, etc, etc, hell 5.7L LS1 is 346CI and the 5.7L SBC is 350CI). That reason alone is enough for all professional engine rebuilders to not use HP/L.

Now, even HP/CI is looked "down" on. "Specific" output (more importantly, area under the curve) is what it's all about. Sure a 400HP 13B might be more reliable then a 840HP LS1 (honestly it's probably dead even, say it's more reliable then a 840HP 351W Ford) but the 840HP V8 would still kick the 400HP 13B's ass all over any track.

HP/engine weight (and overall car weight) is REALLY what matters in the real world. Why do you think LS1's are so popular? Huge power in a compact, lightweight (all-aluminum) design. A fully-dressed LSx motor weighs LESS then my 2.3T Turbo-4!! It takes a miracle and a half to make 400HP with a 2.3T and for saving a few hundred pounds I can have a stock LS1 with headers and a tune make 400HP all day long and be reliable as a rock.

The big point is there's different engines for different situations and different drivers. I would love to have an LS1 FD just as much as a 13B one. If you stuck both in front of me and told me to pick one, I wouldn't be able to do it. BUT, if you said I had to drag race the car I chose in my points series, I'd take the LS1 car. If you told me I had to autocross the car though, 13B. HPDE, flip a coin.

Argue back and forth all you want, but please don't ever mention HP/L again. Or even HP/CI. HP/$ is a far better standard!!

[85rx-7gsl-se]

^ Was referring to the 1500HP 1.5l F1 engines :D not 13Bs.

[P71]

Same difference either way. Total bunk argument from an engineering standpoint, period.

[85rx-7gsl-se]

I know, but boys will be boys. There are going to be 13B nutswingers and LSx nutswingers. As far as the F1 vs. Top Fuel, the F1 is much more impressive in my book since it has to have more longevity than a one-pass Top Fuel engine.

[P71]

So what about the 5-second Top Alcohol engine? "Only" 5,000HP on Alky (instead of nitro) and they go the whole race (3-4 qualifying passes, then 4+ elimination runs). Or what about Super Stock? 1,000+ HP N/A V8's going an entire season without a rebuild (24-25 races at 8-12 passes each). You're still not seeing that the ENTIRE F1 engine made the same HP in race trim as ONE piston in a Top Fuel motor!

Look, I love F1 (a LOT), but it's apples-to-grapefruit here. Engines are soooo hard to "compare" to each other, and when you hit race-specific engines it gets even more so.

That's why a 400HP boosted 13B and a 400HP N/A LSx mean so little to one another. Throw that same turbo on the LS and tell me what happens. 600+ HP is what, with no loss in drivability.

You guys should be proud though. The LSx is pretty much the only sane swap for a 13B. Any other V8 is going to be way too heavy, and way too underpowered. Sure you still see SBC's and SBF's into FB's, but they become drag cars only. Even a stock 12A can run rings around those swaps on an autocross course! The LSx is still the world's most advanced V8 engine. It didn't hit the streets until 97 (Corvette, 98 for the f-bodies) and the basic 13B was available when, 84? So it took 15 years for the V8's to "catch up" on a HP/$ and HP/weight setup.

[Roen]

There are the BMW and Merc V8's out there that blow the LS9's out of the water........but then HP/$ goes way down. I'm not sure about the weight either.

[P71]

Don't forget the LSx has the 3rd largest V8 aftermarket on the planet behind it. Sure there's some $100K+ cars with V8's that beat an LS on HP (not on torque though!) but the LSx is available to the everyday "common man", and being that it's not tuned to the edge straight off the showroom floor, more power is a phone call away!

[Signal 2]

Assessing the shortcomings of the 13bREW's stock cooling system and IC isn't exactly 'news'.
Comparisons per liter of displacement? Comparisons per pound of engine weight? Torque comparisons? Fuel efficiency? Engine longevity/reliability?
Defending the 13bREW on an objective basis is difficult, that's why advertising agencies come up with catchy phrases like "Fahrvergnugen" (VW) and "It just feels right" or "Zoom Zoom" for Mazda. In the end, owning a rotary, particularly a FD is not unlike Homer Simpson repeatedly touching the stove to see if it's still hot. Doh!

[IR Performance]

In my opinion it is a matter of personal preference. Both engines have upsides and downsides. Those that don't think you can stick a decent turbo in an LS1 FD should see my friend Joe's twin turbo ls1 fd that dynos nearly 600 rwhp on pump gas.

[1QWIK7]

P71 is soo on point in this thread.