Don't you mean 92.5HP per liter? When you compare HP to displacement, you must compare apples to apples, just like intelligent engineers do, not through PR or salesmen's eyes.

Strange, how a car that's heavier than an RX-8, with a much larger engine that makes over twice the horsepower can get the same or better fuel mileage than the "efficient" rotary. That car is the '06 Corvette.

 

who the hell buys a v8 or rotary for gas mileage????

 

Wait,

Didn't the rotary get banned from Le Mans by the guys with big v8's because it was too fast or something? :o (I remember reading somewhere about something of that nature).

Reliable...yeah you drive the **** out of piston engines it won't be reliable either, I've seen 7k v8's with forged internals, bored out, etc, go in 30k miles, my friends living proof.

He had a 1996 Merc. Cougar V8 and I had the 1995 Ford Thunderbird LX V8, both had the same power stock as the GXL when it comes down to 1/4 mile times but my friend opted to take the big bore v8 from a modular 4.6...guess what...all that mad torque and horsepower only got him to 13's and even then guess what happened to his engine...the timing chain for the cams ATE threw the guide from the torque and blocked up the oil pick up line and burnt his engine up...yeah piston engines are reliable!

It all comes down to the man behind the wrench, my bird lasted over 200k miles and it was in spec, a buddy was in his tbird (no power adders) with 250k doing 12's but you see the thing is here, we both babied the **** out of the cars.

I've seen just as many piston engines blow up as I have rotary engines.

Personally, I prefer rotary engines, they are small and easy to work on.

As for the person who said you can take apart a v8 in the car...haha don't try that on a modular 4.6L v8, you'll have NILL room and good luck boring it out with it in the car.

I personally could care less for a v8 in a japanese car, I don't like having all that weight (my tbird weighed close to 5k lbs because of that damn engine which is why it was so slow). I like the rotary and that's what I'm sticking to...

- Tech

 

first make some research about the weight and second yeah i guess 30k miles is pretty reliable for a rotary...that's pretty rare.

 

No his 30k mile piston engine is warped due to it not being able to feed enough oil...essentialy the metal to metal heated it up without the oil...the pressure gauge was disconnected at the time due to the fact that it was acting bogus before the engine was put in so he was buying aftermarket guages (about a week too late).

The SE I had went 130k miles before I found out the previous owner overheated it and blew a coolant seal (he said that was normal for it to run hot, its because the clutch fan wasnt suffecient...I know now thats bs!).

Like I said, my car's got over 180k on the chasis and 80k on the engine (supposdley, I see an R on the block so I don't doubt it).

 

How long will this argument persist? Honestly.

 

I still laugh my *** off when that argument comes up.

Search for a post made by me in the Other Engine Conversions section. My car is 60lbs heavy to the rear with the iron block LT1.

Oh, and as far as mileage goes, I get 18MPG in town and 26MPG while running 90 with the A/C on.

It all boils down to what you want out of your car. Do you want to stay high in the RPM range all the time in order to take advantage of the power there, or do you want to be able to hit it anywhere across the RPM range and have instant power?

 

if all v8's got 18 and 26 miles per gallon wouldn't everyone be buying v8's right now durring these gas hikes???? I think you fudge your numbers buddy. Especially cause I have a v6 truck that gets less gas mileage than that and it's been babied since day one. I don't believe you for a second. Plus like I said before. Who buys a freakin' sports car for the gas mileage?

 

My bro's Z06 consistently gets high teens MPG around town in stop and go traffic. Of course, no one is claiming that ALL V8s get excellent gas mileage. My friends V8 Magnum Durango gets 11-12 MPG.

I don't think anyone buys a sports car for the gas mileage; however, if you could have excellent gas mileage AND the sports car performance, why would you turn it down?

 

You don't believe me? Louisiana isn't very far from here. I'll head over there and you can ride shotgun for a few hours while I burn the fuel away and when we fill up afterward, I'll let YOU do the math. Then you can come back on here and tell everyone you were wrong.

You have a V6 truck that's underpowered and has to work harder to get the same job done. I have an overpowered, light chassis and the engine loves it.

Oh, and I didn't do the swap for the gas mileage, it's a nice byproduct

 

ok ok ok these internet discusions never get settled so I'm going to stop like I always do because it just starts going in circles but..................I still don't believe you haha j/k I couldn't stand to sit in a v8 rx7 that long. That would just get on my nerves

 

All V8's do definatly not get 20+MPG. I have a V8 RX7 and a RAM 1500 5.9L, the Ram gets about 13mpg on a good day :P. The RX7 is much better but I haven't done the math yet as my speedo converter box is off for repair.

The secret to a V8 getting awesome gas milage is EFI AND the fact it does not waste near as much fuel that is injected as the rotary does. THATS's where the efficiency argument comes in. Why could my Talon support enough power to go 97mph in the 1/8mi on only 550cc injectors?! Because I am not wasting half the fuel. Why will a 2.0L piston engine make over 500whp on a 60-1 compressor and the rotary will struggle to eek out 425? The rotary is higly inefficient when it comes to turning fuel/air into power.

 

Scared of going too fast?

 

lol, no my 400rwhp rx7 will be fast enough I just couldn't stand the sound, haha.


interesting, not to argue with you but I've seen rx7's in the 475+ hp range with a 60-1 turbo. Of course that turbo is a full turbo upgrade and not a bnr stage III but still gets up there. Now yes they may run rich but hey the name of the game isn't being conservative when your building a race car.

 

Show me a dyno of a 13B with 475rwhp on a 60-1. Tony Farkas made 499.x on an S300 with a LARGE bridgeport and bdc tuning it. An S300 is a slight bit larger than a T66.

 

He was referring to blown engines. Put it in context. Challenging to get power out of a 2.6 or challenging to race the other competetors? Take your pick.



Uh, we dont mod our v8s? We dont know them inside and out? PSH. We dont just throw in any old v8 and race it - but even if you DID youd still have a helluva fast car becuase a RX-7 is so light. Buuut well, we dont do that, we tune it up to hell and back. Its NOT ABOUT DROPPINGA V8 AND RACING. Because you dont know two ***** about modding a V8, this is all you can come up with. You dont even know how intake runner length effects the powerband, single vs dual plane intakes with carburators or the various EFI intakes, do you? You dont know about cam profiles, head flow, chamber size, compression, etc, do you? Do you know about how to set up header lengths and sizes? How about how they put C4 or Cobra Differentials where the T-II pumpkin is so you can get the right gear ratios? Yeah we dont know **** do we. Nevermind Kukris car with zero traction drifting around owned a Z06 and a STi... ON AN AUTOCROSS. Id love to see a big turbo RX-7 do that! Oh, and he ran a what, 12.2 lifting off and coasting through the traps, with no traction? Yeah V8s suck. Too bad the handling and speed arguements were put to rest.



If you had read what I had to say the efficiency was related to BSFC and BMEP - BSFC, or brake specific fuel consumption, is how much fuel it takes to make a given amount of power. Rotaries need a lot of gas. That isnt good for making power, or for fuel consumption. The BMEP limitations, that is, Brake mean effective pressure, is how much specific torque a engine can make - though its defined in PSI in the combustion chamber itself. Its really just torque per liter times a constant, so honestly using just torque per liter is just as good and easier than having to multiply **** by 108.5 all the time. The reason the BMEP isnt as high as it could and should be is because of THERMODYNAMC INEFFICIENCY.

I dont mean FUEL efficiency, I mean the efficiency of turning heat from combustion into mechanical energy. THAT kind of efficiency, Thermodyanmic, is essential and the crux of tuning an engine for racing. Get "Efficiency = a civic" out of your head. Race engines are very efficient at making power, not out of geting gas mileage to put along at city or 'highway' speeds. Rotaries are not nearly as good as piston engines at doing that. And that efficiency DOES MATTER, A LOT. Rotaries dont make as much power per airflow as a piston engine does. Rotaries dont make as much torque per liter as piston engines either. This is because instead of using the heat in the intake charge to cause a expansion and thus a force upon their 'crankshaft' as effectively as a piston engine does, they let some of the heat conduct through the housings and rotor into the engine itself. Thats why their oil temps are so high. Thats also why they have trouble making power.

Now yeah, a rotary can win. But both on paper and in the real world piston engines can out perform them, and do more with less, so to speak. However when the only thing you can look at is OMG BIG DISPLACEMENT LOL ITS A BIG OLD PRIMITIVE V8 PUSHROD PUSHROD LOL!!!1 instead of looking at the facts as they are, you get stuck in a closed mindest of rotaries only. Yeah they can race alright, thats nice. But when all the rotards are acting like they have half the displacement they really have because they measure it differently than everyone else on earth does, and acting like putting in a arguably and practically better engine is dumb or stupid, you can expect a few flamewars.

Im not going to sit here and be told a gas guzzling, thermally inefficient 2.6 liter is somehow magically delicious just because you use the wrong displacement when you spout off about how much power and torque it makes, when I know its not a 1.3. Im not going to sit here and think a torqueless wonder is ******* amazing because you can slap a giant turbo on it and drive around the lag and keep it in the powerband because the transmission is geared right. Im also not going to believe the rotary has **** to do with the handling when its known to all who arent closed minded and having cognitive dissonance as severe as Ive ever seen that even with a 'heavy, primitive v8' it still handles good - even after people report having the nose ride higher on the same springs or a guy with a LT1 (iron block) with P/S and A/C end up 60 lbs heavier on his *** e.d.

A more thermally and fuel efficient engine, better on gas, easier to drive, easier to work on, cheaper to modify, mantain, and repair, that makes more power is going to be a choice Id take over something thats terribly fuel and heat inefficent, with no torque, thats not as reliable and requires an expensive pullout and rebuild when you can rebuild a v8 without removing it from the car and you rarely if ever need to. Sure a gasket might wear out but thats almost idiot proof to do. Oh no, maybe redo the compression rings and some bearings? Thats NOTHING compared to redoing the seals in a rotary, cost or effort wise.

 

350 hp rotary in a how heavy car vs a 500 hp v8 in a how heavy car?

Why not use both engines inthe same car to do the comparsion so its apples to apples, not apples to dogshit. :P

 

It got banned because of trying to set the rules based on its displacement was a clusterfuck. All piston engines are measured by two crank revoultions. Rotaries by Mazda are measured by one. This gives them an unfair advantage as far as regulating displacement and restrictors goes. Its NOT a 2.6, its a god damn 5.2 liter. Lemans was thinking of using a coefficient less than 2 to have it come out to 4.something, but I dunno what happened. Honestly Id like to see rotaries around but with a fair displacement measurement used for racing. Either measure the Rotary with two crank revoultions, or the pistons by one. If you apply that EQUALLY, however, those piston engines look a helluva lot more impressive, especially becuase all of them now get way over 100 hp/liter/

Ok, gotta set a few things straight here. ONE, Modular v8s are HUGE, and have less displacement than a much smaller pushrod engine. Displacement is not external size. TWO, yeah, if the man with a wrench ***** up, well, any engine can go. Three, no ******* way in hell did your engine make it weigh 5K lbs. A BIG BLOCK ONLY WEIGHS ABOUT 600 LBS!

BTW, here, I'll compare a DOHC, modular monstrousity to a Pushrod engine with more displacement but a smaller size, just for you!



Well, yeah, Fords modular motors are big, heavy monsters. You also very rarely see them in a RX-7 because of that A 302 (thats 4.99999999~ liters for ya) is much easier to modify, cheaper, smaller, lighter, etc. You can put one in a RX-7 extremely easily. Oh, and you can get 400 hp out of even a shitty 80s 302 with just a set of heads, headers, and and intake manifold. Stock cam even! Changing out that admittedly babyish cam for something better could net you even more power. Oh, and a 302 has a short *** 3 inch stroke, so revs are easy with that. nice big 4" bore for breathing too.

If youre gonna compare v8s to rotaries, at least stick with something GOOD, like the 302 or 351w, or the Small Block chevy (goes from 302 to 427, thats 5 to 7 literS) or the LT1 and LS1, all 5 of which can have a multitude of modfications and different build paths.

P.S. - Just for the record, my opinion on the modular motors: Ford jumped on the OHC bandwagon without much necessity, probably to make money via advertising (hey, we think pushrods suck too!) and so they can charge more for the engines. The problem is even a SOHC v8 has two camshafts, while a DOHC has FOUR. That means changing out the cam is tedious, time consuming and expensive. Pushrod engines have ONE engine. Futhermore, the big *** heads make it, well, GIGANTIC. And it has less displacement than the relatively tiny 302 beside it!

4 valve heads only outflow 2 valve heads at small bore sizes, and/or at low lift. Well, guess what? Nobody uses a low lift cam in a performance engine, or even a regular car unless you need to (and I dont see why...) and you can just not use a tiny *** bore. Yeah, if youre trying to get headflow out of a Supra I6 for example, with that tiny *** bore you need a 4v Head. But when you can have a 4" bore in that teeny little 302, you dont need 4v heads. Airflow has more to do with the cam and intake tuning (at what rpms it flows) than the # of valves, well, actually it has nothing to do with the # of valves if the bore is big enough!

Yeah, I will admit a 305 (with a smallish bore) sucks because of shrouded valves, but even they with enough work can make some power. But hey, you live, you learn, you refine, and you work with the tradeoffs from a build geometry, instead of AGAINST them. Pushrods with big bores kick ***, and let you have a small engine with big displacement and plenty of airflow. Those are what we use in RX-7s, not some DOHC, expensive, big *** tiny displacement technologically impressive but practically stupid boat anchor.

 

rotards make me laugh. lol

 

"Uh, we dont mod our v8s? We dont know them inside and out? PSH. We dont just throw in any old v8 and race it - but even if you DID youd still have a helluva fast car becuase a RX-7 is so light. Buuut well, we dont do that, we tune it up to hell and back. Its NOT ABOUT DROPPINGA V8 AND RACING. Because you dont know two ***** about modding a V8, this is all you can come up with. You dont even know how intake runner length effects the powerband, single vs dual plane intakes with carburators or the various EFI intakes, do you? You dont know about cam profiles, head flow, chamber size, compression, etc, do you? Do you know about how to set up header lengths and sizes? How about how they put C4 or Cobra Differentials where the T-II pumpkin is so you can get the right gear ratios? Yeah we dont know **** do we. Nevermind Kukris car with zero traction drifting around owned a Z06 and a STi... ON AN AUTOCROSS. Id love to see a big turbo RX-7 do that! Oh, and he ran a what, 12.2 lifting off and coasting through the traps, with no traction? Yeah V8s suck. Too bad the handling and speed arguements were put to rest."


That's stuff any one of the 18007650027636485967 v8 tuners out there are very well aware of. NO big deal. You are not special, you do not hold a candle in the v8 world of darkness, you are not original. Maybe that is not what you want witch is fine, no big deal. For me it's fun because the rotary engine is by far not even half way figured out now because it's hasn't been out near as long as piston engines and to me it's fun seeing the changes being made to them all the time making them more efficient etc... You can keep your v8 and I'll keep my rotary and you can keep thinking you are king kong of the v8 world

 

So, you mean that the rotary is fun because its not 'totally figured out yet'... How isnt it figured out? Trying to make it have a not fucked up combustion chamber? Tryign to make it burn all the air-fuel in the combustion? Havent figured that out yet? Other than using a 'wider' rotor, you cant. Or do you mean how Rotards think its a 1.3 liter? Oh, and piston engines are being modified to make them better all the time. S2K does more with less displacement than a renesis! Piston engines have for a long time now been beating wankels in terms of how much power/torque is made from the same amount of boost. The ONLY thing Ive seen a rotary able to do better than a piston engine is spool up a turbo, but thats because the heat goes into the exhaust gas instead of energy to turn the wheels, and peripherial exhaust ports allow for sharp 'pulses'. But then again a radically ground cam on a piston engine can do the same... or just say **** it and get displacement

Just what point are you trying to make here? And why is this all about some sort of nebulous, in your mind only (because I sure as hell dont know where the hell it is...) "v8 world of darkness" that youre in oppositon to and that some bunch of rotary fanboys are going to fight against? If this is just some sort of consumerist antagonism, like a PS2 vs X-box fight, or Apple vs PC, then just be honest about it and dont start off with ad hominem attacks against people for making a CLEARLY ARGUED AND SUPPORTED ENGINE CHOICE that you happen to not agree with becuase you bought up into the damn marketing behind the wankel and would rather spend more money, for less power, just so you can pat yourself on the back for using the damn rotary and how 'hard' it is to do.

Jeeze, why not go slap a quaziturbine in a FD? Its got all of that brilliantly marketable 'technology' and cutting edge bullshit that doesnt mean anything that you seem to like so much. I mean, its not like anecdotal evidence, or bang/buck matters... or something as straightforwards as power to weight ratio

 

 

Hehe,

Well maybe it didnt make the car weigh 5k lbs, but something sure did (that big *** chasis called the Mn12)...

Yeah the heads are a PITA to work on, cams usually only give about a 20 RWHP net, boring it out to 5.0 specs are where its at...12/13 second car like that as long as you can catch traction...

 

WHAT!?!??!?!?!

 

Tech_Greek, you really dont know a whole lot about cams do ya? LOL. Maybe one specific cam on that one specific engine!

Cams determine where the power band of the engine is, and also determine valve lift. Head flow determines how much air the cylinders will suck in, in CFM, based on valve lift. "20 hp net" is kind of... ridiculous. Cams = porting, lets put it that way. Imagine a nice port job on a 20b. Thats what a nice cam on a v8 does. But well, the racier the cam, the less low end torque and worse idle, etc. Just like with ports. However, you can always put a lesser cam back in and your cam profile has nothing to do with the water jackets or engine longevity :P

Considering it takes a cam and a set of LT headers on a LS1 to give 400 whp... I wouldnt make a blanket statement like that.