Alternative engines

Unit 5302 · 03-13-2001, 03:38 PM

I wouldn't say they are unreliable, just that they have much higher maintenance schedules.

My friends shop has had 4 Ducati's in at a time for scheduled maintenence. As long as they are kept up, I haven't heard of them having many problems.

Well, you can get power out of a rotory engine without turbocharging, but not enough to really impress me for it's external size. As far as the piston type engine design being around for so much longer and getting the benefit of increased R&D efforts, I'll agree, but the rotory engine is also an internal combustion engine which can benefit from some of the idea's that have been implemented into piston engines.

What do you think a N/A RX-7 could make for hp? 180? Nice, but even at 180 it wouldn't be 14 sec car. The older N/A RX-7's made what, 140? I don't think a 2x 40ci engine like in the RX-7 could make more than 200hp without the addition of forced induction. Sure, you could spin the **** out of it to get some more power, the RX-7 redlines at 7,000 under boosted applications, but like I pointed out earlier, their torque production sucks.

They just don't make much torque, which is very important in larger mass vehicles. Look at the Gen III RX-7. It makes a piddly 217lb/ft@5000rpm. That's under forced induction!!! Many forced induction motors will make as much torque as hp, if not more, and they'll make it well below 5000rpm, usually 3500 or below. Even small displacement engines such as the 2.0L Mitsubishi Eclipse made 210hp@6000rpm and 214lb/ft@3000rpm. As many people will attest that engine has huge performance potential, although it's pretty unreliable under those conditions. Let's do a comparo between a few production engines.

Aston Martin DB7
335hp@5750rpm
361lb/ft@3000rpm
3.2L I-6 DOHC 24v? Supercharged.
105hp/liter

Ferrari F360 Modena
400hp@8500rpm
275lb/ft@4750rpm
3.6L DOHC 40v V-8 Naturally Aspirated.
111hp/liter

Ford Escort Cosworth RS
276hp@6250rpm
221lb/ft@3500rpm
2.0L DOHC 16v I-4 Turbocharged.
138hp/liter

Honda S2000
240hp@8300rpm
153lb/ft@7500rpm
2.0L DOHC 16v I-4 VVT Naturally Aspirated.
120hp/liter

Lotus Esprit Turbo
264hp@6500rpm
261lb/ft@3900rpm
2.2L DOHC 16v I-4 Turbocharged.
120hp/liter

Mazda RX-7 TT
255hp@6500rpm
217lb/ft@5000rpm
1.3L (2x40ci) Rotory Turbocharged.
196hp/liter

Mitsubishi Eclipse GS-T
210hp@6000rpm
214lb/ft@3000rpm
2.0L DOHC 16v I-4 Turbocharged.
105hp/liter

Porsche 911 Turbo ('96)
400hp@5750rpm
400lb/ft@4500rpm
3.6L DOHC F-6 Turbocharged.
111hp/liter

After looking at some of those car's you can see that the rotory engine faces some stiff competition. Both the S2000 and the F360 Modena have well over 100hp/liter N/A, the Ferrari also maintains an impressive torque output to boot. Turbocharging enables the gap between potential performance between the rotory and piston engines to increase, but lets be honest. Pound for pound, inch for inch externally, I don't think the rotory is all that hot **** it's been trumped up to be.

Great! The rotory can make gobs of hp/liter, but it takes up about the same amount of room as a small V-8 that's making the same hp with more torque and a better powerband. It's performance can be eclipsed (no pun intended) by a small displacement turbo I-4 taking up less or equal space.

[This message has been edited by Unit 5302 (edited 03-13-2001).]

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03-13-2001, 03:38 PM	#11
Unit 5302 Registered Member Join Date: May 1999 Posts: 5,246	I wouldn't say they are unreliable, just that they have much higher maintenance schedules. My friends shop has had 4 Ducati's in at a time for scheduled maintenence. As long as they are kept up, I haven't heard of them having many problems. Well, you can get power out of a rotory engine without turbocharging, but not enough to really impress me for it's external size. As far as the piston type engine design being around for so much longer and getting the benefit of increased R&D efforts, I'll agree, but the rotory engine is also an internal combustion engine which can benefit from some of the idea's that have been implemented into piston engines. What do you think a N/A RX-7 could make for hp? 180? Nice, but even at 180 it wouldn't be 14 sec car. The older N/A RX-7's made what, 140? I don't think a 2x 40ci engine like in the RX-7 could make more than 200hp without the addition of forced induction. Sure, you could spin the ** out of it to get some more power, the RX-7 redlines at 7,000 under boosted applications, but like I pointed out earlier, their torque production sucks. They just don't make much torque, which is very important in larger mass vehicles. Look at the Gen III RX-7. It makes a piddly 217lb/ft@5000rpm. That's under forced induction!!! Many forced induction motors will make as much torque as hp, if not more, and they'll make it well below 5000rpm, usually 3500 or below. Even small displacement engines such as the 2.0L Mitsubishi Eclipse made 210hp@6000rpm and 214lb/ft@3000rpm. As many people will attest that engine has huge performance potential, although it's pretty unreliable under those conditions. Let's do a comparo between a few production engines. Aston Martin DB7 335hp@5750rpm 361lb/ft@3000rpm 3.2L I-6 DOHC 24v? Supercharged. 105hp/liter Ferrari F360 Modena 400hp@8500rpm 275lb/ft@4750rpm 3.6L DOHC 40v V-8 Naturally Aspirated. 111hp/liter Ford Escort Cosworth RS 276hp@6250rpm 221lb/ft@3500rpm 2.0L DOHC 16v I-4 Turbocharged. 138hp/liter Honda S2000 240hp@8300rpm 153lb/ft@7500rpm 2.0L DOHC 16v I-4 VVT Naturally Aspirated. 120hp/liter Lotus Esprit Turbo 264hp@6500rpm 261lb/ft@3900rpm 2.2L DOHC 16v I-4 Turbocharged. 120hp/liter Mazda RX-7 TT 255hp@6500rpm 217lb/ft@5000rpm 1.3L (2x40ci) Rotory Turbocharged. 196hp/liter Mitsubishi Eclipse GS-T 210hp@6000rpm 214lb/ft@3000rpm 2.0L DOHC 16v I-4 Turbocharged. 105hp/liter Porsche 911 Turbo ('96) 400hp@5750rpm 400lb/ft@4500rpm 3.6L DOHC F-6 Turbocharged. 111hp/liter After looking at some of those car's you can see that the rotory engine faces some stiff competition. Both the S2000 and the F360 Modena have well over 100hp/liter N/A, the Ferrari also maintains an impressive torque output to boot. Turbocharging enables the gap between potential performance between the rotory and piston engines to increase, but lets be honest. Pound for pound, inch for inch externally, I don't think the rotory is all that hot ** it's been trumped up to be. Great! The rotory can make gobs of hp/liter, but it takes up about the same amount of room as a small V-8 that's making the same hp with more torque and a better powerband. It's performance can be eclipsed (no pun intended) by a small displacement turbo I-4 taking up less or equal space. [This message has been edited by Unit 5302 (edited 03-13-2001).]