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It seems like some of the conclusions they reach will be heavily dependent on the specific details of the turbocharger and supercharger configurations.
In any event, I don't think there's a single correct answer because it will be heavily dependent on what you want to do with the car and what trade-offs you're willing to make to get there.
It seems like some of the conclusions they reach will be heavily dependent on the specific details of the turbocharger and supercharger configurations.
In any event, I don't think there's a single correct answer because it will be heavily dependent on what you want to do with the car and what trade-offs you're willing to make to get there.
They actually did their level best to do a like for like test . When they do the road test the turbo car will destroy the SC car running identical boost .
piston engines aside... rotarys naturally allow some of the compression to leak into the next chamber and out of the exhaust. turbochargers recapture this spent energy with the turbine and use it for something good. real good. superchargers do not. for this reason alone turbos belong on rotarys with or without a supercharger, but a supercharger alone is just dumb.
piston engines aside... rotarys naturally allow some of the compression to leak into the next chamber and out of the exhaust. turbochargers recapture this spent energy with the turbine and use it for something good. real good. superchargers do not. for this reason alone turbos belong on rotarys with or without a supercharger, but a supercharger alone is just dumb.
Actually, it made sense to me, they were in a small area, and they did not spool in any of the tries. In a 1/8, 1/4 or even longer rolling race, the turbo would have taken it. I still like SC>TC, call me old school.
Actually, it made sense to me, they were in a small area, and they did not spool in any of the tries. In a 1/8, 1/4 or even longer rolling race, the turbo would have taken it. I still like SC>TC, call me old school.
I would have expected the turbo to still have dominated in those tests given the dyno results . But it seems that instant throttle response is worth quite a bit in tight driving . Open them up and the turbo will take it by a wide margin.
Agree, they need to max the boost on both and see what they can do. Turbo will dominate with no problem.
While the SC may be an "easier" install as is mostly bolt on with very little customization, the turbo has way more options to increase boost/power/all of above.
All that said, I need to turbo my S2 and start walking the walk, maybe next year I'll start with some improvements, cooling, brakes, and a few other mods.
I was surprised as well, would expect the power of Turbo to equalize before it did. Great effort of them.
For a normal car, Turbo. More fun, and faster in a straight line. For lap time, I think SC would be better, at least for a driver who are not that excellent. Engine performing as a NA motor is quite valuable when you are at the limit.
How does that leaking compression pressure know that it is supposed to leak only into the exhaust side rotor face and not the intake side rotor face?
well you know as well as I, it goes forward into the exhaust, and into the previous chamber.. but the compression that goes backwards just pre-charges the next cycle..
you have not invalidated my point.
The whole time watching this little series they did, I kept thinking "Modern turbocharger technology vs. old supercharger technology" seems apparent which should work better.
I went back and watched this again, as I continue to ponder FI options for my track Miata. The supercharger kit they are using is the Kraftwerks, which uses a Rotrex C30-74. There are better options out there for the Miata, such as the Rotrex C30-84 plus better heat management. While the torque "curve" is still linear, and there is still no low end torque, much more peak power is available from a better implementation. Here is an example from Track Dog Racing's Rotrex kit.
One of the main drivers in this decision for me is track reliability. What I am seeing at the track is turbo guys with their hoods up, telling their tales of woe to any and all passers by, and supercharged guys driving all day, without a care in the world.
Hmmm...
.
Last edited by Steve Dallas; 04-13-2017 at 08:27 AM.
I would say that a supercharger has the potential to simplify things for sure. I've always been a fan of the fact that they're predictable, and linear. I prefer superchargers if I have to think of FI. I'm more of an NA kinda person, and it's the closest to that.
I would say that a supercharger has the potential to simplify things for sure. I've always been a fan of the fact that they're predictable, and linear. I prefer superchargers if I have to think of FI. I'm more of an NA kinda person, and it's the closest to that.
I don't want to hijack the thread, but this discussion is interesting and germane to me. We have a lot of Miatas at my home track. They fall into 4 categories, for the most part:
Naturally aspirated
Spec Miatas
Supercharged
Turbocharged
The naturally aspirated cars are generally reliable, assuming their owners take basic reliability steps. They drive all 6 sessions.
The Spec Miatas are similar to the other N/A cars, but are more reliable, because their owners take reliability very seriously.
The supercharged cars are mostly trouble-free. If the owner upgraded the cooling system and otherwise did not skimp on reliability mods, these cars are nearly as reliable as N/A cars.
Turbocharged cars are all over the map. The guys who spent a lot of money on quality parts (Borg Warner or Garrett turbo, inconel studs with safety wire, high quality manifold, etc.) and took water and oil cooling very seriously do OK. Everyone else breaks something by session 2 and spends the rest of the day huddled with the owners of other broken turbo cars.
Building a proper N/A Miata can be inexpensive, if you don't want more power than typical bolt-ons and a new ECU can buy you. Something like 120 WHP is achievable for a couple grand. You can supposedly exceed 150 WHP with a built engine.
A supercharger appears to the be easy button of F/I. A Track Dog Rotrex kit with everything will set you back $5,000 if you install it yourself. It only needs cooling mods you should be doing anyway to keep the water and oil happy. You have no low end torque, but you should be keeping the car above 4,000 RPM on the track anyway, right? Track manners are similar to stock. Not as much fun to drive on the street, though.
A turbocharger ends up being the most expensive option. A good basic kit with a good snail can be had for around $3,600, but the parts needed to make it reliable add up quickly. It easily costs $7,000+ to build a reliable 200 WHP turbo Miata for the track, from what I have seen. A turbo is also harder on rods, and you can expect engine life to suffer as a result. Turbo lag and sudden onset can be issues on track--especially at corner exit. Lots of fun on the street.
Hmmm...
.
Last edited by Steve Dallas; 04-13-2017 at 02:40 PM.
I know, right. Obstacles are ability to pass inspection and that couple hundred extra pounds over the front axle. There are a couple of those out at the track at times, and let's just say they enjoy jumping curbs due to limited ability to turn in. I don't need to pay for custom suspension work on top of everything else...
Seems you are quite knowledgeable about engine braking. Good thing you mentioned nothing about engines breaking.
(old man voice) This reminds me of a story when I was a teenager. I told my girlfriend I could make my 5 speed GXL RX7 stop without touching the brakes on a downhill slope to a stop sign ... she had an automatic base RX7. She didn't believe me, and I downshifted my way to a perfect stop ... she was only mildly impressed and the moment passed pretty quick.
10-20-2016 | 08:48 PM
