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My Mazda RX-7 twin turbo makes use of two small Hitachi HT12 turbos with different blade configurations that operate sequentially over the RPM range. The first turbo spools at around 2500rpm, then at 3800rpm, exhaust gases are bled off to start spooling the second turbo till finally at 4500rpm a valve
closes and both work together to provide full boost up to 8500rpm. The problem is that below 2500rpm, there is very little torque. To solve that problem, the first turbo would be replaced with an electric supercharger, and sequntial operation maintained. Follow the link to below. The second turbo charger could be replaced with a much larger turbo/wastegate combination. With this setup, very high HP figures could be attained whilst improving general driveability in the low rev range.
Mostly baked alternative
http://www.turbodyne.com/product2.html
Or combine the electric supercharger and turbo into one unit. The description of the product makes it sound like it addresses all your needs. [scad mientist, Oct 17 2004]
Visteon Electric Supercharger
http://waw.wardsaut...teon_eyes_electric/
Mostly baked as well [rx7rob, Oct 17 2004]
Honda Dual Note Concept
http://www.electrif...honda_dualnote.html
V6 plus electric performance car [wombat, Oct 17 2004]
hurley-engineering
http://www.hurley-engineering.ltd.uk/
Rotary engine specialist. If you want to know anything about rotary engines speak to these guys. [shifty, Oct 17 2004]
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The low torque experienced probably has much to do with the unusual (nearly linear) torque curve of a rotary engine rather than a lack of boost. I can guess that the way your RX is engineered is a result of the powerplant being ill-suited to take advantage of boost at low rpm. |
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I've always wanted to drive a turbocharged RX, though, just to see what it's like. |
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Also, please post your URLs below your main idea text in the "link" region provided rather than in the idea text. |
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Sorry 'bout the link... new to this website and protocols. I like the mostly baked alternative, though it does look like it's designed for diesels more than petrol engines. |
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You can move it if you want. |
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Bristolz, moved the link just for you. Drive one if you can, it's awesome! I think turbos just don't work at low RPMs that and rotaries aren't good at low revs either, that's why Mazda settled forn the twin setup. |
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Turbos are very good at low rpm in piston engines if they are engineered right and, in fact, are a lot of the reason for their existence. The peaky quality of the rotary must be a very different experience, though. |
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I've driven a late model RX7 twin turbo and they are very hard to catch off boost. Very un-laggy thanks to the twin set up, and the change over is so progressive you don't really notice it. So it's a bad example, and with 8000rpms to work with 2500rpm is to be considered very low down for a boost threshold. |
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You'd almost be forgiven for believing a RX-7 wasn't a turbo car if you didn't get pinned back in your seat. |
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It's only if you are deliberatley forcing the revs to stay low if your used to being a economical driver with a manual shift. Automatic's have a torque converter and kick-down so there's really no issue with low-end boost. A RX-7 ticks over at 2700rpm at 55mph, so drop you plant your right foot then and you have full boost. It's one of the few cars i've driven that doesn't need to go down a gear to overtake in. |
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Only badly designed early rotaries have the linear peaky torque band. I can point out alot of piston engines that are just as bad too. Mazda's new renesis has a near flat torque curve from 2000rpm to 9000rpm, which can only be achieved by a wankel. |
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Turbo cars require a different driving style, turbo lag only happens for the unweary lazy drivers. If you have a smart automatic it does the thinking for you, but in a manual you just need to drop down one gear and its all there. I used to have a turbo car that would do 100kph in first. So when I'd get pissed off stuck behind some slow old van or something, I'd put it in first ... |
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Yeah, I have only driven an older rotary/RX-7 and only once or twice. It had a (heavily) modified engine and seemed very peaky to me at the time. Indeed, the new ones must be a lot nicer to drive. |
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See link of Honda Dual Note. A high revving rotary combined with additional electric motors driving the front wheels as on the Honda hybrid concept would be a great combination. Sub 5-second launches combined with smooth rotary top end power. |
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Most of the early ones are peaky because fools toy with the ports.....leave it stock the way it is and its a beautifu engine but to get the big ponies they play with the porting and hence make the powerband crazy i drove one that had bugger all power till about 6000 then it just pulled so hard but was a bitch in trafic the ports were opened so far that the water jacket had to be rebuilt with liquid metal so it only last about a year before you find coolant everywhere haha but the wankel is a top engine even a bad example like the suzuki RE5 bike shows power everywhere |
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