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RX-7 2nd Gen Specific (1986-92) RX-7 1986-92 Discussion including performance modifications and technical support sections. |
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#1 |
Home-brew Rotary
Join Date: Feb 2008
Location: GooseCreek SC
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Horsepower, ted is the only one that mentioned this.
We dont care if there is more or less horsepower. This is a reliability mod, And for the ppl that remove the emissions system, an don't care about egr. Yeah this might be something significant, possibly new, an I thank Titanium for posting it up. He is contributing to the community a little helpful piece of info here. Lets give it a try here an there and post up results, before bashing it and claiming that this wont make a significant difference. About significant difference. Some of the things we do with our rotaries probably don't make a significant difference. Ive heard of lots of little things to do, weather it comes with rebuilding an engine, removing stuff from the engine(emissions removal), turbocharging, tuning, etc, That help in a little way with performance, reliability, etc. Its not all about a significant difference.
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'89 RX7 GTU, half-Bridge-port S4/S5 NA, E6K, Full RB exhaust, weekend warrior. '83 RX7, The "this might take awhile" project. '87 RX7 GXL, Rest In Pieces. '98 Subaru Impreza Outback-sport, rx7 rescue vehicle, down for repair. '94 Ford Ranger, daily. |
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#2 |
RCC Addict
Join Date: Mar 2008
Location: Honolulu, Hawaii USA
Posts: 1,813
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Hmmmm, I didn't realize critical thinking got thrown out the door just because you think someone is an authority (mind you, I'm using this pretty loosely)...
I didn't realize that just because I'm the only one objecting to these conclusions, it's called "bashing" now... Apologies if I tend to be suspicious of claims from any tom, dick, or harry... Nor I guess you think it's rather normal for someone to call me "teddy"... Funny, cause no one else calls me that. Just for the record, my legal name is "Ted", not "teddy", nor does anyone else call me "teddy". I guess you find it appropriate that someone that I don't care for is allowed to call me that? Oh, if you want to drop your temps and increase spool up on your turbo, might I suggest a turbo (turbine) blanket? These have been used for years and have been proven (and produce more significant results over these posted in this thread). Oh, wait, but you already knew about that, right...? Hey, sorry for raining on your parade. I'll let you get back to your normal scheduled programming, and excuse the blip on your TV screen. -Ted |
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#3 | |
RCC Loves Me Not You
Join Date: Jul 2008
Location: Influx.
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Quote:
The same principle still applies with the turbo blanket. The turbo will only spool as fast as the temp/pressure differential is available (Which I know you know but for everyone elses benefit), so the more heat you keep within the turbine the faster it will spool. Of consequence plugging the hole will give more exhaust gas temperature to the turbine than a blanket alone. This modification would be to isolate the exhaust gases from exchanging heat through contact and heat soak directly to the coolant passages. I imagine one could theoretically further increase the heat rejection benefit of the coolant passages by filling the egr void and plug area with an insulator material (silca comes to mind as an example) and then blocking off the locations themselves. Though I'm personally not familiar with the passages and so can not say it would be a good thing or not and may be more of a hassle than is really worth. More to the point blocking off these passages may at the most provide a good 50-100F (I pulled these numbers out my ass though) temperature difference which to a turbo isn't a whole lot and wouldn't really be noticable when the EGT's reached normal operating temperature. Basically it's something that, by itself, is not worth it to pull your engine and take apart to do. You could however decrease spool time by increasing the temp/pressure differential. There's (more than) two ways to do this. One is to allow a majority of the exhaust gas to go directly to the turbine, or cool down the exhaust gases as quickly as possible after the turbo. One can let their imagination run from there I figure.
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#4 | |
RCC Addict
Join Date: Mar 2008
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How do you get (the silica - "silca"[sic?]) to stick to the metal housings? RTV'ing the passages (on rotor housing, side irons, and intake manifolds) has been done before, but RTV only has a claimed 700F intermittent temperature resistance. Almost anything else will either: 1) burn due to temps? or, 2) come loose due to heat expansion / contraction from the engine. The good thing is that once everything is plugged up, it's a dead end. So, the plugs that are closest to the engine (i.e. rotor housings and side irons) are getting the hottest. The plugs at the intake manifold should hold up fine? -Ted |
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#5 | |
RCC Loves Me Not You
Join Date: Jul 2008
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Silica is glass (or more commonly known as: sand or silicon dioxide). I chose that media as the insulation because it can be small and remove about 99% of the air that would be in the chamber (since the silica particulate is so small). Thermal expansion shouldn't matter much if at all because the particulate itself is so small. When the chamber volume expands the silica will move to compensate, when the chamber volume decreases the silica *should* be able to move to compensate. http://en.wikipedia.org/wiki/Silica Another alternative would be Aerogel. It is mostly composed of air which makes it tremendously light. It also has an increased strength compared to other similar materials of equal dimensions. The real benefit is that they are wonderful insulators. This is the stuff that astronauts have in their suits to protect them from solar radiation (the heat, not the gamma). The trouble is I do not know the thermal expansion rate nor any of it's physical properties. http://en.wikipedia.org/wiki/Aerogel What I would find interesting and I think a little beyond anyone's skill on this forum would be to use thermoelectric coolers to cool the chamber wall and dissipate the heat directly into the insulation that holds them there. Granted you'd need to run wires and find a way to protect them from being melted/fried (probably have to encase them in the insulating material itself). Beyond that you should see a decrease in temperatures without increase in coolant temps (though this is not something for nothing). The trouble is as the heat increases and the thermoelectric device attempts to cool it, the more current will be drawn until either the wires burn up or the ceramic breaks apart. But it's interesting to consider. http://en.wikipedia.org/wiki/Thermoelectric_cooling http://www.fujitaka.com/pub/peltier/...FRJM5Qodnjbf9A
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The Official FC Radiator Thread My Project Thread: Cerberus CCVT Virginia Rotary Group Last edited by vex; 06-26-2009 at 09:52 AM. |
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#6 |
RCC Addict
Join Date: Mar 2008
Location: Honolulu, Hawaii USA
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I am not going to mess with stuff that is basically very small tiny bits of glass.
I've messed with aerogel, but only with speakers...I'll leave that stuff with transducers. Peltier devices are notoriously inefficient devices. By the time you create enough cold to counteract the heat, you've produced enough (or not enough?) current on the order of significant horsepower. So all that did was load the engine down or blow your alternator? -Ted |
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#7 | |
RCC Loves Me Not You
Join Date: Jul 2008
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As for the silica, I don't think it would cause any problems unless the metal deteriorated enough to cause them direct access to the combustion chamber or leak into the oil reserves (which I don't think they would at all unless there was a catastrophic failure). Combining the silica with a metal based epoxy or resin would eliminate any fear that a rouge silica particulate would find its way into a place it shouldn't be. The only other option would be to fill the chamber with insulation material (fiber glass) and some aluminum.
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