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| Tofuball's '94 XFi; It's all about city MPG | |
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| Tweet Topic Started: Mar 12 2011, 08:59 AM (39,446 Views) | |
| Tofuball | Mar 23 2011, 10:04 AM Post #46 |
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Strange Mechanic
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Remember: I am dealing with city conditions, so my MPG might not look that impressive, the focus of this build is almost 100% city MPG: 1) Cold driving for very short distances, but with lots of red lights and stop signs (Example, my trip to work is 3.5 miles, has 4 lights (that are usually desynced so they're red) and four stop signs (those are always red too for some reason ;)) 2) Traffic around here is terrible 3) Lots of hills 4) Usually the vehicle is loaded with cargo and people Warmup runs MUCH richer then it needs to, idle runs richer then it needs to, cruise runs richer then it needs to. All for the sake of smoothness, factory reliability\replication, and the sworn enemy of fuel economy, emissions. I am taking advantage of the fact that my vehicle is not "emissions controlled" to the same degree mandated in newer cars. An engine like ours would strain even more under the emissions requirements, possibly even forced to run an air pump and a pre-cat for warm up emissions. You simply cannot manufacture a car this light and cheap within modern safety standards, so that weaker engine would have to pull a heavier car . . . Take a look at the Gen 1 Honda insight. With all its aluminum frame and plastic parts and lack of a rear seat it still was 200lbs heavier then my car in stock trim (Thanks, hybrid system, for your 200lb battery packs!). The fat new ones weigh in at a half ton more. 1994 was the last year for the true lightweight car in the US as far as I know. DIY is the ONLY way to pull this off in the US, unless you have some way to get around the laws. Check out the Honda Fit. ~30MPG Maybe a manufacturer will step up to the plate and do it, but they're going to have to use some new, possibly expensive tech on a cheap car. (Original insight redesign without hybrid? Unlikely, but possible?) Edited by Tofuball, Mar 23 2011, 10:22 AM.
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| nerys | Mar 23 2011, 10:39 AM Post #47 |
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Grr
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I disagree on DIY being the only way because of laws. they can not do it "by choice" consider if a hyundai elantra or ford fiesta can do 40-45mpg with such LARGE engines and all that NON law required CRAP they add to the cars. put a 1.0 or 1.2 liter engine in the car instead of the 1.4 to 1.6 they use and any of those would start tickling 50mpg. |
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| Tofuball | Mar 23 2011, 10:47 AM Post #48 |
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Strange Mechanic
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Perhaps. Though it still bothers me knowing we are capable of so much more if we didn't have to keep dumping gas into our exhaust to feed these hungry catalytic converters and the like. |
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| Tofuball | Mar 23 2011, 11:21 AM Post #49 |
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Strange Mechanic
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Once instrumentation is tested and in place, my proposed testing order: 1) Factory baseline 2) Factory TBI setup, but running MegaSquirt 3) Factory batch setup 4) Full sequential injection with stock injectors and COP 5) Full sequential with Insight (or similar) injectors and COP Most other mods listed will be determined after this testing phase. That's the plan, at least. MegaSquirt will be retuned for each phase. |
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| Tofuball | Mar 23 2011, 11:49 AM Post #50 |
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Strange Mechanic
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Outside the US they do it all the time ![]() Also, http://www.autoblog.com/2007/05/31/mazda-develops-new-na-1-3l-miller-cycle-engine-for-mazda2-demio I wonder if I should ask 3Tech to make me a camshaft like that?
Edited by Tofuball, Mar 23 2011, 11:53 AM.
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| Tofuball | Mar 23 2011, 07:04 PM Post #51 |
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Strange Mechanic
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![]() Head is almost ready to be milled, just needs holes drilled for the injectors, gotta go out and get a longer bit . . . 9mm in case anyone is wondering. |
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| Tofuball | Mar 24 2011, 06:19 AM Post #52 |
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Strange Mechanic
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Some theory: From my limited knowledge, the stock intake manifold is not an ideal design for power or fuel economy, it is small and unturned. More ideal would be a "log" style intake manifold that would "tune" intake pulses. What in the world is with the stock head design, the exhaust ports shift a hard 90 right before the exit! That's some "backpressure" for you. I wonder if it is intentional for some MPG design theory that I don't understand. I don't think there's enough material to really significantly change the port shape, but I'll see what i can do. This head design is designed more to be flat and not use much material then to be efficient. You want the ports to approach the cyl from much higher angles. |
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| mcmancuso | Mar 24 2011, 09:34 AM Post #53 |
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Yeah I noticed when I rebuilt mine, the exhaust port design is pretty terrible. |
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| Tofuball | Mar 24 2011, 12:04 PM Post #54 |
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Strange Mechanic
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BTW, you just invented the Suzuki K10 Alto. 56MPG claimed on the highway, IIRC. Move to India
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| nerys | Mar 24 2011, 01:20 PM Post #55 |
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Grr
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I don't want to move to india. I want them to start selling what I want HERE. its that or they get nothing hence I don't buy new cars. :-) They do not WANT to make those cars available here because there is less PROFIT to be made on a car that is actually a good deal the the consumer. |
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| Woodie | Mar 25 2011, 05:41 AM Post #56 |
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Enough with the conspiracy theory, it wouldn't sell. With gas over $8, now you've got a different situation. |
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| Tofuball | Mar 25 2011, 02:19 PM Post #57 |
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Strange Mechanic
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Off to the machine shop for a 3 angle, a deck, a drill, and to see if he'll weld some material onto my exhaust ports so that I can get rid of that crappy bend in them. |
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| nerys | Mar 25 2011, 10:11 PM Post #58 |
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Grr
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I don't believe in conspiracies. I have yet to hear of ONE SINGLE legitimate conspiracy. Does the bend actually effect performance much? |
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| Tofuball | Mar 25 2011, 10:38 PM Post #59 |
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Strange Mechanic
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Guy at the shop saw the grooves I cut and looked at me funny. I explained what I was trying to do and we talked a bit, the Tofuball Head is in his hands now ![]() 3 angle valve job, 2 on the face. New guides CCing and raising C/R to 9.8 Drilling out the injector bosses (he said he'd do it because he was curious the result of what I was doing) Possibly welding exhaust I got home and just cleaned the bolts and painted some parts (cast iron grey, and gloss black, both 500F engine enamel) ![]() Painted the injectors too, I will use these for batch and initial sequential testing. ![]() In this picture, you can see how all the injectors are tied into the same line, so they all fire at once stock. Bleh. ![]() |
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| Tofuball | Mar 25 2011, 10:50 PM Post #60 |
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Strange Mechanic
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I think so. |
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