RotaryEvolution

iTrader: (30)

+1

it makes my head hurt when customers come in and complain about fuel efficiency in town.

the auto start feature is a bad idea also, because most 7 owners always have the thought in the back of their mind that their car won't start with each turn of the key, adding this in 50 times during a trip across town is bad mojo.

having fresh engine, wiring harness, tuned ECU and clean fuel system helps dramatically. spending $100 to thousands of dollars to increase mileage by fractions of 1mpg i would consider to just be a challenge and not a practical endeavor.

if you really want to experiment, look up HHO and try working it into the car with a piggyback fuel controller to remove fuel as needed. i have yet to see anyone really spend much time on it and i still have plans to see if it actually works. water is free after all and the kit could be done for less than some of these modifications.

j9fd3s

iTrader: (3)

this is from the training book from 1986. cranking speed is under 470rpm

RotaryEvolution

iTrader: (30)

36 Ms at 77F? that doesn't sound right even for an overly rich cranking map, that is dumping straight fuel into the engine.

RXSpeed16

iTrader: (41)

Hailers did a write up on this a while ago. He figured out that by disconnecting the start signal from the ecu, you could bypass the start map and significantly reduce the injector pulse. The numbers in the chart and his improved setup were verified with a rtek 2.x.

+1 on the hot start anxiety. That is truly living life one stop light at a time.

RXSpeed16

iTrader: (41)

Very interested to see how the mpg numbers turn out. And if there are any side effect to 'parking lot' situations. I don't quite understand how changing the fuel map in closed loop mode would affect the AFR's. I see the cause and effect relationship, but curious how the ecu gets there.

Closed loop mode = Ecu takes a programmed injector pulse and trims it to a target AFR (12.5-14 in Sharingan's example.)
Wouldn't the ecu's closed loop logic negate the fuel tuning and trim it back?

If the rtek 2.x is operating in open loop mode, it all makes perfect sense.

beefhole

iTrader: (29)

I think what it is, is only the first pulse of the injector. After that it probably reads off the regular "map". On my haltech, at ~80degrees I have 66MS! No problems starting and my engine has never flooded. The reason is the engine hasn't really turned at all and pulled in fuel so you literally need to saturate the intake tract in hopes of getting something to the combustion chamber. Like pumping the throttle on a carbed engine before you start it.

Pele

iTrader: (28)

Maybe a thermoswitch somewhere could be arranged to do this.

Never had this problem. Mine usually fails to start cold because I have a crap battery.

Aaron Cake

iTrader: (1)

A prerequisite of a system like auto start/stop is that the car be in good mechanical condition and good tune. Since the owner of such a system would also be chasing mileage, hopefully we can assume the car is in good shape.

Yeah, I still think the idea of chasing mileage in an RX-7 to save money is pretty silly, but for the sake of a challenge, it's an interesting idea. The single greatest gain would be a standalone of course as already discussed. All this other stuff is just a bandaid for an old, stock ECU. With a standalone, auto start/stop could be a viable option.

I can save you the trouble: HHO is nothing but a huge scam and complete bullshit. It has been lab proven as such. If you really want to read the whole thing, there is a topic on my forum which can be found by searching for "hydrogen fuel for cars". It's about 20 pages though.

Ah, then such an auto start/stop circuit would also have to bypass this signal with a relay to avoid the injector priming pulse and radically cut down the amount of fuel during cranking.

As beefhole suggests, that's gotta' be the priming pulse, not cranking PW. 36ms is pretty insane for cranking times.

reo

iTrader: (4)

HHO-- simple physics; it requires more power to produce than it gives.... the only cases of improved mileage are on rich running carb. engines where there is unused energy available to mix. It will lead to more alternator maint. and serious explosion danger. hillbilly economics!

RotaryEvolution

iTrader: (30)

in all honesty, there have been cases where you can extract more than the needed input, i forget the technical term but it is possible. but it really depends on what you are calculating from input versus output. in this case we are not exchanging electricity to electricity, we are using electricity to improve the actual efficiency of gasoline by producing hydrogen and mixing it with the gasoline.

problem i have seen with most people who claim and why it is deemed to be bullshit is that most people are not running tuned or programmable ECUs.

i just don't know until i prove it wrong myself. not a single person has done any real conclusive testing with a ROTARY ENGINE that i am aware of. just because it has been tested in piston engines, and many people claim to see some gains, albeit marginal i do somewhat believe that it is helpful in aiding the petroleum based fuels ignite and burn better when TUNED properly. most are playing with the stock ECU and attempting to tune it only in closed loop with bandaids such as oxygen sensor extenders. the true method would be removing fuel to adjust to how much volume you are producing and pulling back timing at the same time because the hydrogen is much more volatile.

at any rate, don't discount something simply because in your head 2+2 adds up to 4, 2 X 2 also equals 4. we would never progress if people never actually attempted things simply because on paper it doesn't seem viable.

i just find it too hard to believe that so many people are liars out there. while i DO NOT believe that some people are getting 50+ mpg from vehicles that were getting 20-25 before, now THAT is unrealistic and bogus. but if you could pull out ~15% more mileage with just a little bit of maintenance to the system and some decent tuning, i think i would take that.

i do agree that there are a handful of people out there taking advantage of the topic though, selling kits which will not improve upon mileage one bit just to turn a buck. like the sucker at 7 stock last year with the HHO kit on his car, trying to sell it, claiming better gas mileage without a single ounce of data to back it up.

j9fd3s

iTrader: (3)

it depends a little, on a stock car, if you unplugged the 02 sensor, it'll run richer than 14.7:1, how much depends on the throttle opening/rpm etc, sometimes its really close to 14.7 sometimes its in the 13's.

anyways, the o2 sensor pulls it lean, so there is a little bit of fudge room to lean out the base map, it'll still get adjusted to 14.7:1, but it might start closer to 14.7 than it did before.

=profit.

although a 2% change in fuel, ends up being something like .5mpg, its small potatoes

modded cars (big exhaust) can actually go the other way and switch between too lean to run and 14.7:1, which does net good mileage.

Aaron Cake

iTrader: (1)

Only when there is more energy in the system. For example, putting energy into a system to start a chemical reaction which breaks down the stuff already there, releasing energy. However something is always consumed. The greater output energy doesn't come from nowhere.


That's the theory, but it doesn't work.

You'll never produce enough hydrogen to make a difference. In order for this to work, you'd need an onboard hydrogen tank.

The link to the topic on my website is here:
http://www.aaroncake.net/forum/topic.asp?TOPIC_ID=7606&

In that topic are links to several studies of exactly this, where hydrogen and oxygen were introduced into spark ignited gasoline engines and then the effects measured. The amounts of hydrogen needed to make any improvements were orders of magnitude larger than could ever be provided by electrolosys onboard of the vehicle. Down near the middle of page 2 of the above topic you'll see the links. One by UC Davis, one by the US Department Of Energy. I think there's another link later in the topic from the US Military.

Lab proven.

Never equate to malice what can be easily explained by incompetence. We can't assume everyone involved in HHO are lying (though in my life experience, a huge number of people are dirty rotten liars). However what can be called into question is their massive bias, their testing methodology and their complete lack of understanding of the systems they are meddling with. There are a great load of people who post all about HHO on forums and how great it is. Then they try a system, see nothing, and don't have the stones to post back and say "Gee, I was wrong".

RotaryEvolution

iTrader: (30)

i suppose i still am curious regardless of it's disproven theory. rotary engines work on a slightly different chain of events.

if it really helps then great, if not, it cost me the cost of materials which would be about $30 which is less than the OP to this thread has already spent on his mileage efforts and probably also noticed no significant gain.

i just am not the type of person to read something and usually come to a conclusion, i put my hands on it before giving my own -personal- opinion.

sharingan 19

iTrader: (16)

Well this tank might not be the best indication as it has been raining a lot recently:
1) due to my vented hood this has caused a decent amount of alt belt slippage/reduced voltage.
2) ...and more importantly I have been taking advantage of the reduced coefficient of friction afforded by said precipitation to engage in slippery side street shenanigans ;-)

That being said, I'm at 115 miles (all city) and still above a half tank. If I make it to 136 by the halfway mark that's 17mpg which is stock fuel economy, and if I can hit that WITH the spirited driving I would assume that my adjustments have had the desired effect.

I might be taking a small road trip for cars and coffee this weekend though so I may be able to provide more conclusive results in the near future...

In regards to "parking lot situations" that does not apply w/the r-tek as it retains closed loop operation (assuming one has a functioning O2 sensor). I am running the simulated narrow band output from my wb02 to the stock location on the ecu, not sure if that makes a difference. What does make a difference is adjusting the cruise map even in areas where closed loop will ultimately take over. Before/after it enters closed loop the afr's are much leaner now.

Por ejemplo, before I would be cruising @ 13.7 closed loop would kick in - 14.7- get on the gas - 12.7 cruise for a bit-13.7 then back to closed loop. Now, I cruise @ 15.X and closed loop actually richens the mixture. If closed loop engaged immediately it probably wouldn't make a significant difference, likewise if you stayed in closed loop the whole time (highway) it might not make a significant difference. However in the city where you are constantly in and out of closed loop operation it seems to matter.

j9fd3s

iTrader: (3)

i find that with closed loop RICHENING things, mileage does get better, my old gsl-se would do 22mpg in town, and it basically cycled between running and not running when it was in closed loop.


when you're looking at gas mileage, you really need to fill the tank, and divide by miles driven, looking at the gauge isn't accurate at all.

iwant550s

2002 VTR 1000 1/4ml 10.9 sec and 40mpg

Allch Chcar

It's fill up the tank, drive, fillup. Divide the miles by the gallons added and share your MPG.

Range is worthless for comparing FE, plus those gauges are not accurate anyway. Even on-board MPG gauges are infamous for being inaccurate.

Some goods stuff in this thread. I like that the first gen Insight was used for improving aerodynamics. I'm leery about visually modding aerodynamics but a belly pan is almost a requirement IMHO .

The HHO works by injecting Hydrogen into the intake, technically Brown's Gas. It does improve FE but it's only worth it if you DIY and build a decent system. FYI I believe the gains are significant (as in more than 3%) but I believe it's no where past 10% . I haven't looked at the studies in awhile. It's probably worth the $50 for parts including stainless steel but I would avoid it simply because it's such a hassle to maintain. It's basically like a constant science project. No thanks.

GregW

For those of you who think HHO will give you more energy than it takes to produce....

The total ammount of energy in a closed system remains constant over time. What your thinking is that you can get more energy from using fuel to make HHO and then burn the hho along with the fuel than to just use the fuel in the first place.

That makes no effin sense. Sorry, thats not reality. HS Physics 101

There is one way that will however give you better mpg, only create the hho when engine breaking, then use it to accelerate from a stop. I would guess it would be an extreamly small increase in mpg tho. Its called regenerative breaking, much more efficient to just use capicitor/batteries and some motors.

Oh, and for those of you using stainless for your hho electrodes, do you like hexavalent chromate? Well, thats one of the byproducts. Yep, that will make your ***** shrivle up and turn purple as well as give you all sorts of cancer.

Anywhozal, enjoy your hho

Allch Chcar

I am sorry for bringing it back up.

Let's hear some methods of improving MPG that don't require running a current in water.

toplessFC3Sman

iTrader: (1)

Wow, the fact that people here are even taking HHO seriously is... just ridiculous. Anyhow, onto things that could actually help... unless you're running rich, 95-99% of the fuel energy is being released already; there really isn't that much left to unlock, nor anywhere near enough H2 ( the real "technical" term ) being produced to have any effect on the performance.

I've found that cruising at about 15.5 to 16:1 AFR's, with spark timing at 30-40 adv (depending on speed and load) and -10 split (so trailing firing before leading - ONLY when cruising) seems to work the best as far as trading off fuel economy and drivability. All of this is on an S4 turbo engine & drivetrain, with a megasquirt & BNR stage 2, in an S4 'vert - so just about the heaviest, least aerodynamic FC available.
Anyhow, with this and closed-loop, I've gotten a best of 27 mpg at about 65 mph, and regularly get 20-22 highway at 75-85 mph (with a couple excursions into the loud pedal). Cold-starts seem to be the worst for fuel economy; for a couple weeks I was using her to start up in the morning and drive about 3 miles to a car-pool rendezvous point in the morning, then drive home again after work. In this driving, i was getting 10 mpg... no joke. It sucked. I got better than that bombing down ToTD and Cherohala Skyway a few weeks ago, not trying to drive efficiently at all.

Anyhow, to improve the fuel economy, you seem to have the simple ones down:

Undertray - great idea, could definitely help, just make sure to leave vents in it near the rear of the engine bay for hot air from the radiator to exit, as well as along most of the exhaust from the front & especially around the cat, to avoid trapping too much heat & melting things or encouraging thermal run-away in the cat.

Wheel Aero - As discussed above, while properly designed wheel covers can help like on the insight, the FC is not designed for them, and you'd need to either reduce the rear track or wheel width to fit them, compromising the car's handling, or make the body wider, which will increase the frontal area & hurt aero. However, as Aaron showed in the line drawings, a small air-dam in front of each of the tires can help direct air around them. If you extend these under the car to send the air under the whole wheel well & suspension, this will help some

Under-hood Ducting - basically, make sure all the little plastic bits to duct the air from the front opening through the condensor, oil cooler and radiator are there, otherwise you're just creating turbulence under the hood, disrupting air flow through those heat exchangers, and not only making them less efficient, but increasing the drag on the whole car

Stop-Start - don't bother; while it will increase fuel economy when sitting at a light, you'll be using the starter many times more frequently than it was designed for, and invariably wear it out more quickly. Plus, any energy that you use to crank the starter needs to be produced again by the alternator, and since we don't have a "smart" charging system that attempts to only charge on deceleration, you can't essentially "pay for" that energy by using the alternator instead of the brakes to slow down.

Variable Displacement - Not worth it on the FC, or any older car not designed for it. I've tried it by just killing 12V to one bank of cylinders on a V6 volvo, and tested along the same route, same driving conditions, filling up at the same pump before & after each run, on the same day. Ultimately, I got the same fuel economy on 6 cylinders all the time, or using 6 cylinders selectively (mostly starting from a dead stop, since it was INCREDIBLY slow otherwise), 3 the rest of the time. This car only had an o2 sensor in the exhaust from one bank, so I left that bank on to keep closed-loop working even in 3 cyl mode. Basically, unless the engine s more modern than ours with lower friction, you have a real hard time overcoming the cylinders (or rotor) that is just dragging along for the ride. Plus, when OEM's implement this, they de-activate the valves, leaving them closed for an "air-spring" effect, so that the cylinders aren't wasting energy doing any pumping, they are just compressing and expanding the same amount of gas. On an FC, if you deactivate one rotor, you have no way of creating the "air-spring" effect, plus, if you've got the throttle much further open to make the same power from 1 rotor that 2 would normally be making, you're pumping more air, and dumping more oil from the OMP into the rotor that isn't firing. While not catastrophic, your oil consumption will go up, and you'll probably build up all sorts of tar & coke-ing on the inside of the exhaust and O2 sensor from the unburned oil being pumped through the un-firing rotor and cooking in the exhaust.

RotaryEvolution

iTrader: (30)

imporoperly running vehicles waste gas, i suppose that isn't reality either. regardless, proper tuning can only take you so far.

what does it cost any of you to disregard and call it bullshit? nothing, and that's perfectly fine. sorry i brought it up, but that still will not keep me from attempting to see if it does in fact do anything rather than as you all have been doing, read an article and say it's all bogus.

as i mentioned, i prefer to put my own common sense to practical use, most of the clowns were testing it with ABSOLUTELY NO CONTROL TO TIMING OR DIRECT CONTROL OVER FUEL!

as i said, i don't expect much if anything but if you could actually improve upon the combustion quality of the fuel to even squeeze out 15% more per tank? eventually it would return the investment i paid for the standalone on it's own, of which i didn't even purchase it for this reason.

i understand it's open to argument, at least try to be a little bit less of jackasses about it and see that i'm not using used 2 liter bottles here, threaded tubes to move the oxygen sensor, a home brewed zip tied together generator and an '86 cavalier that is in dire need of a tune up for my own experiments.

not as if it's new, almost everyone knows about it now and most don't believe it but ridiculing people for having hope.. well, call me optimistic. most people probably wouldn't believe the things you can do with your hands and a functional brain, and of course the chance of some failures. i can only imagine how many people thought that Felix Wankel was a crazy crackpot... of course this project is still behind my twin charged setup for my car, which will also require trial and error as it is a new concept to these engines.

just the same as my tests in finding the knock threshhold of pump fuels in these engines for the various octane ratings. you can try to formulate it but there is no realistic way of knowing without putting it to test in a real world environment due to all of the variables.

problem with most of the articles is that they usually focus too much on converting energy to energy and how it directly equates. how much energy is in fuel? if they knew exactly how to obtain it 50+ years ago then vehicles wouldn't have been getting 8-12 miles per gallon where modern V8s get 30mpg+ and more each year, there is still more to be had as well!

anyways, ignore the HHO topic and get back to talking about how much drag the mirrors add.

tweaked

iTrader: (4)

On the topic of HHO, just injecting HHO into a fuel injected engine will make the O2 sensor read lean because it aids the combustion so more fuel is burned. you have to buy a little box that alters the o2 signal. Just installing an HHO generator will in fact cause you to use more fuel. Once you correct the 02 signal, you will see gains.
O2 sensors were not designed for burning Brown's Gas. It goes with out saying you have complete supporting mods.

RotaryEvolution

iTrader: (30)

yes it does have prerequisites before anyone could install it and hope to gain anything at all.

this is only something suitable for people who have a standalone because the HHO gas is also more volatile than gasoline is, requiring pulling back ignition timing a bit or you will have preignition issues and broken dowels.

this is obviously not something for just any DIYer, especially with a rotary engine and their more fragile seals.

sharingan 19

iTrader: (16)

My experience seems to be similar this far. After I go through another tank w/these settings to verify results I may switch over to map based timing and try some timing adjustments as well.

I know perfectly well how to calculate fuel economy, thanks. I was simply making a conjecture about what I might get out of the tank based on how far id gone at the time.

Filled up last night: 235.6 miles (all city w/ 3 drift sessions) put in 14.19 gallons which makes for 16.6 mpg.

This is definitely an improvement over the 18.1 mpg I got from my last tank when you consider that tank was 80% highway. Also, considering stock fc's got 17mpg city (w/o drifting, lol) I'm satisfied, and this is just round one.

I will get some highway numbers on the way to/from Rotor Fest in 2 weeks, or sooner if the oppotunity presents itself.

Wms10th

iTrader: (2)

This exactly what I did on my car years ago when the original owner had it. We then took that wire and hooked it to a brake light (normally closed) switch scewed into the passing gear switch hole above the gas pedal. That way all I do is floor the gas pedal and the fuel is cut off during starting. This has worked wonderfully since we did it in '93.