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Discussion Starter · #1 ·
Well, I have a b18b, with I/H/E. I would like to tune it, but the issue is that there are no places to tune within 900km. The local pressure is 93.5 kPa and is well below the normal sea-level 101.325 kPa. So the car could be running either richer or leaner, depending on which map it grabs. Either way, the mods are making the car run rich due to the higher flow rates. So, I have been reading up for a while on tuning and I still have a few questions. I would like to street tune it, and my 6 month old laptop can help me out.


The climate changes from +30 to -30, and there’s a week of solid -40. I know that the air density will proportionally change with temperature. So when it’s hot, we have a lower density air, which will change the fuel map for that temp. Then when it’s cold, the air becomes denser and changes the specific fuel map. So let’s say its 1 bar pressure and it get hot out, so this reduces the atmospheric pressure (0.9 bar) and the computer grabs the 0.9 bar fuel map. For cold, it does the opposite. How do standalones account for this? Or, do u have to tune it for winter and summer?


I was thinking of going for a piggyback. This is because it has the reduced cost, and its features. I know that as you lean out a specific RPM, the ignition will also advance. The change in ignition and fuel, will combine together to achieve the desired A/F at the specific RPM. The nice part is that as you reduce the fuel duty, the ignition advances and you achieve the leaner situation with a smaller reduction in fuel duty when you compare it to only reducing the fuel duty only. This is because as you advance the timing, it gives the fuel more time to burn, and hopefully no detonation.Is this wrong?If detonation occurs; use a higher octane or richen that rpm to prevent?


Another thing about piggybacks is that they change with the stock fuel map. This allows for the stock computer to adjust for the change in temperature. Then the piggyback changes the stock fuel map proportionally, by moving the fuel map into a lower atmospheric pressure fuel map.


I’m not sure what brand of wideband O2 sensor I should use. I want it to be compatible with my laptop for data-logging. Any suggestions? Keep in mind, I have a limited budget.


I don’t think I need a fuel pressure regulator, because I’m just interested in leaning out the car. The only time you need a FPR is for making the car run richer, right?


I don’t think I need Cam gears either, since I’m not trying to change the overlap, and I want to keep the stock overlap. Correct?


Oh, and I’m not intending to go into FI or N/A buildup. It’s my daily driver, and I don’t want to sink too much cash into the car. Just improve the efficiency and available power, while having fun doing it.


I know it's a little long... Any technical advice would be good. namebrand opinions can be kept to a mininium please. You dont have to water down the info either... im in my 4th yr engineering, so more technical is better. even textbook referances are good too.
 

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the problem with the piggyback is that the map you set for the fuel may not be the right advance...they don't match up...you have to tune them separately.

you're better off going to a hondata-like system with an emulator & reflash burner , having atuning shop tune it for you and have them set the basemap for you and then you do te adjustments once you drive around home.

it can get pricey but the costs are coming down on the tuning.

if your heart and budget is set on the piggyback just be aware that you won't get an ideal ignition map. you may get away with running a bit more advance baseline since the lean down in the midrange tends to correlate with MAP sensor voltages moving to more retard in the midrange and part throttle.
 

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Discussion Starter · #3 ·
Now when you do make a new baseline on a standalone, is it a single fuel map for 1 specific pressure, humidity, temp, etc?

Or can that data be put into a computer model to insert more fuel maps at different atmospheric pressures, temps?

The issue is the ability that the computer can adapt to changing conditions in both open loop and closed loop.

I’m not 100% biased towards a piggyback, its just it seems to be the most adaptable with the information I know. My biggest concern is maximizing power, and the computer’s ability to handle a seasonal climate without retuning every month.
 

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you can download basemaps...they're all over the internet if you buy the product...eg. AEM EMS has a downloadable basemap.


I wouldn't start from scratch when you have these available.

well in closed loop, you're not going to need a lot of changing since the O2 sensor is driving everything.

it's the open loop stuff but I doubt you're going to be going nails to tongs full throttle in the winter unless you race on a lake in the winter with it?
 

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Discussion Starter · #5 ·
ok, so you have the entire basemap collection, so when you tune it with a laptop, your only modify one specific basemap. not all of the possible maps... correct?
 

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This is what a VTEC fuel map looks like on a Hondata.

Each point on the graph represents a fuel value at a given RPM/MAP value. Its these values that you adjust based on what the wideband O2 sensor & dyno are telling you.
 

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Discussion Starter · #7 ·
things are not so muddy anymore...

as i can see, you get the base map, and change the fuel for each rpm. each pressure is very closely related, almost linear. this allows us to change the fuel timing at one specific pressure and its good for the rest of the pressures. this is assuming that the change is done by a percentage basis. then for any temperature and pressure, the computer will have an ideal map to work off of.

now that it clear....

its just a matter of price vs features. no need to talk about that.

anyone have advice on the wideband contoller + sensor that can be used with a laptop?
 
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