Anybody have BSFC d16y7? (96-00 civic dx lx)
 

Anybody have a chart or done testing to see what the d16y7 likes? I just go a scan gauge today so I'd like to start playing with driving techniques and see if i notice any differences.
From what i've seen it looks to be 60% load from 1750-2250?

I learned from watching PaleMelanesian (a member of this forum). He had a 96 DX and now has a Fit. I have a 98 DX. For 5 years I have been driving almost every day to work: 75% to max 80% load, 1500 or 1700 to 2000 or 2200 rpm.

My best tank ever was 70mph. PaleMelanesian got at least 90 once and regularly got 80.

Hope that helps...

james

The only Honda BSFC chart I have is from the Insight's 3 cylinder, which appears to have heritage from the D-series:

http://ecomodder.com/wiki/images/e/e...nsight_5mt.jpg


If I were to guess, I'd say peak BSFC happens at closer to 2750-3250RPM on that motor, because of the cam profile, and probably at slightly higher load, closer to 70-80%.

I love your interpretation of the Gen 1 Insight map. I totally agree about the heritage thing. The 2000 Insight was launched in the last year of the 6th Gen Civic (96-00), and lots of engine and trnasmission features were similar. You can see it really clearly in the FSMs. But I can't agree about your RPM recommendation. Why so high? In my experience (and PaleMelanesian's) ... it would suggest, as this map does, that 1500 to 2200 RPMs is the best range. And we drove it at 75% load. 3000+ rpms seems like screaming it.

Take it with a grain of salt, but here's my reasoning:

The Insight's ECA1 is a VTEC(-e) motor, which opens the second intake valve wider after VTEC engagement, which is somewhere between 2500 and 3200RPM depending on load. This gives the engine two torque curves, one that peaks somewhere between 2000RPM and VTEC engagement, and another that peaks at around 4800RPM.

The D16Y7 is a non-VTEC motor, and its torque peaks around 4600RPM, because it has only one cam profile. The cam profile that it has is a compromise between low RPM torque and high RPM torque, which I would imagine would shift BSFC up the RPM band a bit.

Peak BSFC is generally not at peak torque, but there is a relation. Low-RPM combustion efficiency is improved in the ECA1 due to a swirl effect caused by asymmetric opening of intake valves. I can't imagine peak BSFC being at the same RPM in the Y7, so it's more a question of how far up the RPM band it moves.

The tricky part about using the Insight chart is that lean burn creates that first 215 island, which the Civic doesn't have. However the 250g/kWh point a bit above 80Nm is probably the approximate peak efficiency point at stoichiometric.

That said I wouldn't worry about what rpm to accelerate at; when you accelerate hard at low rpm, the engine is less efficient but the "pulse" takes longer, reducing your car's variation in speed. Just pulse in the top gear, it's easier.

I don't think that includes lean burn, based on my understanding of how it works.

I agree with you. That map is normal engine function, not lean burn. Lean burn only engages in light throttle conditions, as I understand it.

I don't agree with this one. On the map above, the Insight engine clearly produces 60 Nm torque more efficiently at 2000 rpm than at 3000 or 4000 rpm. If the Sixth Gen Civic the OP has is similar, then it too is more efficient at 2000rpm.

215g/kWh is extraordinarily low for gasoline. That's a thermal efficiency of 38.7%, which only a few of the most modern powerplants can match.

230-240g/kWh is the correct range for peak efficiency of a MPFI engine with typical compression ratio.

It's lean burn.

I'm aware of how low it is, and I'm still inclined to believe the chart is for stoichiometric combustion, because you can't get that kind of torque with lean burn in the Insight. Peak torque (WoT) in LB is somewhere closer to 50Nm, making that impossible. Any higher and it's necessarily stoich.

Edit: FWIW Honda has since built several engines that exceed the thermal efficiency of the ECA1. The 2.0L Atkinson cycle engine in the 2014 Accord hybrid is claimed to be the most efficient engine ever put into a production car.

So basically, if serialk11r is right, the answer to the OP's question is ... "no" (nobody here has a d16y7 BSFC map, still). lol

Tried it today since it's my first day to use the scan gauge. Going to hot springs I used the 75-80% load shifting at 2250, engine off down hills. 45mpg vs the 38mpg i typically get. Not too bad. Seems to work. 10 miles at 70mph, then ~50 at 55mph, ~10 at 25-35mph.

The real answer is it doesn't matter, because gasoline piston engines are remarkably similar.

One look at the specs of the engine (no VTEC, bore, stroke, rev limit fall within typical range) tells you 240-250g/kWh is probably as good as it gets, and generally there's an island of peak efficiency somewhere in the 2000-3000rpm range at 80+ Nm/L load.

The peak efficiency doesn't even really matter, because it only varies 5-10% within a several thousand rpm range above 1500rpm most of the time. When you drive a car, the engine speed is going to be changing all the time, so you can never be that precise.

Keep a fuel log here at the site, so you can chart your numbers. Using this technique your averages will start to climb right away. Is you scan gauge calibrated?

I don't have a GPS but I used a Tremec gear calc and heres what's odd:
Speedo and RPM read ~74-75mph and ~3150ish rpm which is clearly wrong as im traveling 70mph.
From tremec's website the car should spin 2960rpm at 70 and sure enough with no offset, the scan gauge read 70mph @ 2960rpm. So goofy gauges, but the obd2 signal to the scan gauge is 100% correct.

You are saying that Tremec told you 75 mph and the OEM speedometer read 70mph and the scan gauge read 70 mph? If so, you have your Scangauge speed reading calibrated, but the car might be giving your gauges incorrect information because of tire/wheel size. What size wheels/tires are you running?

[QUOTE=California98Civic;515741]
The reverse. Speedo read 74.5 ish and rs read like 3150.
But scangauge zero offswt read 70 at ~2960, and calculated speed was 70 at 2960 even.
The gauges read incorrect, but the scan gauge is spot on with the distance it should be covering.

I just got a 98 Civic LX and my speedo is about 6-7 mph high. 77 mph on GPS was just a bit under 85 on gauge.

It's an automatic. :(

In my 94 Del Sol, I had to take the cluster apart, pull the speedo needle off, and put it back on adjusted slightly. If the speedometer had been reading off by a percentage, that would have suggested the wrong tire size, but it was about 6mph high at 20mph, and 6mph high at 80mph, which suggests to me that the spring inside of it was just getting tired. After pulling the needle off and adjusting it, the speedometer, GPS, and odometer all agreed.

Here what I mean. The needles are just literally off.
Pic:
https://drive.google.com/file/d/0B1A...w?usp=drivesdk

CA Civic.

What's your target temp for your warm air intake on FWT?

I haven't adjusted mine, but the 2000 Accord speedometer reads ~10% higher than the GPS. I've been at the GPS speed going through speed traps and had no problem

Got my SG this weekend and it matches GPS. Speedo reads high in comparison. Difference between actual ( SG & GPS) is proportional to speed and is consistent so I think it's just the nature of the mechanism. I'll be changing tires in the next few weeks so I'll measure odometer offset after that change rather than measuring it twice.

I'm really considering going to buy a GPS and return it after a day so I can set my car in, but... I really dont wanna be that guy. haha.
But people just don't own accurate GPS units anymore like the mid 2000's, not with inaccurate smart phones so prevalent these days so it is hard to find one just to borrow from a friend or the sort. But With 175/70/13's on I was spinning 2960 rpm @ 70 just like what I got in my calculations on what the drivetrain should spin at that speed. So it seems accurate in the obd2 rpm signal but the gauges always have that steady margin of error like you stated.

I've checked my Samsung Galaxy S5 against the $$$ gps speedo on several boats. It also matches my Garmins. Only thing I think you should be concerned with as far as GPS accuracy is terrain. They're best on level ground.

Sorry I missed this query. I like 130s and 140s. I set the ultrafauge alarm for 150+ ... not that there is anything "emergency" about that number, but I like to know when it is climbing like that. It is rare, but it does happen.