The BSFC chart thread (post 'em if you got 'em)

[ever_green]

Originally Posted by WD40

ever green: the one you list as 1.8L honda sohc i-vtec (2006 140hp civic)
is the same one that tom o shows for the VX
http://www.thelic.org/users/tomo/CivicVXdyno.jpg
what I really want to know is how to understand what its showing.
Can someone explain how to read it?
thanks Dennis

it just means you are better off fuel economy wise operating at 3500 rpm when accelerating at full throttle. in reality something like 2/3 throttle at 2500 rpm would be more efficient. Lots of stuff can happen at full throttle including open loop enrichment or throttle tip enrichment...ignition retardation due to knock. I personally use my scangauge 2 to monitor my acceleration. I accelerate at ~23 deg IGN and/or 70% engine load at 2500 rpm.

[some_other_dave]

Originally Posted by WD40

what I really want to know is how to understand what its showing.
Can someone explain how to read it?

It is three graphs on one page. Each graph uses RPM for the X-axis, but they all have different measurements for the Y-axis.

One line is the maximum torque produced by the engine--at WOT (Wide Open Throttle). This is the one that goes roughly across the middle of the page, and its Y scale is at the right. It ranges from about 12 kg*m at 1000 RPM, to just under 18 kg*m at 5000 RPM.

One line is the maximum horsepower produced by the engine at WOT. This is the line that goes up to the right, and its scale is at the left side of the page. It ranges from less than 20 HP at 1000 RPM to just over 140 HP at 6500 RPM.

The line near the bottom of the page is the BSFC at WOT as well. Its scale is also at the right of the page. It looks to go from just over 250 grams/horsepower*hour at both 1000 and 6500+ RPM, down to about 220 gm/hp*hr at 3000 RPM.

This last line is what we, as efficiency enthusiasts, are interested in. But it isn't enough information (there is NEVER ENOUGH INFORMATION! ) because it only tells us about WOT. To determine the best acceleration range, we would need a BSFC map that shows BSFC at all throttle positions, not just WOT.

The graph is helpful, but a full map would be much better.

-soD

[rmay635703]

Has any ever found a BSFC chart comparing different AFR ratios to one another for ANY motor?

[ERTW]

Another key is anti-tuning. Tuning an intake manifold boost VE, and hence fuel usage (keeping bsfc constant). If you take your 12" long runners, and cut them to 4", you lower VE and boost fuel economy.

Late intake valve closing (Atkinson) reduces pumping loss, and hurts low speed VE (retard the cam a tooth or two). This lowers dynamic compression - the source of the power loss - so you can raise CR to bring back performance, and boost adiabatic and fuel conversion efficiency. Slap a turbo on to bring performance to standard, and you have a Miller engine.

[ever_green]

Toyota/Lexus 2GR-FSE fuel consumption map

[bikenfool]

Some interesting charts on the ford eco-boost. Including some BSFC charts, but they are not complete.

http://www.umtri.umich.edu/content/Dan.Kapp.Ford.pdf
http://www1.eere.energy.gov/vehicles...ich_2011_o.pdf

[betasniper]

I cleaned the Saturn 1.9L BSFC (DOHC), included imperial units, Constant Horsepower curves, Engine Load %, and extrapolated to redline.

Magenta Line is "Optimum Efficiency Line"

[betasniper]

Approximate Vacuum readings on Magenta Optimum Efficiency Line:

6.7"hg at 1000 rpm

6.5"hg at 1500 rpm

5.7"hg at 2000 rpm

5.0"hg at 2500 rpm

3.8"hg at 3000 rpm

2.3"hg at 3500 rpm

1.3"hg at 4000 rpm

0.9"hg at 4500 rpm

0.2"hg at 5000 rpm

WOT at >5100 rpm

[AdrianD]

BSFC chart for a 2.5 Turbo Diesel Jeep Cherokee (VM Motori engine)

[ERTW]

I just read that the 2014 Stingray gets 330 g/kWh in V8 mode, 275 g/kWh in V4 mode.