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

[tasdrouille]

Originally Posted by s2man

That's what I was trying to say in the shift timing thread. 7/9 = 77% of max torque (or load). Examining a bunch BSFC maps, and measuring the extents and center of the peak efficiency island, I found the average center point to be 72% of max load. Hence the question; Can we believe the LOD output on the scangauge as a good indication of engine load?

I just installed an air dam on my TDI today and as I was coming back from work I was looking at my boost gauge when it hit me.

If a SG can accurately output engine loads, then all other things being equal, this would be an incredibly easy way to test aero mods. You get a baseline load at 75 mph, install your mod and look how the load differs at 75 mph again.

[s2man]

Originally Posted by fabrio.

For an correctly reading of BSFC, the map it must be without the torque value, but with the % of PME max(pressure, average real).

I think the torque can be as useful as the engine pressure (BMEP). Yes, there are losses due to friction and respiration. But I think the torque Y axis still gives us a good measurement of force, since higher pressure in the cylinder will result in higher torque. BSFC maps seem to use torque and pressure interchangeably.

Originally Posted by fabrio.

For to go the engine in the optimal fuel economy (in this case by 250 gHP/H), it is necessary the needed load. In normal operation, in flat road, in the last gear and without acceleration, it is impossible go to optimal area of BSFC.

Yes, we are talking about accelerating, not normal operation. But at normal operation, we should also be able to change the engine load slightly through gearing. Higher gears will make the engine turn slower, needing more open throttle and higher load to put out the same power.

This thread has me thinking about what I should do next. I have parts for two tests: a full rear-body lip for air-flow separation testing, and an adjustable throttle limiter for acceleration tests at different throttle positions. I was planning to do the aero test first, but now the throttle position has my mind occupied. I watched the LOD out put on the ScanGauge today, and I can not believe I'm reaching such high loads at low throttle positions.

[MetroMPG]

Originally Posted by tasdrouille

You get a baseline load at 75 mph, install your mod and look how the load differs at 75 mph again.

The difficulty with this is LOD is an instantaneous gauge on the SG. It's difficult to get an accurate picture, since it fluctuates readily.

I wish those gauges were also "averaging" like the "trip" MPG function. Then you could reset the gauge as you pass a marker and record the average reading when you pass a second marker. Even with a short duration, it would be much more reliable data than trying to read instant figures.

[tasdrouille]

Originally Posted by MetroMPG

The difficulty with this is LOD is an instantaneous gauge on the SG. It's difficult to get an accurate picture, since it fluctuates readily.

I wish those gauges were also "averaging" like the "trip" MPG function. Then you could reset the gauge as you pass a marker and record the average reading when you pass a second marker. Even with a short duration, it would be much more reliable data than trying to read instant figures.

I had the chance to play a little more with the SG today and that's what I realised.

[Daox]

I really just wish it did datalogging.

[cfg83]

MetroMPG -

Originally Posted by MetroMPG

The difficulty with this is LOD is an instantaneous gauge on the SG. It's difficult to get an accurate picture, since it fluctuates readily.

I wish those gauges were also "averaging" like the "trip" MPG function. Then you could reset the gauge as you pass a marker and record the average reading when you pass a second marker. Even with a short duration, it would be much more reliable data than trying to read instant figures.

Maybe you already know this, but you can change the duration of the instant gauge :

ScanGaugeII With XGauge Manual - Page 25
http://www.scangauge.com/support/pdfs/SGMan5_0.pdf

MORE -> MORE -> RATE
This sequence will allow you to change the gauge update rate.
RATE FAST>
<NORMAL SLOW>
The update rate defaults to NORMAL. In some cases, a faster update rate
can be used. If this causes some updates to be skipped or irregular
operation, FAST should not be used. In some cases even NORMAL can
be too fast and lead to poor operation. In these cases, SLOW should be
used. PWM and all the CAN modes can usually use FAST rate. VPW,
ISO and KWP modes may have a problem with a rate higher than
NORMAL.

However, I don't know if this is doing accumulatoon, .

CarloSW2

[cfg83]

Daox -

Originally Posted by Daox

I really just wish it did datalogging.

Supposedly that feature is "in the pipe", but it hasn't happened (yet).

CarloSW2

[MetroMPG]

Originally Posted by cfg83

However, I don't know if this is doing accumulatoon,

Unfortunately, no, it's just the refresh rate of the instant gauges (and, I suppose, how often the average is updated on the trip/tank stats).

The MPGuino will likely have these features... eventually

[RH77]

I've searched for a while and haven't found anything close to a BSFC chart for a Honda non-VTEC engine. A recent Autospeed article had a good one for the Insight, but it's a radically different engine and VTEC-equipped.

If anyone comes across one, I would appreciate it. Thanks

RH77

[fabrio.]

same problem with my opel tigra engine, the X14XE
Could you tell me how I can find the bsfc of my car?

thanks