Buddy just got a Dyno that measures BSFC!

[dremd]

We are still about 2 weeks out from making the first pull.
Dyno is a Land and Sea 1600 hp (engine only) unit it will be used primarily for performance; but it is already set up to do BSFC charts.

I'm pretty excited to see it in action.

Anybody have any experience with creating BSFC charts?

[jimepting]

Dyno work is always exciting.

My guess, just that, is that the dyno will plot the horsepower, torque and perhaps a several other related variable such as BSFC, but will not generate the full BSFC contour such as those in this ref:

http://www.autospeed.com/cms/A_110216/article.html

I base this on fact that the BSFC contour is multivalued over much of the operating range, and therefore difficult to measure. The usual BSFC measurement desired is that which corresponds to the high RPM side of the contour, to be used to estimate fuel consumption as a function of time. When displayed in this way, BSFC is a very powerful tuning parameter.

But, my dyno experience is based on a 30 year old Go Power dyno, so I may well be wrong. Keep us informed. It will be interesting.

The Land & Sea Defense Team - Lawyers Miami Ft. Lauderdale Dade Broward Palm Beach Fl Keys

is a very nice and complete web site.

Wish I could join you in your dyno work. Some of my most interesting engine development time was when I was able to do engine dyno work. Chassis dynos just don't compare.

[dremd]

I *assume* that this dyno will do full curves; it can measure the following 1) load on load cell (torque) 2) air flow 3) fuel flow (yes there is a sensor) 4) egt 5) afr 6) rpm 7) manifold pressure.
It can control 1) load 2) throttle position.

I promise to post more when he gets it up and running.

[jimepting]

A BSFC "curve" is different from the BSFC "contours that most folks are thinking of and which are shown in the above ref. Problem is that there are two values of BSFC for each engine RPM, over some portions of the RPM/torque curve. It would require the acquisition of considerably more engine data to map out the contour map. That would involve running the engine much longer. A single full power pull traces a pattern across a portion of the BSFC contour.

But, I don't really know the answer of certain. It will be nice to see.

As Wayne Gertes over on CleanMPG recently pointed out, BSFC curves aren't really all that valuable for solving the question of optimum RPM in fuel economy terms. The problem being that the BSFC data is for full throttle and that is virtually never the situation when one is attempting to find the best fuel economy. It is valueable for NASCAR racer and others who operate their engines at full throttle for considerable times.

Anxiously looking forward to your first data.

[dremd]

I don't know by any means; but if it means anything but the dyno is designed to do endurance runs; 1600 gallon tank for cooling which the current owner actually boiled (while at the previous owners shop) during an endurance run (various throttles + loads for 12 hours) on a 700 hp+ 502 marine engine.

I'm *assuming* that some sort of similar run could be made to get the contour.

Also anxiously awaiting first data.

[TestDrive]

Originally Posted by jimepting

As Wayne Gertes over on CleanMPG recently pointed out, BSFC curves aren't really all that valuable for solving the question of optimum RPM in fuel economy terms. The problem being that the BSFC data is for full throttle and that is virtually never the situation when one is attempting to find the best fuel economy.

Is Quick BSFC question(geared towards folks with ATs) - Post#19 the post you're referring too?

___A BSFC map is useless because they are based on WOT. A partial load map is what you would be looking for but an engine or vehicle on a bench does not equate to a real vehicle on the road in - 20 to 110 degree F temps.

I've seen the numerous instances of the assertion that "BSFC maps are based on WOT", but I've yet to see an authoritative citation to backup it up. I'm no expert, but I find it difficult (if not impossible) to believe that data in the 500 rpm -1000 rpm/15.6 Nm - 31.2 Nm range of this NOT ATYPICAL BSFC map/chart was generated at WOT!

It's not labeled, but I believe the line of heavy dots across the top is the BSFC curve at WOT.

[tasdrouille]

BSFC lines can be very useful when they plot bsfc against load for a given rpm and an external variable condition.

If you get a chance to put your TDI on the dyno and have some spare time. I would like to see 2 bsfc lines.

One line at 2000 rpm from 0 to 100% load with a big fan blowing on the IC.
The same thing but with a heater blowing toward the intake and no fan on the IC.

Log MAP, MAF and IAT at the same time if possible.

[dremd]

Originally Posted by tasdrouille

BSFC lines can be very useful when they plot bsfc against load for a given rpm and an external variable condition.

If you get a chance to put your TDI on the dyno and have some spare time. I would like to see 2 bsfc lines.

One line at 2000 rpm from 0 to 100% load with a big fan blowing on the IC.
The same thing but with a heater blowing toward the intake and no fan on the IC.

Log MAP, MAF and IAT at the same time if possible.

I'd love to put my TDI on it; but unfortunately it is an engine Dyno; and I'm to lazy to pull the engine out of my Daily Driver.

Now if somebody happens to have a spare alh + harness + ECU in a few months we're game.

[theunchosen]

Waht does your buddy do that he wanted an engine Dyno? They are superior because there are fewer variables to influence relationships, but it comes at the cost of inconvenience. Most people prefer either to be able to hook the wheels in and run it for ease of use, and the only times I've ever seen anyone use engine dyno was for a spec engine and configuring and testing it for racing applications(because its so much work to tear your engine out just to dyno it).

[dremd]

Originally Posted by theunchosen

Waht does your buddy do that he wanted an engine Dyno?

Well His real job is a BMW Tech; but he build Motors. Most of his projects are for road racing, but also some 4x4 stuff and a little Marine.

Originally Posted by theunchosen

They are superior because there are fewer variables to influence relationships, but it comes at the cost of inconvenience.

Typically he's building the motor anyway; often times the vehicle isn't a) finished or b) in state. This is *typically* more convenient to him.

Originally Posted by theunchosen

Most people prefer either to be able to hook the wheels in and run it for ease of use, and the only times I've ever seen anyone use engine dyno was for a spec engine and configuring and testing it for racing applications(because its so much work to tear your engine out just to dyno it).

This is definitely mostly for racing; a good bit of which is long run I've never seen a chassis dyno that is large enough for his motors and can vary load.

I've only done work on chassis dyno's myself. I no longer have easy access to one.

As a bonus here is the blue Supra backing up to the Dyno at Hennesey last month. That's a friends Road Race Z06 on the dyno in the background, heads, cam 56x rwhp; smooth as can be.




I'll snap some pics of the engine Dyno next time I'm over.