260 Dyno numbers

[Vinnie]

Do any of you gents have "real world" dyno numbers on a solid 260 Merc? (Powerhead or propshaft)

Thanks guys.

:cheers::cheers:

[mdc]

Here are some dyno results for various 2.4 and 2.5 motors http://forums.screamandfly.com/forums/showthread.php?t=8614&highlight=dyno+results+260

[STV_Keith]

Here are some "dyno" sheets from my 260. I'll try to explain them since they aren't the normal sheets you would see.

http://www.speedcraving.com/stv/data-acq/horsepower.jpg

This graph represents horsepower (yellow graph) based by RPM (bottom axis). Mind you, this is for one cylinder only, #5. Assuming all cylinders are pulling the same, it appears to make a max of about 52-53hp at 8300rpm or so. The HP curve is nice after about 5500rpm, but that's where the prop really bites. Before that, it was spinning a bit, reducing the load on the engine.


http://www.speedcraving.com/stv/data-acq/torque.jpg

Same graph, but for torque. Peak torque appears to be at 5500, but might be lower as this was about the first point the motor was under a heavy load (prop bite). This was with a 29 Mazco - don't know if I can find something to lug it down off the bottom.


http://www.speedcraving.com/stv/data-acq/cycle2466-maxhp.jpg

This is the highest HP spot on this "pull". It occurred at 8333rpm (reading the boxes down the right side of the graph). Instantaneous HP, 55.9 (335.4 assuming all 6 cylinders pulling the same), instantaneous TQ 35.2 (211.2 for all 6), we'll skip IMEP, max cylinder pressure was 623psi at 18*ATDC, so on and so forth.

Anyway, these graphs were made by collecting cylinder pressure data on a running engine. When you know how much pressure is in the cylinder, and know bore/stroke, you can calculate how much HP that pressure made. This is theoretical though, since rotating assembly losses are not included. This would be the best case scenario, EVER. :)

Hope it helps.

[fyremanbil]

Very trick stuff. Were did you put the pressure transducer?

[DBR]

Here are some "dyno" sheets from my 260. I'll try to explain them since they aren't the normal sheets you would see.

http://www.speedcraving.com/stv/data-acq/horsepower.jpg

This graph represents horsepower (yellow graph) based by RPM (bottom axis). Mind you, this is for one cylinder only, #5. Assuming all cylinders are pulling the same, it appears to make a max of about 52-53hp at 8300rpm or so. The HP curve is nice after about 5500rpm, but that's where the prop really bites. Before that, it was spinning a bit, reducing the load on the engine.


http://www.speedcraving.com/stv/data-acq/torque.jpg

Same graph, but for torque. Peak torque appears to be at 5500, but might be lower as this was about the first point the motor was under a heavy load (prop bite). This was with a 29 Mazco - don't know if I can find something to lug it down off the bottom.


http://www.speedcraving.com/stv/data-acq/cycle2466-maxhp.jpg

This is the highest HP spot on this "pull". It occurred at 8333rpm (reading the boxes down the right side of the graph). Instantaneous HP, 55.9 (335.4 assuming all 6 cylinders pulling the same), instantaneous TQ 35.2 (211.2 for all 6), we'll skip IMEP, max cylinder pressure was 623psi at 18*ATDC, so on and so forth.

Anyway, these graphs were made by collecting cylinder pressure data on a running engine. When you know how much pressure is in the cylinder, and know bore/stroke, you can calculate how much HP that pressure made. This is theoretical though, since rotating assembly losses are not included. This would be the best case scenario, EVER. :)

Hope it helps.

There are a few people on this board including myself that would love to have this test equipment. Have fun, i am sure you will learn a bunch. Way to go.

Dave

[STV_Keith]

Interesting stuff for sure. My only problem is that on my budget (which is about $0), there's not a whole lot I have to test at this time.

FMB, the sensor is a water cooled type that is drilled through the head, through the water jacket and seating in the backside of the combustion chamber. I did all three cylinders in one head, tested all 3 and picked the one with the highest cylinder pressure to measure. Sorry, apparently no picture of the head...just this one of a mock-up head I did to figure out how to machine the head to install the sensor, and to get the sensor lengths.

http://www.speedcraving.com/keith/merc/turbo/head/head_b-2.jpg

[Vinnie]

Very inpressive to say the least!:thumbsup:

[RBT]

how many pressure sensors can you run?, would be cool to see in the crankcase also........ on all six at the same time...

[STV_Keith]

Just comes down to the money. The system I have is setup for only 1 sensor. They can handle up to 8 with the more expensive boxes. Put it this way though...EACH pressure sensor is upwards of $1300...I wasn't buying a box of them. ;)

[Vinnie]

Keith,

Those are great numbers on your 260. What have you done to it?

[Markus]

Vinnie, read this first.


This is theoretical though, since rotating assembly losses are not included. This would be the best case scenario, EVER. :)

[Vinnie]

Vinnie, read this first.

I saw that. I was wondering if not stock, how it would compare to one.

I thought it may also have been done on a regular dyno. Would be interesting how the 2 numbers compare..

:cheers::cheers:

[fyremanbil]

I've done it on a dyno waaay back in the day when it was first available thru Superflow. We drilled a small hole and installed it in the deck area of a BB Chevy just above the ring travel. The loss to friction was not much in % output, but I can't remember the exact %. Those sensors were much more expensive back then, and we crushed 2 of them in testing:eek:

[STV_Keith]

That 260 is BONE stock, down to stock exhaust adapter, reeds, etc. Probably 140hrs on it when that was recorded.

[jimmybrie]

Very interesting... what is the sample rate of your equipement?

Who makes those sensors, just curious is it especially made for this application?

Did you made the software that processes data?

Nice machinning:thumbsup: