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cloudmaster_321 03-26-2009 10:00 PM

dyno result questions......
 
I was looking at my print out and saw in the comments "leaned out from 5200 on up." The last column of the dyno report has
a/f 1
1ambda

I know it means air/fuel, but don't know what the rest means. Anyways, here's the a/f from 4500 up.

4500 - 1341 449.9 hp
4600 - 1329 453.4 hp
4700 - 1314 457.2 hp
4800 - 1298 459.6 hp
4900 - 1291 461.1 hp
5000 - 1290 463.1 hp
5100 - 1286 462.9 hp
5200 - 1280 463.5 hp
5300 - 1262 461.1 hp
5400 - 1241 457.7 hp
5500 - 1217 446.1 hp

I'm not sure how low is border line too lean and what isn't. Any help with this, i'd like to know what rpm's to tune the prop for.

800XCR 03-27-2009 07:56 AM

You posted exhaust temps

GLH 03-27-2009 08:04 AM

Air fuel should be a number around 11 preferably under or above if you want more power and blowing it up.... like I always do!

Rookie 03-27-2009 09:30 AM

It looks like it went Fat the more you spun it.
And they do look like EGT #'s.

cloudmaster_321 03-27-2009 10:01 AM

hmmm, ok, i'll have to take another look at the sheet when i get home. I don't remember seeing any numbers like you guys are mentioning. Is that something that is not usually on the dyno report?

Rookie 03-27-2009 12:02 PM

I was referring to the 1341-1217.

jeff1000man 03-27-2009 12:09 PM


Originally Posted by cloudmaster_321 (Post 2830078)
I was looking at my print out and saw in the comments "leaned out from 5200 on up." The last column of the dyno report has
a/f 1
1ambda

I know it means air/fuel, but don't know what the rest means. Anyways, here's the a/f from 4500 up.

4500 - 1341 449.9 hp
4600 - 1329 453.4 hp
4700 - 1314 457.2 hp
4800 - 1298 459.6 hp
4900 - 1291 461.1 hp
5000 - 1290 463.1 hp
5100 - 1286 462.9 hp
5200 - 1280 463.5 hp
5300 - 1262 461.1 hp
5400 - 1241 457.7 hp
5500 - 1217 446.1 hp

I'm not sure how low is border line too lean and what isn't. Any help with this, i'd like to know what rpm's to tune the prop for.

Without even getting to the A/F ratio, if the engine stops making power at 5000, IMO it really doesn't make any sense to prop it any higher than that.

cloudmaster_321 03-27-2009 01:35 PM

Looking at stricly hp numbers, i'd rather spin at 5200. But if it's lean like what was written in, might not be a good idea. The only other thing i remember seeing that had to do with fuel was psi. And it said something like .4 pretty much the whole way, then .3 at the end......

jeff1000man 03-27-2009 02:46 PM

If you prop it at 5000 with a full gas tank, then it will spin up a little higher later in the day when you ar running low. If you propr it up over 5K then you will just be un necessarily reving the engine when you are running lighter.

GPM 03-27-2009 03:23 PM


Originally Posted by cloudmaster_321 (Post 2830482)
Looking at stricly hp numbers, i'd rather spin at 5200. But if it's lean like what was written in, might not be a good idea. The only other thing i remember seeing that had to do with fuel was psi. And it said something like .4 pretty much the whole way, then .3 at the end......

They may be the BSFC numbers

cloudmaster_321 03-27-2009 06:40 PM

Took a look at the sheet here, just says fuel psi. Nothing about air fuel ratio...

hallj 03-27-2009 07:25 PM

Throw a decimal point between the first two numbers and you have A/F...............Possibly.

cloudmaster_321 03-27-2009 08:33 PM

:readinghelp:

No idea.......

hallj 03-28-2009 05:23 PM

Does the sheet have the torque readings?

Does the torque follow the suspected a/f number.

To a point torque will increase as the a/f decreases numerically.

with a gasoline N/A motor you will usually see 12.8 a/f produce the most torque at a given load range.

Jeff


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