Analyze my dyno #s!!

0hOneGT · 05-10-2009, 06:45 AM

Got my car on the dyno for the first time ever today, mainly just to get baseline numbers as I don't really have much in the way of performance at this point. Just thought i'd throw the numbers up here to see what you guys think, as i'm not really all that knowledgable about interpreting the results. Anyways, here's the info:
03 Mach 1, mods- JLT intake, weld-in flowmasters, and a sniper tune.

262 rwhp, 276 ft/lbs torque

How do this numbers look? To me they seem a little low based on other Mach 1s that i've seen, which have seemed to be in the high 260/low 270 rwhp range stock. I did feel as though my car wasn't running to it's full potential. One thing that came to mind was that today was a pretty hot day, with the dyno printout reading 86 degrees with 20% humidity (don't know if that makes a huge difference or not) and my car definately was not as cool as it could have been prior to the runs.

Also, my A/F ratio was about 15 from 3,000 to 3,500 rpm, then dropped and hovered slightly above 13 all the way to 6,500. Not really sure what that indicates, so if some of the tuning gurus on here could enlighten me, that'd be great.

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teej281 · 05-10-2009, 09:38 AM

Well from my experience, your numbers are a tad bit low for a 4v. But that is probably due to the temperature when you had it done. The air/fuel ratio is way lean. You are goign to want to richen the mix down to when youre wot you are at about 12.5-12.8ish from what ive been told. Now that is kinda conservative i guess but i really wouldnt risk much more than that because for the very little power you will gain, you could hurt something by being too lean. And there is a point where you are too lean and wont make good power. If i were you, longtube headers, gears, and a tune would probably help you out tremendously.

01GT4.6 · 05-10-2009, 09:52 AM

stoich is 14.6:1 but when the loud pedal is mashed you'll want to around 13:1

cliffyk · 05-10-2009, 02:23 PM

Did they use a tail-pipe mounted AFR sensor? It is not unusual for the lower RPM readings from a tp-sniffer to be a bit lean because of free-air being draw into the tail-pipe in between exhaust pulses.

The 13:1 higher revs is where many like it. Here in Florida, because of the heat, I head for 12.5:1 as it burns a bit cooler and let's me use a bit more spark advance.

I also run a 180° thermostat which keeps the ECT rock steady at 185° to 190° and allows a bit more timing headroom as well.

0hOneGT · 05-10-2009, 03:56 PM

They did use a tail-pipe mounted AFR. Should I still aim for richer a/f? Especially in lower rpm.

cliffyk · 05-10-2009, 04:06 PM

Are you using Special Forces or Commando?

The reason the lower revs were 15:1 (they were probably 14.7:1) is because you were likely still in closed loop mode. There OEM tume imposes is a significant delay, and holds the engine in closed loop mode until load, TPS, and rpm reach pretty high levels--Special Forces does what it can do safely to make this better, but there's still quite a bit of room for improvement if you know what to change and have a low-level tuning tool like Commando with which to make changes.

With a wideband sensor you can see immediately when the PCM goes to open loop mode, that's what happened in your dyno run when the AFR suddenly got richer after 3500 RPM.

If you are using Special Forces let me know, and let me know what selections you have made in setting things up--I can provide some SF tips...

Intervention · 05-10-2009, 04:08 PM

Usually with a NA engine, you want to shoot for anywhere from 12.8-13.2. My tuner usually lets it run SLIGHTLY rich at the very top for a bit of added safety and to allow for even more revs if I decide to raise the limit.

You can see how crazy rich my car was at stock.

At the bottom right where it lists the temp/humidity it should list "SAE x.xx" You can see that on my recent run (309) it was at SAE of 1.00 meaning that both the uncorrected and the corrected numbers were very close to 309whp. My stock run (258) was at .97. This means that the computer took off 3% of the uncorrected numbers. So, the car actually made 265 that day, but the computer put it to SAE corrected.

SAE corrected is simply a way to correct for temperature and humidity changes and therefore give the dyno figures an "even playing field"

Any way you could scan the graph in?

cliffyk · 05-10-2009, 05:41 PM

If it was a Dynojet dynamometer get the .drf file from the dyno shop--you can then download the WinPEP program from Dynojet and graph and compare your own files to your heart's content.

That's how I graphed mine...

0hOneGT · 05-10-2009, 06:22 PM

Quote:

Originally Posted by cliffyk

Are you using Special Forces or Commando?

The reason the lower revs were 15:1 (they were probably 14.7:1) is because you were likely still in closed loop mode. There OEM tume imposes is a significant delay, and holds the engine in closed loop mode until load, TPS, and rpm reach pretty high levels--Special Forces does what it can do safely to make this better, but there's still quite a bit of room for improvement if you know what to change and have a low-level tuning tool like Commando with which to make changes.

With a wideband sensor you can see immediately when the PCM goes to open loop mode, that's what happened in your dyno run when the AFR suddenly got richer after 3500 RPM.

If you are using Special Forces let me know, and let me know what selections you have made in setting things up--I can provide some SF tips...

I'm using the special forces software, the only selections i've made so far are for the cold air intake and catback. I've not touched the AFR modifier at all as of yet. Tips would be appreciated

0hOneGT · 05-10-2009, 06:26 PM

Quote:

Originally Posted by Intervention

[IMG]
Usually with a NA engine, you want to shoot for anywhere from 12.8-13.2. My tuner usually lets it run SLIGHTLY rich at the very top for a bit of added safety and to allow for even more revs if I decide to raise the limit.

You can see how crazy rich my car was at stock.

At the bottom right where it lists the temp/humidity it should list "SAE x.xx" You can see that on my recent run (309) it was at SAE of 1.00 meaning that both the uncorrected and the corrected numbers were very close to 309whp. My stock run (258) was at .97. This means that the computer took off 3% of the uncorrected numbers. So, the car actually made 265 that day, but the computer put it to SAE corrected.

SAE corrected is simply a way to correct for temperature and humidity changes and therefore give the dyno figures an "even playing field"

Any way you could scan the graph in?

SAE numbers on both of my runs were .99, so there is some type of correction to be made there? Don't have a scanner at the moment, i'll see if I can get a clear pic of the sheet later on tonight.