Dyno Question

krtillison · #1 Thu, July 21st, 2011, 08:24 PM

‪Kyle's Powerstroke on the chasis dyno 3‬&rlm; - YouTube

So here is one of the 5 pulls. As it says 275 hp 515tq with evolution on 100 hp setting. Is this about what everyone would expect to be, higher, or lower? Any input would be great. Thanks. Also we tried using the inductive clamp around the wire but RPM would not stay steady. It would read around 700 then jump to 2000. Any thoughts?
P.S. Outside temp was 95, humidity was 43%, elevation 974 feet

***Power Hungry*** · #2 Thu, July 21st, 2011, 10:33 PM

DynoJets are really twitchy with the inductive pickups. Some trucks have no problem, others get all jittery like you were seeing. Our DynoJet at Edge was the same way. Not much you can do except switch to an optical sensor and run off the crank.

As for the run itself, 275/515 is a little lower than what I'd expect to see, but given the heat and humidity it's not all that bad. However, looking at the run itself (basically, the length of time the run took) I'd venture to say that the engine wasn't loaded enough to make peak boost and that probably cost you some horsepower. You were definitely making fuel but the turbo didn't seem to catch up. When we'd run on DynoJets, we would brake a little bit to give the turbo a chance to spool up and then let off the brake and start the run. This would give is the best numbers. Also, what gear was the run done in? The reason I ask is that the torque numbers seem a bit low for the HP. He should have been in 4th on a 5 speed or 5th on a 6 Speed. This gives a 1:1 ratio through the trans and helps reduce parasitic losses.

BTW - What was the HP on the stock setting?

Thanks.

krtillison · #3 Fri, July 22nd, 2011, 07:19 PM

The truck was in 4th gear and on stock it made 222/403. Thanks for the feedback too, and for answering my questions.

krtillison · #4 Fri, July 22nd, 2011, 07:35 PM

...and by 4th i guess it's technically 5th even though it's 4th on the knob. Im just bouncing ideas off of you, but I when i went to the track with it the attitude monitor would back down 20%. It never tried to back me down on the dyno, so I would think that would confirm your suspicions about the dyno not loading the engine fully.

***Power Hungry*** · #5 Fri, July 22nd, 2011, 08:04 PM

What did you happen to run at the track?

krtillison · #6 Fri, July 22nd, 2011, 09:22 PM

16.7@87 mph

***Power Hungry*** · #7 Fri, July 22nd, 2011, 11:18 PM

At 87 MPH in a 7000 pound truck (approximate, incl. driver) you would be making an estimated 313 HP, which is about what I'd expect to see from a decent running Super Duty.