Scangauge II horsepower

[BadBrew]

I just received my new scangauge II, after doing the calibration for fuel, I ran it a few hundred KMs then I discovered the horsepower x-gauge.I ran my car at 154HP @6000rpm on my '05 base automatic Vibe. At first, I was touching myself because I thought this weekend wax was giving me all those new horsies but then I remembered that this car was 130HP and it must be an error. Anyone else had some experience with this tool?

[Kamikaze]

I have a SGII w/Xgauge but never knew there was a HP thing... hmmm. tell me more... did you have to enter anything in to get the x gauge or was it already available?

[BadBrew]

check this out http://www.scangauge.com/support/horsepower.shtml

[Kamikaze]

sweet, I haven't looked there in quite a while... I'll have to try this and see what happens.Of course the accuracy of this isn't going to be that great, but still fun none the less.

[Sublimewind]

So, how is this supposed to measure HP?? I've got a G-Tech and it uses accelerometers to measure.... You MUST enter the vehicle weight for it to even resemble accuracy... Even then it's not THAT accurate..

[BadBrew]

You can also calculate the HP with this according to http://www.howstuffworks.com/question622.htm (Torque x Engine speed) / 5,252 = HorsepowerThere's no place to enter the vehicle weight but it asks for the engine size I get 134.801 ft.lbs of torque

[Old Tele man]

...unfortunately, that equation assumes you know the engines' torque value at any given rpm, which typically is not true. Usually, the only two "known" values are: HP@RPM and TORQUE@RPM, and the two RPM-values are different, with RPM-torque usually occuring at about 2/3's of RPM-hp (for 4 cylinder engines)....however, that equation does enable you to calculate the TORQUE at the HP-rpm and conversely the HP at the TORQUE-rpm, then you can roughly "guess-ta-mate" the engine's TORQUE values at any RPM between the two initial RPMs (above) by simply assuming a LINEAR interpolation.For example, the 1.8L 2ZR-FE numbers are 132 hp @ 6000 rpm / 128 lb.ft @ 4400 rpm. So, backsolving we can determine the torque at 6000 rpm and the hp at 4400 rpm:6000 rpm = 132 hp / 116 lb.ft4400 rpm = 107 hp / 128 lb.ft...so, roughly, the torque value falls off about 7.5 lb.ft for every 1000 rpm between 4400 rpm (torque peak) and 6000 rpm (hp peak)....unfortunately, BELOW 4400 rpm, it's a guessing game, because some engines (long-stroke) have gradual torques increase from idle up to the torque peak, others (short-stroke) have a low torque at idle and increase rapidly toward the torque peak. So, without having seen the actual engine-curves for the 2ZR-FE engine, we can only guess that the torque rate-of-rise from idle is roughly the same as its fall-off above the torque peak (remember, we're only guess-ti-mating here), or about -7.5 lb.ft/1000 rpm.