Dyno Testing

allansieben

allansieben

X1/9 Time
Hey! I had an opportunity to have my X tested on a dynometer today! The BC Vintage Race Car Club was holding a dyno event at a local mechanical shop hear in Abbotsford. For 30 bucks, I got to run my car on the dyno and with surprising results!! According to my owners manual, my car rates at 75 HP SAE. The Dyno measured 80 HP at the wheels, and 85 ft lbs of torque! Not bad for a 30 year old car I'd say! And with a stock FI engine to boot!

Anyone else ever have similar or better results? Just goes to show ya how well built these engines really are.
Allan
 
Hmmmm

Allan,

Are you certain that the numbers don't include a correction factor to estimate flywheel power from the dyno readings?

///Mike
 
Allan,

Power output can be checked by an engine dyno or a chassis dyno (rolling road), which is how your car was apparently tested. Due to driveline losses, power numbers generated on a chassis dyno will be quite a bit lower than those generated on an engine dyno. In order to make for easier comparison to the more commonly seen flywheel power rating, output numbers generated on a rolling road are often multiplied by a correction factor.

The figures you quoted would be quite good if they were measurements of flywheel power output, but they'd be stupendous if they were the raw chassis dyno numbers. In short, I was asking if the figures you quoted were flywheel power output (arrived at through a correction factor) or wheel power output.

Regards,

///Mike
 
Do you have the dyno run chart? The chart with your calibration weight is key. The numbers look high but who knows, lots of mysterious numbers on this forum. Scan the chart and post it. Looking at HP vs rpm. Also would help to know the brand of dyno, dynojet, dynapack, etc. That also makes a huge difference.
 
Technical

According to the club, those numbers are measured at the wheels.And yes, I will scan and post the document that came with the test. Allan
 
Good stuff and thanks. Very interesting, Mustang dynos are very conservative, i.e. if you measure 80whp you are really like 89 to 92 on a dynojet. So your numbers say you really have something there. The rpm and HP all looks good. For a stock FI engine you are still breathing at 6500 rpm but normally the stock system flow is maxed out at 5500ish rpm (mass air flow flap opened all the way). It all looks legit and good though by the chart. With that said however, I may have read this wrong but I understand your engine is completely stock and if this is true then you are roughly producing 90ish hp at the crank, 20% over stock with no mods (est 17% tranny loss). That seems odd, the engine still breathing beyond the 5500rpm point as well and the afr ranging from 13.2 to 14.9 does not add up to me. Can't refute data, data is king, but I am sure you can appreciate my observations. Next I build a motor I am going to send it to you to "bless" because it looks as if you have that magic touch :). Thanks for the data.
 
Thanks for the chart. The power figures are quoted as "engine power" so I'm guessing some sort of correction factor was built in, although I don't see mention of one.

Surprising that the engine keeps pulling that high. My stock FI motor is nosing over around 5k RPM. Even if a correction factor was introduced it still appears to be a strong running 1500. Is it really dead stock? Right down to having a catalytic converter?

Cheers,

///Mike
 
Cat Was Pulled Years Ago

Oops! Sorry, forgot to mention that the cat was pulled out, but that was all. Rest is bone stock. Allan
 
Figures are listed as "engine power" in the summary at the bottom of the sheet... so there must be some mathematical correction factor... which would assume a 1:1 fourth gear ratio too... which an x19 doesn't have... even things like tyre size can affect the rolling road figure.

All the same 78hp at the engine is about right for a stock FI engine, as is the 82lb/ft torque figure.

SteveC
 
In the past, I've read an article on how two 'identical' engines coming off of a production line were like night and day when compared to each other. In this case, the vehicle in the (R&T ?) article was a Jeep Cherokee. While I don't have an quantifiable data, I do have a few solid visual observations, so I can say they're may be something to his hot 'stock' engine. When my X had 20K miles on it, in the dry, I could occasionally get the rear tire (tires) to break loose on a 1st-2nd shift. My engine would also pull strongly into the mid 7000 RPM range. The same engine, now with many more miles on it, is a sluggish dog. It runs out of steam at about 5K RPM, even after a rebuild, and a few bottom end take-aparts after the fact to see what was/is going on. Weakened valve springs? Worn cam lobes? Clogged fuel injectors, which I don't buy into too much? Some other mechanism accounting for the lower power? I don't know, but it's just not the same. It's still quite drivable, with excellent mileage and emissions, but I do miss that high RPM part. Anyone want to speculate?
 
I agree that stock motors can vary greatly in power. My brother and I raced Yamaha RD 350 bikes in the stock class and mine was noticeably quicker and smoother than his even though they were factory stock. Probably explains why Spec Miata engine builders will go through boxes of pistons trying to find a perfectly matched set of pistons.

According to 124 spider folklore, removing the original style cat was worth 5 hp and if true I suspect similar results were true for Xs.

A nice event for Freakout or any other Fiat gettogether would be dyno runs. Lots of folks have trailerable dynos.
 
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