Originally Posted by fast68plymouth
Quote
Have you found the Moroso slide rule to be fairly accurate compared to actual dyno results?


I have. But you have to look at the whole situation....... da, how good the car is, head wind or not, track prep, etc....... and then there is always the question about how accurate the dyno numbers are.
In decent(but not killer) air, a good stock or super stock car will outrun the Moroso chart..... and often by quite a bit.
(Using the Moroso chart, my friends Stocker has run enough speed show the hp to be 108% of what the STP power was on the dyno. Even racing in Vegas the car shows within 5% of the STP power, and that’s a track with an altitude adjustment factor).

A mediocre street/strip car may have a hard time showing within 15% of the dyno numbers, and a typical half way decent bracket car should be able to get within 10%.
And a car that’s not set up for the track at all might show numbers that are 20-25% low.

If you look at the post by gregsdart about his last track outing with his new fresh-off-the -dyno combo....... he is within 10%.
Greg’s 154 speed shows 845hp, motor made 920 on the dyno....... STP corrected.
8.2% correction.
It just happens to work out that Greg’s uncorrected dyno numbers are very close to the what the on track numbers show.
After all, you’re not racing in corrected air.

Plugging Wades results into the Wallace calculator to correct the run to zero DA shows 9.36@143.
143@3200 shows 720hp on the Moroso chart, which still works out to over a 16% correction to get back to 860hp.

However, if you take the fuel flow and bsfc numbers from Wades dyno sheet, and calculate the uncorrected HP, you come up with a number that’s just under 700hp.
Much closer to what the in car performance was for his last outing.




Thanks for the reply. I've never personally had a dyno vs. moroso chart comparison but a couple of friends cars with dyno'd engines seem way off compared to the moroso chart on the mph.(even accounting for corrections as you've mentioned above) I attribute that to the latest fad of loosey-goosey converters.
the part I've used on the moroso chart as a guide is the mph vs e.t. I work on which ever is the weaker of the two and once you get them in line, it seems that's about as quick/fast as that particular combo is going to go.


'86 Maple Grove KOS Mopar low qualifier......true street legal with no power adders.

NOS-used when losing since 1940.