Quote:
Originally Posted by Steve C.
"I thought we decided comparing results from different dynos was “iffy” at best. Maybe I misunderstood."
Murf
In addition to the potential different results from different engine dynos, how about comparing actual engine dyno results from a computer simulation program.
Example, I know on the Performance Trends Engine Analyzer v3.2 program on the input you can use either "Standard" or "SAE" Dyno settings for the running conditions/weather. If using the Standard setting it will give you much higher numbers. Using a Performance Trends program I also found the results can suggest peak power at a higher rpm than the actual engine dyno results. Actual intake manifold runner lengths and runner volumes for input are necessary, no guesses. Same with cylinder head flow with input at the proper valve lift as required in the instructions. And actual carb cfm, not what they might be rated at. Etc, etc. NO GUESSES ! You need to know the specs of your engine combination for accurate results.
Now the question are the results from a computer or did the OP have the engine tested on a actual engine dyno.
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I think comparing dyno results from one engine to another is simply bragging rights and meaningless - especially when comparing one manufacturer engine to another.
Are all dyno's identical enough to provide exacting results if I were to span the country spot testing an assortment of dyno's with the same engine? Does each dyno operator use the exact same procedures as the "other" guy. Are altitude, outside temperatures, and humidity always taken into consideration and each dyno session hermetically controlled to have the exact same room temp, air pressure, and humidity percentage?
So dyno number comparisons are meaningless from one dyno to the other, but may be meaningful to the specific engine being dyno'd on that specific dyno with any/all adjustments being made to that engine while being dyno'd, or being dyno'd after any parts adjustments, changes, or modifications. Otherwise, comparing dyno spec sheets from one dyno to another, one engine to another, or one location in the country to another is meaningless.
Dyno results can also be meaningless in that the tune can be completely different once installed in the actual car - where the rubber meets the road. So all that was fine tuned on the dyno to get those stellar bragging numbers no longer applies.
It is real easy to dissect one guy's build and then throw out what he should have or could have done as if he made a mistake.......or is an idiot - this or that head, this or that cam, this or that intake, this or that carb. If I use iron heads and provide my dyno numbers, don't insult me and say I should have used KRE heads and that would have really woken up the engine. Why not simply suggest a 6-71 blower while at it because that would really wake up the engine as well. For some, it is budget, for others it may be a step in getting to the bigger build, and for others, maybe that is all they were looking for from there build/car. Not EVERYONE needs or wants that easy magic "500HP" that is so frivolously thrown about here. I can't believe how I was ever satisfied with the tire smoking results of the factory provided 400CI in any of the GTO's and Pontiacs I have owned. What was I thinking?
Many of these posts always seem to go sour and turn into a peeing contest and not focused on the OP's original post. Why?
Don't give me the "well that's how we do it here," or "you need to not be so sensitive," or " if you don't like it find another forum" response. I can handle all this crap just fine and some of my posts are deleted for throwing comments back that are considered too harsh or insulting. Yet, some of these posts, although not directly attacking, are an insult, rather than support, guidance, or suggestion. Know when to add a worthy comment and know when to zip it up.
I have a set of Speedmaster heads and I think the point of this post was about those heads, on the OP's engine, and their results, ie, another engine build we can use as reference - I'm interested in that, and that alone, not what other heads or cam or intake I should have used, and not what other dyno sheets reveal.