80/20 Rule
So if there is 5 hp gain on a 250 hp engine, that's roughly 2%.
5 hp on 250 hp is pretty doable with a jet change because that is measurable with some degree of confidence on a chassis dyno. It's also measureable as mph at the track although somewhat more subtle depending conditions and consistancy.
I'm not sure about 20% but I will go with 5-10% of WOT power is often left on the table after spending the time and money with engine mods or bolt on.
(If its off more than that, it probably doesn't run well at all.)
In this post I pointed out how much power can be gained by testing jet changes. Not just peak, either.
These runs were made on the same day on the same chassis dyno.
70,74 to 66, 72
Lets call it 11 hp gain on 267 or 4% improvement in power for 5 runs.
or we could say its a change of 8% in fueling. LOL
Was there much more in there? Not alot. Runs 13 and 14 were very similar and we can see the main air bleed relationship to the jets was beginning to get lost. So at that point it gets into a bit more time and knowledge. I'll actually be reinstalling that carb this summer, so yea I'm in that 20% or 5%
When this came up in the other thread which has a title about "performance" I defined how much is left on the table in percentage of maximum.
So if there is 5 hp gain on a 250 hp engine, that's roughly 2%.
5 hp on 250 hp is pretty doable with a jet change because that is measurable with some degree of confidence on a chassis dyno. It's also measureable as mph at the track although somewhat more subtle depending conditions and consistancy.
I'm not sure about 20% but I will go with 5-10% of WOT power is often left on the table after spending the time and money with engine mods or bolt on.
(If its off more than that, it probably doesn't run well at all.)
In this post I pointed out how much power can be gained by testing jet changes. Not just peak, either.
These runs were made on the same day on the same chassis dyno.
70,74 to 66, 72
Lets call it 11 hp gain on 267 or 4% improvement in power for 5 runs.
or we could say its a change of 8% in fueling. LOL
Was there much more in there? Not alot. Runs 13 and 14 were very similar and we can see the main air bleed relationship to the jets was beginning to get lost. So at that point it gets into a bit more time and knowledge. I'll actually be reinstalling that carb this summer, so yea I'm in that 20% or 5%
