80/20 Rule
I'll throw some numbers on the BUILD VS. the TUNING.
The hp and AFR gains I posted earlier in this thread were on a new engine.
I paid $5k for the engine and paid a shop to install it along with some other work. I'll be generous and say the removal and install was $1000. (They didn't actually do the swap, but they did remove the old engine and drop the new one in place - loosely bolted to the mounts and trans. Then I had it flatbedded to my garage where I finished it. )
The cost of the dyno runs that day was around $300. I'd have to dig through a file for the actual, but it was at least $250.
Gains.
> Engine with new cam. Untuned about 17 hp gain peak, and an engine with core plugs that weren't rusting out. We can consider the price difference between just pulling the engine and installing new plugs as the baseline or not. So lets say $5000 for around 20 hp.
> Dyno session consisting of 6 runs with customer (me) making the jet changes. Call it $350 for 10 hp, plus the advantages of cleaner running plugs etc etc.
On the other hand I've made changes that cost me money and cost throttle response, torque, and horsepower. What a bargain! But it happens all the time. The advantage of not testing and tuning is not having to face that reality.
I think the rule 273 is thinking of is the one relating to cost vs performance.
I first encountered this concept in a review of the F20 fighter jet program. I don't recall the stated 'rule' or ratio of cost to performance but thought it was like 90/10 99/1. But I agree with 273 that its probably more a figure of speach rather than some actual rule. My recollection with the fighter jet was the concept was the last 1% of performance drove the costs (and maintanence requirements) through the roof.
Quick search on the internet finds this from Wayback Machine
and these claims:
Among its Teen Series contemporaries, the F-20 was offered as a low-cost option; cost-wise it was estimated in 1983 that the unit fly-away cost of the F-20 (based on a 150-unit buy) was $10.7 million, compared to the F-16/79 at $11 million and the F-16A at $12.4 million. Unit life-cycle costs for the F-20 estimated as high as 40–50% lower than for the F-16. Another estimate of the F-20 found it less expensive than other designs like the $30 million F-15 Eagle,[33] or $15 million F-16 Fighting Falcon.[34] The F-20 was projected to consume 53% less fuel, to require 52% less maintenance manpower, to have 63% lower operating and maintenance costs and to be four times more reliable than average front-line designs of the era.
from Northrop F-20 Tigershark - Wikipedia
I'll throw some numbers on the BUILD VS. the TUNING.
The hp and AFR gains I posted earlier in this thread were on a new engine.
I paid $5k for the engine and paid a shop to install it along with some other work. I'll be generous and say the removal and install was $1000. (They didn't actually do the swap, but they did remove the old engine and drop the new one in place - loosely bolted to the mounts and trans. Then I had it flatbedded to my garage where I finished it. )
The cost of the dyno runs that day was around $300. I'd have to dig through a file for the actual, but it was at least $250.
Gains.
> Engine with new cam. Untuned about 17 hp gain peak, and an engine with core plugs that weren't rusting out. We can consider the price difference between just pulling the engine and installing new plugs as the baseline or not. So lets say $5000 for around 20 hp.
> Dyno session consisting of 6 runs with customer (me) making the jet changes. Call it $350 for 10 hp, plus the advantages of cleaner running plugs etc etc.
On the other hand I've made changes that cost me money and cost throttle response, torque, and horsepower. What a bargain! But it happens all the time. The advantage of not testing and tuning is not having to face that reality.
Amen!
But the magazines, you tubers and 'experts' everywhere make it all seem easy to 'just' bolt-on [fill in the items] of their favorite sponsor or whatever.
That makes sense.
I think the rule 273 is thinking of is the one relating to cost vs performance.
I first encountered this concept in a review of the F20 fighter jet program. I don't recall the stated 'rule' or ratio of cost to performance but thought it was like 90/10 99/1. But I agree with 273 that its probably more a figure of speach rather than some actual rule. My recollection with the fighter jet was the concept was the last 1% of performance drove the costs (and maintanence requirements) through the roof.
Quick search on the internet finds this from Wayback Machine
and these claims:
Among its Teen Series contemporaries, the F-20 was offered as a low-cost option; cost-wise it was estimated in 1983 that the unit fly-away cost of the F-20 (based on a 150-unit buy) was $10.7 million, compared to the F-16/79 at $11 million and the F-16A at $12.4 million. Unit life-cycle costs for the F-20 estimated as high as 40–50% lower than for the F-16. Another estimate of the F-20 found it less expensive than other designs like the $30 million F-15 Eagle,[33] or $15 million F-16 Fighting Falcon.[34] The F-20 was projected to consume 53% less fuel, to require 52% less maintenance manpower, to have 63% lower operating and maintenance costs and to be four times more reliable than average front-line designs of the era.
from Northrop F-20 Tigershark - Wikipedia
