rubyredponycar
Active Member
I would take it for a dyno myself but mines already been removed. 🫨That would be interesting!
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I would take it for a dyno myself but mines already been removed. 🫨That would be interesting!
You're right, it's not linear.I assume you arent referring to me. I didn't say anything about hp. The long term fuel trims were +20%. Fact. Theres at least 2 of us that have seen that.
I dont think anyone would ever assume there is a linear relationship between intake tube size and HP on an NA Coyote
That’s what I’ve been saying!!!How is this thread 7 pages now? Pretty simple remove it to get your 10 CRANK hp back (keep the sleeve in will ya?). end of story.![]()
Obviously!You're right, it's not linear.
Let's do some math then:
Let's calculate the CFM airflow for both the 90mm and 98mm diameter tubes, assuming they are both 24" long and have an FPM value of 1,000.
For the 90mm diameter tube:
First, we need to calculate the cross-sectional area of the tube:
Area = πr^2
Since the diameter of the tube is 90mm, the radius (r) is half of that, which is 45mm.
Area = π(45 mm)^2
Area ≈ 6,361 mm²
Now, we'll convert the area from mm² to in² by dividing it by 645.16 (since 1 in² = 645.16 mm²):
Area ≈ 6,361 mm² / 645.16
Area ≈ 9.87 in²
Now, let's calculate the CFM:
CFM = FPM × Area
CFM = 1,000 FPM × 9.87 in²
CFM ≈ 9,870 ft³/min
For the 98mm diameter tube:
First, we need to calculate the cross-sectional area of the tube:
Area = πr^2
Since the diameter of the tube is 98mm, the radius (r) is half of that, which is 49mm.
Area = π(49 mm)^2
Area ≈ 7,547 mm²
Now, we'll convert the area from mm² to in²:
Area ≈ 7,547 mm² / 645.16
Area ≈ 11.72 in²
Now, let's calculate the CFM:
CFM = FPM × Area
CFM = 1,000 FPM × 11.72 in²
CFM ≈ 11,720 ft³/min
Difference in CFM airflow between the tubes:
Now that we've calculated the CFM airflow for both tubes, we can find the difference in CFM airflow between them:
Difference = CFM (98mm tube) - CFM (90mm tube)
Difference = 11,720 ft³/min - 9,870 ft³/min
Difference ≈ 1,850 ft³/min
So, the difference in CFM airflow between a 90mm diameter tube and a 98mm diameter tube (both 24" long) is approximately 1,850 ft³/min, assuming an FPM value of 1,000 for both tubes.
So, if we assume that the CFM values we calculated earlier for the 90mm and 98mm tubes were based on a pressure differential of 10" of water, we can use the following equation to calculate the new CFM values at 28" of water:
CFM at 28" of water = CFM at 10" of water × √(28/10)
For the 90mm tube:
CFM at 28" of water = 9,870 ft³/min × √(28/10)
CFM at 28" of water ≈ 17,570 ft³/min
For the 98mm tube:
CFM at 28" of water = 11,720 ft³/min × √(28/10)
CFM at 28" of water ≈ 20,940 ft³/min
Generally, a naturally aspirated engine produces approximately 10-15 horsepower for every 100 CFM of airflow. So, using this rule of thumb, an extra 1850 CFM could potentially result in an additional 185-277 horsepower (calculated as 1850 CFM ÷ 100 CFM × 10-15 HP).
Now we take those horsepower figures and divide by the 28" of water standard.
185/28 = 6.6 hp to 9.9 hp.
^^ that's what your gaining. I'm too lazy to calculate just the choke point.
Using the scientific method and double blind studies, you can easily validate what threshold of measurable differences a normal human can accurately feel. I don't know if scientists have wasted their time with this particular field yet (but probably), but anecdotes I've seen over the years confirm pretty well that a 10 hp difference in a 470-hp car is completely invisible to your ass dyno. Not to mention common sense. I'll expand a lil more below if you care.Help us understand how any person can absolutely understand what another can or cannot feel. I’d love to see that science.
And while we’re at it, what tactile experience is not “in your head”? I’d postulate that human nature dictates that our perceptions are in fact our realities. Does that mean they aren’t real?
Dyno results are the closest thing to empirical facts that are pertinent to this discussion, and likely carry the fewest variables. The rest is a combination of unprovable conjecture and opinion.
Placebo effect, brotato.Except if it’s in his head, his mind does work that way…
I'm pretty certain it has less to do with the weight and more to do with the starting HP. You might feel 10 hp in a Miata because you're starting with (depending on the generation) 100-180 hp.But mostly because it weighs 4000 lbs. 10 HP difference can be felt in a Miata
I'm a bit confused by what you're saying. If you're saying "you can feel more than 10hp" meaning you need more than a 10hp gain to feel the difference (20-25 hp in your examples), then I somewhat agree. But I still think you need quite a bit more than 4% to feel a difference. See my above reply.I don’t know man my butt dyno can tell if I’m running 87 or 93 octane. I think you can tell more than 10 hp gained. Also that’s wheel HP so the crank is going to feel much more lively. You will feel that especially in a manual. It’s about a 4% increase. Lots of guys get a 93 tune and can few the difference and might only be 25 HP over stock. E85 is more noticeable. If taking out an airflow restriction makes almost 20hp you will feel that.
Yes, that’s what I mean. For example while driving your in different conditions and air temps you could easily experience plus or minus 10 hp on a cool day vs a hot day or elevation. That probably won’t be noticeable except extreme cases.I'm a bit confused by what you're saying. If you're saying "you can feel more than 10hp" meaning you need more than a 10hp gain to feel the difference (20-25 hp in your examples), then I somewhat agree. But I still think you need quite a bit more than 4% to feel a difference. See my above reply.
EDIT: I would say by the time we're talking about 20+ hp to the wheels, it might start to become noticeable, at least depending on where those gains are, and how much the torque curve is impacted.
I have a thread asking about that specifically and basically got told “it’s not a problem” people run 7s through it, on and on.Meanwhile, everyone in here is driving around with the 2.25" factory exhaust neck down....
Yeah, I've been told the same thing by forum vendors, and on a stock or nearly stock application (or even mild boost) Im sure it's fine but no one is going to convince me that on 800+ wheel HP that some power isn't being given up. The factory resonator chokes down again at the outlet where it is welded to the exhaust pipes.I have a thread asking about that specifically and basically got told “it’s not a problem” people run 7s through it, on and on.
still hard to believe there is no dyno or track testing with before/after on that specifically
oh I'm sure there is. But it doesn't MATTER which is the point.no one is going to convince me that on 800+ wheel HP that some power isn't being given up
Plus Im the type that will lie awake in bed, and ponder how Im going to "fix" or "improve" any little silly thing. Not sure how many hours of sleep I have lost thinking about the exhaust neck down, but it ain't zero.oh I'm sure there is. But it doesn't MATTER which is the point.
You can spend unlimited funds/time and remove every little niggle theoretical restriction and net nothing useful. Life is about pursuing *USEFUL* improvements.
I got a tune on my GT almost as soon as it came off the showroom floor, not because there was an extra HP or dozen, I did it because the stock drivability SUCKED from the factory and I have low tolerance for STUPID interfering in my enjoyment of the act of driving. Ditto rip and replace suspension, bushings, etc. My F150 wasn't 90 days old before every damper was replaced with Bilstein and lowered 2/4 so it would corner and drive tolerably.
The trap may be ouf of my intake, haven't looked - I got this 2nd hand but given the prior owner is m6G member, likely. But if it isn't, I would remove it for no other reason than to stick a thumb in the eye of the EPA even if it COST me horsepower.
Masturbating to miniscule HP increases is the very definition of pointless exercise.
and some people are like that. In some cases it leads to useful/beneficial innovation. For the rest, there is Xanax.Plus Im the type that will lie awake in bed, and ponder how Im going to "fix" or "improve" any little silly thing. Not sure how many hours of sleep I have lost thinking about the exhaust neck down, but it ain't zero.
Power to weight ratio is the defining factor of perceived increase in power. If I have a 2000lb car with 100 hp, and a 4000 pound car with 200 HP (same Power to weight ratio) then by increasing the output of both engines by 10%, they net the same increase in power to weight, and therefore have the same perceived increase in power.I'm pretty certain it has less to do with the weight and more to do with the starting HP