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Calm down princess. I'm not the one that can't figure out why my buddy Billy Bob can outrun me when my telephone says I'm making a million horsepowers.
 

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Discussion Starter · #42 ·
Calm down princess. I'm not the one that can't figure out why my buddy Billy Bob can outrun me when my telephone says I'm making a million horsepowers.
Now this new piece of technology tells us horsepower. Get with the times old timer or just stop wasting oxygen. Why youre at it though learn to read. I have an idea of why the car doesnt mph as fast, which I said in the last response and about 4 other times in here.......TIRES..... fact is thats the opposite what everyone always says would give a higher mph. I know what power my car makes and on what tune and what pulley, but you probably wouldnt know anything about how tunes work, too much technology for you to comprehend right?
 

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What it's telling you is that the two cars aren't as similar as you think, you just fail to comprehend it. I don't think there's anything wrong with the tool, it's the user.

There is a whole lot more to it than power and weight. And that is why you can have two near identical appearing cars, yes one is substantially faster.
 

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Discussion Starter · #44 ·
What it's telling you is that the two cars aren't as similar as you think, you just fail to comprehend it. I don't think there's anything wrong with the tool, it's the user.

There is a whole lot more to it than power and weight. And that is why you can have two near identical appearing cars, yes one is substantially faster.
Im not failing to comprehend anything, youre failing to comprehend that basics of this thread. Im not asking for any fixes to my car or to help with the setup, Im simply asking what are some things that contribute to mph differences in cars that are similar in power and weight. I have my car figured out, my car is not a drag car, I just got done autocrossing it, then to a road race, then ran some 1/4 mile runs, its not a one trick pony and I know how to set it up, but I didnt have drag slicks on it, I had the street tires on, because I also drive the car a ton. Can you quote where I said there was something wrong with the tool? Can you also look back where I specifically said How does traction affect the MPH times? And everyone responded with the typical "usually cars that spin run out the back faster". Well my point is that not always the case. So Im going to put a slick on my car, set the suspension for the slick and then Ill see how much MPH I pick up while also improving the 60' time. I wont change the tune nor the power the car is making. The only thing that will change will be the tire and traction. But in theory by what everyone always says, I should slow down (Mph) once I hook up, That was the point.
 

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I don't buy into the spinning equals high mph idea. My car will run nearly the same mph weather it spins or dead hooks, and I've seen plenty of other examples.

However, lugging an engine down will hinder acceleration, and that will limit mph. If your car dead hooks and boggs, it will likely loose mph. If you find that happy medium, you will likely gain mph.

And that gets back as to how the right or wrong (for the application) clutch or converter can make or break a car.
 

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Venomv8 - look, I apologize. I was having a really bad day and didn't mean to take it out on random people on the internet.

I still think there is a little over reliance on technology sometimes. "Now this new piece of technology tells us horsepower" Well maybe and maybe not. It's just a number after all. I'm willing to bet there are going to be too many variables between 2 different cars to point to one single factor like tire spin to explain differing mph.
 

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He puts slicks on it and it will probably have a quicker ET but a slower MPH. Nothing slows a car down like having to drag a half flat slick down the track. I have seen many cases where having a Drag Radial on the car compared to a slick was a 2-3 mph gain based just on reduced rolling resistance. Drag Radial construction being one part of it and having more psi in the tire, 17-18 psi compared to a slick at 8-14 psi.
 

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Discussion Starter · #48 ·
He puts slicks on it and it will probably have a quicker ET but a slower MPH. Nothing slows a car down like having to drag a half flat slick down the track. I have seen many cases where having a Drag Radial on the car compared to a slick was a 2-3 mph gain based just on reduced rolling resistance. Drag Radial construction being one part of it and having more psi in the tire, 17-18 psi compared to a slick at 8-14 psi.
We will see, Im not going drag radial being a stick shift. The current tire on the car cant be pinned in first, has to be babied in second and then about half way through 2nd can finally be floored once wheel speed is up. Because of that I can leave on the 2 step either it just blows the tire off, so I have to basically let off the clutch and ease into it. The best 60' I could get was a 2.0 worst was 2.3 trying different things. With that being said regardless of lugging the tire down, I will be on a 15x10 light wheel that weighs half the street 18x12 rim on the car, and the tire on the car weighs 32lbs compared to 26 slick. We will see what happens with it, the thing Ill be fighting is the weather now, its way hotter right now than it was and the DA has been about double what it was on those runs.
 

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Discussion Starter · #49 ·
Venomv8 - look, I apologize. I was having a really bad day and didn't mean to take it out on random people on the internet.

I still think there is a little over reliance on technology sometimes. "Now this new piece of technology tells us horsepower" Well maybe and maybe not. It's just a number after all. I'm willing to bet there are going to be too many variables between 2 different cars to point to one single factor like tire spin to explain differing mph.
No worries here, thanks for the input
 

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Average operating rpm ( shift point fall back rpm ) and average power in those rpms. The two cars must be geared different and have different working rpms? Or shifted differently? The one with the most average usable power should run faster.
 
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lol at all the millenials that think their electronic devices have to be telling the truth. If you have 2 or more cars at the same dragstrip on the same day and one is much faster than the others then that just means it's much faster than the others. Doesn't matter if it's due to more power or a more efficient vehicle. Trying to figure these things out by "but, but, but my dragy says this!" won't get you far. Concentrate instead on what it would take to make yours faster than theirs.
Ok boomer
 

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Discussion Starter · #52 ·
Average operating rpm ( shift point fall back rpm ) and average power in those rpms. The two cars must be geared different and have different working rpms? Or shifted differently? The one with the most average usable power should run faster.
All good points, Im having a lapse in memory on the gear in the other car but I do know its different because its an 8.8 rear compared to my 9". I want to say the fox has a 3.73 where mine is a 3.89
 

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Discussion Starter · #54 ·
8.8 vs. 9in could be a big part of it.
Could you expand on that? I mean besides the obvious difference In gear ratio what differences would one rear to the other see. Say the gear ratios were near identical like a 4.10 to a 4.11, would you expect to see such differences in mph?
 

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When my car with drag radials spins, the car is slower to the 1/8th in both ET and MPH. Of course it also has a slower ET and MPH at the 1/4. But when it would normally gain 32MPH (no spin) between the 1/8 and 1/4, it might pick up 34-36mph on a run it spins.

When comparing 2 nearly equal cars, the analysis should always start with the incremental numbers down the track.
 

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Could you expand on that? I mean besides the obvious difference In gear ratio what differences would one rear to the other see. Say the gear ratios were near identical like a 4.10 to a 4.11, would you expect to see such differences in mph?
The 8.8" takes less HP to spin. The 9" while stronger has more parasitic drag due to the placement of the pinion gear. The 8.8" pinion is about center to the ring gear, while the 9" has the pinion mounted lower on the ring gear. This causes the pinion to try and "climb" the ring gear and results in more drag, plus the fact that the 9" pinion has an additional bearing on the end, which increases drag, but also increases stability in high load applications.
Nothing wrong with an 8.8" for holding power. Built right they will handle well over 1K power.
 

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Discussion Starter · #57 ·
The 8.8" takes less HP to spin. The 9" while stronger has more parasitic drag due to the placement of the pinion gear. The 8.8" pinion is about center to the ring gear, while the 9" has the pinion mounted lower on the ring gear. This causes the pinion to try and "climb" the ring gear and results in more drag, plus the fact that the 9" pinion has an additional bearing on the end, which increases drag, but also increases stability in high load applications.
Nothing wrong with an 8.8" for holding power. Built right they will handle well over 1K power.
That makes sense but if both cars were making equal power at the rear wheels that would already be accounted for correct? Sure the car with the 9" might make a little more with a 8.8 but for analyses purposes say both cars put out exactly 800rwhp on the same day, same dyno back to back, then what difference would it make on the track between the 2 rearends? Would the 9" cause one car to have a slower 60' but once it were rolling it wouldnt really make a difference in mph?
 

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That makes sense but if both cars were making equal power at the rear wheels that would already be accounted for correct? Sure the car with the 9" might make a little more with a 8.8 but for analyses purposes say both cars put out exactly 800rwhp on the same day, same dyno back to back, then what difference would it make on the track between the 2 rearends? Would the 9" cause one car to have a slower 60' but once it were rolling it wouldnt really make a difference in mph?
It's a mistake to compare peak rear wheel HP on 2 different cars from a dyno to actual track performance. As others said, the engine that produces the most useable average HP from the starting line to the finish line will be make the same car faster.
 

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I had one engine, a 287” that was 46 better then a 291” but it had such a narrow power band, it was a few hundreds slower. But mph was 2 better. Same car. For what that’s worth.
 
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