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I don't know what dyno's were used. If he was on a Mustang dyno and made 798rwhp and you were on a dynojet making 770rwhp, then the power difference is a lot more than 30rwhp.
 

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Does it weigh less?

It obviously works better. If it is accelerating better through the first half, it will already be running faster at the beginning of the second half of the track.

If all it took was power, anybody could build a fast car. But that is the reason why there are plenty of 500 hp cars that routinely outrun 700 hp cars.
 

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Yes if you could drop your 60 ft time a half of a second your MPH would be faster at the stripe. While your car is spinning the tires you are not accelerating as fast as a car that is not spinning the tires . More acceleration equals more MPH.
That ain’t alway true. Don’t ask me why. I don’t know why. But, when I had slightly more tire spin then I wanted, my mph always, always picked up. Et was a different story.
 

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Discussion Starter · #24 ·
Does it weigh less?

It obviously works better. If it is accelerating better through the first half, it will already be running faster at the beginning of the second half of the track.

If all it took was power, anybody could build a fast car. But that is the reason why there are plenty of 500 hp cars that routinely outrun 700 hp cars.
Its a 50lbs difference. The biggest difference is traction. I have good suspension but street tires and suspension changes are minimal because it doesnt matter much when the tire breaks loose. I will be going on a 28" slick in a few weeks
 

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MPH and ET also depends on how shallow or deep you stage. Not a huge amount but it makes a difference. The deeper you stage the less MPH and a slower ET will result
 

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Peak hp numbers don't always tell the whole story. You could have one 800whp setup that makes that much power or close to it for 500-1000 rpm through the powerband while the other peaks at 800whp at the last moment. Like the comparison between a 6.2 ZL1 with a positive displacement blower versus a 6.2 SS with a centri blower. They can have very similar peak numbers but have massively different averaged power numbers throughout the powerband.

Out at the Dallas rolls I see this type of perplexity over the race results vs dyno numbers quite often. My little NA LS swap 6.0 84 C4 Corvette doesn't make but 420-430whp but it carries 400+ from 5300-7000. I trounce a lot of guys that make a lot more whp than I do. The guys are always looking for a nitrous bottle or calling bullshit on my dyno numbers. Avg hp (area under the curve), weight and aero is what makes my car shine on the street.
 

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Peak hp numbers don't always tell the whole story. You could have one 800whp setup that makes that much power or close to it for 500-1000 rpm through the powerband while the other peaks at 800whp at the last moment. Like the comparison between a 6.2 ZL1 with a positive displacement blower versus a 6.2 SS with a centri blower. They can have very similar peak numbers but have massively different averaged power numbers throughout the powerband.

Out at the Dallas rolls I see this type of perplexity over the race results vs dyno numbers quite often. My little NA LS swap 6.0 84 C4 Corvette doesn't make but 420-430whp but it carries 400+ from 5300-7000. I trounce a lot of guys that make a lot more whp than I do. The guys are always looking for a nitrous bottle or calling bullshit on my dyno numbers. Avg hp (area under the curve), weight and aero is what makes my car shine on the street.
very good points. I will say I never thought about what you said before. Makes good sense.
 

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Good air can make it run better. Aerodynamics makes a difference. Some tracks have "Happy" MPH clocks. One track I ran at used race at my MPH was 5 MPH faster than any where else. Bottom line is unless it is same day, same track it is not really apples to apples.
 

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Discussion Starter · #29 ·
Peak hp numbers don't always tell the whole story. You could have one 800whp setup that makes that much power or close to it for 500-1000 rpm through the powerband while the other peaks at 800whp at the last moment. Like the comparison between a 6.2 ZL1 with a positive displacement blower versus a 6.2 SS with a centri blower. They can have very similar peak numbers but have massively different averaged power numbers throughout the powerband.

Out at the Dallas rolls I see this type of perplexity over the race results vs dyno numbers quite often. My little NA LS swap 6.0 84 C4 Corvette doesn't make but 420-430whp but it carries 400+ from 5300-7000. I trounce a lot of guys that make a lot more whp than I do. The guys are always looking for a nitrous bottle or calling bullshit on my dyno numbers. Avg hp (area under the curve), weight and aero is what makes my car shine on the street.
That is all good info that doesnt get discussed much, however on the combos Im using as examples both have near identical power curves as they are pretty much the exact same
Motor and both centri supercharged. The dyno sheets look identical as they climb with boost his is just about 30 over mine. Mine was at 15psi, his was at 16.7 psi.
Good air can make it run better. Aerodynamics makes a difference. Some tracks have "Happy" MPH clocks. One track I ran at used race at my MPH was 5 MPH faster than any where else. Bottom line is unless it is same day, same track it is not really apples to apples.
They were done on the same day on a dragy, the results I gave were from the dragy, however he has slips to back up his times which were spot on mph wise to the slips.
 

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Pull some power out down bottom till it hooks a bit and roll half of what you pulled back in after the 100’ mark.
 

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One chassis probably has a lot less rolling resistance, and the other chassis is "bound up" so to speak. One is working in favor of making it down track and the other is fighting against it. Aero, as mentioned previously can be a huge factor. I have seen where a rear spoiler change has netted over 3 mph gain based on that alone. Made one pass, speed was 120, change spoiler, next pass 123+, put spoiler back to original, speed dropped to 120. Even took pictures at the big end of the track as the car crossed the stripe, rear of the car was pushed 2" further down with the spoiler in the original position.
 

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One thing that nobody has mentioned is whether the car is being drove out the backdoor.Speed is not measured at the finish line.Speed is calculated by the time you trip the first light & when you trip the last light.If you drive it past the last light,you will always have higher mph then when you let off at the finish line.
 

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I thought NHRA changed the mph lights so the finish line Is the end of the ‘trap? Used to be what, 66’ Past the finish line?
 

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Discussion Starter · #34 ·
One thing that nobody has mentioned is whether the car is being drove out the backdoor.Speed is not measured at the finish line.Speed is calculated by the time you trip the first light & when you trip the last light.If you drive it past the last light,you will always have higher mph then when you let off at the finish line.
Thats good info, but these tests were done on a dragy, so not exactly sure how its calculated but from my understanding its the mph at the distance you travel the 1/4 mile and no where past that.
 

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Things are always being changed so you may be right.The first mph light was 60' before the finish line & the second light was 60' past the finish line.They can't figure mph with just one light.MPH is time over distance so there has to be two lights but they could have changed it to a light 60' before finish line and one at the finish line.If that is true then their mph is not what the car is doing at the finish line.
 

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Don't know what a "dragy" is but assume you mean dragstrip.If you try to come up with a mph by using e.t. for the whole trip then you would be way off.At starting line you are doing 0 mph or maybe 2-3 mph when you trip light.I set 26 different IHRA mph & e.t. records wth my Chevelle.Best e.t. ever was at Rockingham.10.72 e.t & 127mph.If you tried to come up with mph over the whole quarter then it would have been less than 90mph.
 

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Discussion Starter · #38 ·
Don't know what a "dragy" is but assume you mean dragstrip.If you try to come up with a mph by using e.t. for the whole trip then you would be way off.At starting line you are doing 0 mph or maybe 2-3 mph when you trip light.I set 26 different IHRA mph & e.t. records wth my Chevelle.Best e.t. ever was at Rockingham.10.72 e.t & 127mph.If you tried to come up with mph over the whole quarter then it would have been less than 90mph.
A dragy is a satellite device that registers all the normal acceleration times that a track does and it is very accurate. Its been almost deadnuts on to the track times.
 

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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.
 

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Discussion Starter · #40 ·
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.
That might be the dumbest comment on this thread. What the fuck does this have to do with the dragy said this? The dragy is super accurate and has been confirmed numerous times on an actual track to be damn near identical. So you just sound like a moron acting like technology cant be right because its new. The thread was about two near identical cars making within 20hp of each orher and weighing almost the same, in fact the only real difference is me being a heavier driver, the cars are very close. So it has nothing to do with excuses, it has to do with why near identical setups would mph so differently. The fact is people like you dont have an answer to the questions posed, yet for some reason felt it was necessary to make a post that offered no education on the topic. Youre probably one of the ones that always says a car that hooks at the line will MPH slower than the one that spins. This post proves that not to be true 100% of the time, and so the question is posed if that were true why would the car that spins off the line, has a worse 60' because of the spinning, MPH so much less? There are several good posts in this now on things people dont take into account, it has nothing to do with horsepower, weight. What I will figure out is if putting a slick and getting traction helps the MPH that much. I already know traction is the main issue, theres nothing left to figure out, and adjusting my suspension for a tire that wont hook regardless is a waste of time. Ill save the work for when the tires come in.

Oh and PS, you should get a new joke, using the whole millennials thing for everything makes you look like a retard, especially when you arent addressing a millennial in the first place.
 
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