The Unofficial MINI 1/4 Mile Time Database
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Joined: Jul 2005
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From: Flitwick UK
If you took a Mini engine and put it on an Engine dyno and it made 300bhp, take that same engine and put it in a car and take it to churches it might make 279 hub horsepower, put it on a set of rollers it might make 255 tire / whp but it all works back to 300bhp at the flywheel.
Dont forget I haven't done this I'm just using the above as an example.
So that same Mini goes and runs 110 in the 1/4 at 2900lbs, 3 horsepower figures but same result.
Some guys over here actually done this in one day engine dyno then 3 rolling roads.
Dont forget I haven't done this I'm just using the above as an example.
So that same Mini goes and runs 110 in the 1/4 at 2900lbs, 3 horsepower figures but same result.
Some guys over here actually done this in one day engine dyno then 3 rolling roads.
nope... just you
still waiting to see your calculations on how your system works on the strip when you can't measure wheel slip or driver error.....
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Joined: Jul 2005
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From: Flitwick UK
OK so the drag strip produces 2 sets of info per run:
ET (elapsed time) = how quickly you go from start to finish
MPH - how fast you are going when you go over the line
ET - this is where the driver skill / car setup comes into play - knowing your car well and when and at what RPM to launch it, selecting the right tyres etc
MPH (the gift for the tuner) as the MPH allows you to calculate how much power the car is generating to get you finish line. Even if you have a bad run, wheel spin, your MPH will tend not to be too badly affected.
If you go here and look at row 66 and row 77 these were run on the same day at the same weight 53 minutes apart
Row 66 run 12.5943 @ 115.34
Row 77 run 11.7722 @ 115.93
You cant find a better example of mph = horsepower
I look forward to your public apologies
ET (elapsed time) = how quickly you go from start to finish
MPH - how fast you are going when you go over the line
ET - this is where the driver skill / car setup comes into play - knowing your car well and when and at what RPM to launch it, selecting the right tyres etc
MPH (the gift for the tuner) as the MPH allows you to calculate how much power the car is generating to get you finish line. Even if you have a bad run, wheel spin, your MPH will tend not to be too badly affected.
If you go here and look at row 66 and row 77 these were run on the same day at the same weight 53 minutes apart
Row 66 run 12.5943 @ 115.34
Row 77 run 11.7722 @ 115.93
You cant find a better example of mph = horsepower
I look forward to your public apologies
OVERDRIVE
Joined: Aug 2006
Posts: 7,201
Likes: 8
From: Norfolk, VA
The formula Paul's using (I believe it's 'HP = weight * (trap speed/230)^3') is the old "Fox Formula", named after the physics professor that developed it in the 60's. Fox figured that trap speed was determined by the following factors:
1) vehicle weight
2) engine power, and the details of the torque or horsepower curve
3) coefficient of friction of the tires on the track
4) aerodynamic drag
5) moment of inertia and frictional loss of moving parts
6) drivetrain gearing
7) shifting mechanisms
8) location of the vehicle's vertical and horizontal center of gravity
9) driver skill
Of those factors, he found that the first two factors (horsepower and weight) had by far the highest correlation with changes in trap speed, with a correlation value of about 0.92.
That allowed him to make a first-order approximation of BHP using only the vehicle weight and trap speed that's actually pretty darned close to reality.
There are other similar approximations where the constant in the denominator or the exponent is different, but they're all pretty close, with the correlation factor ending up in the 0.92 to 0.93 range. The best one I've seen is the "Lucius best-fit" formula:
BHP = weight * (trap speed/215.4)^3.31
The correlation factor for that one is slightly over 0.93, as tested using about 250 late-model examples from "Road & Track".
OVERDRIVE
Joined: Aug 2006
Posts: 7,201
Likes: 8
From: Norfolk, VA
If you want to read about the methods & research behind Fox's formula that Paul's using, I believe it's included in "On the Physics of Drag Racing", in the American Journal of Physics, Volume 41, Issue 3, pp. 311-313 (1973)
I can't find an online reprint of it for obvious copyright reasons, but you can order a copy from any number of sources, or if there's a college library near you, they probably have a copy.
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From: Flitwick UK
In terms of science, this formula allows us an increased understanding of how the the engines that we are working with daily, work. So the methods aren't totally controlled but the results allow us to ponder and observe the physical evidence, in the data collected ( the timing ticket), and analyze this information to explain what and how things work - fairly scientific and far harder to fudge than dyno figures, i'd say.
And ultimately, just another tool in the armourary of the tuner, surely?
The question should surely be why we would not use this tool to demonstate the effectiveness of our products? After all in science isn't more effective to have a significant amount of data to analyse not just data from one source - call 1320ft of black tarmac and the trap speed, the control.
And ultimately, just another tool in the armourary of the tuner, surely?
The question should surely be why we would not use this tool to demonstate the effectiveness of our products? After all in science isn't more effective to have a significant amount of data to analyse not just data from one source - call 1320ft of black tarmac and the trap speed, the control.
In terms of science, this formula allows us an increased understanding of how the the engines that we are working with daily, work. So the methods aren't totally controlled but the results allow us to ponder and observe the physical evidence, in the data collected ( the timing ticket), and analyze this information to explain what and how things work - fairly scientific and far harder to fudge than dyno figures, i'd say.
And ultimately, just another tool in the armourary of the tuner, surely?
The question should surely be why we would not use this tool to demonstate the effectiveness of our products? After all in science isn't more effective to have a significant amount of data to analyse not just data from one source - call 1320ft of black tarmac and the trap speed, the control.
And ultimately, just another tool in the armourary of the tuner, surely?
The question should surely be why we would not use this tool to demonstate the effectiveness of our products? After all in science isn't more effective to have a significant amount of data to analyse not just data from one source - call 1320ft of black tarmac and the trap speed, the control.
OVERDRIVE
Joined: Aug 2006
Posts: 7,201
Likes: 8
From: Norfolk, VA
Here's another example of how trap speed isn't really affected by all the same factors that affect elapsed time:
Here, his elapsed times varied by almost 3%, but his trap speeds were all within a half a percent of each other.
Here, his elapsed times varied by almost 3%, but his trap speeds were all within a half a percent of each other.
Banned
Joined: Jul 2005
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From: Flitwick UK
We had a controlled environment which produced scientific data that et can change where as mph stays constant.
Dont hold back just get Danny's car which is the most powerful M45 on Churches dyno, weigh it & run it, how much simple does it get? put the video on youtube for the world to see.
Dont hold back just get Danny's car which is the most powerful M45 on Churches dyno, weigh it & run it, how much simple does it get? put the video on youtube for the world to see.
We had a controlled environment which produced scientific data that et can change where as mph stays constant.
Dont hold back just get Danny's car which is the most powerful M45 on Churches dyno, weigh it & run it, how much simple does it get? put the video on youtube for the world to see.
Dont hold back just get Danny's car which is the most powerful M45 on Churches dyno, weigh it & run it, how much simple does it get? put the video on youtube for the world to see.
yep.. you controlled mother nature and the human element... I'm sold
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From: Flitwick UK
We always try to get within 1% when we're comparing data or claiming NPB
OVERDRIVE
Joined: Aug 2006
Posts: 7,201
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From: Norfolk, VA
As as for "mother nature", I don't know how much time passed between the first run and the sixth run, but doesn't it seem rather unlikely that the environmental changes would be *just right* to keep all six runs within 0.5 MPH of each other, especially considering that the trap speeds didn't consistently increase or decrease? In fact, if you rank his runs from fastest to slowest in terms of trap speed, it went 1-4-6-3-5-2.
Last edited by ScottRiqui; Oct 26, 2008 at 06:19 PM.
3rd Gear
Joined: Aug 2007
Posts: 160
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From: Clovis, CA
Oh come on Jan, the evidence is in the above posts! Thankyou ScottRiqui for making it so easy to understand. Maybe I should use the 1.15 formula below for my car... sweet, 272.3 WHP, i'm finally running the same as the US guys!
Big Howe - you can tell my exhaust has issues just from the dyno graph, thats amazing! Where is your graph and mods?
Big Howe - you can tell my exhaust has issues just from the dyno graph, thats amazing! Where is your graph and mods?
Hey Guys,
Delay:
Sorry for my delay in post/response, I had a complicated journey home to Austin involving (to mention a few):a leaking tire/wheel valve, a night spent in the parking lot at Discount tires, a sidewall blow-out on the same wheel just 12 miles after Discount, and about 20 hrs, which should have taken 5 hrs. It was an adventure for sure. I came very very close to taking a spare wheel, but thought that I can't take the whole damn garage. I have a pump and plugs, I am covered.........or so I thought.
Dyno:
Call the shop (Autoscope 972-867-7467) to get PDF versions of your dyno plots, they can email it to you. I spoke to the shop about the dyno accuracy, and my take away was that they had similar complaints, gee thanks for taking care of the problem before our event.
They had the action to check for any software updates and investigate what Jan had complained about, which is water cooling to the dyno itself. It seems like we were working it maybe a little too much for no active water cooling.
Also, from what I can piece together, including chats with Jan, if we take our results and multiply by a factor of 1.15X we should be much closer to the 'real' numbers for the car, this would be for hp and torque. Maybe Jan can comment here.
My dyno time:
I only needed 1 hr on the dyno, and finished with a 212hp/170tq on that machine, scaling that would indicate a 244hp/196tq max, and I can live with those numbers. My MINI is a beast, AND driveability has been improved all around.
Track day:
On Sunday, Gnatster Jan and I went to a BMWCCA event at the Eagles Canyon Raceway (see the Gnatster earlier posts). I had my first ever track day and was as green as can be. It was an incredible experience that will be repeated!
I have learned that my car is much faster than I am capable to drive it, but I am catching up!
Thanks Gnatster for the organization, thanks to Jan for the nice new map/tune, and great to meet everyone that participated. It was great fun, and I am happy to be a part of it.
Delay:
Sorry for my delay in post/response, I had a complicated journey home to Austin involving (to mention a few):a leaking tire/wheel valve, a night spent in the parking lot at Discount tires, a sidewall blow-out on the same wheel just 12 miles after Discount, and about 20 hrs, which should have taken 5 hrs. It was an adventure for sure. I came very very close to taking a spare wheel, but thought that I can't take the whole damn garage. I have a pump and plugs, I am covered.........or so I thought.
Dyno:
Call the shop (Autoscope 972-867-7467) to get PDF versions of your dyno plots, they can email it to you. I spoke to the shop about the dyno accuracy, and my take away was that they had similar complaints, gee thanks for taking care of the problem before our event.
They had the action to check for any software updates and investigate what Jan had complained about, which is water cooling to the dyno itself. It seems like we were working it maybe a little too much for no active water cooling.Also, from what I can piece together, including chats with Jan, if we take our results and multiply by a factor of 1.15X we should be much closer to the 'real' numbers for the car, this would be for hp and torque. Maybe Jan can comment here.
My dyno time:
I only needed 1 hr on the dyno, and finished with a 212hp/170tq on that machine, scaling that would indicate a 244hp/196tq max, and I can live with those numbers.
My MINI is a beast, AND driveability has been improved all around.Track day:
On Sunday, Gnatster Jan and I went to a BMWCCA event at the Eagles Canyon Raceway (see the Gnatster earlier posts). I had my first ever track day and was as green as can be. It was an incredible experience that will be repeated!
I have learned that my car is much faster than I am capable to drive it, but I am catching up!Thanks Gnatster for the organization, thanks to Jan for the nice new map/tune, and great to meet everyone that participated. It was great fun, and I am happy to be a part of it.
Last edited by BigShow; Oct 26, 2008 at 06:24 PM.
5th Gear
Joined: May 2008
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Bigshow, you guys still don't get it. I don't care. You guys across the pond seem bent out of shape you can't beat Jan's numbers. That's what started this, Paul calling Jan out. You guys could be be running 400hp with the same combo as me, I don't care. Seems all of your ego's are bent out of shape, "your car runs 260, why is mine at 238?".
I'm not the kind of person that needs a bunch of BS records in my sig to make me feel better. That's why you don't see me pimping my mods list and various dyno graphs.
If it makes you feel better you can call me a liar too.
I'm not the kind of person that needs a bunch of BS records in my sig to make me feel better. That's why you don't see me pimping my mods list and various dyno graphs.
If it makes you feel better you can call me a liar too.
Banned
Joined: Jul 2005
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From: Flitwick UK
Unfortunatley you're wrong big Howe, its you and Jan that dont get it.
You and Ben have both the same FLYWHEEL horsepower you just have different HUB and WHEEL readings, see post 153.
Dont forget its YOU and JAN who have to provide evidence that these formula's aren't right.
Just saying that there not right isn't an arguement, put your money where your mouth is and go and prove it.
You and Ben have both the same FLYWHEEL horsepower you just have different HUB and WHEEL readings, see post 153.
Dont forget its YOU and JAN who have to provide evidence that these formula's aren't right.
Just saying that there not right isn't an arguement, put your money where your mouth is and go and prove it.
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From: Flitwick UK
[quote=BigShow;2526475]Oh come on Jan, the evidence is in the above posts! Thankyou ScottRiqui for making it so easy to understand. Maybe I should use the 1.15 formula below for my car... sweet, 272.3 WHP, i'm finally running the same as the US guys! quote]
ROTFLMAO and to think you wold only be a couple behind Danny for a lot less dollars
ROTFLMAO and to think you wold only be a couple behind Danny for a lot less dollars
5th Gear
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You never answered the question, how are equating hub vs. tire vs. flywheel hp?
I don't have to do anything, it's you that is obsessed with the Dyno numbers and proving that they are wrong. I'm not saying your formulas can't get you close, what I've always said is there are too many varibles over the dyno to say they are spot on and right every single time.
When you convince the SAE that your method is more accurate, I'll take my car to the 1/4 mile to get my hp readings. Until then you can call Jan, Church's and myself liars if you like, it doesn't hurt me one bit.
I don't have to do anything, it's you that is obsessed with the Dyno numbers and proving that they are wrong. I'm not saying your formulas can't get you close, what I've always said is there are too many varibles over the dyno to say they are spot on and right every single time.
When you convince the SAE that your method is more accurate, I'll take my car to the 1/4 mile to get my hp readings. Until then you can call Jan, Church's and myself liars if you like, it doesn't hurt me one bit.
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Joined: Jul 2005
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From: Flitwick UK
Also, in terms of 'science', just out of curiosity how does one come up with a multiplier of 1.15? What is the basis for multiplying a HP figure to get it closer to 'anticipated or expected' figures?
Just wondering if this is a formula that we need to be taking into account in the UK when dynoing.....
Just wondering if this is a formula that we need to be taking into account in the UK when dynoing.....
Banned
Joined: Jul 2005
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From: Flitwick UK
You never answered the question, how are equating hub vs. tire vs. flywheel hp?
I don't have to do anything, it's you that is obsessed with the Dyno numbers and proving that they are wrong. I'm not saying your formulas can't get you close, what I've always said is there are too many varibles over the dyno to say they are spot on and right every single time.
When you convince the SAE that your method is more accurate, I'll take my car to the 1/4 mile to get my hp readings. Until then you can call Jan, Church's and myself liars if you like, it doesn't hurt me one bit.
I don't have to do anything, it's you that is obsessed with the Dyno numbers and proving that they are wrong. I'm not saying your formulas can't get you close, what I've always said is there are too many varibles over the dyno to say they are spot on and right every single time.
When you convince the SAE that your method is more accurate, I'll take my car to the 1/4 mile to get my hp readings. Until then you can call Jan, Church's and myself liars if you like, it doesn't hurt me one bit.
People get obsessed with numbers, even though Mini-Racer is happy with how it drives, he's not happy with the number.
And thats the whole point, everyone will judge there car by yours and batruggers without an understanding that its just a number, if you were at Texas you might of made 222 who knows.
Loui's car makes good hp on the dyno and goes well on the road but come to the track and it doesn't performs like JawF430's though they make similar power, If Loui had been like you he would be quite happy with the number, but he isn't, we know there's something wrong. Its just finding it.
Say Loui's car has a wiring / sensor / ecu fault, the dyno hasn't picked it up, its the dragstrip that has, when we find it should I tell the whole community? If I was like that you wouldn't have the RMW cam or the RMW street header.
All we do is verify what we have and what we have done and have fun and brain ache doing it sometimes.
I suppose this could be all about people buyng the dynolicious and seeing what there running nd not being happy with the number they see, have you run yours big howe on one?
Last edited by Paul Webster; Oct 27, 2008 at 04:17 AM.