Author Topic: Fabr's Car-VW/busa crossbreed  (Read 263070 times)

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Offline Engineer

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Re: busa/VW crossbreed?
« Reply #30 on: October 20, 2008, 10:56:18 PM »
Did you add in the secondary reduction when you did the math??  Its 2.352.  (The reduction from the crank to the clutch basket).  I could not find the same site that I googled at first, but this site agreed on the ratio's:  http://www.dixonarchive.com/hayabusa/performance1.htm  Many of the sites I checked did not include the secondary reduction, but showed the same tranny gear ratios.  They are theoretically correct if all you cared about was the tranny.   ;D  If you didn't use the secondary reduction your numbers would be less than half.  Remember this shit can't be wrong because I found it on the internet. ;D


I also gestimated on the torque figure....  Dunno what a turbo does to it but all the horsepower numbers were at around 10K-RPM so torque would be around half of horsepower.  (torque = (horsepower x 5252)/engine speed)  Ok, so the stock 2008 has 178 HP at 9800 Rpm, gives us 95ft/lbs.  (Peak torque was actuall at 10,200 but I am to lazy to convert it from metric)  So with our reduction (2.352 X 2.615 = 6.15)  (6.15 x 95 ft/lbs = 584.25 ft/lbs)  And if I understand correctly you plan on running a turbo so it will be worse.  ;D

Surely 600 Ft/lbs wouldn't hurt a box designed for 40 hp?  ???

I know you don't need a math lesson Fabr.  I just wanted to show everyone how I came up with the numbers.  I even used a calculator so it must be right.  ;D

Offline Punkur67

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Re: busa/VW crossbreed?
« Reply #31 on: October 20, 2008, 11:08:33 PM »
The rated hp on these motors is after the reduction. Otherwise when all of these cars were dynoed you would see 600ftlbs at the tire. actually  even more after the diff or sprockets did their reduction also. You may see more out of the bus box after going through the r&p but im shure the parasidic loss would surely make up for all the gained hp.
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plkracer

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Re: busa/VW crossbreed?
« Reply #32 on: October 21, 2008, 12:24:12 AM »
Yeah, but torque is calculated to be off the crankshaft. It's in ft/lbs at the rated rpm.

plkracer

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Re: busa/VW crossbreed?
« Reply #33 on: October 21, 2008, 12:26:25 AM »
Did you add in the secondary reduction when you did the math??  Its 2.352.  (The reduction from the crank to the clutch basket).  I could not find the same site that I googled at first, but this site agreed on the ratio's:  http://www.dixonarchive.com/hayabusa/performance1.htm  Many of the sites I checked did not include the secondary reduction, but showed the same tranny gear ratios.  They are theoretically correct if all you cared about was the tranny.   ;D  If you didn't use the secondary reduction your numbers would be less than half.  Remember this shit can't be wrong because I found it on the internet. ;D


I also gestimated on the torque figure....  Dunno what a turbo does to it but all the horsepower numbers were at around 10K-RPM so torque would be around half of horsepower.  (torque = (horsepower x 5252)/engine speed)  Ok, so the stock 2008 has 178 HP at 9800 Rpm, gives us 95ft/lbs.  (Peak torque was actuall at 10,200 but I am to lazy to convert it from metric)  So with our reduction (2.352 X 2.615 = 6.15)  (6.15 x 95 ft/lbs = 584.25 ft/lbs)  And if I understand correctly you plan on running a turbo so it will be worse.  ;D

Surely 600 Ft/lbs wouldn't hurt a box designed for 40 hp?  ???

I know you don't need a math lesson Fabr.  I just wanted to show everyone how I came up with the numbers.  I even used a calculator so it must be right.  ;D
Well, 600ft /lbs at 350 rpm is only 40 hp... :) Just kiddin ya. I've been preaching this for a while over at mbn and no one but fabber has believed me. If you kept the bike in 6th but shifted the car trans then that would be better.

Offline fabr

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Re: busa/VW crossbreed?
« Reply #34 on: October 21, 2008, 05:55:13 AM »
I think we have a winner
Well, 600ft /lbs at 350 rpm is only 40 hp... :) Just kiddin ya. I've been preaching this for a while over at mbn and no one but fabber has believed me. If you kept the bike in 6th but shifted the car trans then that would be better.
That's because of the desire to believe something that sounds too good to be true.
Yup
"There can be no divided allegiance here.  Any man who says he is an American,
but something else also, isn't an American at all.  We have room for but one
flag, the American flag... We have room for but one language here, and that is
the English language... and we have room for but one sole loyalty and that is a
loyalty to the American people."
Theodore Roosevelt 1907

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Re: busa/VW crossbreed?
« Reply #35 on: October 21, 2008, 03:48:02 PM »
I to am curious to see some technical literature that states rather it is at the crank or at the rear wheel...I have found nothing that claims either... I dont see many busa dyno sheets showing 600 lbs of torque when dyno'd at the rear wheel..

Admin

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Re: busa/VW crossbreed?
« Reply #36 on: October 21, 2008, 03:55:32 PM »
Looking back at the dyno results from our 2006 Hayabusa vs. ZX-14 comparison reveals that the Suzuki churned-out 156 hp and 94 lb-ft of torque on our rear-wheel dyno. Through a bit of extrapolation comparing Suzuki's claims to our own previous findings, we can assume that the new bike will register around 175hp and 105 lb-ft at the rear wheel. One company already managed to get the new Busa on a dyno they brought to the introduction and their results concur with our arithmetic. At the drag strip the bike backs up the big power numbers with editors able to post impressive times despite only two passes each due to time constraints.

and here is the article i copied it from...Lets see some more..I got to say im with punkur67 on this, the specs are after the reductions etc...
http://www.biketestusa.com/Article_Page.aspx?ArticleID=5375


plkracer

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Re: busa/VW crossbreed?
« Reply #37 on: October 21, 2008, 04:39:09 PM »
The hp rating is at the rear wheel. Hp is torque times rpm divided by 5252. If that was the actual torque at the rear wheel, and say the wheel was 24 inch diameter, the bike would only exert 105 lbs of force to the ground in that gear.

It is measured at the rear wheel, but they do calculations to place it on the crank compared to what speed the engine is turning.

Admin

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Re: busa/VW crossbreed?
« Reply #38 on: October 21, 2008, 04:50:53 PM »
Please back that up with some techy print.. ;D I am very confused here myself..

plkracer

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Re: busa/VW crossbreed?
« Reply #39 on: October 21, 2008, 04:55:31 PM »
I don't have any techy print on hand. A ft/lb is 1 pound acting on a lever that is 1 foot long. Is the radius of the tire is 12 inches, that is one foot, and that would be 105 lbs acting on the outside of the tire.

A dyno measures everything in hp, then converts back to ft/lbs. This is how I understand anyways. HP is basically just a power figure like watts. 746 watts is one hp. Once they have the hp numbers, it doesn't matter where you take hp from, you will just have some loss the further down the line it is. To find the torque, they basically take the hp number at a particular rpm, multiply by 5252, then divide by the engine's rpm to get torque at the engine. To find the engine rpm, if it's not hooked to a tach, they use gear ratios and the speed of the dyno to calculate backwards.

plkracer

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Re: busa/VW crossbreed?
« Reply #40 on: October 21, 2008, 04:57:07 PM »
If the torque values were based exactly what the wheel input into the dyno, then a different wheel size or different gearing would yield different torque numbers.

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Re: busa/VW crossbreed?
« Reply #41 on: October 21, 2008, 05:20:41 PM »
If the torque values were based exactly what the wheel input into the dyno, then a different wheel size or different gearing would yield different torque numbers.

well it does doesnt it?

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Re: busa/VW crossbreed?
« Reply #42 on: October 21, 2008, 05:40:21 PM »
Ok I am in agreement here with most of the boat...

Offline fabr

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Re: busa/VW crossbreed?
« Reply #43 on: October 21, 2008, 05:42:06 PM »
I don't have any techy print on hand. A ft/lb is 1 pound acting on a lever that is 1 foot long. Is the radius of the tire is 12 inches, that is one foot, and that would be 105 lbs acting on the outside of the tire.

A dyno measures everything in hp, then converts back to ft/lbs. This is how I understand anyways. HP is basically just a power figure like watts. 746 watts is one hp. Once they have the hp numbers, it doesn't matter where you take hp from, you will just have some loss the further down the line it is. To find the torque, they basically take the hp number at a particular rpm, multiply by 5252, then divide by the engine's rpm to get torque at the engine. To find the engine rpm, if it's not hooked to a tach, they use gear ratios and the speed of the dyno to calculate backwards.
Wrong,wrong,wrong.NOTHING is measured ever in HP.HP(something imaginary in reality) is a mathmatical function of TORQUE(something that is physically measurable), RPM and the constant 5252.  HP=torque x rpm/5252Chassis dynos measure torque at the REAR wheel times  RPM of the wheel divided by 5252 to get REAR WHEEL HP and TORQUE figures.Any claims of HP at the crank when measured on a CHASSIS dyno will be CALCULATED guesses at best.Wheel diameter is also included in the calcs but for simplicity we'll keep it to basics.
"There can be no divided allegiance here.  Any man who says he is an American,
but something else also, isn't an American at all.  We have room for but one
flag, the American flag... We have room for but one language here, and that is
the English language... and we have room for but one sole loyalty and that is a
loyalty to the American people."
Theodore Roosevelt 1907

-----------------------------------------------------------
 " You have all the right in the world to believe any damn thing you'd like, but you don't have the right to demand that I agree with your fantasy"

Offline Punkur67

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Re: busa/VW crossbreed?
« Reply #44 on: October 21, 2008, 06:02:11 PM »
All this being said you are only putting 180-250hp through the bus box. Ignore the fact of the reduction. 180-250hp is coming out of the output shaft and in to the bus box. Then you have more power loss through the box. I think we are getting a little complicated here. This setup is like bolting on a gear vendors overdrive which allows you to split gears. you just have 4 gears instead of 1.
Its better to be a smartass than a dumbass!

 

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