Mike270412
Golden Boy
Thanks Roy.I just spit coffee out my nose.
Track speed vs ground speed or mpi viper 162 vs summit t3 174
- Thread starter rightsideup
- Start date
did the coffee leave a trench in your snot? then we could figure out the rate of speed of the coffee leaving your nose
rusty
GBCA Member
I knew I would regret saying that.....
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rusty
GBCA Member
Tonight I will calculate centripetal force required vs the available.
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Mike270412
Golden Boy
Actually, its exactly what we're talking about. You're trying to hang your hat on the perceived "weight" advantage that doesn't exist since the NA sled loses HP.
500 lb Doo with 140 HP at 5000': 3.57 lbs/HP
650 lb Yammy with 180 HP at 5000': 3.61 lbs/HP
I whipped up this spreadsheet so you can see what the P:W is with the 3% loss is at elevation.
| Elevation (in thousands) | HP | Loss | Corrected HP | Power to Weight Ratio |
| 163 | 163 | 3.067484663 | ||
| 1 | 163 | 4.89 | 158.11 | 3.162355322 |
| 2 | 158.11 | 4.7433 | 153.3667 | 3.260160126 |
| 3 | 153.3667 | 4.601001 | 148.765699 | 3.360989821 |
| 4 | 148.765699 | 4.46297097 | 144.302728 | 3.464937959 |
| 5 | 144.302728 | 4.329081841 | 139.9736462 | 3.572100989 |
| 6 | 139.9736462 | 4.199209386 | 135.7744368 | 3.682578339 |
| 7 | 135.7744368 | 4.073233104 | 131.7012037 | 3.796472515 |
| 8 | 131.7012037 | 3.951036111 | 127.7501676 | 3.91388919 |
| 9 | 127.7501676 | 3.832505028 | 123.9176626 | 4.03493731 |
| 10 | 123.9176626 | 3.717529877 | 120.2001327 | 4.159729185 |
The physics of it suggests that at 5,000', the Doo does not have any "accerelation" advantage since its pushing the same mass to power ratio. Only difference would be traction. In the tight tight trees...going uphill...from a dead stop...I get what you're saying, but the reality is there is a compromise in a sleds ability, trading in 100% of a sleds ability for track speed in most situations, to gain a very slight advantage(with respect to floatation) for riding in the tight tight trees 10% of the time is only going to be appealing to 0.1% of the riders out there. Otherwise, the 180 kit is much more fun for everything else that you encounter on the hill. Just my opinion.
Mike270412
Golden Boy
Look Sheldon!!!A spread sheet!Are these numbers already on your whiteboard?
rusty
GBCA Member
Your confusions (conclusions) are only valid at the end of the crank. And does not include the moment of intertia that would be different on both sleds. Redo calculations with pounds per square inch of weight vs hp and your getting a bit larger picture. Also with the cvt system the infinite gearing can be ignored in calculation. And as for the volume of air controlled at altitude by the waste gate..... It's by pressure not O2. Even on a air to air system losses are still seen due to elevation.
Although o2 is involved in the calculation boost pressure is the deciding factor on the delta p of the fuel rail.
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Although o2 is involved in the calculation boost pressure is the deciding factor on the delta p of the fuel rail.
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b_doornenbal
Active VIP Member
Not sure where you find a 500 lb doo ready to ride.... i think you starting weight numbers are a bit off
Caper11
Active VIP Member
This thread is about track speed vs ground speed. Just reading reviews on the T3 and having no actual seat time on it like I do with the viper, the T3 should have less ground speed and less track speed than the viper.
There was no comparison on the same hill or in the trees between my 800 163 and the viper. The viper had instant throttle response and build both track speed and ground speed faster than my XM. Which made it for a fun sled to ride, yes it was heavy but having instant throttle response made the sled feel lighter.
I have rode with 1100t in deep snow and they do really well getting around, the owners fatigue quicker because of the weight and power they have to control, but it's the same chassis. The stock 15 1100t I rode after the viper did feel different, even tho the power is almost the same between the two. The viper felt stronger and smoother due to IMO a better engine and better clutching.
Like I said before I'm not a 4 stroke guy but the viper impressed.
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There was no comparison on the same hill or in the trees between my 800 163 and the viper. The viper had instant throttle response and build both track speed and ground speed faster than my XM. Which made it for a fun sled to ride, yes it was heavy but having instant throttle response made the sled feel lighter.
I have rode with 1100t in deep snow and they do really well getting around, the owners fatigue quicker because of the weight and power they have to control, but it's the same chassis. The stock 15 1100t I rode after the viper did feel different, even tho the power is almost the same between the two. The viper felt stronger and smoother due to IMO a better engine and better clutching.
Like I said before I'm not a 4 stroke guy but the viper impressed.
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Without getting too technical, shouldn't we be using the actual torque values and not fabricated HP numbers if you want to calc it correctly.
Point wasn't to give an engineering degree, was just to show that the power to weight wasn't that much when you factor in boost. Not sure where I'd find a stock one with 163 HP at the Allen Creek parking lot either......haha - yes the starting numbers are off. I know. Point was to show the BEST case scenario for the NA sled and it still averages at elevation.
Someone please tell me that I didn't factor in rider ability either. LOL
HANDSOME
Member
I went from a yamaha turbo to a xm 163 stock. I now want to sell the xm and go to a viper.
Pistonbroke
Active VIP Member
190 Nytro. Full tank of fuel. Rider 250 lb full of horrible breakfast wrap and bitter coffee. Took home 800 mod class win in drag racing yesterday.
bigfish
Active VIP Member
OOC ZigZag
Active VIP Member
Apples apples oranges oranges the T3 174 boosted will eat the yammi boosted competitionhe stock T3 will kill a stock 4 stroke Yammi. Soooo If the 4 strokes turboed and the Doos stock the turbo will chew the Doo.JMHO
Cheers
Cheers
bigfish
Active VIP Member
you can get the yammi stock with the turbo & warranty,its no diff than getting the t3 174 snow check option
but if it makes you guys feel better to say it will kick the unboosted viper no prob it will,but how many do you think will have one without the turbo.
OOC ZigZag
Active VIP Member
you can get the yammi stock with the turbo & warranty,its no diff than getting the t3 174 snow check option
Ok so you can order a Yammi with a turbo point was a stock T3 will chew a stock 4 stroke and a boosted T3 will bury a boosted 4 stroke. The price diif for the 4 stroke with the turbo kit what 20 + K. T3 174 for aroumd 15 k. Alot more bang for your buck with the T3 JMO though lol.
bigfish
Active VIP Member
um no the viper with turbo kit is 16-18000$ the t3 doo is 17500$,& if you have been around any good set up turbo sleds the 4 will chew the 2 most of the time,in the trees the 2 will be easier to ride.they each have there place & both will put a smile on your face,we are lucky to have the sleds we have now they are better than most 25000$ mod sleds from 10years ago.
snopro
Active VIP Member
I'm not interested in delving into the whole which sled is faster argument but $17500 for a T3 174? Cmon?
Exactly. Anyone who's ACTUALLY ridden with a decent 4 stroke can prove the whole "4 strokes can't keep up" statement wrong in a matter of minutes. I think too many of these guys are bowing down to the T3 like its the new Jesus. Its not even in the showroom and already its "murdering" boosted sleds....LOL
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