[tomtom11]

people say that the xi will launch better because of better traction but once the two are moving the i pulls away. the reason for this is because the xi has to put power to all four wheels accorind to people. but i thought the xi only puts power to the front wheels when it feels them slipping? so i could see the i start to pull away because its lighter but i dont get the whole power to all four wheels thing? and how much faster is the i once the two are at like highway speed? thanks

[KyLu II]

Yes

[timmahh]

There is a bias towards the rear on the xi, but the front wheels will always be getting some power I believe. Not sure what the standard f/r power ratio is.

The xi jumps off the line with all 4 wheels under power, and it's hard to slip/burn all four tires, so the car just launches [we have a V8 fulltime 4WD vRunner and it's fun to stomp it, just leaps forward]. Once you're up to speed I don't think it's going to provide any straight line 'racing' advantage, and you do have some drivetrain powerloss because of the additional components and a slightly heavier car.

[plague]

power has to be distributed from the motor through the drivetrain components, through the axels and finally to the wheels. you lose power along this travel. two wheel drive cars will lose approx 18% while AWD, much more obviously.. the I will slowly pull and pull on the xi stock for stock. this is why tuned 335i's are just as fast as the Audi R8 (v8 model)... AWD drivetrain loss not to mention the quattro system is heavy...could you run with your legs alone or faster applying weight to all four limbs galloping like a gorilla?? exactly. ok JK That not similar at all.

[Litos]

s....e.......a.......r......c..........h........

[tomtom11]

ok so the i would start to slowly pull away stock vs. stock. but lets say the i is stock and the xi has a jb3 on say map 1 then would they be equal or would the xi pull away or is that still not enough for the xi to beat the i?

[gtenedio]

Dont think it would be a drastic difference. Def a lot more drivetrain loss and heavier- but from a dig tey might just be half a car apart since the xi has the jump on the i

[michaelalex17]

i dont think the OP is asking who would win in a race from a dig up to like 150mph. he is asking if both cars start at 60mph and go to 150mph how far ahead would the i be. and how much extra power the xi would need to stay next to it. i'd say map 1 on the jb3 in the xi with 11psi instead of 8.8psi would be more then enough to compensate and the xi would win. someone else chime in if i'm wrong.

[plague]

Originally Posted by tomtom11

ok so the i would start to slowly pull away stock vs. stock. but lets say the i is stock and the xi has a jb3 on say map 1 then would they be equal or would the xi pull away or is that still not enough for the xi to beat the i?

oh god yes. haha. jb3 is boosting your hp figures by like 80hp crank lol. that's more than enough. a jb3'd xi would be much faster than a stock i yes sir.

[michaelalex17]

but map 1 isnt boosting to 80 more horsepower that like map 5ish

[plague]

it will still be enough. idk the jb4 maps I run procede.

[michaelalex17]

and i dont know procede maps or whatever they're called. map 1 on jb3 is like 11psi. stock is 8.8psi. so would the 11psi rape an i that is stock?

[michaelalex17]

anyone?

[plague]

yes. it would

[cstmx_ryder]

Yea it would.....diff between 8 psi and 11 psi is roughly 30 hp.

Originally Posted by michaelalex17

and i dont know procede maps or whatever they're called. map 1 on jb3 is like 11psi. stock is 8.8psi. so would the 11psi rape an i that is stock?

[Alpine Whiteboy]

The "i" is not an "almighty monster" vs the "xi"... Are you kidding me? a tuned jb3 (xi) vs a stock (i) is no comparison.....

[tomtom11]

alright thanks guys

[MeeTsenPu]

Default power distribution for Xi is 40% (Front) and 60% (Rear). With up to 100% power to either axle if enough slippage is detected.

[DJKhan85]

Originally Posted by MeeTsenPu

Default power distribution for Xi is 40% (Front) and 60% (Rear). With up to 100% power to either axle if enough slippage is detected.

How is 100 percent of the power sent to each axle? Anyone ever look into the way the xdrive system distributes power?

[MeeTsenPu]

Originally Posted by DJKhan85

How is 100 percent of the power sent to each axle? Anyone ever look into the way the xdrive system distributes power?

There are some good in depth threads in the AWD section discussing power distribution.

[Alchem]

I like the x-drive for being able to put all the power down while the i loses traction. Even at highway speeds its not that big of a difference.

[DJKhan85]

Originally Posted by MeeTsenPu

There are some good in depth threads in the AWD section discussing power distribution.

I did some checking in the AWD forum to confirm my answer.

The X-Drive system CANNOT send 100 percent of engine power to the front wheels. If both rear wheels lose traction then it can technically be considered 100% power to the front wheels because the rear wheels aren't doing anything.

I've been over the design of the x-drive t-case and there is just no logical way to divert 100 percent power to the front axle.