Differential & axles power limit

[Vassilakis]

Hi,

I'm planning my single turbo F80 build, will probably go with Deka stage 3 clutches.
Do anyone know what the power limit is for the stock differential and axles?
Will do street driving and some track days, no prepped surface driving. I'm thinking it's cheaper to snap an axle than blowing up the transmission or the diff.

[DeezBluBallz]

Are you building an engine? I went single turbo, and did XHP on my trans. Works perfectly, and no issues. My DCT clutch doesn't slip at all.

[Vassilakis]

Originally Posted by DeezBluBallz

Are you building an engine? I went single turbo, and did XHP on my trans. Works perfectly, and no issues. My DCT clutch doesn't slip at all.

Yes, I’m going built engine. Aiming for 850+ whp/ 1000+ crank.

What power level are you currently on?

[DeezBluBallz]

760’s whp. I don’t have the answers you’d need, as that likely needs more parts thrown at it for sure.

[M 4 FUN]

Torque and grip is what kills drivetrains. Not horsepower it self. Lots of factors to take into consideration here.

[Vassilakis]

Originally Posted by M 4 FUN

Torque and grip is what kills drivetrains. Not horsepower it self. Lots of factors to take into consideration here.

Hello fellow Swede! Yeah I know, that’s why a wrote power limits and not hp, and also said I won’t do prepped drag strips. ☺️
I’m wondering if the stock ones will be good for track days with a stickier tires if I run 850+ whp. When do people start upgrading?

[astris]

Just in case you weren’t already aware, at 850whp you’re not going to have traction. You’ll be lucky to hook in 4th gear. With 18” drag radials you might be able to get traction in 3rd gear on the street if it’s hot and the surface is good.

For reference I’m at 700whp, on KW Motorsport 3 Ways, SPL rear traction links, SPL rear adjustable toe arms with lockouts, on 305/35/19 R888R. I have stock trans with XHP Stage 3 and stock axles. No issues.

On the street I can only get traction in 3rd gear with hot tires. 1st and 2nd is useless at wide open throttle.

However, I’ve heard of people snapping multiple axles at lower power levels. It matters when you can put the power down. 600whp from a dig on a prepped surface is going to be harder on the axles than 700whp that spins.

[headstart101]

Where did you get 305/35/19 R888R tires?

[Vassilakis]

Originally Posted by astris

Just in case you weren’t already aware, at 850whp you’re not going to have traction. You’ll be lucky to hook in 4th gear. With 18” drag radials you might be able to get traction in 3rd gear on the street if it’s hot and the surface is good.

For reference I’m at 700whp, on KW Motorsport 3 Ways, SPL rear traction links, SPL rear adjustable toe arms with lockouts, on 305/35/19 R888R. I have stock trans with XHP Stage 3 and stock axles. No issues.

On the street I can only get traction in 3rd gear with hot tires. 1st and 2nd is useless at wide open throttle.

However, I’ve heard of people snapping multiple axles at lower power levels. It matters when you can put the power down. 600whp from a dig on a prepped surface is going to be harder on the axles than 700whp that spins.

Thank you! Year I know, will have a low boost map and a boost by gear as well.

How are the SPL working for you? Heard of some people having problem with some arms bending or snapping. I'm planning on full SPL kit and MCS 2-way or 3-way.

Yeah, then it's like I thought. However it's cheaper to snap an axle than to destroy something else in the drive line.
Might just start with stock clutches and upgrade further down the road if I'm getting problem with clutch slipping.

[astris]

Originally Posted by headstart101

Where did you get 305/35/19 R888R tires?

Typo. I meant 305/30/19, but it looks like they discontinued 19” 305s!? Damn it! I’ve been spinning them like there was an infinite supply. 🤬

[astris]

Originally Posted by Vassilakis

Thank you! Year I know, will have a low boost map and a boost by gear as well.

How are the SPL working for you? Heard of some people having problem with some arms bending or snapping. I'm planning on full SPL kit and MCS 2-way or 3-way.

Yeah, then it's like I thought. However it's cheaper to snap an axle than to destroy something else in the drive line.
Might just start with stock clutches and upgrade further down the road if I'm getting problem with clutch slipping.

Boost by gear sounds awesome. Who’s doing the tuning?

My SPLs have been flawless. Rear feels very predictable and there’s more camber adjustment when lowered. I tried flattening the rear a bit to see if it would help with traction. I’m at -1°. It helps a tad. I’d probably stick with -1.5”.

I don’t drive the car often, but I do drive it pretty hard when I do.

[Vassilakis]

Originally Posted by astris

Boost by gear sounds awesome. Who’s doing the tuning?

My SPLs have been flawless. Rear feels very predictable and there’s more camber adjustment when lowered. I tried flattening the rear a bit to see if it would help with traction. I’m at -1°. It helps a tad. I’d probably stick with -1.5”.

I don’t drive the car often, but I do drive it pretty hard when I do.

I’m gonna tune it on MHD, probably the tuner that have tuned Mike’s at 4N Motorsport shop cars, or if I find someone else that will do a good job.

Good to hear! Will be fun to play around with my settings when done.

That’s the right way. 😎 I do the same with my supercharged R8 right now. Doing powerslides, ice driving and hooning around. Figured this build will be better suited for the task, and cheaper if I break stuff lol.

[Vassilakis]

Originally Posted by astris

Typo. I meant 305/30/19, but it looks like they discontinued 19” 305s!? Damn it! I’ve been spinning them like there was an infinite supply. 🤬

What wheel specs are you running? Do you have a photo of the fitment?

[astris]

Originally Posted by Vassilakis

What wheel specs are you running? Do you have a photo of the fitment?

Apex VS5-RS. 19.9.5 ET22, 19x11 ET44. The R888Rs have really square shoulders, and I’m relatively low, so if I hit bumps they’ll rub a bit on the fender liners. No big deal though.

My full build thread with pics here: https://f80.bimmerpost.com/forums/sh....php?t=1917181
Pics of the wheel/tire setup burried in there somewhere.

Side note: I love Stockholm. Södermalm is rad and Omnipollo Kyrka is one of my favorite. I think I did actually did go to Omnipollo Hat everyday as well. 😂

[Vassilakis]

Originally Posted by astris

Apex VS5-RS. 19.9.5 ET22, 19x11 ET44. The R888Rs have really square shoulders, and I’m relatively low, so if I hit bumps they’ll rub a bit on the fender liners. No big deal though.

My full build thread with pics here: https://f80.bimmerpost.com/forums/sh....php?t=1917181
Pics of the wheel/tire setup burried in there somewhere.

Side note: I love Stockholm. Södermalm is rad and Omnipollo Kyrka is one of my favorite. I think I did actually did go to Omnipollo Hat everyday as well. 😂

Thank you! I’ll look it out.

Small world, not to many have been here. Stockholm is a beautiful town. Unfortunately most of us get used of it and don’t appreciate it as we should.

[M 4 FUN]

Originally Posted by Vassilakis

Hello fellow Swede! Yeah I know, that’s why a wrote power limits and not hp, and also said I won’t do prepped drag strips. ☺️
I’m wondering if the stock ones will be good for track days with a stickier tires if I run 850+ whp. When do people start upgrading?

Hi!
Well, the diff itself can handfle all you throw at it. I've seen people snapping driveshafts with over 1000 hp and sticky tires but that has been extreme cases on dragstrips so i don't think you have to worry.