Build Log: M57 X5

[MillerMav]

Killer trip and great upgrades. Nice one!

[ucsbwsr]

After the winter road trip I picked up a set of Pirelli Scorpion Verde A/S tires. 295/40/20. I will run these as an temporary solution as I am still going back n forth with keeping a 20x11 square setup or going to a staggered 20x10F 20x11R. With the snow tires and cargo box removed I was curious to see what kind of MPG gain there would be. It's hard to get pure highway MPG figures that don't get diluted with my aggressive city driving.

I was able to get some clean highway runs in, only ~40 miles total but the drive was an out and back on the same stretch, average speed was 65mph and the return was 35mpg, nice!


I became fond of the looks, strength, and weight of the Camaro ZL1 wheels and didn't see putting the Style 612Ms back on so they were sold


Mountain bike! \M/


20mm spacers were replaced with 30mm for flushness in the rear


Before


After



Installed my 3" QTP exhaust valve. These slip on clamps made installa breeze and I am happy with the results. I still need to mount the switch in the cabin.




Front suspension is now completely refreshed, new OEM top hats, bushings, sport bump stops, KYB struts, and H&R 1.2 springs.




With the rear suspension things are a bit more complicated...

Researching on RealOEM and on other sites I heard that the rear struts for non-air equipped E70s have longer struts and taller (cupped) strut mounts, in a particular photo where someone was comparing the air vs non-air rear struts it looked like the sturt body was the same but the stanchion was longer on the non-air. So my though was to install the non-air struts and mounts on my X5 which, based on my info at the time, would allow 2" more suspension travel before the bump stops came into play, allowing better ride quality when lowered. However after ordering 2 sets of new rear struts (both air and non-air) it became apparent the 2" length difference is 100% in the sturt body so my plan fell apart.

Non-Air TOP vs Air BOTTOM


Here is the 2" difference in the strut mounts. Air=Flat Non-Air=Dome


Another X5 owner was brainstorming with me and he had the idea to run the shorter "Air" rear struts with the domed non-air mounts; the idea being with domed strut mount would allow the strut extra room to move on a lowered vehicle and hopefully allow for proper strut function at a lowered ride height. I gave this a shot and after about 1 week or testing I came to the conclusion that this combo also wasn't ideal, ths strut was operating at essentially full length. If the sturt only saw compression this is probably OK and better than having the sturt working while significantly compressed however, knowing that the suspension will articulate and extend periodically I could see this damaging the strut when if it was topped out.

To conclude what really needs to happen is to take these 2" taller non-air struts mounts, have 1" of material removed, and have them welded back together. This should allow the strut to operate in an acceptable range on a lowered vehicle.

With the short strut + domed mounts installed I knew the strut might perform better at an even lower ride height to I adjusted the rear down another 3/4". With the strut bolt removed you can see how the strut at full extension sits in relation to the control arm.





I raised the rear back up and reverted to the shorter air strut and flat strut mount. Ride quality isn't as good as it was with the taller mount but I know won't be potentially damaging the strut.


Check this out. A tuning company is pushing the limits of the M57 motor with their 335D. I can't imagine it staying together long at this power level (and 50% nitrous) but these numbers are crazy for a STOCK engine and STOCK turbo M57. Just nuts!

[spyro235]

65mph on the dash, on cruise control for the 35mpg run? If so... Maybe I need to get some of that oil additive you used...

I'll have to pop along at 65mpg on a flat stretch of road and see how my car does. I really don't know what it would do. Plus, we have different tunes. Looking forward to the results of the 3.15 too! Mpg is the goal for me.

For the rear lightbars, where did you route the wires to for the drivers side unit? I don't really see any nice pass through like the passenger side had right above and behind the exhaust tip.

[ucsbwsr]

Originally Posted by spyro235

65mph on the dash, on cruise control for the 35mpg run? If so... Maybe I need to get some of that oil additive you used...

I'll have to pop along at 65mpg on a flat stretch of road and see how my car does. I really don't know what it would do. Plus, we have different tunes. Looking forward to the results of the 3.15 too! Mpg is the goal for me.

For the rear lightbars, where did you route the wires to for the drivers side unit? I don't really see any nice pass through like the passenger side had right above and behind the exhaust tip.

I didn't use cruise control, not a fan of it if I am trying to be economical, it is aggressive with the throttle to maintain speed where I have better control driving myself.

For the wiring I just tucked it up and zip tied it safely out of the way, no real tricks, just common sense.

[robinasu]

Too bad about the short shock / tall upper shock mount combo! Maybe using some wide aluminum bar as a spacer in the cup could be an option? A hole in the bar, and threaded rod and a coupler (plus a bunch of red thread locker) could extend the shock threads, essentially making a super thick flange. Or, drill out the studs, use longer bolts and machine a quick spacer.

I bought some Bilstein B8 shocks and the tall upper shock mounts - hope they work or I will have to figure out something.

[ucsbwsr]

I had a chance to execute the 3.15 rear end swap, I will be making a separate thread on this but will add some cliff notes here. For those who have done diff swaps, the change from 3.64 to 3.15 doesn't offer any surprises. Install was straight forward. The downside is acceleration from a dig isn't as dramatic but normal daily driving benefits from the gearing as the X5 has a lot of torque and has no issue moving itself along. The real benefit of this comes at highway speeds, I did some stretches at 60-65mph and it was returning ~35mpg which is what the 3.64 mustered. 65-80mph is where the 3.64 would fall apart and MPGs would drop down to the low-mid 20s, with the 3.15 at 70mph the X5 was still returning 35mpg. I still need to do some testing at higher highway speeds, 80+mph, but the X5 is definitely not as affected by the added speed. I will be swapping in the front diff to complete the gearing conversion and recommend this mod to others who value highway MPG and a less dramatic driving experience overall.

I was able to get a drive from San Diego up to Orange County, just under a 200 mile round trip, mainly flat with some rolling hills. On the drive up I was able to get 32.2mpg and this included 10 miles of urban driving to a shop. On the way home I got 35.1mpg highway only. Unfortunately I wasn't able to hand calculate the figures, this is based off cluster read-out and mine is usually 0-1mpg optimistic so take it for what it's worth.




Big Ass Wrench


If you recall I was playing around with running the shorter rear-air struts with the taller (2" taller) upper strut mounts from a non-air X5 and the goal was to get proper strut actuation while lowered. the air strut with the air mount was too compressed and the air strut with the non-air mount was too extended so I made some 1/2" and 3/4" spacers out of plastic cutting boards which are used to space the taller non-air mount down bring the strut into normal operating range.

To accommodate the spacers I needed to replace the OEM M10 studs with longer versions, after some research I found that ATVs run M10 wheels studs and with all the crazy modding that is going on in that industry, some companies make extended wheel studs to accommodate spacers. I found some that gave me an extra ~20mm of usable thread length.

Old studs out


Extended studs


Building spacers


I made 2 sets of 1/2" and a pair of 3/4" so I can space the mounts as needed between 1/2-1"


What's interesting is how little stanchion travel BMW allows before the bump stops come into play on the rear struts. There are 3 OEM bump stop options: short, medium, and long with the short being sport, long being for 3rd row, and medium for X5s spec's in the middle.
Looking at the meidum bump stop install you can see there is only about 10mm of travel before the bump stop is activated, this is why most X5s ride so poorly when lowered, most are riding on the bump stops, literally.


Here is the medium BS in the back and the sport (short) bump stop installed.


Here is a sport trimmed.


I installed the medium bump stop and paired with a 1/2" spacer which positions the strut in an acceptable operating range but closer to the "extended" side of the spectrum as opposed to "compressed." I know I am still mis-matching the dampening characteristics of the strut with squished air bags but this is a step in the right direction, more testing to do.


I got around to installing the switch for my QTP exhaust valve. I ditched the huge/ugly/hard-to-operate switch QTP supplies for a sleeker momentary switch I bought off eBay, I wanted a more OEM look and easier operation. The goal was to mount the switch in an easy to access location that was also a bit out of sight, and I wanted to mount the switch into a panel or piece of trim that could be easily replaced if I wanted to revert back to stock. Very happy with how everything came together.



With the dark theme of the X5 the taillights and their bright red bothered me a bit so I got some Lamin-X smoked film. This is the lightest they make and offers the "dark-cherry" look I was going for. I also used some knifeless tape to cut the film so that it was only on the red and the white/clear sections have no film.

As a lighting nerd this is a step in the wrong direction in terms of illumination and safety so I had to offset that. I upgraded the rear turn signal and brake light bulbs to Diode Dynamics LED bulbs, I also coded the light module to do a double hazard flash. The bulbs are significantly brighter and combined with the instant-on flash of LEDs the turn signal more effective now than it was in the OEM configuration, even with the tint.

[MillerMav]

Great work as always! If I were to ever get a new job and do more highway driving I would certainly perform those diff swaps, that's a great bump in MPG's.

[Best4x4xFAR]

You are aspiring.

I find myself reading your build thread and day dreaming about working on the X5, but then the reality of work and family life smacks me right between the eyes.

I have a long list of a) Needs and b) Wants, but the reality is that I can hardly find enough time to wash the X5, or fit in an oil change. Have no clue where you find the time..

More power to you..

[ucsbwsr]

Originally Posted by Best4x4xFAR

You are aspiring.

Have no clue where you find the time..

More power to you..

1) Thank you
2) I work from home and don't have kids

[crystalworks]

Originally Posted by Best4x4xFAR

You are aspiring.

I find myself reading your build thread and day dreaming about working on the X5, but then the reality of work and family life smacks me right between the eyes.

I have a long list of a) Needs and b) Wants, but the reality is that I can hardly find enough time to wash the X5, or fit in an oil change. Have no clue where you find the time..

More power to you..

I have that same thought every time I read one his updates.

Kids/wife/house/fleet take up all of what used to be my "modding" time.