Looking for tips: Modifing a 4.8is
 

Good day,

I am new to the BMW forums... my current project is a 2005 Subaru STi which I have modified significantly. I am close to my goal with this vehicle (550 AWHP, 10 second 1/4 mile pass and 30MPG + capable) and am considering moving to an X5. My specific interest is the 4.8is

I joined the forum to collect information about the 4.8is... I want to learn about the performance modifications that are commonly used and the performance gains that can be reliably achieved using them.

Please let me know if you can help me learn about the modification potential for this vehicle.

Thanks,

Jeff B
LINK to my webpage

There are supercharger kits out there for the 4.6is, maybe for the 4.8 but not proven.

Other than that you are looking at the basic bolt-ons from Dinan and a few others.

I'm sure you could build up the motor quite a bit, with 4.8l and only 345hp there is plenty left on the table, but you'll be charting new ground.

Thanks for the feedback... I hope to find some other crazy ones (like me) that have pushed it a little... want to make sure there are no abnormal weak points to deal with.

I asked around a bit too but came up empty handed. It would be great to see one of these go beyond bolt-ons.

i think your best bet would be getting a 4.6is, theres no supercharger kit (that i know of) for the 4.8is. I think theres more potential in the 4.6.. plus there are a couple for sale on this site actually. VillaJoe has his silver one for sale, it has like 30k something miles, and Hit Redline has his black one for sale that has like 90k miles? Definitely should look into it

Another plus with the 4.6 is that it doesn't have the air suspension. If I were building one of these with a lot of power I would definitely want coilovers.

You could also look into engine swaps - the V10 would be a blast

+1


http://www.xoutpost.com/articles/x5/...-x5-4-6is.html

I know this is an old For sale but u get the idea of some of the potential:

http://www.xoutpost.com/classifieds/...s-s3-sale.html

Wish I could find someone who is really pushing it... I would like to know how the engine and drive-line components would handle 600+hp at the crank...

I did run across villajoe and redlines for sale... very nice and tempting...

Thanks...

Yes.. I found those too.. but still no one running one down the 1/4 mile yet.. there must be some other crazy ones (like me) out there....

FYI.. my current winter beater is a supercharged toyota 4runner.. it is only making 300 at the crank but can run mid 14's in the 1/4 mile... my summer car (subaru STi) makes 640 at the crank... runs mid 11's

I am looking to sell the STi, give the 4runner to my son and buy one performance vehicle (X5?) that I can drive year around and satisfy my need for speed...

Good info... thanks...

I am kind of a rebel so I really like to make lots of power with little engines... the V8 would be overkill compared to my previous projects... but it would be a blast just the same...

Before jumping into the X5, I need to make sure the driveline components (and stock engine internals) can handle the power. I read a few posts about the transfer case being weak in the X5 (spline to drive shaft failures)...