N55 VRSF DP / FBO review, vs. N54

[patsbimmer1]

I'm excited to see this on a dyno!

[i_love_cars]

GunMetalGrey said:

The waste gate should be taking care of this. The diverter valves should not bleed off boost when you are on the throttle. 

Has anyone ran a twin turbo setup on the n55? Or only a larger single.

Edit:Unless the n5x has some crazy system going on?

The problem is that the diverter valve on n5x are shitty plastic. This was not remedied for the N55. I have an aftermarket charge pipe, but until I do some data logging I won't be able to see if my stock diverter is shot. It does happen under high boost, albeit not a guarantee. I blew both of them on my N54 within doing 4 WOT pulls after I was Stage 2 FBO, lol. Needless to say I immediately went to buy forge DVs. If it ever stops being wet outside, I will be taking the car out for some more WOT to log and see if it's all in my head. I could just be paranoid due to my past experience with N54. 

nobody is running twins on an N55.

[Bobdudeman1988]

iirc the n55 diverter valve is on the turbo correct? and a bog warner turbo. i haven't heard of too many failures with it.

[i_love_cars]

yea it's attached the outer housing in front of the turbo. It's not directly attached/mounted to the turbo itself because it would melt to lava instantly  

here is a diagram for reference: 

http://www.1addicts.com/forums/attachment.php?attachmentid=621288&stc=1&d=1324300903

[Bobdudeman1988]

Just like the newer vw turbos. Theu have issues with the diaphragms tearing.

[i_love_cars]

i need a new car.

[Bobdudeman1988]

mines a 2007, and now killed with bad cam bearing ledges .  be happy lol

[i_love_cars]

noooooo the dreaded cam issue. FIx that shit. Car season is upon us.

[Bobdudeman1988]

Indeed. Too busy to fix.. it will remain fubar till i acquire time and monies..

[i_love_cars]

whoa whoa, a car enthusiast without enough time and money? well now I've just heard it all......as I sit here crying myself to sleep every night knowing how much a Stage 2 turbo + clutch + LPFP + meth will cost me. 

we'll get there someday 

[Bobdudeman1988]

Ive been relabled as community bmw mechanic. Lol. Dont have time to fix my stuff and Work has me pinned down horribly. Looking desperately to aquire a new welding/fab job. But i dont wanna derail your thread. How was the installation of the dp? Easier than the n54?

[i_love_cars]

my threads exist purely for mindless bantering. we're all good here. IMO easier install given only 1 clamp to deal with. Getting the clamps off those turbos is a pain in the ass. But at the same time, I like having a lot of clearance to work with and if you just remove the transmission bracket that's attached to the stock downpipe, it's certainly easier but still not as much as I'd like. When I do the turbo (assuming all goes well and I can actually buy it next year), I will probably remove the engine mount as well because that would make it extremely spacious and easy to work in, especially in terms of getting the O2 sensors off. 

I personally would not recommend anyone ever doing DP installs on n5x without a lift. Having to reach up to the turbo clamp from laying on your back is just a fucking pain in the ass.

[Bobdudeman1988]

im 6 ft tall with long arms. Having done dp installs on the lift and on the floor i prefer thw floor lay a blanket down and i just lay on my back the whole time lol

[DrLeadFoot]

Jordan's Dyno Pull

https://youtu.be/APqODmudRKU

[Earl]

What'd she make?

[GunMetalGrey]

i_love_cars said:

I personally would not recommend anyone ever doing DP installs on n5x without a lift. Having to reach up to the turbo clamp from laying on your back is just a fucking pain in the ass. 

Ha, I can't tell if it would be worse or better with a lift. Helped Spence do his, was a real pain, especially without all of the tools I am used to having at my disposal!

[i_love_cars]

about what you'd expect from a stupid N55. 

335/380. I'm gonna go back after I get my protune and hope for 345/400. I think a Cobb with Protune will put it more in line with a JB4 which are putting out higher FBO numbers on N55s than OTS cobb maps, but that's because JB4 is mostly just a boost controller with very aggressive targets. I am 100% sure the limits of the N55 stock turbo even with the best tune is around 350 whp. Needs meth/e85 to push closer to 400. 

I'm now officially saving my pennies for a bigger turbo. I won't be satisfied till I'm blowing kids out of the water north of 500 hp. If my daughter didn't just have an estimate for braces come in at $4700, I'd already have a turbo ordered.

Edit: at least I got my lowering springs installed Friday evening and they look pretty good, so at least one thing makes me not want to sell my car -

[patsbimmer1]

Regardless of your dyno numbers, your car is still one of my absolute favorite looking BMW's on the road right now.

[KaiserRolls]

Does anyone ever dyno these before installing parts? To get baseline #s? Then again after stuff has been added. And do it all on the same dyno?

Just curious

[i_love_cars]

I do. I did that with my N54, which produces very similar numbers to the N55 in stock form, so no sense in me paying for another dyno of a stock N55. I do all my dynos locally on a DynoJet. This was an exercise in showing how much less you can squeeze out of an N55 turbo before it runs out of breath, compared to N54. Both of which I have owned, and both of which I have had identical mods on. AS well as to get my baseline of FBO on N55 before my longer-term mods start moving the needle more and I can compare to that.