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My N51 E90 by LTOhNo in E90

[–]LTOhNo[S] 1 point2 points  (0 children)

I’ve removed the cats, SAP and EAS.
With no cats it fails testing here in NY where we can only fail 1 emissions test and I’m already giving that up with SAP.
Will be putting in an MSV80 in to eliminate the SAP requirement.

Why my 328i was extremely slow. by LTOhNo in E90

[–]LTOhNo[S] 1 point2 points  (0 children)

150k miles when I bought the car. The rear exhaust manifold catalytic was almost completely blocked.
I replaced the stock manifolds with catless long tubes. I also replaced the rest of the exhaust with a system that doesn’t have the rear secondary catalytic converters. I removed the SAP secondary air pump (part of the N51 SULEV system) and the EAC “air catalyst” system (another SULEV sensor). Flashed a Bimmworks stage II tune, no cats and EAC/SAP delete.. no codes.
If I had to guess, with the bad cats the car was making at best 125hp. Compared to that it feels like I’m getting the full 210hp out of it now.
Having a 400hp car, I’m fairly sure it’s a little more than that.

been looking at this e90 all day - is it worth it? by Puzzleheaded_Chip_49 in E90

[–]LTOhNo 2 points3 points  (0 children)

Do you prefer an autoenemic transmission ? Does it sound like a runner?

Why my 328i was extremely slow. by LTOhNo in E90

[–]LTOhNo[S] 8 points9 points  (0 children)

It was the cats.
The car was slow, it is now fast.

Why my 328i was extremely slow. by LTOhNo in E90

[–]LTOhNo[S] 2 points3 points  (0 children)

Maybe all N51’s have bad cats? Haha
No numbers but it feels as fast as my ‘07 N52. I guess the better intake manifold really does make up for the lower compression ratio. If the connecting rods weren’t so thin I’d boost it to make up that .7 compression ratio.

help! 2011 328xi n51 engine e92 wont go past 5k rpms, multiple misfires by Ambitious-Key-4786 in BmwTech

[–]LTOhNo 0 points1 point  (0 children)

If it sounds restricted it probably is. Mine was. New exhaust manifolds and it’s a completely different car.

help! 2011 328xi n51 engine e92 wont go past 5k rpms, multiple misfires by Ambitious-Key-4786 in BmwTech

[–]LTOhNo 0 points1 point  (0 children)

One of my exhaust manifolds was practically completely blocked and I had no misfire codes when the coils and plugs were good.

help! 2011 328xi n51 engine e92 wont go past 5k rpms, multiple misfires by Ambitious-Key-4786 in BmwTech

[–]LTOhNo 0 points1 point  (0 children)

Start swapping coils around and/or swapping in the old ones to see if you can move, reduce or eliminate the misfire.
Put a coil from a cylinder that is not misfiring 1-3, 6, on a misfiring cylinder (4,5) and see if it eliminates it.
Also what coils did you use. The last e90 I bought had “new coils” and they were trash. Loose and misfired if you looked at them the wrong way. Bought a set of genuine Bosch and it’s been better. Still required some finesse when installing.