SULEV cars 3 stage manifold??

[lucasplagenza]

It's my understand so far in my research that the 3 stage manifold and DISA valves come on the 30i trim cars, however I just found some info stating that SULEV n51 cars also have the 3 stage manifold, is this true? Do sulev cars just have the manifold and not the disa valves? Would a 3 stage manifold swap off a 30i be pointless on a sulev n51 car? Hope someone knows a bit more about this.

[b1aze]

Originally Posted by lucasplagenza

It's my understand so far in my research that the 3 stage manifold and DISA valves come on the 30i trim cars, however I just found some info stating that SULEV n51 cars also have the 3 stage manifold, is this true? Do sulev cars just have the manifold and not the disa valves? Would a 3 stage manifold swap off a 30i be pointless on a sulev n51 car? Hope someone knows a bit more about this.

Yes the N51 has the 3 stage manifold and DISA valves. There is no benefit to swapping a 3SI off a 30i onto an N51

[lucasplagenza]

Originally Posted by b1aze

Yes the N51 has the 3 stage manifold and DISA valves. There is no benefit to swapping a 3SI off a 30i onto an N51

So the compression ratio difference is the only reason the n51 doesn't have more power?

[b1aze]

Originally Posted by lucasplagenza

So the compression ratio difference is the only reason the n51 doesn't have more power?

I’m sure there’s a tuning aspect to it also but yes.

[lucasplagenza]

would a tune be as worth while with the lower compression? I know most of the tunes can be programmed to the n51 but i wonder if they're less effective than the n52

[b1aze]

Originally Posted by lucasplagenza

would a tune be as worth while with the lower compression? I know most of the tunes can be programmed to the n51 but i wonder if they're less effective than the n52

Fundamentally speaking, yes the tune would be less effective. Less compression generally means less capability but that doesn’t mean gains aren’t possible.

[blackberryq10android]

Originally Posted by b1aze

Fundamentally speaking, yes the tune would be less effective. Less compression generally means less capability but that doesn’t mean gains aren’t possible.

he would get a higher performance tune with the 3 stage manifold already installed on his car, without having to install anything else compared to an n52 that doesn't have it to begin with. See stage tune or AA

[sibanez]

I just had a dyno tune performed on my N51 equipped 128i, it made a huge difference. Peak horsepower is up 10, and torque jumped by 15. The biggest increase is a nearly 25hp boost between 3.5-5k. The compression ratio isn’t that big of a deal.

[rjahl]

Originally Posted by sibanez

I just had a dyno tune performed on my N51 equipped 128i, it made a huge difference. Peak horsepower is up 10, and torque jumped by 15. The biggest increase is a nearly 25hp boost between 3.5-5k. The compression ratio isn’t that big of a deal.

I thought the N51 ran a 25HP crankshaft deficit to the stock n52 /330 tune. I would think a good tuner could get all of that back, so maybe 17-20 at rear wheels.

Have you looked through the "official dyno thread" in the E90 N52 sections? Lots of dyno sheets in there. A quick search dug up a N51 in the mix but that had headers.

Maybe you should post your dyno sheet in that as well.

[tankertoad]

My understanding is that mod-for-mod, the n52 can make about 10 more hp due to compression. Not something you'll notice. Plus, the n51 has a much longer warranty on many parts.

[BikeNHV]

Originally Posted by sibanez

I just had a dyno tune performed on my N51 equipped 128i, it made a huge difference. Peak horsepower is up 10, and torque jumped by 15. The biggest increase is a nearly 25hp boost between 3.5-5k. The compression ratio isn’t that big of a deal.

Can you share who did the dyno tune?
Was this vs. stock, or did you already have an off-the-shelf tune?

[rjahl]

Originally Posted by tankertoad

My understanding is that mod-for-mod, the n52 can make about 10 more hp due to compression. Not something you'll notice. Plus, the n51 has a much longer warranty on many parts.

A tuned N52 with no hardware mods can add about 15 HP at the crank for a total near 270. The N51 being 10hp weak should be around 260, that's 30 above the original 230 crank HP. I'd be looking for more than a 10hp whp bump from my n51 tuner

FYI, somewhere in my old,old books I remember something like one point in compression ratio is with 2% power.

You would think that the tuner would have started with a 330 tune and adjusted from there. Assuming he really built the tune rather than using some "canned" tune.

[tankertoad]

FWIW, I just had a Dynojet run of 232 at the wheels with an n51 with AA headers/tune and PE.

[rjahl]

Originally Posted by tankertoad

FWIW, I just had a Dynojet run of 232 at the wheels with an n51 with AA headers/tune and PE.

Did you get a dyno before the tune/mods?

[tankertoad]

Originally Posted by rjahl

Did you get a dyno before the tune/mods?

No, the car came that way. I suppose I could dyno again without the headers/tune for a data point.

[sibanez]

Originally Posted by BikeNHV

Can you share who did the dyno tune?
Was this vs. stock, or did you already have an off-the-shelf tune?

While peak HP is only up 10, you can see that midrange is up 25hp+ starting around 3.5K. The change in torque is really present, the car pulls smoothly up the sides of mountains now.

The baseline is the factory mapping. Mods are only exhaust (SuperSprint, no secondary cat) and AFE intake.

This was on a Mustang dyno, which are much more conservative. Car feels a lot better, going to take it Summit Point for a TrackCross next Sunday.

[rjahl]

Originally Posted by sibanez

While peak HP is only up 10, you can see that midrange is up 25hp+ starting around 3.5K. The change in torque is really present, the car pulls smoothly up the sides of mountains now.

The baseline is the factory mapping. Mods are only exhaust (SuperSprint, no secondary cat) and AFE intake.

This was on a Mustang dyno, which are much more conservative. Car feels a lot better, going to take it Summit Point for a TrackCross next Sunday.

I found an interesting post from the past. Several N51 dyno reports in the spreadsheet.


https://www.bimmerpost.com/forums/sh...php?p=18937153