N51 vs N52 Modding Possabilities

[jb2178]

OK - Reading the N52 post but didn't want to thread hijack anybody. I have the N51 since I bought my 08 in Rhode Island - so that means I have the three stage intake manifold, secondary cats and lower compression. I also just checked and the exhaust manifold is different as well.

What I'm thinking - and correct me if I'm wrong - but if/when somebody produces a set of headers for our car, that with the magnaflow exhaust would give me a 10 to 1 compression version of a 130i WITH a full aftermarket exhaust ... of course the car may throw codes due to extra sensors and so on but what else am I missing?

And how much of a hp difference is there in a 10 to 1 versus 10.7 to 1 compression ratio? is that 30 hp or 5 hp?

We really need a side by side N51 vs N52 stock dyno's - I am looking to move back to the Tampa area and would be available if there's a stock N52 out there who wants a dyno done.

[Bimmer-Bob]

Originally Posted by jb2178

What I'm thinking - and correct me if I'm wrong - but if/when somebody produces a set of headers for our car, that with the magnaflow exhaust would give me a 10 to 1 compression version of a 130i WITH a full aftermarket exhaust ... of course the car may throw codes due to extra sensors and so on but what else am I missing?

The software in a High Output N52 (130i, etc.) will be different no matter what hardware changes you make to your car. And really, what would be a "10:1 compression version of a 130i," anyway. That's sort of like saying I have a 230 hp version of a 130i right now, lol.

Anyway, the transmission and rear end are different on the 130i as well.

[jb2178]

Originally Posted by Bimmer-Bob

And really, what would be a "10:1 compression version of a 130i," anyway. That's sort of like saying I have a 230 hp version of a 130i right now, lol.

Is it? or would a full exhaust on an N51 be more like a 250 hp version of a 130i?

Software could possibly get fixed with an AA tune? Tranny and rear end will have to remain but how much different could they be?

I know - I'm just day-dream modding on a Monday but I thought it could be interesting.

[Dackelone]

I touched on chip tuning for the 128i in my 135i flash tune post. Go all the way to the bottom of my post to see the 125i/128i flash tune.

Basically you can get 130i level HP (PS) for your 128i/125i.


Got my car tuned/flashed in Germany…

http://www.1addicts.com/forums/showthread.php?t=528152


You can contact Marcel from www.MS-Tuning.de you can send him your ECU and he can flash it. But this service isn't cheap at around 1K euros. But it is the only way to get 130I levl HP out of a 128i motor.

The only other option is a Burger Tuning power box with gets your 10 Hp for a few hundred dollars.


NA motors:

N52 and N51 tunes
280 PS and 325Nm


125i tuned dyno run…




Here are two videos of a chipped 125i Vert vs a 130i. Keep in mind the Vert is much heavier than a 130i!

Dackel

[jb2178]

Originally Posted by Dackelone

Here are two videos of a chipped 125i Vert vs a 130i. Keep in mind the Vert is much heavier than a 130i!

Thanks for the contact and nothing personal meant but this is the kind of second hand info I'm not after here... "How many other mods did the chipped 125i have" "how does this compare to an AA tune" "how does this prove the driver wasn't at full throttle in the slower car" - You say "only way to get 130I levl HP out of a 128i motor" but really, there's one guy/company I can call and that's it? Nobody else in the world can replicate this performance? - Yes there's a dyno but at the end of the day I don't want racing videos shot via handicam as the proof I should invest in a $1000+ tune... I want raw numbers or people familiar with the N51 vs N52 engine to talk about the differences in the engine specific to the 1 series... so you are telling me that dispite the N51 128i's extra cats and different compression ratio it's capable of more hp than a 130i without those limitations?

That sounds like crazy civic performance talk - "15+ hp from a muffler with 'greddy' stamped on it". I had my 95 civic and this info just doesn't get to the heart of the question - which is "If you put a full exhaust on an N52 128i vs an N51 128i which would be faster?" - sorry I didn't spell it before.

[Dackelone]

There are only a "handfull" of tuners in Germany that can tune the DISA manifold. Four or five tuners - I think in DE. Do some research and you will see. Everyone else can ony get you less than 15HP. The German tuners know how to get the 130i level HP.

I was only trying to help/point you in the right direction. Lets see what you come up with. I won't be holding my breath. Just look how many yuners in the US offer flash tunes for the 135i - and no one offers a 128i tune. There is a reason for that.

[Bimmer-Bob]

Originally Posted by jb2178

this info just doesn't get to the heart of the question - which is "If you put a full exhaust on an N52 128i vs an N51 128i which would be faster?" - sorry I didn't spell it before.

It depends.

First you have to ask, which engine is more powerful stock? BMW gives the same numbers for both the N51 and N52. Seems awfully convenient to me. Personally, I'm inclined to believe that the N51, which is basically an N52 subjected to stricter emissions controls, is less powerful (even if only marginally so).

Second, you have to ask which exhaust? And how much power can one expect to gain from any exhaust?

In any case, I don't see why the N51 would benefit from an exhaust in any appreciably greater way than the N52. Or maybe I don't understand what you're asking exactly?

[wolfe]

I wonder if the fact the German tuners have easy access to cars with factory 130i ecus gives them a big headstart? I doubt that's very practical for the US tuners

[Greenkirby21]

Originally Posted by wolfe

I wonder if the fact the German tuners have easy access to cars with factory 130i ecus gives them a big headstart? I doubt that's very practical for the US tuners

probably helps

[Drawn05]

I have a digi-tec remap on my 125i.

I also have the pref exhaust and intake.

Digi-tec advertised the remap to increase the engine output to 270hp/200kw. Now, my engine might be making that much power but it is certainly not getting to the rear wheels.

I didnt have my car dynoed before hand but I did afterwards at a bmw dyno day about 3 months ago. I have an AT and made 140rwkw compared to a stock MT 135i that made 187rwkw on the same machine.

This was on a dyno-dymanics machine so these figures arent the 'corrected' or other bs figures given by other dyno machines.

The biggest problem with modding the n51/52 125/128 is the drivetrain losses that are inherent with the models. The drive shaft. output shaft and transmissions on the 135i are much better than for the 125/28 and even 130i. The torque converter on the GM auto is designed for 170kw/230hp and doesnt handle the extra engine power properly. It can be swapped for the 130/330i version but that will set you back $2k, and its just too much cash for too little gain.

[jb2178]

Originally Posted by Bimmer-Bob

In any case, I don't see why the N51 would benefit from an exhaust in any appreciably greater way than the N52. Or maybe I don't understand what you're asking exactly?

The reason I think that is because a full exhaust would remove the secondary catalytic converters that come on the N51... the intake (sorry exhaust manifold, posting before coffee) manifold is also different on the N51 but I'm not sure why.

[AW128i]

There is a lot of speculation as to what effects the reduced compression ratio, additional cats, and 3-stage intake manifold have on the N51 compared to a N52. Both engines are rated at 230 hp and 200 lb-ft by BMW. Of course, there is also a version of the N52 that has the secondary cats and that too is rated at 230 hp and 200 lb-ft. Being that BMW can't underrate the engines (anyone remember the Mazda RX-8 controversy?), logic tells us that all three engines make at least 230 hp and 200 lb-ft. If you do some digging into the origins of the N51, you'll find that there is a lot of speculation that the N51 is actually slightly more powerful than the N52. I've never seen comparison dynos, but I sure would love to! I'd certainly lend my car to the cause.

With all that said, I've spoken with Active Autowerke about their 128i tunes and they stated that they can tune the N51 and achieve very similar results to what they claim for the 1-series N52 variants. They seem to be a very reputable vendor, so I have no reason to doubt them, but so little is known about the N51 that I'm leery about making the leap.

[jc5988]

Originally Posted by AW128i

There is a lot of speculation as to what effects the reduced compression ratio, additional cats, and 3-stage intake manifold have on the N51 compared to a N52. .........

just drop by with some info as i was checking out this thread before i decided to give it a shot on my N51.

Apparently, stock 328i N51 and N52 all have very similar torque line, i have compared to many 328i N52 dyno chart, it looks like BMW's engineer did good job of hiding the DISA effect so both engine feels the same.


Biggest difference on the DISA is at the low end torque. There is a 15tq jump from early 2k to 3k rpm, it is quite useful on the freeway with it, more instant pull in 6th gear.

as far as the lowered compression ratio, 0.6 maybe account for 5 to 7 flywheel hp differences from 255hp N52. A performance exhaust or an intake will take care of it.

here is my dyno of ESS tuned vs the Stock, only mod is the bmw performance intake for both run and within 20min apart from each run.

[AW128i]

Originally Posted by jc5988

Is this comparing stock to ESS tune with BMW performance intake? Or ESS tune to ESS tune plus BMW intake?

[jc5988]

Originally Posted by AW128i

Is this comparing stock to ESS tune with BMW performance intake? Or ESS tune to ESS tune plus BMW intake?

sorry, both run are with the performance intake already.

ESS tune dyno'd first then the stock after, within 20min apart, so condition are all same.

I think the stock number will go a bit lower since the ECU dont have time to adapt the stock map just flashed on. I had the ESS tune map on for a couple hundred miles already.

[Dafttt]

Damn, that is a nice jump in tq from 0-4k, where you should be realistically driving within daily.

Performance intake aside, any N52 owners with 3-stage intakes here? After reading countless good reviews from 328i owners I'd like to hear our side of the story. (does it even fit? sorry I'm newbz)