BMW N51 Turbo build

[N54Yankee]

Originally Posted by rjahl

You need to be careful comparing HP output between these motors. The turbocharged N54 puts out full boost pressure and torque at 1,500 RPM and tapers that down by 6,000RPM when peak HP is produced. While the supercharged N52 is the opposite nothing down low and keeps building boost until redline.

You can't look at peak boost and HP by themselves.

I’m not just looking at that but the entire package, as I mentioned before which includes what the BMW engineer said about bolting a turbo on it. I know Centri chargers quite well, I have one on my C6 and it doesn’t make noticeable boost till 2500 rpm but there up you better be holding on to the wheel with both hands.
But he’s going turbo and it will make substantial boost lower then 2500 and be making serious power quickly up the tach from there.
Too much hp, tq no matter how it’s made won’t make a difference in car not built for it. Power WILL find weaknesses.

[xshadowspy]

Originally Posted by N54Yankee

I’m not just looking at that but the entire package, as I mentioned before which includes what the BMW engineer said about bolting a turbo on it. I know Centri chargers quite well, I have one on my C6 and it doesn’t make noticeable boost till 2500 rpm but there up you better be holding on to the wheel with both hands.
But he’s going turbo and it will make substantial boost lower then 2500 and be making serious power quickly up the tach from there.
Too much hp, tq no matter how it’s made won’t make a difference in car not built for it. Power WILL find weaknesses.

Lets just wait and see what it makes on the dyno lol. This is a dyno graph by the other N52 Turbo I've been talking about at 12psi on the ebay turbo which is smaller then my boost labs 5855 turbo.

Also looking at ordering some precision racekwork ignition coils. N54 Aluminum intake manifold and a oil cooler. as well as the Milvs.

[xshadowspy]

Better shots of dyno graph and his setup. 12psi

[Rmtt]

Nice numbers. I bet it makes that little car really feel alive!

I was trying to look for transmission ratings in the few boosted threads over on the "3" series board. I swear I seen about 350whp was the extent of what the manual transmission would take.

But who knows until you try it....right?

[xshadowspy]

Originally Posted by Rmtt

Nice numbers. I bet it makes that little car really feel alive!

I was trying to look for transmission ratings in the few boosted threads over on the "3" series board. I swear I seen about 350whp was the extent of what the manual transmission would take.

But who knows until you try it....right?

That guy has a manual I believe he told me upgraded his clutch 🤔

[LcossE82]

Originally Posted by xshadowspy

Better shots of dyno graph and his setup. 12psi

Holy. I need another stimulus check now 🥴

[xshadowspy]

Update

So went to the fabricators shop m3 is coming out Wednesday according to him and my manifold will be done this week. So my car is going to be able to be dropped for install. I now need to take off my AA headers and install my stock ones back on to pass smog since I'm from California then car will be going in for the turbo lol. I'll take pics of the manifold when it's finished hopefully this week like he said. I'll keep the thread updated but June will be the month finally get to see this all come together.

[Rmtt]

Nice....been wondering about this project!

I could seriously see me doing something like this. I would be happy with 300/300 to the wheels in this platform as a daily.

Car is a blast now...and I'm probably at 250/220. As I mentioned....I already have a weekend car making plenty of power.

This could satisfy my regret of selling my E46 M3.

[xshadowspy]

Originally Posted by Rmtt

Nice....been wondering about this project!

I could seriously see me doing something like this. I would be happy with 300/300 to the wheels in this platform as a daily.

Car is a blast now...and I'm probably at 250/220. As I mentioned....I already have a weekend car making plenty of power.

This could satisfy my regret of selling my E46 M3.

Yeah man it's just been a whole lot of waiting honestly lol. But should finally see the light of day early next month!

Well with a baby turbo at 5psi the N52 made 313whp 😂 with so little boost so definitely would be worth it! The turbo manifolds for the N52 will be for sell after mine has been fitted so if you want to end up putting together a kit you can!

[N54Yankee]

Originally Posted by xshadowspy

Yeah man it's just been a whole lot of waiting honestly lol. But should finally see the light of day early next month!

Well with a baby turbo at 5psi the N52 made 313whp �� with so little boost so definitely would be worth it! The turbo manifolds for the N52 will be for sell after mine has been fitted so if you want to end up putting together a kit you can!

You believe that number? Stock N54 twins do 8.8psi on an engine which is designed for optimum turbo power and they make about 260-270 stock on the rollers.

[FLATBMW]

Originally Posted by N54Yankee

You believe that number? Stock N54 twins do 8.8psi on an engine which is designed for optimum turbo power and they make about 260-270 stock on the rollers.

YES!

It's no secret that lots of German tuners can get good power out of the N52 N51, their definitely very underrated!

[rjahl]

Originally Posted by FLATBMW

YES!

It's no secret that lots of German tuners can get good power out of the N52 N51, their definitely very underrated!

You should look at the N52 dyno results thread on the E90 pages. Don't care where your tuner is from, without hardware charges it's very hard to get much better than 250 RWHP with this motor when naturally aspirated. Need new cams, Intake and probably head work.

Because the N52 has better air flow than the N54 it's going to make more HP for any given boost pressure. Also the stock load targets on the N54 reduce boost pressure at peak HP while most custom single turbo N52s are still pushing boost way past 6500 RPM. Further distorting the peek HP values.

From memory the stock 335 maps run something like 11 lbs of boost at low RPM and drops to 7 psi at 6,000 RPMs.

Edit: I pulled load targets from an Z4 335I and translated those into boost targets. Notice the boost target at 6,000 RPM, it's below 6 PSI. While max boost is over 8 PSI it's at such a low RPM that it has no affect on the peak HP produced.

[FLATBMW]

block from a 125i (n52) with the head of an E46 M3

[N54Yankee]

Originally Posted by FLATBMW

YES!

It's no secret that lots of German tuners can get good power out of the N52 N51, their definitely very underrated!

Originally Posted by rjahl

You should look at the N52 dyno results thread on the E90 pages. Don't care where your tuner is from, without hardware charges it's very hard to get much better than 250 RWHP with this motor when naturally aspirated. Need new cams, Intake and probably head work.

Because the N52 has better air flow than the N54 it's going to make more HP for any given boost pressure. Also the stock load targets on the N54 reduce boost pressure at peak HP while most custom single turbo N52s are still pushing boost way past 6500 RPM. Further distorting the peek HP values.

From memory the stock 335 maps run something like 11 lbs of boost at low RPM and drops to 7 psi at 6,000 RPMs.

I’ve been seeing those videos for years, Dyno queens and nothing more. Anybody can bolt together an engine and make it last a couple runs on a Dyno for the cameras. These cars are seldom seen on the track and the scant few I did see was fooling around at moderate speed for garnering customers on forums. No track times, drag strip times just Dynos and a few doing advertising on a track. I’ve been reading this site for many years and many have tried SC’ing and turbos on the N52 without much success and usually throw in the towel after losing their shirts and minds trying to get it right and making the power they said they would initially, they never did. Do a search on all those here that said forget it. More often then not Dyno queens sell parts and that’s about all.

New cams, intake, pistons, injectors, fuel pumps, oil coolers, coolant coolers, IC, head work, full exhaust, not to mention the rest of the drivetrain, will help but good luck making a lot of power on a engine block and holding it together with magnesium with thin cast cranks and trying to keep that head where it belongs. They won’t hold together for long at all. BMW built it that way for economy's sake not making big power same goes for the rest of the driveline. Great engine for what it was made for though, wonderful car. BMW thought of covering all the bases, both economy and power in small sized coupes at the time and made two specific plants for both.
I do wish the Op in your quest and hope you get what you want.

[xshadowspy]

Originally Posted by N54Yankee

You believe that number? Stock N54 twins do 8.8psi on an engine which is designed for optimum turbo power and they make about 260-270 stock on the rollers.

yeah i believe it lmao I have the dyno graph. 5psi.

[xshadowspy]

Update
So unfortunately like I stated previously I'm trying to get my car to pass California state emissions before the turbo going on seemed like everything was going well returned the car to stock and was going to get it tested this weekend then send it off for turbo install anddd I got a check engine light today saying cat 2 is most likely no good. I'll attach screenshots of the code reader but yeah this is major setback now. So I'm take it into BMW and get it serviced under the SULEV warranty hopefully it all gets replaced for free I'm not sure.

[FLATBMW]

Originally Posted by xshadowspy

Update
So unfortunately like I stated previously I'm trying to get my car to pass California state emissions before the turbo going on seemed like everything was going well returned the car to stock and was going to get it tested this weekend then send it off for turbo install anddd I got a check engine light today saying cat 2 is most likely no good. I'll attach screenshots of the code reader but yeah this is major setback now. So I'm take it into BMW and get it serviced under the SULEV warranty hopefully it all gets replaced for free I'm not sure.

Do we need the 2 secondary cats that people typically remove or just the header cats? Just a minor setback but I feel your pain! I really want to do an LS swap but with the smog laws here in California I think it would be a huge hassle! You should be covered under the SULEV warranty, I took my car in about six months ago and BMW did a ton of work covered under the SULEV warranty, they even gave me a loaner for about a week. One thing my service advisor who is also a fellow car enthusiast asked me was if I was running any tunes etc. I imagine if you bring your car back to stock you should be good. He mentioned that if I failed smog the part causing the failure would be covered under warranty.

[xshadowspy]

Originally Posted by FLATBMW

Do we need the 2 secondary cats that people typically remove or just the header cats? Just a minor setback but I feel your pain! I really want to do an LS swap but with the smog laws here in California I think it would be a huge hassle! You should be covered under the SULEV warranty, I took my car in about six months ago and BMW did a ton of work covered under the SULEV warranty, they even gave me a loaner for about a week. One thing my service advisor who is also a fellow car enthusiast asked me was if I was running any tunes etc. I imagine if you bring your car back to stock you should be good. He mentioned that if I failed smog the part causing the failure would be covered under warranty.

Thanks for the info man! Hopefully SULEV covers it then! Got a friend who also works in the BMW shop. The smog laws are definitely strict here, was planning a dirty smog but honestly it sounded like to much of a hassle. But you only need the header cats depending if you got a regular smog check up they just hook up the computer to your car. If you have to have it star certified they'll check over your car and might see your secondaries are gone. I've been running a stock tune for 2 weeks now so I don't think they'll pick it up and my friend the tech there will probably grab my car so he'll do all the work. But hopefully this is a quick fix my appointment is on Monday!

[chris_flies]

Originally Posted by N54Yankee

I’ve been seeing those videos for years, Dyno queens and nothing more. Anybody can bolt together an engine and make it last a couple runs on a Dyno for the cameras. These cars are seldom seen on the track and the scant few I did see was fooling around at moderate speed for garnering customers on forums. No track times, drag strip times just Dynos and a few doing advertising on a track. I’ve been reading this site for many years and many have tried SC’ing and turbos on the N52 without much success and usually throw in the towel after losing their shirts and minds trying to get it right and making the power they said they would initially, they never did. Do a search on all those here that said forget it. More often then not Dyno queens sell parts and that’s about all.

New cams, intake, pistons, injectors, fuel pumps, oil coolers, coolant coolers, IC, head work, full exhaust, not to mention the rest of the drivetrain, will help but good luck making a lot of power on a engine block and holding it together with magnesium with thin cast cranks and trying to keep that head where it belongs. They won’t hold together for long at all. BMW built it that way for economy's sake not making big power same goes for the rest of the driveline. Great engine for what it was made for though, wonderful car. BMW thought of covering all the bases, both economy and power in small sized coupes at the time and made two specific plants for both.
I do wish the Op in your quest and hope you get what you want.

Have you ever heard of Bimmer Performance Center, and their shop turbo 328i race car? They RACE the thing at 500whp. Didn't blow the engine until they passed the 600hp mark, then replaced it and put it back. As far as I know, it's been racing ever since. N52 trans gave up long before the engine, so they did an N54 trans. Really cool car. Same car that did 9,000rpm on the dyno repeatedly, was dyno'd with an open intake manifold (half cut off, basically making velocity stacks), and was the guinea pig for all their tuning. Also, only the outer block of the N52 is magnesium, almost everything structural is aluminum, so it's still quite strong, and it's proven.

The N52 was raced for years in Grand Am in both the 328i and 128i. The 335i and 135i never raced in such a fashion.

[Rebellato]

Originally Posted by chris_flies

Have you ever heard of Bimmer Performance Center, and their shop turbo 328i race car? They RACE the thing at 500whp.

[N54Yankee]

Originally Posted by chris_flies

Have you ever heard of Bimmer Performance Center, and their shop turbo 328i race car? They RACE the thing at 500whp. Didn't blow the engine until they passed the 600hp mark, then replaced it and put it back. As far as I know, it's been racing ever since. N52 trans gave up long before the engine, so they did an N54 trans. Really cool car. Same car that did 9,000rpm on the dyno repeatedly, was dyno'd with an open intake manifold (half cut off, basically making velocity stacks), and was the guinea pig for all their tuning. Also, only the outer block of the N52 is magnesium, almost everything structural is aluminum, so it's still quite strong, and it's proven.

The N52 was raced for years in Grand Am in both the 328i and 128i. The 335i and 135i never raced in such a fashion.

I moved on from this but since you quoted me, As a matter of fact I have heard of BPC and that’s exactly who I was referring to in my post you quoted. Making a one off car to suck in customers is common and that exactly what that car was, a one off. Claims of power numbers on a Dyno with no verification, no track times at VIR or drag tracks to confirm power made, blew parts up numerous times and never did make available to the public, that tells us a lot, doesn’t it?

If the block was strong enough to handle 500-600 there’s no way BMW would have even considered making the N54/55 or even any of the recent I6 M engines, they’d still be using updated variations of the the super light weight 52, they’re not and the reasons are obvious. Even many of the very mildly boosted( 100+-)versions have been running into big problems.
The platform has been around for well over a decade, how many street 400-500hp N52 powered cars do we see on this forum? Zero. Or even 300whp for that matter. Rare as hens teeth on 300hp cars if any they are very short lived.

Fantastic, light weight platform in stock form or moderately modified but FI, not so much. IMO

[golfer23rm]

Originally Posted by FLATBMW

block from a 125i (n52) with the head of an E46 M3

Anymore details on this?