Torque lost after installing S52 cams and Alpina manifold on M52

[deni2s]

I have M52B28 engine with Simota CAI.

I did a "before" dyno on Friday, car was running ok, everything looked fine. From Monday till Wednesday bmw authorised service installed S52 cams and Alpina manifold from B3 3.3. They told me, that they reseted adaptations, engine is running smoothly, but pre-car oxygen sensor for bank 2 (cylinders 3,5,6) is not heating and should be changed. It wasn't available, needs to be ordered and delivery might take a week or more.

So I was driving hard for 2 days for the engine to adapt around 500km total, but I wasn't impressed very much with the results and on Friday went to "after" dyno without changing the oxygen sensor (and I thought, that most probably it was dead before "before" dyno, so I wanted to check the gains from cams and manifold).



"Before" run is dashed. As you can see, I lost lots of torque, and only on the high revs above 5500 there is some gain. Not very usable on the street. Everyone tells me, that it shouldn't look so bad. We did around 4 runs on the dyno, the curves were the same, but on the first run results were better, probably when engine or coolant wasn't very hot, but still loosing torque. Values are on the wheels in 4th gear and on very pessimistic dyno.

Any ideas what could be wrong? Just the O2 sensor? Cams timing? Leaks? Etc?

[Vinci]

Not sure that it makes much difference, but dynos should be done in 5th gear on these cars.

In a lot of other cars, 5th gear is an overdrive gear, but in the 6cyl Z, 5th gear is 1:1.

[rf900rkw]

Other than the dip at 4500, the results are what I would expect. Mods like this don't gain torque, they just shift the RPM it peaks at. Lose on the left, gain on the right. As far as the dip, assuming the dyno isn't in error, you have induced a standing harmonic in the intake that is really causing issues. Start by double checking your cam timing.



Can your dyno operator plot the gear ratio? That would tell us if there is a dyno/traction issue.


For my cars, I dyno in 4th gear because I don't like spinning street tires to and beyond 160mph.

[deni2s]

We also did the dyno in 5th gear too, and the curve was very similar, just a little bit higher values, maybe by 5 whp or something like that. In the "before" dyno difference between 5th and 4th was around 10 whp. Dyno operator was feeling more comfortable in 4th gear, I don't know why, I told him that 5th gear is 1:1.

About the dip - isn't that the vanos change? I had seen similar dip at the same rpm on other m52 dynos (it was even called "vanos bomb" - http://www.r3vlimited.com/board/showthread.php?t=327183). I was looking at other dynos with m50 manifold and s52 cams, and mostly they are not loosing so much torque. For example this dyno: http://www.eurosporthighperformance....2_vs_Stock.pdf . The gains are much bigger than looses.
And Alpina manifold should loose low end torque even less than M50 or not at all, as I know.

To check the cam timing, cam cover needs to be removed right? New gasket, etc, all that trouble? (Thinking also about installing beisansystems.com vanos kit)

[rf900rkw]

The Vanos switch happens at 5200,and manifests itself as a flat spot in the curve. There is something else causing that monster dip. The first thing is to verify the dyno run. Graphing roller speed vs engine speed (aka gear ratio) will tell if there was any slip or dropouts.

There is a lot of crap and bogus advertising out there on these mods. People want to sell. People want to buy. People want to believe. A good understanding of the basics of engine dynamics can help you sort through the claims.

I can't say about the Alpina manifold. I can say the M50 manifold cost me 30 ft-lbs at 5K on my boosted S52.

As long as the gasket is fairly new, you can reuse it. These rubber gaskets are not retorque sensitive, just age.

[deni2s]

I think dyno operator checked roller speed, when you are telling me that. Because of that dip we did few more runs, and all of them showed the same. And I hope that replacing oxygen sensor will make some improvement.

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I found similar thread with very similar dyno and problems (lost torque too much):

http://www.bimmerforums.com/forum/sh...l-DYNO-numbers

Owner of the car claims that there was one cam misaligned, and after fixing that car went much better. Unfortunately he never posted a dyno after fix (I went through all 10 pages). People are saying, that the dip is from m50 manifold (alpina manifold in my case).

[deni2s]

The Vanos switch happens at 5200,and manifests itself as a flat spot in the curve. There is something else causing that monster dip.

According to this thread http://www.bimmerforums.com/forum/sh...r-VANOS-engage and this http://www.romraider.com/forum/viewt...11368&start=15 Vanos switch happens at 4200 rpm for M52.

[328 Power 04]

Yes it is at 4128 rpm in the flash when stock.

When you put S52 cams, you should raise the vanos off level to around 5000 rpm to gain the torque back, and erase that dip.
With proper tuning you can make it much much better.

Have you seen the BMW MS41 section on RomRaider?

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Those dyno results show something wrong with either the cam install or something else. I have a similar setup, and the torque loss was about 5ft-lbs (7Nm) at peak.

[deni2s]

Yes it is at 4128 rpm in the flash when stock.

When you put S52 cams, you should raise the vanos off level to around 5000 rpm to gain the torque back, and erase that dip.
With proper tuning you can make it much much better.

Have you seen the BMW MS41 section on RomRaider?

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Those dyno results show something wrong with either the cam install or something else. I have a similar setup, and the torque loss was about 5ft-lbs (7Nm) at peak.

Yes, I checked RomRider section about vanos yesterday. I think I will contact seller of chiptune and will ask about that, as it claims that it is good for s52 cams.
I agree, that something is wrong. I found that there was no clamp fitted on hose from manifold to brakes, maybe there was some leak (I will do another dyno hopefully tomorrow to check if that was the problem), but I also ordered vanos repair kit from beisansystems to do it while checking cams timing and new oxygen sensor. Hopefully all that will give better results. Do you have Alpina manifold or m50 or something else?

[328 Power 04]

On my 328, I have M50 manifold, 7.6cm diameter cold air intake, S52 camshafts on the original mass air flow. The car has the original pink top Bosch injectors. On US 93 (RON+MON/2) octane, equivalent to 97-98 RON octane as used in Europe.

I have an old dyno sheet on a dynojet with 187whp with just M50 manifold, no software (chiptuning), no S52 camshafts at the time. On same dyno the car makes between 165-170whp when stock. Torque at the wheels was 178.5 ft-lbs (242Nm) at 4000rpm, has a slight dip at 4100-4300 (VANOS off area) and back up to 242Nm at 5000rpm.


I would go over the camshaft install again, and make sure it is timed correctly. Also check for more vacuum leaks.

At top dead center, the camshaft square ends MUST be perfectly parallel to surface of the rear of the head, all while the timing chain is completely tight.



You should get a VAG KKL cable with the FTDI FT232R chip, and read the flash yourself.

[deni2s]

Thanks for all the info, I found mechanic who has an experience with m52 engines, he will install vanos repair kit when I will receive it and check cams timing and everything else at once.

You should get a VAG KKL cable with the FTDI FT232R chip, and read the flash yourself.

Can you point me some item on ebay I should look at please? I don't have experience at chiptuning (just lots of reading and I am quite good at IT stuff) and I see there are so many options, don't want to waste my money on something that is not very usable and needs to be upgraded later to something more advanced when I will get more experience. And I prefer using Mac computer (I know, that most chiptuning software is on Windows platform).

[deni2s]

Status update:
Chip seller agreed that there were no changes for S52 cams on chip and sent me update to flash on my chip, which turns off Vanos at 5000rpm and not 4000rpm. I bought the required cable and did the update. That should remove that dip on dyno graph. I also spotted using cable log function that my o2 sensor is not giving any output (no adaptations recorded at all), which is probably because o2 sensor needs to be changed and car has some diagnostic fault code written which prevents engine from running in closed loop and it uses stock maps without adaptations (which are needed for different cams and intake). Probably that was the reason why the engine didn't have all the torque it should. Car is now at the experienced mechanic, who will install new o2 sensor and clear error codes (so that engine can start running in closed mode and adapt to new config), he will also check cams timing and do vanos repair (preventive measure) by using beisansystems.com kit. Car should be ready tomorrow.

[328 Power 04]

I will get back to you about tuning recommendations. (I'm "Enabled" on RR).

[deni2s]

I will get back to you about tuning recommendations. (I'm "Enabled" on RR).

Cool! I am very interested in that! Lots of new things to learn, now reading some book about chiptuning basics.

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Status update: Just got confirmation from mechanic that both cams were timed incorrectly (installed at authorised bmw service).

[BimmerBreaker]

Glad you are getting this sorted out! Put those S52 cams I sold you to good use!

[deni2s]

Glad you are getting this sorted out! Put those S52 cams I sold you to good use!

Thanks, I hope this will be sorted out very soon Interaction with you was the most pleasant and worry free in all this tuning process which took me over a year including that order of broken schricks before I got your s52 cams!

[deni2s]

Status update:
Looks like I had sorted everything out. The cams were not timed - that was main problem. Did the timing correct, installed beisansystems.com vanos repair kits, changed o2 sensor. But the chip was still throwing out o2 sensor errors (together with muffler flap errors). The problem with that was, that chip tuner sold me the chip from 323 car, which has different o2 sensor configuration and has muffler flap - my z3 has only one pre-cat o2 sensor and no muffler flaps. So I copied from that chip ignition timing maps, vanos maps and some limiters to my original ecu chip, no errors anymore and engine started to adapt and now drives very good and fuel consumption is even better than before! I plan to measure the car on the dyno later to see the differences.

[deni2s]

Finally measured on the dyno. Feel free to comment what do you think!

[ADAz3M]

Well that looks much better!

[328 Power 04]

You can change the vanos off point to 5200rpm. It will smoothen it even more.

The change delay is around 200rpm anyways.

Very nice!