Would the overlap from the N52 cam opening sooner result in lowering the dynamic CR?
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100WHP by installing an N52 exhaust cam in an N55.
- Thread starter 9krpmrx8
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Would the overlap from the N52 cam opening sooner result in lowering the dynamic CR?
Overlap cycle occurs when the exhaust valve is about to close and the intake valve started opening.
In high boosted applications, opening the exhaust valve earlier (about 10-15 degrees) helps in reducing pumping loss at mid to high rpms. At low rpms opening the exhaust valve earlier reduces overall power.
I answered this already, you can also see the video showing the initial plots pre-tuned how both curves overlay. Below 4000rpms the engine lost power with the original tune. To recover this loss they must of adjusted vanos settings and ignition settings. I'm not sure why they did not see gains above 6300rpms, that is strange to me. I'm sure a better tuner can get more power.
Only revision 4 of the tune, so I am sure we will work it out. Great info, thanks for taking the time to post it. I'm surprised no one has tore your head off yet though hehe.
BTW, the info on WEBCAM you just shared is full of mistakes. I cannot believe companies that are in this business (making or regrinding camshafts) cannot get their act together and produce correct data.
Anybody with common camshaft knowledge can spot mistake in the data.
N52 is not a DOHC 12v, since when?
All duration info in both sheets(N52 and N55) are incorrect. It is impossible to have duration number of 280+ degrees at 0.010" lift, that is unheard of and the engine will not even idle below 2000-2500rpms. Do they even check the info they produce before they release to public.
Base circle at 1.180" that is wrong, it should be 1.396" as I stated earlier which is about 35.45 - 35.5mm for the exhaust cam. I'm not sure what the base circle is for the N52 and N55 intake cam but for the N53 and N54 intake cam has a base circle of 41.80mm (1.645").
Just sharing the info I was sent. Any of you guys willing to take on the project and cover all aspects in a video? I think I'm retiring from this forum lol.
Who sent it to you? Just sharing info is fine, but when it is blatantly wrong people will have questions.
He is just stating a general rule of thumb. At face value, the "gain" supports that the cam improved the mid-range. Reality is that nothing was gained over what a PS2 @ 22.xpsi was already making. From what I am seeing, no one has proven CobraMarty wrong yet either in has calculations showing the cams share similar profiles. You're still at square one in that this was a bonk comparison.
I’ve stated earlier that the N52 and N53 exhaust cam has more duration than the N54 and N55 exhaust cam.
I have the data.
Where did you post the profiles showing the difference between an N55 cam and an N52 cam? All you did was point out that someone else's data was wrong from what I saw. Then you made a general statement about cams. More duration doesn't automatically mean higher VE and more power either. That needs to be proven and a graph showing normal PS2 power doesn't prove the N52 cam provided anything. Not being rude to you. Just continuing to keep the thread on track based upon what we know as it has been provided in this thread. I don't see you denying that the N52 cam gained nothing. You said yourself you don't know why the power curve didn't shift at all in the provided dyno. I do see where you said the N52 cam opens the exhaust valves 12-14* sooner than than the N55 cam. Not sure how you came up with that though care to elaborate more for us peons? All I see is that N55 cam has a larger base circle and an assumption that the N55 cam has the same cam lift?
I see someone just posted on Facebook yesterday that BCP installed a big boost 3.3 kit and an N52 cam into their N55. Maybe results would be better seen with that turbo and exhaust manifold. His dyno results were less than earth shattering. Just about every dyno of BB 3.2 and 3.3 kits I can find are higher than what he put down with the work done at BPC.
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Read post #107. I have the cam data because I invested the time to purchase some used cams (N52, N53 and N54) and measure them on my personal equipment, all that is explained. BTW, I don't have a n55 setup, my 2009 335i is a N53/N54 hybrid similar to Hydra.
What does owning or not owning an N55 setup have anything to do with validating that the N52 exhaust cam has more duration and more area under the curve vs the N55 exhaust cam?
'Cause we haven't seen a good comparison of someone running an n55 cam versus n52 cam to judge whether it's an improvement on the curve. Just the other guy's single sketchy comparison. And your earlier comment (#107) acknowledges you're making assumptions about the n55 cam profile (since you don't have one).
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