[justpete]

Originally Posted by Mike.

hm, Ill show you how I came up to that conclusion. Lets call it 217 at the wheels on a dynodynamic Well, they read 12% lower than d.jet
so 12%*217=26.04 which equals 243 whp on a dynojet.

Now driveline loss is around 20% so 20%*243=48.6

So the estimated crank HP is 243+48.6=291 hp

I could be totally off, but thats how I got my number ha

Got it, thanks. Didn't realize you were making a conversion to a dynojet. So far the accelerometers in the car produce a hp calculation on the track roughly equal to the DynoDynamic measurement. And the original before-anything dyno yields 230hp at the crank with an 80% driveline efficiency which is where the 80% came from.

[hassmaschine]

Drivetrain loss is not 20%, don't kid yourself..

[hassmaschine]

Originally Posted by TheAxiom

I'm sure that's what he's saying. There is more room for using the DME to advance the cams, so installing them retarded a few degrees (since the current map settings have them maxed out) would allow for more top end power.

Yes that is exactly what I'm saying. Mind your piston/valve clearance of course!

[hassmaschine]

So I've been working on my XDF and going through all the VANOS maps (there are a LOT! want to disable cat heating? that will make it way simpler, lol). it's had me thinking.

The total intake vanos spread is 70 degrees - it's timed from 120-50 degrees (120 is full retarded, 50 is full advance). If I understand correctly , I think that means that if you installed the cam as stock, it is 14 degrees advanced. that is way, way too much - if anything, for high RPM performance we'd want it ground with some retardation instead.

I think it can be compensated for but I don't really understand why he ground it with an advance built in. the whole point is this motor has VANOS, so you can have whatever advance/retard you wish. Unfortunately, even with 70 degrees of adjustment it's already maxed out from the factory. That's why grinding it with a bit of retard (10 degrees would match the S54!) or just adjusting the timing would make sense. it also makes setting up the VANOS maps a pain in the ass because you have to adjust all 5 bazillion of them.

You might have to retard it 24 degrees to achieve a 130 degree target - basically a range of 60-130 degrees (S54 is 70-130). there are only a few cells in the part throttle map that are less than 60 degrees so it would have little or no effect on low end torque. the way it is now, it's as if you advanced the entire VANOS curve by 14 degrees. duh, it lost power! and unfortunately, there's no way to adjust for it because it's already as far as it can go. :|

Another question I have though - is cam timing even adjustable? If it's not, I think that cam is scrap unfortunately. I hope it's adjustable for your sake!

Also - while I do still want to physically measure the cams, the published specs are out there - 255 on the intake cam, 263 on the exhaust cam (this is reduced to 252.3 & 255.6 with valve clearance included). 10mm of lift as we know - S54 has us beat here at 12mm. :|

Now, typically you want an intake/exhaust ratio of something like 70%, meaning the exhaust flows less because it's already under pressure (hot gasses) and the headers help scavenge the exhaust flow. So the cams are usually either the same duration, or the exhaust is a little less. In this case, BMW has made the exhaust cam with a longer duration than the intake. I think the reason is because of the way the stock exhaust is designed - with the cat only about 12"(or less) from the head, there isn't much ability for the stock manifold to provide any scavenging effect.

Now, once you put in some long tube catless headers, you get some real scavenging effect. However, because the exhaust duration is so much longer than the intake, the intake/exhaust ratio is too high and you actually over scavenge. So you're actually sucking some of the intake charge straight out the exhaust!

I think what would benefit us is actually reducing the exhaust duration, or even swapping a stock intake cam to the exhaust side. I'm even thinking it might be possible to put the intake on the exhaust, and have the longer duration on the intake side, but I'll have to look at your cams to know what the shape of the profiles are. But that won't get you any more lift, so maybe doing a regrind on the exhaust cam, using that for the intake, and then for the exhaust either use the stock one or an intake cam. I dunno - there are possibilities.

FWIW, the S54 intake and exhaust valves aren't much larger - 35/30.5 vs 34.2/29. I think the RPM range could be extended 10% easily on the stock head.

did you get both the intake and exhaust cams reground? did he adjust the lobe centerline of the exhaust cam too? I hope not - hopefully you can adjust your LSA back to at least stock!

[justpete]

If it's scrap it's scrap. *shrug*

Sucks but that was the risk coming into it.

I'm checking on whether the cam timing can be adjusted and postponed the exhaust install since before and after dynos would be pointless.

I would think the cam(s) should be degreed as far retarded as possible while maintaining clearances and if possible would this be an offset that would need to be entered into the DME in order for the system to work correctly?

[hassmaschine]

Yeah. I think it should have some adjustment. I'd think if it doesn't work the grinder would want to fix it. It's realy a prototype!

Yes, whatever lobe center it gets set to would be put into the DME.

[justpete]

Oh yeah, you'll have the stock cams by Tuesday if UPS tracking is to be believed...

[Taskmaster]

Originally Posted by Rob43

No one would have the answer to this question Until someone actually gets them welded up, Welding unfortunately adds about $35 per lobe so that would get expensive quickly. I'd just get them re-ground the way they are, I sent/Emailed my guy that pic of the "Hollow" intake N52 cam from 1ADDICTS & he said it shouldn't be a problem. With you sourcing the cams & sending them to me, I think the price would be about $499 & you'd get them back in 4 weeks with all the needed specs. Rob

There is also this...

[justpete]

Originally Posted by TheAxiom

There is also this...

Cool! Nice to see another option arise.

I think the regrinds would've turned out well if relative timing hadn't been dicked with. And if I could've got the data soon enough to permit proper degreeing of the cams on install. We may be able to correct it but that remains to be seen, and it'll be yet another unforeseen expense, possibly two if it requires iterating the correct timing. And all this besides trying to get the DME coded correctly. It may be impossible simply due to valve clearances but this also remains to be seen.

[justpete]

Originally Posted by hassmaschine

I'd think if it doesn't work the grinder would want to fix it. It's realy a prototype!

Yeah, theoretically, we'll see about that, too.

[justpete]

Looking through Bentley I'm not sure it's possible to mechanically time the cams unless custom machined arms for the cam lockdown tool were fabricated assuming it's even possible to use one at all. Anybody know enough about the N52 to say one way or the other? It's a race weekend so I can't get an answer from the shop until next week. TIA

[hassmaschine]

If you degree the cam you don't need a locking tool. The point of of the locking mechanism is to time the cams as stock (it locks them to the stock position). The question is, is it possible to rotate the cam a few degrees? I'd think a race shop should be capable of degreeing a cam.

[justpete]

Originally Posted by hassmaschine

If you degree the cam you don't need a locking tool. The point of of the locking mechanism is to time the cams as stock (it locks them to the stock position). The question is, is it possible to rotate the cam a few degrees? I'd think a race shop should be capable of degreeing a cam.

Thanks. I was thinking the camshaft locking tool could be modified to set a specific angle and hold them in place. From what you're saying it's probably easy for the shop to degree them. Won't know till next week. Dammit...

[andrey_gta]

User KevinB the owner of the n52 UK race car could have input on camshafts

[justpete]

Regrinds appear to be a total loss for a number of reasons. Likely intake and exhaust got swapped when ground, or something. Cam card makes no sense, dyno makes no sense, scrapping them and having new cams installed. Keeping original stock cams in case somebody who knows what they're doing turns up to regrind them.

Also talking with Procede about a custom dyno tune with the stock cams since Shiv tuned the shop's SCCA turbo car which runs a stock DME.

[Taskmaster]

[justpete]

Originally Posted by TheAxiom

Yeah, it appears they don't understand Vanos _at all_

What a waste of time and money.

[631twentyeighteye]

Bummer. I just swapped cams on my bike and it entirely changed the power curve for the better.

[_Ryan_]

Originally Posted by justpete

Also talking with Procede about a custom dyno tune with the stock cams since Shiv tuned the shop's SCCA turbo car which runs a stock DME.

Custom flash with the OFT?

[Mike.]

ah, you gave it the old college try!

[TSM330i]

You might want to contact RMP Motors. They've been racing the N52 for a few years now. Back in 2012 (I don't know what they're making now), they made 279HP at the rear wheels and use both vanos and are controlling them both. They run the engines up to 8500rpm. Of course, this is a race engine, but they may be able to help.

http://www.rmpmotors.com/

[Taskmaster]

Originally Posted by Mike.

ah, you gave it the old college try!

Cherry o old chap!