Take a look at these camshaft specs...

[peterblais]

Hello,

I'm a VW guy and just picked up an m3. Planning on throwing some cams in it. Anyways, one of the cam companies I have used a lot in the past for volkswagen stuff offers some grinds for BMW. They are european so they do not really have any info on the american "S52" engine. They offer this camshaft for M50/M52sv, and they state it needs "custom" valvetrain- it is a hydro lift camshaft btw. Regardless, they aren't familiar with the valve springs in the american S50/S52, so it is a bit of a judgement call as to if I can get away turning to 7k with these cams on stock springs or not. I'd rather not change the springs / retainers until I get around to properly building a cylinder head.

Here are the specs:

Intake / Exhaust

Duration .1mm+cl:
OEM :230 / 231
CAM :275 / 275

Duration 1mm+cl
OEM :195/195
CAM :237/237

Maximum Lift
OEM :9.00 / 9.00mm
CAM :11.15 / 11.15mm

Lift at TDC
OEM .15 / .45mm
Cam 2.05/2.65 mm

I'm a 4 cylinder guy to the heart so i'm not looking for fat low end torque by any means. This is the hottest hydraulic lifter grind they offer and they call it a pro street / rally grind.

I tried to compare it to sunbelts and to evosports but the sunbelts are measured at different lifts and the evosports don't give you any real measurements of any kind (what good is a duration # without a lift to match). They seem hotter then the shricks on paper. They do have a couple of less aggressive grinds as well.

So, would it be possible to get away with this camshaft set on OEM valvetrain with a conservative rev limit? FWIW it does note that the VANOS travel must be limited, it does not say to what, although i'm sure an email would sort that out.

[peterblais]

bump

[ScotcH]

If this is for a street car, there really is no reason to stray from Schricks. They are proven, have the power in a usable range, and are pretty cheap. Why reinvent the wheel? I suspect with the specs you posted, the power will be WAY up there in the RMP range, ie, not really usuable on the street.

Now for a track car, everything changes of course.

[peterblais]

These are quite a bit cheaper then the shricks because we have an account with them. I think they would make more power up top as well of course at a good hit of torque down low.

To modify the vanos is it possible to simply place a machined puck inside to mechanically limit the travel of the cup / splined plunger? I was looking at some pictures of one apart and it looks like something I could whip up on my mill, and be able to avoid too much trial and error with funky install procedures.

They have a 268 / 268 advertised cam as well as some others between that and stock. I'm really looking for big peak numbers though, eventually I'd like the powerband to be 5-8500-9kish. Nothing can be less useful on the street then my *other* car haha, 1.8L low compression in a 2800lb car that doesn't spool till 5500. ;) Talk about a dog out of boost. The cams I use in that are a 272/286.

[ScotcH]

Yes, you can limit the Vanos like that, but you might as well try Dr. Vanos ... he does that as part of his rebuild service.

[peterblais]

My car had a new vanos unit put on it about 10k miles ago, found the receipt in with the p/o's paperwork. Unless it starts making some noise I'd probably just pull it apart and shim it, although I do realize it'll take a little bit of guestimating (its just a linear relationship so it should be relatively easy to take a good guess at the required shim) to get the proper travel.

I'm just wondering if I can get away without changing the springs right away on these, the cam company (cat cams, btw) isn't very familiar with the S52 although they are familiar with the M52. I've seen a few measurements of the stock valve springs kicking around but nothing I trust enough to send in to them.

I was hoping to find somebody who has a good idea what the sunbelts or evosports really are (cam doctor printout, maybe?) and see if these are in that ballpark. The other option is to put them in and just get on the dyno and start working up in ~500 rpm increments looking for float, although that isn't entirely foolproof.

[Rennmeister M3]

Good luck dude, I can't even find valve moments for most of the cam choices we have. There is really @#$% all for cam info out there. Alot of people in this community just bolt it on and go, there is little in the way of actual RnD done at the member level, and companies aren't about to divulge all their info.

You're in your own boat with this one. Best thing to do is buy an OEM spring and test it yourself. That way you have a physical test you can perform in regards to bind length, etc.

[peterblais]

Yes- thats what I will do. I don't have enough time on my hands at the moment to be haphazardly bending valves using the good old scientific wild ass guess method.

I could get cam doctor printouts if I could get my hands on cams, but spending 4-5k to buy a collection isn't in the cards.

Cat has a good selection between OEM M52 and 310ish degree solid lifter grinds. 6 or 7 grinds in all. Like I said the 275 / 275' are the hottest "hydraulic" lifter grind they offer.

I might just throw in some supertech springs / retainers too because short of pulling apart my head its hard to say if a 70k mile spring is on par with a stock one. I just got this car and I'm way too in love with driving it to pull it apart just to test a spring lolol.

Compared to a vw / audi 1.8t, changing springs on these looks like a day on the beach, so whatever.

[RRSperry]

Isn't Josh and EuroSport in SLC? I'd go talk to him.

[peterblais]

Yup they are next door to the metals place I buy from.

[pbonsalb]

I'd like to see 8500 rpm on either hydraulic lifters or a stock bottom end. Both would be incredible. For how many seconds do you need to do this?

[peterblais]

It wouldn't be on stock bottom end, that much is for sure.

[autocross97]

well the part numbers for m50 and s50 springs are different on real oem, pelican parts has the springs for the M3 listed as the same springs used in the 318. i dont know if thats of any use but i found it interesting.

what kind of prce difference are you looking at here? i've been looking for aulturnatives to schricks and sunbelts.

[pbonsalb]

There was recently a lengthy thread on cams that are more radical than the Shricks that are most commonly used -- Sunbelt and Eurosport. Stop in Eurosport since you are nearby and hopefully you can get some information out of them for your application.

http://forums.bimmerforums.com/forum/showthread.php?t=913025&highlight=eurosport+cams

[peterblais]

The cams you are speaking of are EVO sport, not eurosport. Eurosport is local to me, and they sell a shrick based kit. I'm sure they would advise me to run shricks lol.

That was a typo / mistake for the first few pages of that thread it gets cleared up a while in. I've pretty much scanned every recent cam thread I can find on here, the real thing is neither sunbelt or evosport give out much information on their cams so they are not useful for comparison short of buying a set and measuring them up.

[pbonsalb]

Hopefully, then, the cost savings you will realize by buying the relatively "unknown" or "unproven" cams that you have in mind will prove worthwhile. Give them a try and let us know how things are going in a few thousand miles and the dyno results. Most of us don't have this theoretical cost savings opportunity, so we go with what is supported by vendors here. There are occasional pioneers, and you could be one of them.