M50/52 3.0 Stroker

[Ben 0]

It doesn't work that way - you'll get more hp from the cams **if** you increase the c/r, not in addition to. Arguably same with the exhaust, unless the std exhaust (and intake - a different issue) isn't a restriction on uprated cams. To put it another way, if you want the 15% on the cams you may *need* to increase c/r, change headers and modify intake. They don't add.

Are you trying to say cam duration doesnt affect hp output?

Holding a valve open longer even with standard compression would create more power.

Take kerry's engine above^^ M52 with higher duration M50 cams.

If he took the cams out his hp would drop . And Im guessing hes using

the standard 10:1 CR. If he was to go hotter in the cams again he would see more

power albeit at higher RPM.

Yes compression helps with hot cams but its not needed for a hp increase.

If you do reach that power goal, you'll need new injectors, the remap, all the parts including cams - sounds to me like $000s - maybe not $6500 but you could sell your M50 to cover some of it.

I already have B32 injectors and I can get both cams for under $500. The tune is the only

price Im not certain on because that can obviously vary.

(edit - and the one David (silverfox) did was 220rwhp, so start there - I guessed a higher conversion factor for Gavin's dyno as my 2002 only made 102rwhp, so surely its a big factor, lol).

I calculated the above in a way to get the lowest figure from the outlined possible increases.

If I had have calculated from whp you can bet someone else would say "you cant do it like that"

A quick guess would say Id come within 10whp of what I originally said though.

You have raised one point I was pondering though, does Gavins dyno exaggerate figures

compared to others?

[Silver Fox 43]

In my experience with dyno figures, Gavin's is at the lower readout end rather than the higher one.

I'll say one thing for Gavin, and that's that he's fairly conservative when it comes to figures and tuning. You'll end up with a very drive-able car which won't explode at the first track day, but will perform as well as he can make it, and the printout will be what it is, he doesn't doctor dyno figures for the sake of impressing people.

[CamB 48]

I really do hope this works out - seriously. Its awesome when stuff can be achieved on a budget.

Longer duration cams mean more overlap and may need a higher static compression ratio to achieve the same dynamic compression ratio.

The engine will make more power if it flows more air at higher rpm - if anything restricts it at higher rpm or lowers the VE (not maintaining the c/r would do the latter) ... maybe then it won't make more power.

By the way, I've basically surpassed my technical limits about here - further questions may be met with blank stares as I won't know the answer :)

A final thought - these guys offer a kit to add Sunbelt cams to an S52B32 which is 5% bigger than an M54B30 (oops - 5% not 6.7% as its 3150cc). They show 265rwhp with the mods listed and track pipes (not cats). For a 3l, thats just over 250hp. I think a US spec S52B32 has 10.5:1 compression ratio.

http://store.bimmerworld.com/bimmerworldsu...m-kit-p749.aspx

It will be hard to improve on that. You might pick up a few hp in the headers. Its already got plenty of compression and they're already warning against revving any higher (noting you'll have a diff setup).

Another perspective - an S50B32 makes maybe 260rwhp plus any tuning mods. That's from 11.3:1, individual throttle bodies, awesome headers and 7400rpm - ie, 100hp/litre at the crank. Its not easy.

Edited March 7, 2011 by CamB

[hybrid 1043]

Also very interested to see how this works out!