2002 Head flaws

bigmansm · #1 (**permalink**) 02-28-2006, 09:32 PM

Why does everyone complain about the flow in the 2002 head?

I really want to pick up one of these cars and turbo it, but everyone is telling me to swap an m20 because the 2002 head is junk.

What's the deal? Get technical...

Villanuevas_BMW · #2 (**permalink**) 03-03-2006, 12:37 PM

Not really too confident in my knowledge of the heads, but I'll give you what I got. There are really three heads for the M10, the difference is really in valve size and the domeage which is a variable for the compression. The real problem with the heads is the camshaft drive system, not sure if the flow is the real problem here because a good camshaft can solve some problems. The problem with the cam drive is that it cant use roller rocker setup, some people have tried but the way it works with the distibutor is the limiting agent and wont work. Many people try to get the most from the cam drive with a better cam and lighter parts like titanium valves and rockers. Most people go with the M20 route because there is more of an aftermarket for it and parts can be cheaper since the M20 is the engine from the E30 which is more "mainstream" in the BMW world. A turbo setup a with fuel injection is more common than a carb setup. The M20 is already setup with EFI so complications maybe less than an M10. I guess what it really comes down to is "Bang for the buck". Im sure you already know that it would probably take more money to get power from an M10 than an M20. M20's are pretty strong, Ive been in a car with just a chip and was impressed. Hope this helps somewhat, try to contact Kris (oldskoolbmw) , or try www.2002faq.com ,a lot of real tech info there, if you dont mind the forum setup there.

bigmansm · #3 (**permalink**) 03-04-2006, 11:17 AM

so 1 vote for the m20 setup

CleanAzzE30z · #4 (**permalink**) 03-04-2006, 09:33 PM

Due to the low state of tune from the factory and the durability-friendly single cam configuration is my guess.

Mariano

OldSkoolBmw · #5 (**permalink**) 03-17-2006, 12:51 PM

Well it's not that the 2002 head flows bad. It's actually quite good. Metric mechanic has a list of stock head flows available on their website if you want the breakdown. You have to dig a little but it's there. I have the pics of them if you can't find them. The problem with the 2002 like a few have discovered is the rear end and the stub axles. The rear end is about a 280-300HP worthy unit and the stub axels are good to somewhere around there. Take for instance TEP's Old Turbo 02. I ran into one of the mechanics who built it (small world eh?) and at a brief 340HP on the dyno if it caught traction the diff was in pieces. Another with a turbo m20 at 280 and he's on his 5th unit. If you want 240Hp then you might get away with stock parts but anything more you're pushing the envelope. So before getting one of these sleds and turbo'ing it I'd make sure what your HP goals are. 2L and 7000 rpm and a turbo... easily more than what the diff can. I'm busy trying to put 4wd and a sr20det from a pulsar into mine. Did I mention after 200hp traction is horrible. Back on topic. The heads are fine and can flow. I've got a 15+% gain over stock with creative porting. I've also made a set of 1.5mm oversized titanium valves and had plans for what was gonna be a desmodromic conversion for these heads for really high RPM. 9500+ Roller's never worked because the rocker arm ratio varies during lift due to the width of the pad. This creates an issue with the roller having a fixed contact point (rather mostly fixed) vs the rocker pad's width. Needless it was just time to quit trying to fix a dead horse and go with new. a 75 shot of nitrous will get you a 13 second quarter with one of these cars and sidedrafts.