1st update for 2008!
Stock 3.45 LSD has been installed:
And ITB setup work has started:
And also the adapter:
By the way, tim_s was right about something :eek: those ITB's are indeed 50 mm in diameter, not 48 mm as I remembered. Good thing I did not bet with him!
Adapter is made from 2 x 10 mm aluminum plates bolted together. Intake port holes were done mostly by 8 mm drill, we tried smaller and larger but they were slower. Holes have now been filed smoother and once I can put the adapter to head and ITB's I will sand the ports to correct shape. Thin gasket made by gasket paper goes between the plates, I think I use original M42 gasket between adapter plate and cylinder head and original S50 O rings between adapter and ITB's.
Fuel rail and injector control rail come from M42, they seem to be perfect fit as they are. I however need to remove two supports from fuel rail, they block atleast one vacuum rail hole.
Vacuum/idle rail comes from S50. It needs to be cut from two places (to get rid of useless middle ITB for M42) and then welded together again. Also air feed pipe needs to be cut out from the discarded part and put back in shortened rail.
I think airbox will be made out of glassfiber, I got a book about competition car composites as christmas present and I'm studying it now. Then I need some intake runners with bellmouths too, possible made from glassfiber too.
I don't think I will use stock (or even the larger E36 M3) filter housing due space restrictions. One idea is to put a largest possible BMW OEM panel filter (I'm not too keen on cone filters...) in front part of airbox in similar manner it has been done on E46 M3 CSL. That solution provides large surface area filter for adequate airflow but might slightly affect airbox tuning. Also, air metering thingamajik (whatever it will be in the end) needs to be BEFORE filter, perhaps causing problems with dust etc.
M40 flywheel and spare set of M42 cams are ready to be sent for machining, hope to get them done soon
Much pondering going on what needs to be done before track season starts, there's 3,5 months to go in Finland. As said earlier, I need to think about the power I'm going to get due sprint class limits. It's either around 155 hp or 195 hp I need to be with current weight.
Almost 155 hp can be had with a good chip and 98 octane fuel alone, I'm sure ITB's alone on top of that would bumb me out of snail pace class... Then I would be in the same class as E36 325' and 328's!
Then the question is how much I could get with ITB's, solid lifter conversion, 260-270 degree and 10,5 mm lift regrind cams and a chip that is designed to work with 256 degree Shrick cams.
Shrick cams + chip is often quoted to give about 160-165 hp but that is well short from 195 hp goal. ITB's might give some help as would higher rev limit due solid lifters but I am not sure how much.
Interesting things to ponder
