Originally posted by 930gt-40r
I wanted to do the whole bosch injection sys with pressure sensing, but after buying the plenum, harness, and software it would come out to almost 5 grand which is right know out of my reach. I would love to do it but I guess my accel dfi will have to due for now. Im sure it could be tuned to run close to the bosch/protomotive setup, but there is something about having the stock porsche designed part-throttle curves and map sensing that makes my pulse raise.
With a decent, modern aftermarket EMS, you can tune ALL engine parameters for these motors (and pretty much any older motor/setup for that matter) to only run better than stock by someone that truly knows what they are doing. Aftermarket EMS gets a bad wrap because it can be very complicated to deal with and very easy to get wrong. Most modern aftermarket EMS' (except maybe SDS or some of the really simplistic ones) have superior software and superior hardware componentry compared to the stock Motronic, plus lots of advanced features that will generally increase efficiency and performance.
Wydryd, divided housings do definitely aid in spoolup. It's really fairly simple actually. You are dividing the total surface area and adding a slight restriction, which has the effect of increasing exhaust flow velocity. Quicker velocity means quicker spooling. It's much the same basic concept that people use when porting heads. Also, depending on the exact setup, with divided housings you can also take advantage of pulse tuning by grouping the proper cylinder pulses into 2 separate runners that stay separate all the way to the exhaust housing. To give a general example, all I4's have a 1-3-4-2 firing order. You'd group cylinders 1&3 into one runner and 4&2 into another runner and keep them separate all the way to the turbo. Generally, from what I've seen this tends to have more of an effect in shorter manifold designs like you'd find on a compact I4. On F6's, our headers are generally a decent amount longer so I doubt if you'd notice much effect if any. Running the divided housing alone is all that would really be necessary.