I suppose you have not studied Porsche 951 engine more closely? It's far more advanced engine compared for example to M40 8V engines. That engine is full aluminium one. Valvetrain is much sophisticated, it does not have rockers like M40 has, camsaft pushes directly lifters. Also cylinders are aluminium coverd with alusil coating, BMW moved alusil/nicasil about 1,5 decade later. Guess what car/model was the FIRST one to have a full Motronic enginemanagement system ? Yes it was Porsche 944 n/a model. Turbo was launched for model year 1986. Turbo versions Motronic with additional KLR box features also quite advanced knock detection and over boost protection system. Even tough this set up is now over 20 years old it still offers lots of possibilities for extra ponies.
There are a lot of MAF/MAP kits available, some of them uses even SMT6 boxes you are using as well. I hope you do not get me wrong, you have done a great job there, it's just hard to belive with 0.7 bar pressure your engine produce over 220 HP even with advanced cams, hopped up compression ratio etc.
Here's one quite advanced 944 turbo engine my good friend is just building. It has Darton 104mm MID sleeves with Wössner pistons. I am building quite similar setup except i am using Porsche 944 S2 alusil block which is already 104mm bore. I am using Mahle 104,5 mm Ferrostan coated pistons, like original 2,5 L engine with 100mm bore has. Heads we are using are modified a lot by a local specialist, who have all necessary equipment (flowbench etc.) available.The valves are sodium filled Chevy big block ones made by Manly. Here's few pictures taken from my friend's engine, my own build up is still more or less at the starting point.
Here's another friends engine (a 3.0L). It produced 430 hp (dynoed) with 0.88 bar. When break in perioid is over the boost will be turned to 1.2 bar, it should produce more than 500 hp, at least fun usually starts from 1.0 bar
Our engines have several items which has been custom made for us. Here's several:
Cam gear which give a lot of tuning possibilites
Rods. These are also made here locally. Builder who make these has been doing special engine parts professionally 25 years. Products are mainly used by scandinavian rally cars, also lot of finnish drag race teams use his rods. He guarnteed our rods can handle at least 1000hp and over 1000nm torgue. Should be enough for our "mild street engines"
New throttlebody will be also slightly bigger. Old one with Edelbrock Mustang unit.
If you look closely pictures from my friends engine you can see same kind of throttle body installed.
Some "freshed" items for my engine build:
The only negative side to build these engines is the price, which will be between 12000€-15000€ depending what parts you are using
Here's interesting E30 turbo conversion :
http://www.r3vlimited.com/board/showthread.php?t=84137&highlight=Turbo+M42&page=12With 13 psi = 0.896bar 267 whp. Engine is a 2.0L 16V M42, so i hope you see my point, if you say well over 220 hp with 0.7 bar from a 8V 1.6 Liter... that car even features a Link Plus EMS, which is a very good system and gives a lot of possibilities over a piggy backed Motronic's.
