ok, i bought this turbo manifold a while back and i want to rebuild an m10 that is sitting in my garage so it will be strong enough to handle the boost, i would like it if you guys could read this over and maybe disregard the age of the article and shoot some modern suggestions as to a setup including a turbo to use, i am hoping someone may be able to draw me a map on the setup for my car. its an 84 318i. heres a pic of the turbo manifold and the write up that came along with it.
Visits to Turboland of Mountain View
from BMW CCA Roundel, February 1988 by Paul Kunz
BMW's 318i is not known for its great engine performance, being the weakest BMW ever sold in the States. But it is a great handling car with 300 pounds less weight than its sister, the 325e. The solution according to Steve Dinan's Dinan Engineering of Mountain View, California is to add a turbo, and so about a year ago I paid a visit to his shop to see what turbocharging was all about.
I arrived at Steve's shop to take a test drive of a 318i Turbo. Steve was busy with an owner of a M635CSi, now the proud owner of the first M635CSi Turbo. Yes, you read that right, a turbo added to the M-machine which gives it 440 horsepower. To accomplish this and have the engine survive isn't easy; the compression ratio is lowered from 10.5:1 to 7.7:1 by using shorter, racing quality, connecting rods. With these components the redline is increased to 7300 rpm. The head gasket is replaced by one made of copper and the exhaust manifold that feeds the turbo is their own design and made of ductal iron to take the heat. I am impressed with the engineering that goes behind the conversion.
Getting back to the purpose of my visit, a test drive in what now seems a very humble 318i Turbo. Humble compared to the M but not compared to what comes out of the Munich factory. The IHI low mass turbo starts kicking in at 2000 rpm and is at full 9 PSI boost at 3100 rpm. What effect does it have? How about 0-60 Mph in an estimated 6.5 seconds; and a measured 1/4 mile in 14.6 seconds? It's been dyno tested at 183 hp with catalytic converter; without the converter one could produce another 20-30 hp.
As Steve explained, it is not just adding boost and other mechanical modifications. An eletronic black box, which monitors engine rpm, the air-flow meter and amount of boost, was specially designed for Dinan and added to the car's electronics. It's called Dinan Turbotronics. It is spliced into the coolant temperature sensor input of the OEM computer so as to fool the computer into providing a richer mixture, which is needed to make use of the extra air and to prevent detonation (pinging). The air flow meter has a different spring rate to match the turbo over the full rpm range, and the fuel pressure regulator has been changed to provide higher pressure. The Turbotronics box has many switches and easily changeable resistors so that the same box can be used for all their turbocharging conversions and yet be 'tuned' for each application. Sounded to me like true Silicon Valley hot-rodding.
Getting back to the test drive, Steve took me for a short ride to warm up the engine and demonstrate the car's handling capabilities. Besides the turbo conversion the car also had the Dinan Engineering Stage 4 handling package. The car was lowered about 1% inches which was quite noticeable. It rode on 205/50-15 Goodyear Gatorback tires with l5x7 rims. Steve felt the car was lowered too much, not leaving enough suspension travel, but BMW has left such wide wheel openings people want to use it up to make it look 'good'. In Steve's hands the car was very fast around the freeway cloverleaf course he has around the shop; I don't recommend riding with him if you have a weak heart.
Now it was my turn to take the car out; Steve let me play with it for about an hour. What a rocket of a car it was! Beginning from a standing start, this car smoothly went up to 3700 rpm, at which point you were at maximum boost, then it really took off with the 6500 rpm redline coming up almost instantly. A quick shift to second and you found yourself at 4000 rpm under full boost again. In another instant you were at the redline and shifting to third. Steve said that this keeps happening until you redline it in fifth at an indicated 136 mph, but I wasn't brave enough to try that. It didn't matter which gear you were in, full throttle after 4000 rpm meant that a gear change was up very soon. This car really knew how to move! Yet, in the traffic of Main Street it could be handled quite tamely; the traffic was even more frustrating to take knowing what you had under the hood raring to go.
My hour was up and I dutifully brought the car back. This car was test bed for the turbo conversion that Dinan was going to market. But alas, with only two year's production of 318is its not worth the cost of certification. This one-off car was sold to some lucky person (a BMW CCA member, by the way) for about $18,000.