This is a very common question asked about the Tii engine, so I’m going to share one asked that fits the discussion.
I have a euro 73,74 tii engine with the larger 9.5 pistons and newly rebuilt pump and injectors. Was wondering what it would take to get 160, 180hp from this motor? And would the pump need modifications as well ? Would it be drivable ? What would such an upgrade cost? Appreciate any opinions and experiences.
For a 30-50hp increase, there are several things that could be done to increase your engine’s performance with and without pump modifications.
There are several approaches to doing this. Answering this without making it a “how to” article on the subject which has been done in 100 different ways over the years, let’s cover specifically what you said.
What would it take? Would the Pump Need Modifications?
Horsepower improvements from 160-180 hp without changing the pump:
- Increase your displacement with larger pistons up to 2.2 liters
- Increase the torque with a longer stroke, using the E30 M3/S14 crank
- And then improving the exhaust system to a larger diameter free flowing system
Horsepower improvements from 160-180 hp that require modifying the pump’s fuel delivery curves
- Increased induction and air intake by using multiple throttle bodies or larger bore throttle body in addition to the modifications listed above.
Alpina Throttle Bodies
A word of caution about Tii engines It’s important to note that a different camshaft other than stock has proven to create more problems than it helps. Historically, BMW used the same camshaft lift and duration from the 1600 1 bbl Solex all the way to the 170hp 2002 turbo.
Would it be drivable?
There are many 2002′s on the road with engine performance modifications in the horsepower range you mentioned, but not using the base of the Tii fuel system to do it.
With different cam, head improvements, bore and displacement changes, stroke changes and dual side draft Weber 40s or 45s carbs instead. It’s possible to have a drivable car, and making the assumptions that how much fuel you consume is directly related to how often you keep the accelerator pedal on the floor 
What would it cost?
As a rule of thumb, as costs go, an engine with these kind of modifications could easily cost one half to twice as much as the cost of rebuilding the engine in stock condition.
Last update: 2007-01-03 21:26
Author: tiiregister
Q. How many air filters are installed in a 1972 BMW 2002 Tii and in which direction are they installed, with the open ends of the filters facing the spouts on both ens of the unit or facing in towards the center of the canister. Thanks Burt
There are (2) identical elements, both are open toward the center of the housing. Clean air enters the snorkles, passes thru the elements and enters the throttle body.
Engine view with airbox
Last update: 2009-04-13 17:23
Author: Jim Gerock
How to identify a 2002tii exhaust manifold
We are asked many times how to identify a 2002tii exhaust manifold. There seems to be several for sale which appear similar but are not. For example:
What is the difference between the exhaust manifolds fitted to tii’s and standard 2002′s? Were the original castings the same or was there a difference in the casting? Also, have the manifolds changed; i.e., are new replacement manifolds the same as those originally fitted to tii’s? Currently, the tii exhaust manifold seems to be the only manifold available through Mobile Tradition (excluding the thermal reactor which is also available – for $2000!). What’s up with that? -Jerry
The good news is that adding the tii manifold to any BMW 2002 engine will improve the performance in terms of gas mileage and horsepower because of better flow. The original manifolds, especially the 1975-1976 models were restrictive to meet early EPA pollution standards and eventually warp the head due to the extreme heat produced by them compared to the original design.
When you place the old style and any 2002tii manifolds side by side, it is easy to tell the differences. As the saying goes, a picture is worth 1,000 words.
Click the photo to see the full resolution photo.
Tii Exhaust - Click to view