Dean
Member
Here's something GM learned back in the 80's.
It seems mid range power can be built if you increase the length of the passage between the inlet (air filter) and the cylinder.
One way they did it, was to design an intake manifold in which the passages crossed from one side to another.
It was called "TPI", which stood for "Tuned Port Injection".
If you take both your hands and clasp them together, with your fingers interlocking, you'll have a pretty good illustration of what that manifold looked like.
Keeping with that train of thought, you might want to discard the stock intake pipe and build your own.
Saw the flanges off so you can reuse them, and weld them to a longer pipe (or cut the stock pipe in half and weld in a length of pipe that has the same inside diameter as your current one.
How much longer? I couldn't say. That's going to have to be a trial-and-error thing, unless you can find some kind of mathamatical formula that'll give you the answer (or at least get you in the ball park).
Also, an overbore kit will build power in the mid range and a little of the upper end.
I found that out, back when I was messing around with VW Beetles.
My dad had a european '67 1300 (that had the steering swapped over).
He found a '68 1500 for me, but the engine came in 3 boxes, so we rebuilt it over the winter.
Once it was done, he put it in his car (thanks dad!
), because it was time to rebuild his engine.Now understand that the difference between the 1300, the 1500 and the 1600 is simply the bore size. Everything else is the same (VW did that on purpose).
With a 5mm larger bore, he noticed that the car could pass slower vehicles much more quickly.
When he rebuilt his 1300, he picked up a set of 1600 cylinders and pistons and used those and although it didn't seem to take off any quicker, it didn't lose as much power at highway speeds (90-100kmh) as it did with the smaller stock cylinders.
Same goes for any engine, even these little buzz bombs, so it might be something to keep in mind, should you ever find yourself with some time and a little extra cash.
Dean
