930 upgrades - where's the limit

[pac]

In another post somebody commented about a 930 engine rebuild as being 'not of a good mix' for the parts used. I wonder where is the line between doing a 'streetable upgrade' or 'going full out with no return to the street'.

How would a '76 930 dedicated track car look like in terms of engine parts? How would it compare -performance wise - to, say, 911 RSRs rebuilds?

[beepbeep]

I don't quite understand the question?

A 930 engine is nothing but 3.2 engine with turbo, shabby fuel system and choked intake/exhaust.

Performance-wise there is no comparision. A fully stock 930 engine will deliver approx. same power as highly tuned RSR engine, while reving less. It will also produce more torque = more swept area under power curve = more accelleration trough gears from same power.

There is no sharp line between streetable and non-streetable. It's fully possible to build fully streetable and docile 600hp 930 engine. It's almost impossible to build fully streetabe 300hp N/A engine. Personally, I believe best start for building a hot turbo engine is by selling the 3.3. It's a mix of crappy parts. All that's good is already there on 3.2 (same case, same crank). All that's better exist only on 3.2 but not on 3.3 (fuel injection, bigger ports, better plenum).

People think 930 engine is some sort of magic bullet for performance but it's really just a very conservative engine that works well but isn't optimal for extreme tuning.

[pac]

Thanks Goran. What I actually had in mind is to understand the engine differences between the '76 930 and the 934. My interest in this is around historic racing and the local reg limitations as to the year. This leaves no options for a 3.2 or 3.3 upgrade. Rather than trying to mimic the 934 (cost wise it's hopeless anyway I think) I am trying to understand how a racing version of a 1976 930 could look like from a engine mods/parts perspective.

[Henry Schmidt]

The 934 had a flat fan, twin plugs, huge port, wild cams and most had a pair of water to air intercooler.
Other than that it was stock.
They were both CIS engines after all.

Your 3.0 turbo offers some real challenges. First no intercooler. This truly limits horse power potential. Next very small ports, low compression and a fairly crude ignition.
That mixed with a lame exhaust system and you have a real bog meister.

I like the 3.0 turbo engine but now stock. With port work, a better exhaust, updated distributor, slightly higher compression and some good cams you can do away with most of the lag and make 300+ hp to boot. Add twin plug and get it up to 340 hp or so.
Fun to drive without a huge investment.
Are there better ways to build a turbo? sure Will they fit your criteria? probably not.

74 Turbo Project

[pac]

Henry, how would the hp look like by adding racing headers, sports intercooler and a k27 turbo?

As for the intercooler, I can add one since the 934 also had one - althought not the same.

Also, why do you say that the above combination 'will do away with most of the lag'?

[pac]

Ok - I see you have the K27, but no i/cooler