Theoretical 4 cyl Power Limit.

[MD]

Coming up to Christmas with much a more relaxed mindset, I have begun to do some daydreaming of possibilities. The YouTube channels are full of what seems to be mythological horse power numbers disappearing into thousands.

The previous numbers of 100hp/litre were considered really slick numbers if you could reach them in a motor build. Things have really moved on.

Understandably these high hp engine are not without modifications. So what is the theoretical maximum production Alfa engine of the 105/116 capable of producing sustainably without self destruction and how do we get there?

Feel free to join the discussion..

[Duk]

What sort of fuel are you looking to run?
Obviously E85 gives very large advantages over 98RON petrol.
NA or forced induction?
Road car or circuit racing?

I would guess that controlling the heat within the engine (obviously there are no oil squirters for the pistons) and maintaining dimensional stability of the cast aluminium, open deck block, will put a pretty decent limit on things.
Keeping all of the combustion gasses inside the cylinders will also be a challenge. No MLS gaskets being available means applying some of the old school tricks.

A dry sump oil system or a good vacuum scavenge pump setup would be a good idea, to get the windage out of the crank case.

I think getting oil squirters into the block would be a priority for long life.
To emphasize how effective they are, Toyota use 3 squirters per piston in the GR Yaris engine.

With a modern turbo or a centrifugal supercharger, 400hp is probably reasonably doable without distorting the block too much.
Whether that would survive the heat soaking of circuit racing, is another matter.

I think it was MENDE's (from GTV6.com) business that had developed a 1 piece main bearing girdle for the TS block. And either a mono sleeve or probably a bit better, a deck insert to close the top of the block, would be an obvious upgrade.

With a more robust block, good quality rods, pistons, bearings, clearances and lubrication system, you might be able to push the engine to over 600hp without munching the main bearings.

[MD]

That's a great shopping list for Christmas you got there Duk. I would like to see a 4 valve head and a lighter crankshaft in that bag. Making that a reality is not impossible but a tall order indeed.

[NSharpley]

There's a rumour Beninca's got 700hp from a Nord engine.  Turbo of course.

I don't know the details but I saw it drive.   Absurdly fast.

[Craig_m67]

Sounds like an awful lotta work.. can we not just bolt in the 1750tbi or a 2.0L from a Giulia.  I wonder if the 2.0L would fit.. it's pointing in the right direction

[MD]

Would be a possible solution if you could make it work but it isn't realistically possible. Been there and had to resell all the gear that came with engine. It's a complex engine and requires precise engine management and the onboard ECU has a limit to its upgrade. Beyond that, the ECU is looking for a hundred inputs that are not there if it going to live in another car other than the original. There are no "off the shelf" after market ECUs that can program that sucker.

On its own it just doesn't make enough ponies.

Motec were going to charge me $1 000 a day for a week for the Giulia to be run on a dyno so they could decode the Factory ECU. So I was up for their fees, plus a dyno all day for 7 days, the basic program loading up on the latest Motec product to just get the Giulia engine running in a racing chassis.

Looking at $20K for the experiment. I just walked away from it all.  Lots of modern engines have an umbilical chord tied to the parent chassis like the Giulia and the brilliant Infinity 3.5L V6 to name another.

[Duk]

I think if you are prepared to do an engine conversion, then just suck it up and jump to a Japanese one.
A Honda K20 or 24 is a fairly modern choice, still uses port injection and can be made to work much better.
Older school icons like the Nissan SR20 and Mitsubishi 4G63 would be obvious contenders.

Spool Imports use to list the option of making custom cranks to your specs. Maybe they still offer that service.
There was a minimum order of I think 5 and obviously cost would be quite high.

Years ago someone on one of the Alfa forums noticed the Mazda BP (1.8 litre twin cam 16 valve) head was very close to fitting on the Alfa block.
That could be something to look into. But keep in mind that they use belt driven cams.
Though it's probably easier to convert a belt drive head to chain drive, rather than the other way around.
I use to own 1 and from memory they were a reasonable, but unremarkable head. A solid 16v design and had reasonably sized inlet ports. Not the stupidly oversized ports of say, the original 4AGE engine.

[festy]

Depends on your definition of "sustainably"
With a forced induction motor running on methanol you could ditch the entire cooling system and grout fill the block to gain a lot of rigidity - fine for 1/4 mile drags but wouldn't last long in a street or circuit car   

If engine conversions are an option, then it'd be hard to beat the power gains of ripping the driveline out and replacing with batteries and hub motors.

[Craig_m67]

@MD.  Interesting, glad somebody considered it and had a crack.

Personally I think an EV conversion when batteries become light/(e)denser/cheap (pick any two) would be $20k better spent.  Unpopular opinion I know.  And off topic..