2.2 upgrade options?

[David 23]

I'm considering giving my 2.2 a little more giddy-up. Currently the engine is hi compression (exact number unknown) and has Weber Carbs. It runs great, I just want some more power. What are my options in various degrees of improvement? Budget is of course a concern, but I'd like to know what options are suggested.

[TimT]

Cams and exhaust...

a 2.2 is a great engine, but upgrade paths are expensive

[David 23]

Originally Posted by TimT

Cams and exhaust...

a 2.2 is a great engine, but upgrade paths are expensive

Thanks for the reply. The engine currently has headers and free flow exhaust, exact cam is unknown but it has cams that are more aggressive than a stock profile. I was hoping for info on pathways to the easiest/cost effective displacement increase? 2.5, 2.7, etc.?

[RWebb]

yes, for more moola you can go to 2.5L

2.7, 2.8 is for 7R cases AFAIK

you can also put a modern EFI setup on it for more power, driveability, and fuel mileage - a guy on Rennlist is doing that - but not for the faint of wallet

[darrin]

another options is to mothball your 2.2 (if #s matching, or sell if not) and replace with a healthy 3.0 or 3.2 -- suspect this would be a more budget-friendly to add the "giddy-up" you're currently missing

[jpnovak]

Where do you want more power? Low rpm for take off, mid rpm for acceleration and passing, or high rpm for really spirited driving?

Cam choice will dictate your effective power band. Without knowing exactly what cam you have it is hard to make suggestions to change. If the current power band is to your liking but you just want more then you have to add capacity by boring the PC set or adding more stroke. As mentioned this does start to get expensive.

A 2.2 can be upgraded to:

A 2.3 by changing to 85 (86mm) Pistons and cylinders.
A 2.5 by changing from 84 to 90mm pistons and cylinders [requires boring the case spigots]
A 2.4 by changing to a 70.4mm crank and rods
A 2.7 (2.8) by adding the 70.4 AND 90mm (92mm) PC set [requires boring the case spigots]

Any of the above would require splitting the case - and that usually means a large machine shop bill to bring the old and likely twisted Magnesium case back into acceptable standards. Usually when you look at the cost of the machine work it can be more cost effective to upgrade the engine.

IMO a high compression, short stroke 2.2 is where its at. Plenty of go for a light weight early Porsche. Especially if the engine is in the middle (based on the 914 in your signature).

[Jack Stands]

If it’s for a 914-6, the 2.2 could be bumped up to 2.5 by using 2.7 cylinders, but need special Pistons to give high compression with the 66mm crank. Between parts and machining, you’re looking at $$$.

I’d agree that finding another engine would be best. A 2.7 (properly built) is great and light in a 914-6.

[David 23]

Yes, it is for the 914-6. This is all very helpful, exactly the type of information I am interested in.
I realize dropping a 3.2 in makes more practical sense, but that idea doesn’t appeal to my mechanical aesthetics. I’d prefer the smaller high reving engines as has been suggested.

[Jack Stands]

Have you seen Bruce Anderson’s book where he details options for increasing the horsepower of the various engines Porsche produced? The 2.5 liter engines with the short throw (66mm) crankshaft used to scream in the 70s race classes.

[David 23]

Originally Posted by Jack Stands

Have you seen Bruce Anderson’s book where he details options for increasing the horsepower of the various engines Porsche produced? The 2.5 liter engines with the short throw (66mm) crankshaft used to scream in the 70s race classes.

I will read it, thanks for the suggestion. I don't know how I had forgotten about that book.