Not very. At what point is there incentive for capital investment into new plant, and who will pay for it? Not saying it's impossible, but it's a consequence to some significant POD elsewhere, I reckon.
What industry there is on the island is in the North - H&W, later Shorts, etc, so there's not a base to grow from - evolution is easier than revolution...
The nearest market is Britain which is already a world leader in heavy industry, and as it falls behind it's because the US is replacing it, supported by a large internal market that Ireland can't replicate.
Interwar, maybe a Rosa's Red Germany or a Communist France might inspire Britain to throw money at Ireland? Big PR barrier to overcome there though.
Avoid WWII post-Munich and maybe the Axis would woo Dublin, but they've got a lot of work to do to modernize Italian and Spanish production and will probably prioritize those first.
Not sure that there's a compelling argument that Irish entry into WWII would have resulted in a lot of money, tooling, or orders going there. I guess if you could get some sort of low-volume domestic aircraft, automobile, or tractor production going via subsidy in the 20s, there would be a chance to expand it here, but it has to be working first, and frankly if Ireland is in the war, the economic hit from pulling men of service age from the workforce and getting quite a few of them killed may well outweigh the advantages of any wartime orders. Maybe a tax-exemption for a French or Dutch aero manufacturer to set up an alternative factory in the 30s, followed by an evacuation of staff in 1940? Might butterfly Shorts move to Belfast?
OTL Germany, Japan and South Korea see heavy investment through the Cold War, but Ireland isn't a buffer against Communist expansion in the same way.
Maybe get a UK Labour Government to go full Trotskyite and the US will seek a counterweight to it?
Late 20th century booms in manufacturing in the Far East are driven by low wages and regulatory costs, but those result in easy labour flight to the UK and EU in Ireland's case, plus competition against German manufacturing in the EU regulatory regime is an ambitious direction to choose to take.