No there isn't any line which says 40 kn to be exact. But HAL's engine div. stated they can uprate it to 30 kn (15-20%)
RR engine isn't expensive it's the Honeywell which raised the price.
The point of bringing two diff engines is that despite one is of smaller dimension it produces similar thrust than bigger one.
So only a 25 kn will fit on Jags isn't true you can put a higher thrust engine as long as it fits the airframe dimensions with minimal changes.
Period.
The discussion started
@Chandragupta Maurya saying that DRDO is developing an engine for Jags.
I clarified it about being an HAL venture not DRDO.
HAL venture in context of Jaguar is only HTFE25 with an afterburner, which would provide a thrust of approx 40kn.
Rest of it is digressing from the original discussion.
To summarise:
1. Engine program for Jags is not being run by DRDO.
2. HAL from its own internal accruals has developed a TD of HTFE25 and an afterburner section for HTFE25, which can generate approx 40kn.
3. The only Indian solution that's feasible is (2) above. I mention Indian solution cuz the original post I replied to mentioned DRDO to mean(to me) Made in India.
4. The HTFE 25 cannot be uprated to 40kn of dry thrust without increase in dimensions. That's my assessment cuz of 60% increase in thrust.
5. What RR or Honeywell is offering may be a subject matter of a separate discussion.
Edit- Didn't realise you put a period too. So as u said.
Period.
.
