I've personally installed a half dozen oem fw's that range from 11.5-14 lbs. All have been machined professionally, and balanced, and at this time, none of them have ever given me any headaches. In fact, I've recieved praise from customers who absolutely love the mod.

Anyway, I recently made the decision (based on finances) to go with a P30 flywheel on my boosted GSR. Now, the fw is a good one because it maintains the 9 mounting holes for the clutch PP, and weighs in at 17.5lbs. It's a jdm unit that shows no signs of abuse, and for the price (free) I couldn't go wrong.

Fast forward to my machinist who wants to take the inner ring off the fw in order to properly press out the dowels. This should drop about 2lbs from the FW itself, which would take me to a healthy weight, but I'm not sure about the safety aspect. We've all heard horror stories about fw's expoding, etc. I know the ITR fw is a 14lbs unit, but unfortunately no one was able to answer my question about how they get it that low. Is it a P72 lightened, or it's own cast?

So here's the question.
Running about 300whp, and 200lbs of torque, an ACT hd pressure plate, and street disc, what is the lightest that you would feel safe running on a factory FW?

 

here's my ITR fw thread if anyone wants to read it. There's some info in there, but still no answer to my question.

https://honda-tech.com/zerothread?id=938656

 

my ls fw weighed in at 19 pounds stock i had ACT lightened it for me they took 7 pounds off so it now weighs 12pounds and no problems

 

I've found the same thing in the past DRAGLS.
I ran a number of lightened oem flywheels through to 8400 rpm, under boost, on the drag strip with no problems. In fact, I take the clutch out 3-4 times per year to inspect it and the flywheel (I had a PP split on me once).

I'm sure I will be okay with a 15lb oem unit, but man, I wish someone could answer my question about ITR flywheels.