Poita's FA5 Turbo Build (Pic heavy)

[aLmk]

mine seems to hold boost throughout though and I have an 8lb flywheel

Were you tuned from start o finish on the 8lb flywheel? From what I gathered he was not, so that could be why you're able to hold boost all the way.

[Poita]

I started tuning with the oem flywheel. But the Fx300 started to slip @ 14.7 psi. So I bought a CC stg 4 (6 puck sprung) disc and their 8lb flywheel as well.

the oem flywheel held 14.7 psi till 8600.
But with the 8lb flywheel I had to add a lot of preload and still need to add to hold boost.

But my supposition was the same as aLmK's by the time.

[aLmk]

Ya I'd say it has to do with there being less load on the motor. Are you controlling boost with a mac solenoid?

[Spaz]

crazy, I'm gonna talk to my tuner about this and see what he says

[Poita]

Oh and I almost forgot to mention... After installing the new flywheel lag has gotten worse!
I'll check if I still have datalogs to post here

[aLmk]

Oh and I almost forgot to mention... After installing the new flywheel lag has gotten worse!
I'll check if I still have datalogs to post here

That makes perfect sense, the lighter weight flywheel is going to put less load on the motor thus causing the turbo to spool later. Same reason why the turbo will spool faster in 4th than in 1st.

[Poita]

That makes perfect sense, the lighter weight flywheel is going to put less load on the motor thus causing the turbo to spool later. Same reason why the turbo will spool faster in 4th than in 1st.

Yup.
That's why I'm not sure which flywheel to use...
Looks like the oem is the best choice

[Frostydc5]

i used the comp 11lbs flywheel before i went twin disk and it was perfect never had any issues

[aLmk]

It's not that the oem is better or the lightweight won't work. It's simply that he was tuned with a heavier flywheel so his boost isn't as high now. Turbo boost pressure is all based on load and changing the weight of the flywheel changes the load in the engine.

[Poita]

damn updates!

My coolant was disappearing and I found no visible leaks on the turbo, radiator hoses or anywhere. Oil aspect was OK. So I had a clue what could have happened...
Did a leak down test yesterday and as soon as I started to pressurize cylinder 3 got some bubbles coming from the radiator.
Head lift? Did some tests with 19 psi while ago. Maybe I've reached the headstuds limit, they were torqued at 80lbft.

I'll be waiting 7 working days for my head gasket, and then I'll apply 100lbft on the studs. Hope they don't break.

Since the car is down, I'll install the 75A innovative mounts that just arrived and do a recheck for leaks.



It could be worse, but this is the first time I had to stop the car since I gone turbo