This is going to be a bit of a long post, apologies !
2004 350z - DE - 135k (burning a bit of oil but no streams of smoke! - full bottom end rebuild this coming winter - funds pending)
Dyno session 1
Over Christmas I did my timing chain (no issues before, just age/mileage) and I decided to do cams (JWT C8), springs, revup oil pump, water pump etc.
On the first dyno session, aside from these things done the car had stock headers, stock intake, straight pipes, cobra sports y-pipe back (2x 2.5" to 3", then 3" back).
Intake temp:10 deg (Feb)
310bhp (@fly) (it's a comparison to my first dyno there back in Nov 2012)
Dyno session 2
The next dyno session I had added the following by this point:
Kaaz 1.5 diff
Z1 'Race' intake with the large 6" velocity stack and filter
Note - the very first runs we did had the stock intake connected, we noticed it was down and thought it was odd. So I then installed the Z1 intake but the dyno was the same.
So my initial conclusion was that the Kinetix was causing the loss but clearly started to extend the power curve further to the right. hmmm
I had assumed (with a couple of other folks) that my car could breath in properly but not out, however it doesn't seem that was really the full issue.
Intake temp: 24 deg (May)
292bhp (@ fly)
Dyno session 3
PPE long tube headers (JWT advised spec on these).
HP Ignition coilpacks (decided to refresh them as I had original ones on the car).
Motordyne XYZ-pipe with resonator.
Intake temp: 25-27 deg (Aug)
Pink line is from May, so you can see the PPE's have gained at the lower end at least.
Knock detection disabled (was troubleshooting idea)
Once again comparison to Feb (WHP)
Ok, so we made the low end come up nicer now, and the curve itself looks quite nice - however, the numbers aren't, in comparison to my initial run of the year.
Jez also disabled the knock sensor for a couple of runs too, just in case that was causing a problem, it made a few more hp but nothing obviously wrong there.
This seems like either the Kinetix is struggling for some reason (but hasn't on other cammed NA cars - it stretches the power curve to the right), or something else has gone wrong (timing?).
Engine parts as of August 2019:
Kinetix Velocity plenum
JWT C8 Cams & springs
Z1 3" Race intake with 6" velocity stack/large filter
Ferra stem seals
PPE Longtube headers (spec advised by JWT)
RevUp oil pump
Motordyne resonated Y-pipe
3" back Cobra Sports resonated exhaust
New waterpump/timing chain/gallery gaskets/o-rings etc
Stock heads/bottom end (rebuilding in winter)
HP Ignition coils
I did a dry comp test back in Nov, the results were around 185-195psi.
After doing the cams this year my compression was down to around 155psi.
JWT said that the pressure would be down perhaps by 15psi but not to this extent.
So maybe I didn't do the November testing correctly (I'm sure I did) but with this current one I know I did it properly for sure.
I decided to do a wet compression test, followed a day later by a leak down test, here are my results:
Wet Comp was about 7% more than dry (around 165psI).
Leak Down (I'd imagine anything over 8% isn't ideal but I knew the rings are worn):
So that confirms what I knew anyway, the rings are worn (no problem as bottom end stuff is waiting to go in).
I couldn't hear any obvious air leaking or bubbles in the coolant overflow.
Could that result just be a mix of the C8's/rings and the relatively low HP readings due to rings ?
I've messaged back and forth with a few of you on here (plus JWT and the US forum), and your input has been hugely appreciated !