hi all, i.ve got a built b16 that i am currently tuning off boost until i receive my garret turbo manifold etc, the problem is that the engine feels very weak compared to stock compression and i was thinking that this might be due to the need to change the cam timing and i have the adjustable pulleys so i needed to know what sort of direction i should take so looking for some advice to start off with, also what effect is to be expected on the ignition timing should i advance or retard due to the lowered compression ratio??

 

By Lowering the compression ratio I dont belive you will need to advance or retard it untill you actually start throwing some boost at the motor than your gonna deff want to retard the timeing a little. However if you timeing is off you will deff notice it. Get a timeing light and see were your timing marks are.

 

i set the mechanical timing to 16degs just like stock but power feels unbeleivably crap so i imagine some changes must be made to either cam timing and ignition timing or both??????

 

it feels weak becuase of the compression drop

 

i'd run a leakdown on it, because my 9:1 b16 felt almost identical to my stock b16 on factory slugs

 

Do you have any way to monitor your engine vitals such as egt, knock, afr... If not, and your that worried about it, get on a dyno. Or save your money till your boosted and then get on a dyno.

In my mind it would make sense to advance the timing just a bit on lower compression due to more volume of fuel and air that needs to be burned. Also, sense your technically na right now, maybe advance your intake cam a degree or two and keep your exhaust cam set at zero. Then again all engines tend to be a bit different and like different settings.

Did you tear apart your engine to build it? Or is it all stock other than low compression pistons?

As stated before: feels weak due to compression drop

 

My short block is fully built inc AEBS sleeves, Eagle conrods, clevitte 77 bearings, srp pistons, arp bolts etc. i am also using a plx300 wideband with a neptune RTP to tune, been returning the ignition settings off boost to factory and they are much better i put a little advance and the engine didn't seem to like it maybe a little retard will pick the power up a little , i,m also sure the cam timing will also boost the power a little too!

for now i'm waiting for the EGT Gauge to arrive!) i'll just be conservative for now!(

thanx for the replies guys basically you confirmed my plan of tune !)