bennyhonda7

have topline bearings, vitara pistons,eagle rods, in ad16a6 in my 95 coupe, with z6 tranny wtf it gets an oil psi light, the compression on all 4 is around 120-125 ignition breaking up under boost not even 20 miles on motor...what could be going on?

splitime

Built wrong... very low compression motor with those pistons in an a6 (7.5:1)... or a combo of both.

bennyhonda7

wouldnt i still be able to feel boost etc...go decently fast...i thought that with lower compression i could run more timing, and more boost...what the expletive even if there was 7.5.1 wouldnt it still be a decent motor with more boost...or should I mill or head swap...z6 maybe...

splitime

Its just low, ie: crappy when out of boost. It shouldn't cause motor to fail or anything though.

If you are getting an oil light, I'd check oil levels, check that wiring to oil (dummy) light is connected firmly,

Beyond that, the breaking up could be timing, plugs, tune etc.....

platinum00

what management are you running

why are you boosting the motor with a oil light on

fix the oil light and get the car tuned and i bet most of your problems go away

platinum.

bennyhonda7

so the motor should run pretty decent in boost then correct? i can boost more and run more timing with the lower comp ie have more torque in boost...? and i stopped driving when the light flashed and have yet to drive it im a pulling the pan and checking the pump

platinum00

good idea.

are you running the car un-tuned? it kinda sounds like it

platinum.

bennyhonda7

actually im running uber i have a wideband, and am using my d16a6 map from before the build 6psi,dsm450s 14b turbo, stock motor...now with different comp i need more timing the fuel is still fine actually a little rich...

platinum00

does the car run fine out of boost.

platinum.

sohc_turd

wouldn't low oil pressure possibly point to poor main bearing clearances and other things??

How where the clearances when you put the motor together? plus, whats your total timming @ the boost levels your running?

i'm no pro builder but thats what i would have checked.

bennyhonda7

runs fine out of boost...and below 60%throttle...

redzcstandardhatch

i HATE topline bearings... i've seen them fail a couple times, quickly. you might want to think about making sure they arent falling apart and causing low oil pressure. did you check the clearances on the bearings?

HiProfile

Well what ignition timing maps did you use? I'm going to guess your timing is messed up due to the obd0 head/motor converted to obd1. Check your base timing, it should be 16*. Also check to see that the ign map is the correct one you'd be using for the a6, and that it does have a bit more timing added due to the veeery low compression.

My suggestion would be just to get a z6 head, since you're 2/3 of the way there. That way you can start with a real stock ign map and still have a rough base fuel map to tune from, as well as have around 8.5:1 compression. BTW, z6 heads are about 34.6cc, a6 is 38cc.

bennyhonda7

i just really want to get the car running and then possibly head swap etc....yeah possibly ignition adjustment...