Yes i know it sounds like a another stupid thread but im at a loss for ideas. Its a k20z1, in a ef. The setup consists of a AFI sidewinder,Precision billet 6262(82hotside),Single Tial 44mm, 2.5 inch hotside and 3 inch cold side piping and a precision 650hp core. All Couplers and clamps are brand new. Turbo was sent back to precision and everything is ok. The car idles at -20 in vac. I boost leaked the car 20 times and its not leaking anywhere.Checked wastegate also and its NOT stuck open As i hit it going down the street it will rev out 1st 2nd and 3rd and will make NO boost. It actually wont even go to 0 vac it hovers around -5 to -1. Any help would be greatly appreciated. I dont have anymore ideas as to wut the problem can be.

 

Do u have ur full exhaust system put on? What kind of boost controller

 

Idk if u tried but take ur cold side piping off and rev the motor and check if its blowing out air.. I mean if all your clamps are brand new it can't be a boost leak unless its out of your bov. And other than that a huge vacuum leak at idle. Or if your wastegate is stuck open all the time it won't make boost.

 

Its a 3 inch down pipe going undercar. Boost controller is a PWM solenoid. I tried a run with the turbo direct to wastegate and using electronic. i can use a air gun and blow from cold side through intercooler then out the hotside and turbo very easily. no restrictions in intercooler at all. Car does not have a BOV.

 

see if you have oil, may sound odd but you never know.

 

Turbo Spins freely, has oil...

We even went as far as removing ALL charge piping, I hooked up a capped off 2" long pipe and stuck a boost gauge on the pipe and hooked it directly to the outlet of the turbo to eliminate the charge piping and intercooler, setup the 2 step in KManager at 6000 rpms and hammered on it (all part throttle maps were tuned, and standard safe boost fuel and timing numbers were setup).

The boost gauge never went over .5 psi...

At 6000 RPMs, loaded on the dyno at full throttle the car makes less than atmospheric pressure in KPRO, on the boost gauge and also logging on the dyno pressure sensor.

Motor makes good compression, the valves are properly adjusted...

Everything I can think to eliminate as a variable for what is causing this issue has been eliminated at one point or another...

 

just thinking out loud, wot should net 0vac. period. i think thats physics.(im not being a smart *** again just thinking out loud) how is the clutch? is it failing enough to not load the engine up enough?

just a thought.

 

You checked to see if your wg fire ring is there?

 

At WOT it doesnt reach 0 VAC. Clutch is fine. Even at an idle when u rev it, it still doesnt reach 0 Vac. Fire ring is in wastegate and its not stuck open. Ive exhausted my phone on people to call. Everyone i talk to after explaining wut ive checked says the turbo. Precision says the turbo is good and i also put a smaller BPS258 on it and it does the exact same thing.

 

Does it seem very "slow to rev"?
If you cant even reach atmospheric pressure at wot,somethings definately up. Is the cam to crank timing dead on?
What were compression test #'s?

 

- Does it make OK power on the dyno for an NA car? Or is it way down?

- If it is way down, cam timing (should show as bad compression though)

- I'd say check the TB for way less than full opening, and check the IAC system (some people plumb to open air) - but you did the test with the capped pipe on the turbo so.....

- Exhaust is an open downpipe? Because I have heard of a muffler that was broken inside and a flap of steel moved and blocked the exhaust outlet, but that car still made 15 psi of boost.

 

yeah Chris def have him pull off the wastegate and check to see if the firing ring is there.

 

Interesting! WOW I am so friggen curious as to what the hell is causing this??? Let us all know what you find out! Hope its something simple...prolly is! GL with everything man!

 

hmm... never reaches 0vacuum at full throttle? sounds like there's a restriction on the exhaust side. maybe the exhaust manifold has a restriction? or the turbo, or somewhere after the turbo?

 

The car revs and drives normal and has really good power. Compression checked out at 200 across the board. Im sure if we can figure out why it wont make 0 vac it will fix the boost problem.

 

Weird.

 

nope, noticed nothing out of the ordinary while tuning the part throttle maps...only when I start doing the 0 column (i like to dial these in DEAD ON, and use the built in calcs for the boost tables) did I notice I couldnt hit the last column, even at higher RPMs.

yep, 100%

this is what baffles my mind...without the car running, ECU shows 0, so I know the map sensor can read that amount and send voltage to the ECU

 

Stock Cams? Absolutly sure nothing leaking around intake mani? Weird.

 

As far as i know they are stock cams. Did a leak test and nothing is leaking from thier.

 

I agree with lugnuts.check the tb for full opening.

 

TB is wide open when pedal is to the floor. Think this might be a motor problem but what?

 

is the turbo spinning?

 

You sure the boost guage is working.....

 

is the i-vtec going crazy? cam over lap could cause the boost to just blow through?

 

I was just gonna say that... Also what map sensor are you using? i had a hondata 4bar at my first dyno session and my s300 showed it would not go below -2 in. of vacuum.when the engine was off it would show 0 in.and when we started it back up it stuck at -13 in.I swapped it for an omni unit and was fine after that.