Forum » General Tuning Discussion » Help, no boost building

Help, no boost building

General Tuning Discussion

Discuss all things tuning in this section. News, products, problems and results. 


Page 1
Author
487 Views

Hello , we got a car that came with a problem that is not building boost. We tested on the dyno and it sounds like wastegate flutter, so we changed the wgdc to 100 (3 port solenoid) to test if boost was building but nothing happened. Is a 35 psi turbo but we only reach 15! So we removed the external wastegate (tidal) and left the turbo fully closed and still we only got 15 psi. We tested for leaks (smoke test) at 15 psi and no leak detected.

We are now stuck, we are planing to remove the turbo , headers and uppipe to check for leaks but I would like some help with ideas to figure it out what is happening.

Did it sound like flutter on throttle? if so it is likely hitting turbo stall in which case check for restrictions in air flow; intake, intercooler and exhaust.

Yes it does sound like you mentioned so we are we are starting to tear down the motor, headers , chargepipe etc. Also while on the dyno we saw lots of oil coming out from the vents on the camshafts (considerably spill on the dyno), After that we saw that the oil on the engine was pretty low, we performed compression test and no leaks were detected, also PCV semms to be ok. Also at idle the car after a run starts runing very rich at idle, also when you do the run, the afr drops doen the mid 10.

Any other ideas let me know i deeply appreciate it.

Have you got the ability to do a leak down test? It's not normal to get considerable amounts of oil coming out the cam cover events, it should only be vapour.

I would check the turbo for leaky seals also, there is a chance you've over sped it if it's been ran in stall areas. You shod also look pre-turbo, as in air filter to turbo, a restriction here can cause big issues

Also, since you say you have had some rich startups, etc maybe check to see if the fuel has diluted the oil to a thin and smelly mess. It may not be contributing to the current issue, but it may have something to do with the cause.

Chris , I will perform the test you mentioned and let you know. Thanks for the advice!, also i will check the oil to see.

We performed the leak down test using snap on equipment, no loss at 100 psi in all four cylinders. We also cheked the viscosity the oil and it seems to be ok. The wategate had a minor leak on the air connection (tidal ) but is now fixed. We tear down the whole charge pipe system after the turbo, checked the intercooler and it looks ok, also we cleaned the air filter and all piping.

Next step is to build the car with a different turbo, if you think there might be anothing we can do let me know, i´ll appreciate it.

Regards

Hey guys

So we changed the turbo tu a blouch 22g, we checked all the exhasut system, changed the seal from the downpipe to exhaust, changed the wastegate to a new tial, revised the oil system and nothing changed! 15 psi of boost.

When we performed the test we noticed that the vacuum line that goes from the 3 ports solenoid to the wastegate was not connected so i suppose it was shut all the time , still no boost.

Another thing we noticed is that at idle the map boost read 0 psi, not negative, when testing in sport mode with traction control system on the car started to drop the power, took off the traction control but no power.

Any other ideas? I really need you help!

hey guys , if a cilunder has almost no compression, will this affect boost?

I saw something similar recently with a bad MAP sensor

How are you measuring the boost? It could be a split hose to the sensor or as error404 says, it could be a broke sensor.

If a cylinder has no compression you would have a very rough running engine, has this been since the loss of power? Is the engine AFM controlled or MAP sensor?

We measure boost Directly from the ECU using cobb accessport log info. On the other hand strangely the car doesnt not run rough or anything, that seems very strange. THe engine runs AFM based load, not speed density.

I would try testing the pressure sensor and lines just to rule it out

If you are not getting below 0 at idle then you may have an intake manifold leak which would also explain your lack of boost pressure.

Spraying carby or contact cleaner around the manifold at idle and seeing if the idle speed lifts is a good way to identify leaks.

As closure, propeller was damaged due to increase EGT so it was not spinning at adecuate RPM.