I installed a T3-T4 on my 1.8L Civic and it works great until it hits 6lbs and then it rapidly drops to 0 boost..... I thought it was a weak BOV but I blocked it off and still hit the wall. I have 400cc injectors so it is not them.

Here are the specs:

Compressor, A/R.60 - Inducer 54.3mm Exducer - 71mm (inlet 3" outlet 2

Turbine: A/R .63 Inducer 65.25mm Exducer 56mm.

Exhaust is 3" V Band with race muffler and not CAT.

Thoughts on why this stalls???

Charlie.

 

Tuner, or ECU related....nothing to do with turbo

 

I have considered that, and I certainly have not discounted it. But tough to pinpoint. I am using the SDSEFI.com ECU and I have a lot of faith in it, as I have used it for years and never had any issues, but it certainly could be something I have programmed that I have not figured out.

I wondered about the MAP sensor. It is supposed to be a 2 bar unit. But I wondered if it was labeled wrong, and I ended up with a 1 bar sensor, if that could be the cause?

I do appreciate the reply and I will study my programming more...

Charlie

 

So it was working fine with a different turbo previously, and all you did was change to the T3/T4 and this started happening?

 

Understood, but compressor surge has to do with the BOV's ability to keep the compressor wheel from reversion on a physical /mechanical level, and not on a level related to your software adjustments. That's what I'm getting at. If you're not getting proper stable vacuum, have an issue with the BOV isn't venting properly, or have an issue with even the throttle body physically opening/closing properly, then we can start looking at compressor surge. But even a MAP sensor or TPS sensor issue, unless you have it directly tied into the physical act of opening the throttle body by way of Drive-by-wire, or other software-connected parameter, compressor surge is not your issue, even if you just changed turbochargers. Going "T3/T4" going from 2Bar- 1Bar, means that your issue is in the calibration of the voltage signal of the sensor in conjunction with your ECU, and doesn't fall into the physical symptoms and parameters of the "compressor surge" category.

Just trying to point you in a better direction as you're giving more information.

 

I appreciate your reply.

I have temporarily blocked off the BOV to ellminate it as the cause. The ECU has parameters for MAP, TPS, RPM, temps etc. I have reviewed all the programming and nothing stands out as being the culprit to cause the stall when I reach 41" of MAP.

I have been lookingt things over very carefully and found a few things that might be related but I doubt it.
1) I did fine two of the injector plugs slightly loose.
2) There was one coupling on the intake that was slightly loose.
3) I loosened up the preload on the wastegate accuator arm. thinking that there may be a slight chance this has increased the ramp-up of the pressure to be too much too fast.

Hopefully I can do more testing this weekend....

Charlie

 

Ok it goes to lets say 6psi then what happens.Goes to 0 psi and then back to 6psi how slow,
what you hear?
Where you are measuring boost for the boost gauge?
Can you post a video?

 

perform a boost leak check. That should be the first step to diagnosing ANY boost related problem.

 

I appreciate all the help.

The short answer is that my knock sensor was being too sensitive and it was activating an agressive retard in the timing.

The long answer is that I had been gun shy about pre-ignition after losing compersssion on a previous engine so I had my aftermarket ECU programmed to be too sensitive and to agressive on the retard. This set up is so loud that I had it set this way because I had no confidence I would hear the tell-tale knock. After watching the plugs like a hawk, and desensitizing the knock retard value in the ECU, I found that I could go beyond 5000 rpm easily.

Thanks again for all the help It helped me work through various solutions before finding the real culprit.

Charlie