Unusual boost behaviour

[ghoonk]

Had my Evo IX GT for 3 months and just started down the Dark Side with the installation of a Greddy Type-R (Stiff spring) BOV (the IX's mag turbo has been known to be very vulnerable to compressor surge -- we've had at least 6 cases here in Singapore alerady), and an AEM Short Ram Intake.

Weird thing was, with the AEM SRI. my boost was spiking at 1.3 bar (stock spikes at 1.45 - 1.5 bar) and then hovering between 1 bar and 1.2 bar (stock boost holds at 1.3 bar)

Is this normal behaviour?

I've been advised that an Apexi SAFC-II might help, along with the Apexi N1 catback exhaust system. What do you guys think? I'm new to modding for Evos

[turbolarry]

Is the ECU/boost control solinoid still controlling boost?

[ghoonk]

Yup. The car is stock, save for the BOV (which wasn't the cause of the problem), and the AEM (which appeared to be). No boost controller, just a bunch of gauges, speed cut remover, and a lot of carnauba wax

[turbolarry]

I have yet to work on a IX, but it's normal for stock VIII ECU's to pull boost at the top. IX's are probably the same. A boost controller will hold it better.

[ghoonk]

Great! Thanks for the tip. Looks like I'll be trying to get my hands on an Apexi AVC-R unless anyone has any other recommendations

On a side note, I'm currently on Mobil1 0W40 engine oil, running in 36 degrees C ambient temperatures. Have been toying with the idea of switching over to Royal Purple 15W40 for daily driving (I'll switch to a 20W50 if and when I get this car to the track). Has anyone here tried Royal Purple? Is it any good? And more importantly, is it likely to be too think for my car?

[Fourdoor]

The non-stock intake pipe can mess up the readings from the mass airflow sensor, and result in the ECU pulling back boost trying to compensate. Do NOT run an aftermarket boost controler to correct this problem without first getting some kind of fuel tunning to correct the problems caused by the aftermarket intake.... either that or put the stock intake back on the car. Until you reach the point where you want to upgrade the turbo a panal filter upgrade in the stock airbox is your best option.

Keith

[ghoonk]

Thanks for the tip. Did as you suggested and everything is back to normal. Now toying about with the idea of switching over to a Nisei intercooler. Someone reported 24 more whp on a dyno with 30Nm more torque, and the ic uses the stock piping.

[Fourdoor]

Glad to be of help.


The stock intercooler is a pretty good piece for something that comes from the factory. Have you considered following the upgrade path laid out on the site here? People seem to have really good gains that way.

Keith