TUrbo Surging when Using Boost Controller

[nissan_gtr35]

Howdy Yall,

Wondering if anyone has any ideas as to what the asnwer to the following problem might be.

I have an '89 R32 Gts-t with HKS exhaust, apexi airpod, HKS EVC III, Blitz Turbo Timer and pretty much standard everything else engine wise. Now my problem revolves around the use of the EVC. When i run the car on stock boost (ie boost controller on monitor only) it works beautifully however when i turn the boost controller on it does the exact opposite of what it should, that is control the boost levels. If i set the boost at a modest 0.80 kg/cm^2, my turbo timer tells me that it is peaking at around 0.9 kg/cm^2 and above in some cases. If i set it at 0.85 kg/cm^2 it peaks at over 1.0 kg/cm^2 according to the timer and when it is on boost the turbo keeps surging. Basically the power to the wheels will rise and then drop off a bit, rise and drop off a bit and so on.

Since this has happened ive kept the controller off so as to not do any damage to the car till i can get it working properly. Not sure if it might be dodgy wiring, broken connection or what, so any help would be greatly appreciated.

Thanks

Laine

[BHDave]

Can the duty cycle of the solenoid be adjusted using the evc? If so then you should probably drop it down a bit to bring the turbo on a bit slower.

I have seen guys running 100% gain on blitz ebc's and on the dyno it was causing boost to bounce around wildly.

You will also find that the gauges you are using to check boost aren't properly calibrated. my DSBC reads very high (1.2bar when making ~1bar) vs my boost gauge which reads slightly high.

[Sydneykid]

What you are experiencing does not sound like turbo surging to me, more like missfire due to the spark plugs not liking the extra boost. When was the last time you changed and gapped the plugs?

[nissan_gtr35]

Ah ok, well i had the car fully serviced about 2 months ago, however I think i better check the plugs and make sure they are ok.

And yeh ill have a look at the solenoid duty cycle but not being much of an expert on that stuff i cant say ill have much luck!

Thanks guys and anyone else with any ideas id welcome your comments too.

Laine