Hey,

I have a Greddy turbo, unknown BOV (VTA) 2.5" turbo back exhaust and the link ecu. My issue is that the car will not boost past 10psi - all that happens is the exhaust just splutters. It seems like there is an invisible map limit that interferes at 10psi - up to 10psi the car is very rapid, but who wants 10psi when you can 12.

I've recently changed to NGK BK7's, gapped to 1.1mm. My initial thoughts were it could be spark plug gap related so I phoned the NGK tech line - they seem to think the symptoms are not spark related, more a boost problem.

So, what do you guys think? Greddy stock wastegate or BOV issue. I'm guessing I have boost leak, but will defer to your superior knowledge of these things.

I don't ask many questions on here, so I hope you guys will cut me some slack.

Cheers

 

You're certain it's a mechanical (boost control) issue?

Some thoughts:

1.1mm seems like a lot for the stock ignition system at this boost level, but the symptoms here would be much more intermittent, not a brick wall.

Does the Link ECU have a boost-limit function? I'm not talking EBC, but an overboost protector (similar to a rev limiter). Honest question. I don't know if Link has this feature, but if it does, make sure it's not what's causing this.

For that matter, what are you using for boost control?

 

Thanks for your response there Joe.

I have an EBC controlling boost. My boost target is set to 180kpa and the map limit is at 195kpa, so I shouldn't be having map limit issues at 170kpa I wouldn't have thought.

 

Try upping the threshold to see if that changes. Could be off?

 

I had similar symptoms when my brother put fancy platinums in my car, throwing some 7s back in solved the problem. By my math, your 1.1mm gap is .043"!!!!! That's WAY too big for stock ignition & boost. Cut that gap down to .025" (.63mm) and see if that works.

Joe - when I had that problem the symptoms were as he describes, FWIW.

 

+1

 

It worked, thanks

 

Glad you got it fixed.

FWIW I had the problem described by joe with MS once. Changed the value and fixed it.