Mcgoo Posted June 1, 2010 Share Posted June 1, 2010 Bit of a strange one this. (you don't have to read it all, just down to the red bit) After replacing a faulty IACV VSV my BOV (HKS SSQV) has gone quiet, especially when on the first turbo, also tubby 1 seems slightly less responsive. It used to be the case that turbo1 would happily spin away with very little throttle input and feathering it would give a lovely little 'chatter' and 'woosh' from the BOV. Since replacing the vsv it only gives a 'chirp' at best. Also it seems to take more throttle input to get turbo1 boosting although it does still boost fully at 0.7bar.Its not massively different but enough for me to notice when driving round town. Turbo2 is behaving as expected coming online at 4k and giving 1 bar (as per restrictor ring). The strange thing is, if I unplug (electrically) the IACV VSV then tubby1 seems more responsive again and the BOV makes all the right noises. I've been reading a lot of info on here and on max-boost.co.uk and the way I see it the IACV vsv shouldn't really effect tubby1 a great deal. At least not until the transition point anyway. So is it just the case that I got used to how it drove and sounded with a knackered IACV vsv and now all is as it should be, or is something a miss? If all is ok can I just adjust the BOV screw to give me the chatter noises back again as I have the older type SSQV? Thanks for reading. A bit of history on the initial boost issue for those that are interested enough to read it. While investigating a general lack of boost that had tailed of over time, I discovered that the VSV controlling the IACV was knackered (open circuit). This was a surprise to me as the 2nd turbo still appeared to be coming on-line when it was supposed to. The car felt like it was doing all the right things ie 0.6 to 0.7 bar up to 3500rpm then a dip followed by a rush at 4k to around 0.8 to 0.9bar. I used to get around 1bar during the colder months so initially put it down to the warmer weather. With this in mind I got a Blitz dual SBC spec r to raise it to higher levels when I wanted it. After fitting it I realised that I had a problem when max boost was 1 bar despite the ratio being turned up. My first thought was a boost leak so I checked the pipe work and replaced a couple of suspect hoses. No change. Next I tried TTC (5min mod) and it went like a rocket! Boost was now controllable on the EBC and very strong. This led me to checking the VSV's and discovering the faulty IACV vsv and replacing it. The car now feels fantastic and pulls very strong, its just the quiet BOV and the slightly slower to react turbo thats concerning me so back to the top................ Quote Link to comment Share on other sites More sharing options...
Gaz6002 Posted June 1, 2010 Share Posted June 1, 2010 TBH, I'd be happy if my BOV didn't make a noise at all. But it doesn't, so that doesn't help you Have you tried playing with the spring on the BOV? They're adjustable... Quote Link to comment Share on other sites More sharing options...
Mcgoo Posted June 1, 2010 Author Share Posted June 1, 2010 TBH, I'd be happy if my BOV didn't make a noise at all. But it doesn't, so that doesn't help you Have you tried playing with the spring on the BOV? They're adjustable... I know the noise is not to everyone's taste. I haven't played with the adjustment on the BOV yet as it was fine until fitting the vsv. I can't see why it would make any difference when I unplug the vsv? Would the boost characteristics change just with the ECU seeing the vsv connected? Quote Link to comment Share on other sites More sharing options...
Mcgoo Posted June 2, 2010 Author Share Posted June 2, 2010 Drove a few miles in the last couple of days and slowly the car has began to feel and sound like it was before, which I thought was strange. It then dawned on me that I didn't reset the ECU after carrying out the work!! DOH!! So I suppose It's taken awhile to adjust itself? I really didn't think it was that essential. Lesson learnt Quote Link to comment Share on other sites More sharing options...
Guest spanky333 Posted June 3, 2010 Share Posted June 3, 2010 Can't believe this as I too have just changed a knackered IACV VSV and have the exact same problem as you (quiet BOV). However I did reset the ECU, but have not really driven it far since. So going on what happened to you "Mcgoo" I'm hoping once the ECU re learns itself it will come back as i do like the Blitz BOV sound. Quote Link to comment Share on other sites More sharing options...
Mcgoo Posted June 3, 2010 Author Share Posted June 3, 2010 Can't believe this as I too have just changed a knackered IACV VSV and have the exact same problem as you (quiet BOV). However I did reset the ECU, but have not really driven it far since. So going on what happened to you "Mcgoo" I'm hoping once the ECU re learns itself it will come back as i do like the Blitz BOV sound. I've probably driven 50 or 60 miles on a-roads since, I wouldn't say it's quite as vocal as it was before but it's somewhere close. Quote Link to comment Share on other sites More sharing options...
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