Guest Clunsey Posted August 23, 2009 Share Posted August 23, 2009 I know I have asked this before but I never got an accurate answer. I want to fit an atmospheric BOV to my 1998 VVTi, tiptronic J-spec. However I have had mixed reports on doing this and also on various electronic gadgets that can get round the reported problems of running rich/lean. Could people please tell me of there experiences on this. Thankyou Quote Link to comment Share on other sites More sharing options...
legendswraith Posted August 23, 2009 Share Posted August 23, 2009 I have a HKS SSQV fitted to my vvti and no problems as yet. Quote Link to comment Share on other sites More sharing options...
Guest Clunsey Posted August 25, 2009 Share Posted August 25, 2009 Thanks Legend, surely there must be some other suggestions advice out there please??? Quote Link to comment Share on other sites More sharing options...
legendswraith Posted August 31, 2009 Share Posted August 31, 2009 Think the problem is that most shy away from the vvti supras due to the complexity of the system etc when everything goes tits up or adding bits too it so most of the supras on here are MAP based rather than MAF as the vvti is. If you put the BOV on the throttle body side i would imagine that would reduce the Rich/Lean problems as the dump would be further away from the sensor etc so less variation. That said mines in the stock position and i have had no problems as yet. Also see the thread on whether a BOV is needed besides for the noise makes for good reading Quote Link to comment Share on other sites More sharing options...
MarkR Posted August 31, 2009 Share Posted August 31, 2009 I had issues with mine running overly rich and back firing on full BPU. I replaced the HKS SSQ BOV with the stock one and it was fine. No need for an aftermarket one until way past BPU unless you like the poser noise... Quote Link to comment Share on other sites More sharing options...
legendswraith Posted August 31, 2009 Share Posted August 31, 2009 Out of interest did you have it in the stock location or just in front of the TB on an elbow? Quote Link to comment Share on other sites More sharing options...
MarkR Posted August 31, 2009 Share Posted August 31, 2009 Stock. Quote Link to comment Share on other sites More sharing options...
Pete Posted August 31, 2009 Share Posted August 31, 2009 You really need to the re-circ kit on the VVTi otherwise it will run rich. Quote Link to comment Share on other sites More sharing options...
MarkR Posted September 1, 2009 Share Posted September 1, 2009 Quote Link to comment Share on other sites More sharing options...
legendswraith Posted September 1, 2009 Share Posted September 1, 2009 I assume its from the dump which changes the readings the MAF gets. I also assume as mines an auto and doesn't dump through the gears is why i have seen no effect. Will have to look at it when i have the wideband in Quote Link to comment Share on other sites More sharing options...
MarkR Posted September 1, 2009 Share Posted September 1, 2009 I assume its from the dump which changes the readings the MAF gets. Exactly that.... Mine was a tiptronic until I changed to Manual. Try this: Lift your foot when the gear changes (as if you were changing manually) and then when the gear changes put your foot back down. This used to result in a huge backfire when I did it.... Not so much when I just kept my foot planted. Quote Link to comment Share on other sites More sharing options...
legendswraith Posted September 1, 2009 Share Posted September 1, 2009 Lift foot when accellerating . But yes i understand, by creating the depression further on and increasing the air flow causes a rich condition. May be looking for a recirc kit myself as i have experienced a lesser form of that but i put that down to the car running rich as is. However if i can get some flame out the back as well i may jsut keep it to deter tailgaiters Quote Link to comment Share on other sites More sharing options...
wile e coyote Posted September 1, 2009 Share Posted September 1, 2009 You really need to the re-circ kit on the VVTi otherwise it will run rich. Yes this is what i use and you can somtimes still hear some noise Quote Link to comment Share on other sites More sharing options...
Ian C Posted September 1, 2009 Share Posted September 1, 2009 I assume its from the dump which changes the readings the MAF gets. It's the opposite, it doesn't change the MAF reading as the air has already been measured by that. But then the BOV dumps the air, and then the injectors fuel for the MAF-measured air and, oh dear,. it's not there. Massive rich condition, and potential stall if you do it at relatively low engine revs. -Ian Quote Link to comment Share on other sites More sharing options...
legendswraith Posted September 2, 2009 Share Posted September 2, 2009 Makes sense as well, when you dump the air you have a greater ratio of fuel to air. I ordered the recirc fitting to give it a go anyway, personally as i said i haven't had a problem but for 5 minutes fitting and £20 its not worth ignoring it. Quote Link to comment Share on other sites More sharing options...
MarkR Posted September 2, 2009 Share Posted September 2, 2009 It's the opposite, it doesn't change the MAF reading as the air has already been measured by that. But then the BOV dumps the air, and then the injectors fuel for the MAF-measured air and, oh dear,. it's not there. Massive rich condition, and potential stall if you do it at relatively low engine revs. -Ian That's what I thought he meant Quote Link to comment Share on other sites More sharing options...
legendswraith Posted September 2, 2009 Share Posted September 2, 2009 The way i was viewing it was that the ecu fueled for the rush of air created by the depression left from venting the BOV when the car would be slowing/changing disposition. rather than looking at it as the fueling had already been worked out and now the venting had caused a lack of air, so the ecu would be fooled into thinking there was more mass air there than there was. Which would cause the overfuelling. I get it was looking at it from the wrong angle thanks for the info ian Quote Link to comment Share on other sites More sharing options...
Guest Clunsey Posted September 8, 2009 Share Posted September 8, 2009 Hi people, just to let you know, I have bit the bullet and fitted a BOV. I decided to get one of those HKS SSQV style valves from ebay ( £45 compared to £260 ) The reason behind this was if it did indeed make the supra run like a bag of nails then I could go back to stock without it costing a fortune. The replica valves look the same from the outside, even have hks on them and sound pretty much the same. Anyway, the results. After getting the hoses to allow me to fit it with the different pipe diameters, I took it out for a decent run and the car runs fine. The only thing I have noticed is during a proper thrash and then lifting off is the exhaust pops alittle which is nice but the engine idles fine and picks up fine, no stalling. More than happy with the result. Thanks for all your help lads. Cheers Quote Link to comment Share on other sites More sharing options...
Ian C Posted September 10, 2009 Share Posted September 10, 2009 the engine idles fine and picks up fine, no stalling. Try this - roll forwards at about walking pace in 1st gear, then give the throttle a hefty prod towards the floor, immediately lift off and brake to a stop (putting the clutch in of course). It simulates a quick move up in a queue towards a junction or something and is the best way to stall a MAF/BOV setup. What happens is, you drop the car out of closed loop with the sharp change in throttle position, it adds more fuel for acceleration pump, then you vent some of the air and all that extra fuel hits the cylinders just as the revs drop, from a fairly low value, without the road wheels engaged to help keep the engine turning. Worst case scenario, especially if you're still on the cold start cycle. If you can't stall it by doing that it'll probably never stall because of the BOV -Ian Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.