WAL­TER LAR­SON

NZ Performance Car - - Tech Bov -

NZEFI

We think any tur­bocharged ap­pli­ca­tion should run a blow-off valve, but there are only two rea­sons why you should up­grade from the fac­tory unit. The first rea­son is the cus­tomer wants the noise of it vent­ing to at­mos­phere, and the other is the fac­tory BOV leaks un­der higher-than-fac­tory boost ap­pli­ca­tions — some do and some don’t. If you aren’t run­ning much more boost than fac­tory, there is no real ad­van­tage in chang­ing it. In our opin­ion, a vent-to-at­mos­phere BOV shouldn’t be used with a ve­hi­cle that has a fac­tory com­puter and air­flow me­ter. When the BOV vents, it is dump­ing a whole lot of air which has gone through the air­flow me­ter, which as far as the com­puter is con­cerned is the air that has gone into the en­gine. For ex­am­ple, when you pull up to a set of traf­fic lights and but­ton off the throt­tle, the BOV will open, dump­ing the air out, but the fuel will still be in­jected into the mo­tor, which can of­ten cause stalling is­sues be­fore you come to a halt. Some vent-to-at­mos­phere BOVs run bet­ter than oth­ers with a fac­tory ECU and air flow me­ter, such as the gen­uine HKS SSQV when com­pared with the com­mon TiAL and Tur­bosmart units. To be hon­est, peo­ple nor­mally have one for the sound over any­thing else. If you run an en­gine with an af­ter­mar­ket ECU and no air­flow me­ter, then you’re pretty much free to run what­ever BOV you want, plumbed back in or not. What you need to be aware of when pur­chas­ing a cheaper BOV is that they of­ten leak quite badly in be­tween the pis­ton and body of the BOV. We’ve pres­sure tested plenty of in­ter­cooler sys­tems with replica BOVs on, and a ma­jor­ity of them leak like a sieve. Whereas with the gen­uine ones, you tend to never have a bad one. We think BorgWarner tur­bos with the BOV mounted to the com­pres­sor hous­ing is a great idea, and they’re very ef­fec­tive and suit­ably sized for the turbo al­ready.

Newspapers in English

Newspapers from New Zealand

© PressReader. All rights reserved.