Lets talk about Bovs

[Moff]

On the theme of more Skyline threads..

I have reverted back to a standard BOV a few months ago from a Blitz and my car has not stalled once since then (apart from my dodgy driving).

Why do BOV;s make a car stall ?

Moff

[Squeak]

From the words of Richf:

The advantage is that with a VTA (Vent to air) dump the engine loses a large amount of air when the pressure is vented and this causes the engine to run rich for a fraction of a second and will bog slightly , this doesnt happen with a re-circ because the air is recirculated back into the airstream.

There can be issues with stalling due to this momentary richness with a VTA valve , my advice would be if you can run a recirc dump valve then do but i'm not convinced there is much in the way of hp increases to be had

[Moff]

I thought a vent to atmosphere BOV was designed to stop a turbo from stalling ?

[Squeak]

Alot of people say different things regarding Dump Valves / BOV's. Also when it's safe to use them, Power running them etc.. not very clear IMO

This thread may help Teccy info on BOV's / Dump Valves

[Richf]

Yes BOV can help a turbo from stalling or slowing down but thats different of course to engine stalling, some reckon at lower boost pressures you dont need a bov at all , they will give your turbo a easier time of things though

The MAF or AFM measures the air flow into the system prior to it going through the turbo , the VTA bov just dumps pressurised air out of this system after its been through the turbo causing the engine to run rich as the ECU has adjusted the fuelling based on the data the MAF has sent it , it doesnt know a big lump or air is now missing.

A recirc BOV dumps this pressured air out of the pressured side of the intake back into the unpressurised side in between the maf and the tubbie, because its been measured by the MAF already the mixture is not affected

My HKS SSQV has never caused stalling issues , i have no idea why some BOV's do and some dont , perhaps its the speed at which they open , we are only talking milliseconds here of course

[spaxy]

yeah put my standard one back on today,just fancied a change of noise.i was experimenting by closing off the vac hose with mole grips to see what noise you get.god it sounds good,but i read recently about what compressor surge can do to a tubbie,my hks ssqv never gave me any stall problems tho.

[Bubble]

I read the thread title wrong Moff and thought it said let's talk about boys............thought you had changed sides for a moment

[MR Y]

Originally Posted by Bubble

I read the thread title wrong Moff and thought it said let's talk about boys

And yet you still opened it to have a look

[Spearmint]

Originally Posted by Bubble

I read the thread title wrong Moff and thought it said let's talk about boys............thought you had changed sides for a moment

What do you mean changed sides?

[RoboPope]

It depends on your management unit and if it is ready to deal with loss of measured air. IE MAP rather than measured air volumes through MAFM's. its largely relevent to flamage rather than absolute drivability. I will bored you with detail tomorrow

Pope

[Gareth]

Originally Posted by Bubble

I read the thread title wrong Moff and thought it said let's talk about boys............thought you had changed sides for a moment

So did i Geoff and was going to put down that John mite wont to rethink on going to the nurburg ring with Moff

[Squeak]

Come on guys, shut up with the banter.. I want to learn something here

*eagerly awaits Popes post *