Outer Limits 4x4 Board

Is it possible to fit a BOV (blow off valve) on a 2.8?
a friend of mine was thinking of doing it, i think its ridiculous specially on a 4wd.
but i heard that these motors dont have a butterfly valve which is what creates the vacum needed to make use of the BOV.
apprantly it gets it from the break booster???

can someone shead some light on this.
Thanks

My understanding is the 2.8 Turbo has an internal waste gate that control boost via a diafram linked to the intake manifold (same as all nissan TD). Once the boost exceeds the factory set limit the waste gate dumps the excess gasses (into the exhaust, i think).

For a BOV to work you need a Turbo without a waste gate. So no I dont beleive you can do it to a 2.8

This is only my thoughs

my 300zx twin turbo had internal wastegates on the turbos. It also had factory fitted recirc valves, wich are the same as plumb back BOV's.

The wastegate opens when boost pressures exceed factory limits. But there is still a backpressure thru the intake system when the throttle closes. This is where the BOV comes into effect. I know nothing about Nissan TD turbo setups, so I won't comment on weather it would work or not, but if a reprogrammed ECU is used with higher boost, sometimes it requires the wastegate actuator switch to be disconnected, allowing the BOV to do its job. This allows higher boost to be run with out the wastegate interfering.

I used this setup on my Zed, and was able to run 22psi on the standard turbos with the wastegates disconnected.

I am not saying this would work on the 28TD tho.....

tell him to buy the electronic PCHHHhhhhhhhhhhhhh machine if he is that much of a gong beater..

Bovver Boys..

Cant do it on a vehicle with no inlet butterfly, ie 99.99% of turbos diesels.

Bazzle

Xcited wrote: For a BOV to work you need a Turbo without a waste gate. So no I dont beleive you can do it to a 2.8

A wastegate and BOV are two seperate things.

The wastegate is used to control boost pressure. It is activated via an actuater which operates at a set pressure, when opened it allows exhaust gases to bypass the Turbo compressor to stop it spooling and thus control intake pressure. A BOV on the other hand (mounted off intake on pressured side of turbo) is fitted to the intake side of things, it relieves intake pressure when the thottle is closed, the sudden need for no intake pressure can cause a backpressue in the intake which can stall the turbo thus making it lag more (damage can occur in high boost situations). So at times the throttle is lifted the this pressure is relieved.

Their are essentially two styles of BOV's atmospheric or recirculating. An atmospheric simple vents the air to the atmosphere and thus giving you the PSHHHH sound you so often here. But if mounted onto an engine that runs a MAF, the computer has allowed for this air and adjusted fuel mixtures to suit, so when the air is vented in gives a short period where the engine will run rich. This is overcome by a recirculating BOV, where it vents the air from after the turbo, back to in front of the turbo but after the MAF so that the same amount of air stays (but pressure is relieved) in the intake and stops the vehicle from running rich for short periods.

thanks for those explanation guys, i thought the TD motors didnt have the inlet butterfly, i think ill tell him to go buy the electronic pchhhhh machine like bogged suggested

Mate ... even though Rock Monkey gave a very detailed explanation of the benefits of a blow off valve (a topic of which I know nothing about so he convinced me) it sounds like your mate just wants to add a little Bling Bling to his machine ... not sure it will help him off road but hey ... go for it.

Cheers
Simo

yeah he was born in Los Angeles and has been in Australia for 8 years now, i kinda got him into 4wding and he bought himself a patrol 2.8 TD like mine.

Unlike me he has 20 chromies on it and is thinking of doing more bling bling ridiculous things to it. Once i tell him he cant put a BOV on it he might even change the engine....
yanks with too much money...

X-R-Cist wrote:thanks for those explanation guys, i thought the TD motors didnt have the inlet butterfly, i think ill tell him to go buy the electronic pchhhhh machine like bogged suggested

Convince him to install one. Whilst he is at it, sikaflex a large dildo to the middle of his windscreen at the top.

r0ck_m0nkey wrote:

X-R-Cist wrote:thanks for those explanation guys, i thought the TD motors didnt have the inlet butterfly, i think ill tell him to go buy the electronic pchhhhh machine like bogged suggested

Convince him to install one. Whilst he is at it, sikaflex a large dildo to the middle of his windscreen at the top.

lol
i think i might put one on the back too