**RB2530**

Ok here is a theory I have has for years now but never done the work to prove it...It is just my educated opinion and maybe the other mechanical engineers on the forums may like to comment as well...Anyone else feel free but if you are a non-believer tell me WHY? My theory is that a plumb back BOV will be slightly better at maintaining turbine spool then an atmo BOV. ie on a gear change the reduction in turbine rpm will be lower with PB BOV than if it was a vent to atmosphere... The reason is that with a the PB BOV, air is fed back into the intake pipework or inlet of the compressor. If you look at just the compressor. It is a pump that draws air in and pumps it out. That amount of work the comp does is proportional to the pressure increase across it minus losses. On a gear change the energy input to the comp is close to zero (turbine suddenly is not getting exhuast flow to turn it). So it obviously it slows down. Inertia of the shaft and wheels is what keeps it moving. Without a BOV it slows very quickly because the pressure increase becomes very high. Ok but with any BOV this pressure spike doesn't happen so it won't slow as quickly. BUT Another factor that comes into play is the work the compressor does to draw air in through the air filter and the intake pipe work between the afm and the comp inlet. Normally this region is at a slightly negative pressure depending on how restrictive the air cleaner and intake pipework is... So some of the work of the compressor is expended in just pulling the air through the intake. With a PB BOV though, extra air is introduced into the intake side of the compressor, which on a gear change will overcome this loss. ie for a short period of time, a positive pressure will result in the intake because you are dumping air into this (semi confined due to air cleaner) region. In other words the air exiting the BOV will expand in the intake pipe work will act to keep the compresser sopinning at a higher rpm simply because you are eliminating the losses in the intake. With an atmo BOV, the energy put into the air post-compressor is just expelled into the atmosphere, never to be seen again...Not to mention the poor ECU that desperately adds fuel for air that it doesn't realise, no longer exists... If you understand this so far you may be thinking, well the PB BOV will not be as efficient at reducing the compressor outlet pressure because it is dumping into a semi closed region (depending air cleaner etc) instead the atmosphere. I am not sure either, but when you look at the typical atmo BOV, they don't exactly have free flowing discharge...especially the rice ones I've seen..otherwise you wouldn't get pphhhttsshhhh!

Peter, You have misinterpreted my response. I am all for BOVs. They have a purpose irrespective of much boost you are running. Nissan didn't put the stock one on just cos they felt like it. I was pointing out the problems with atmo venting BOVs. Plumbed back BOVs are perfectly fine. There are many brands available which can be plumbed back...even Turbosmart...

Peter, What makes you 'entitled' to an answer? The reason no-one has answered you could be one or all of the following reasons: 1. Your BOV is an vent to atmosphere BOV. The skyline ECU is not designed to cope with vent to atmosphere and will overfuel on gear changes. This has been covered 100's of times on these forums. Every 2-3 days someone asks this question...The same f*&^in question. Do a search!! 2. Many people hate atmo BOVs. All they do is attract attention.There is no benefit apart from pure rice factor..As if imports don't get too much attention already..Now, every cop think any BOV is illegal...We can't help that they don't understand the difference between legal and illegal BOVs...Fact is, thanks to the atmo BOVs we are even further behind the 8-ball and guilty until proven innocent...ie trying to convince the cop that unlike most other atmo rice sounding BOV cars on the road, mine is actually legal cause it is plumbed back. Too complicated for your average HWP officer... 3. Turbosmart gear comes with good instructions that cover your exact question... Not trying to be harsh, just explaining why no-one answered...

t- peice in bov line I am not sure?? T piece is not factory I think From memory its just a straight piece of hose. All you need to think about is that both these lines run at boost pressure so any hose you use must be good for say 30- 40 psi for stock boost (factor of safety of about 3 to 4). So taped up hose is not good. It will leak if not instantly, eventually. It may squeal as you describe. For the IAAC hose the issue is the 90 deg bend. You could use straight hose (must be oil rated so not garden hose etc) with a brass or steel elbow.

Blue circled hose is hose that actuates BOV. It causes BOV to open and shut as required. Red circled hose is feeds intake air to idle control valve. You guessed it, this controls idle. Car manufacturers don't make a habit of installing hoses that are non-critical. They all have a purpose. Your current mechanics suggestion would be fine . This will allow the car to be driven around enough to find a better mechanic....

School holidays in the UK too???

What boost and ECU are you running? It could be that you are on the verge of the airflow cut threshold of the stock ECU.

Dude, That sort of thing can be done successfully however the way yours appears to have been done is not good. If they are just glued, forget it. It needs to be soldered by someone who knows how to solder. If the guy has used too much heat (common mistake) he may have melted the plastic that holds the pins. This will cause fatigue where the pins attach to the circuit board inside. The right way to do it is as follows: 1. Solder the wires to the pins. 2. Place heat shrink over the pins and the wire. 3. Fill the socket with what they call 'potting'. Jaycar have it. This is like a resin filler that you pour in and it sets hard. It stops any movement or stress on the solder joints and preventing fatigue. My suggestion would be to change the socket. Your current one looks like a reliability problem waiting to happen.

WTF??... Yeah I know this place and they'll throw in a set of clear tail lights and some big f&*^ off stickers as well...pppsstttttchhhh pppsssttcccchhhh

Step 4. Remember back to the days when imported Skylines were only owned by people who could afford to insure them fully.

Find someone who knows what forged pistons sound like when the engine is first started. Get them to listen to it. They are noisy due to larger piston to bore clearance required because forged pistons expand more when hot. I run CP pistons and they have a relatively small piston to bore clearance and I can still tell easily.

I've got something VCT related to add. Not sure if this has been posted elsewhere before but if you are running a VCT head in an application where it is the VCT can't be used you should always look at locking up the cam pulley. I had situation where my RB30DET with VCT head had issue with inconsistent performance and crap idle. As soon as I plumbed up the oil feed to the VCT gallery the engine became much smoother and the idle became very consistent. The build was ok at first but over time these issues crept in.. My theory is that the VCT cam pulley mechanism without oil dries up and can move and stick at different advances. The thinkers out there will say this cant happen because the friction in the cam shaft will always act to retard the cam pulley preventing it from advancing. Thats what I thought too..But when you think about it when you stop the engine if the cam shaft is on a lagging edge of a cam lobe it may have a tendancy to advance the cam. If the mechanism is sticky then once it does advance it may stay there for while. Not positive about this...it is just a theory.. But what I do know for sure is the engine became a lot more consistent in power delivery and idle after the VCT was reconnected. BTW it took a fair amount of playing around with the VCT mechanism to free it up even after the oil feed was returned to it...

One reason is that generally to fit a FMIC you need to cut extra holes in your car for pipework. If you cut holes without reinforcing hole perimeter you have reduced structural integrity of Monocoque chassis..(technically anyway). Any modifications to car chassis obviously needs to be engineer certified... There are other regulations that are State dependant...

Ummm excessive airflow due to poor boost control....Its a feature of the standard ECU that prevents engine damage due to too much airflow caused by increased boost or overboosting ...It acts in the region of peak torque 4000-5000 rpm on the stock engine. As soon as AFM voltage exceeds a threshold it cuts spark until air flow drops.. Don't worry...Its meant to be there...Its probably saved you from a big engine rebuild bill...

Also if you placed the bleed valve in a spot where it gets really hot, the boost you get will vary quite a bit depending on how hot the bleed valve is....

The big jolt is just airflow cut...

A point about your question... The ECU has no idea what size turbo you are running...The good thing about engine management platforms that use MAFs is you can do a lot of mods and the stock ECU will handle it. Safely!!.. Platforms that use MAPs are a completely different ball game... All the stock ECU is worried about is airflow. It matches fuel to airflow. If your airflow exceeds a threshold (which increases with rpm) it progressively cuts spark. This 'is Not' R&R. R&R is triggered by pre-ignition. This is one of the most misunderstood things on these forums. I run a stock RB25DET ECU on an RB30DET with a GT3076R and have done so for 2 1/2 years now. It makes around 280rwkw and afrs are safe. EGTs are good as well. I get around airflow cut by changing exhaust cam timing and introducing a little bit of lag. The ECU doesn't like too much airflow at too low an rpm and if you avoid this, the setup works well. This is not crap and dyno runs were done by a well respected tuner on these forums... So IMO I think your engine will be fine. Airflow cut is the saviour and will occur well before any overly lean conditions occur...

Yep this is Hicas playing up... I have found that whenever I do a wheel alignment or anything where I turn the steering wheel from full lock to lock with the engine off, the Hicas computer goes into some sort of diagnostic mode. The symptom of this is that the Hicas rack seems free to float or do what it wants. The first thing you notice is you have to correct for this with the steering wheel. Typical the wheel is 10deg of centre on straight road... The way I fix this particular issue is to stop the car, turn off engine with wheels facing forward. Wait 10-20 secs and then start the car again. All is fine after that. Now this 'may' be what is happening with your car. OR it could be a fault with Hicas..but definitely something to do with Hicas..

If you are concerned about thermal shock in the block as the thermostat opens consider this... 1. The temperature of the water inside the radiator before the thermostat opens will be the same temp as the ambient air. This will be true no matter what size the radiator is and it will be independant of road speed... 2. Thermal shock will most be severe as soon as the cold water hits the hot internals of the block. What needs to be considered is change in block temp vs time. What governs this how quickly the thermostat opens. They normally open very slowly. They do not open instantaneously. It also depends a bit on the size of the water pump as this dictates water flow rate. 3. A bigger radiator will only change the steady state temp of the cooling system once the thermostat has opened. But the thermostat will start to close if the system temp gets to cool. The system then warms up opens up ts and so on...its a closed loop system so it controls it self. So imo stick with the stock thermostat and the engine probably wont even know it has a bigger radiator on a 'cold day'.

Dude not having a go here, but do you really think you should be playing with brakes??

I wonder if you will feel the same in 15yrs time??

Yep...I earn more than $100,000...But I EARN it...with responsibility and stress!!! I also spent 5-6 years studying with no income and ended up with a $12,000 debt of the privilege...Now I don't begrudge you guys for getting $900. What pisses me off though is when you say we don't deserve it cos we earn enough to start with....

Ok dude lets apply a bit of perspective here....Lets say you earn $65k....Would you be happy with picking several random strangers tomorrow and giving them a total of $450 cash for no reason...Not to mention the fact that you also have already paid a higher percentage of income tax than they did????

Try the mobile number on this page... http://www.full-throttle.com.au/About%20Us/aboutus.htm

Dude they are still trading...I spoke to the guy the other day..They have moved to WA I think...Have a search on their website for a mobile number...It gets through to them...Can't remember where I found it but its there somewhere....