GT-RZ

Bigger and better flowing wastegate is the best way to fix this. With an actuator it gradually begins to open up and is fully open when boost has hit the actuators rated pressure. Problem with this is that you loose pressure inside the turbine which leads to slower spool up and less response. All a EBC does is control a one way pneumatic pressure valve (mechanical ones work fine too ). This way you set the pressure for the valve to open not the actuator (must obviously be >=as the actuator pressure). When the pressure reaches the valves release threshold it flies open instantly and immediately opens the wastegate when it hits the actuator. If the wastegate is too small/crap flow there is the potential for the turbo to not rid enough gas quick enough and a short spike in boost as it all tries to run through the same door. True fix is a larger more flowing wastegate. easy. but really 1-1.5psi spike is nothing i wouldn't worry about it. That being said as others have mentioned it is also important that there is no restriction/loss of pressure to the actuator.

Blow-by as you pointed out can break down oil prematurely. We get all four of our 2000hp @ 800rpm 16 cylinder engines oil tested by Castrol too. They are a very good bunch, Infact Castrol were the ONLY company that would guarantee there oil to not leave unwanted buildup through the system. It's good that you get your oil tested it can show up more than just the oils lifespan. Saves lots of money, especially when you need 200litres for each engine when due for a change..

Main timing belt is longer, that's altered. If you have kept the Rb30 balancer then you will also use the rb30 power/s belt which is thinner. tbh if it's a stock bottom end i would still just switch the balancer to the 25 one, far better and no dramas then. look in the PDF for details on the timing belt.

lol. stock means stock right? I would like to know too, hopefully without paying $$$

Since no Rb30 is younger than your car you could not do it at all. assuming you have the 32? older engine in newer car = no no. If you had an RB30 you could stroke it out but not put a twin cam head on it, i'v asked a few times now. Plus sydneykid they don't know by the engine that it was originally a turbo engine, but by the car that it came out in... If you had a r31 and wanted to turbo it then you need an RB30 from a VL turbo. I was talking to a guy from the r31skylinesclub.com before (i had a 31 a while back) and he mentioned heaps of people got there cars registered as turbo until regency cracked down on it and require the lower compression engine. By that they cant check compression but rather the engine number. An engine from the VL-t is obviously lower comp from factory so that's what they want... I dare say anyone that has been already registered with an R31-t may feel the peril if they are sent back to regency. But really it depends what mood they are in one of my friends was refused rego for a small rip in his vinyl door trim of his r32... Of course there is still the route of backhanders here.... won't say too much but $2000 to the right place and you have no dramas (lets hope you don't get defected every week hah)

How much did it cost? If your turbo is water cooled too (most likely) i wouldn't of bothered.

Christmas for you: http://www.importworkshop.com/nissanskyline.html All the manuals right there. fk $300.

if you weighed in at 1530kg then if everything was perfect, which it would not be. 9.8sec @ 139mph

Can't see why not. Intake and exhaust side seem to work well. On the intake side it needs to be below oil level though and on the exhaust side it doesn't matter as much. Gary seems to have had lots of success with his way and clearly m speed appear to be happy with theirs where it is. Only one return would be needed though i think, -10 or larger.

Hmm just so everyone knows there is plenty of these style pneumatic valves around... you can get ones all stainless, brass whatever you want. electronic if ya fancy. company that springs to mind is SMC they have a stack of one way adjustable pneumatic valves. There is also another that starts with pneu*** can't remember. just thought id add something. Sure i saw one with a nice little marked adjuster on it too so you know the opening pressure, long time ago.

How much bigger?

From what i'v read the majority of bedding in happens within the first drive (or best bit of the hone wears away) that is the most critical time to get the rings bedded in, after that you've missed the biggest opportunity. After that it's recommended to use mineral oil for a while to let the rest fully wear in. If you stuff up the first bit you can never fix it up. unless re-hone and rings.

That will be something special. I have been thinking for a while about getting a stock rod tested just to see what the maximum stresses are! Unless someone knows the metal properties of one then i could work it out... R.I.P.S??? any info It would be very nice to be able to work out the theoretical max of HP vs RPM combination's. The problem with having higher RPM with stock rods is where i'd be worried tbh. theoretically before we take in to account other 'weaknesses' if we were to double the combustion pressures (more fuel,boost) we only double the force on the rods, but if we were to double the RPM we quadruple the force on the rods. Rob, you say your freind was running 8000rpm with stock rods, but what pistons did he have? If he had forged pistons which are generally allot lighter than the standard cast pistons then adrianno was certainly at a disadvantage. Adrianno what max RPM were you using?

Go and find some Rb30's in a wreckers and rip it apart until you find a perfect one. rebuild it with new bearings and rings with a hone and your done. will be an improvement and cheaper . Or if you really have a budget go and do some comp tests on some Rb30's untill you find a nice one then just chuck the head on. Far rather do that than buy a 25 and rebuild that, unless you got it for less than $150 my shortblock cost me $88 from u-pull it. Got two now.

I'm leaning towards just forgetting about the vac setup tbh because of the potential mess if it goes wrong and this is an even worse scenario! Aiming to keep crankcase pressure to atmospheric pressure is a good enough target i think. I think that's possibly why m speed has the return on the first small oil/air seperator, it allows the 'heavy' oil to return to the sump and the air to swirl up and exit to the next catch can where the air is scrubbed clean and vented. Dirtgarage has almost an identical setup on his car to m speed, disregarding the additional head oil drain. For people arguing about oil contamination that argument is flawed in a race car as the oil would be changed after every race anyway. And returning the majority of oil that leaves the engine is obviously a good idea when you have a problem like the 'guy' in your example. Do you mean straight from the cam breathers to the block or through some kind of pressure vent?

Factory has there blow-by vent in the airbox, standard. But i do agree, i was only trying to come up with a simplistic way of achieving a vacuum. I like things to be simple - last thing i would want is an external vacuum pump. When it comes to it i probably won't bother at all and will just vent to atmo... depends what the gauge pressure is in the crankcase when i set it up. I certainly don't want a mess in the intake but that would largely depend how good your filtering is, o well! I would love to see a picture with a little filter on the m speed tank just to finish any possible use on there behalf, but seems that car is top secret--- i emailed them to no success.

I agree with you on the oil mess. lets hope that never does happen! Obviously airbox design is critical on how your vent will work. The factory design is one to be replicated as it has lots of thought put in to it, the intake flow of airmass practically misses the blow-by vent and can exit via another vent giving that stream of airflow and no build up off pressure. Your design seems to operate how you planned it and given that, maybe the vent would not be ideal. The design of an airbox with a blow-by vent should be designed with that in mind. That is a flow of air should be maintained and the vent should not be in the path of direct airflow mass. For those who run just a pod there would certainly be no issues with a positive pressure build up (like the pic of the 180sx above) But an airbox is the better option, for obvious reasons. I think we are over complicating the matter anyway. A vacuum would be a nice thing to achieve but atmospheric pressure or 14.7psi within the crankcase is more than acceptable if it can be maintained. It really depends on how serious of a machine you are building. when every last HP counts a vacuum would help for many reasons. My new setup will be done like m speed (like the picture, bearing in mind the red dot is not connecting to the line on the front....) i'm going to setup a gauge on the block and observe, after that will depend if i setup a vacuum system, be it re-circ utilising venturi effect in the intake or exhaust. I will definently be making an aribox so i'll have to decide before i do this!! With all the extra breathers and drains in place the vacuum or atmo doesn't really matter, it would just be the cherry on the icing.

I think you have confused my picture BB. the red dot is supposed to represent the oil return at the back of the head, that's why it's a broken line not solid.. i sort of guessed where it sits in in relation to the front (probably shouldn't have placed it on that line to avoid confusion) I changed the image a bit: So what your saying is that the intake pressure you are reading is far greater than that of your crankcase pressure? By pressure i'm referring to evenly distributed force (atmospheric pressure) As that's the only one that would affect our crankcase given that the vent would be situated @ 90* to the direction of airflow mass from the airbox intake. Where is your pressure gauge located relative to the direction of the engine intake and airbox intake? If your gauge is located anywhere in the airflow masses direction you are simply reading a locailsed pressure from the velocity of airflow mass, which won't affect our crankcase vent too much. Adding to that airbox design is not as simple as some would believe. If you were to have only one entrance then disregarding the engines intake you only have one exit, too. And rejected mass (ie not needed by engine) will recirculate back out the intake, effectively slowing down intake air velocity and decreasing the effective intake size. You will not increase the airbox atmotpheric pressure. Simply choke and slow down any incoming airmass velocity which is part of the idea of having a directed intake. A vent situated after the engines intake (to wheel arch? your choice) would prove far more efficient as only fresh air would be directed to your engines intake and it would be utilising maximum airmass velocity and not being choked by recirculated air exiting your entry. And like i said before, only an atmospheric pressure rise within the airbox would reduce any blowby vent's efficiency. If you can show that you have an evenly distributed pressure increase inside your airbox (which i doubt) then you may have a valid point. But like a menioned earlier, i really don't think having atmo pressure (15psi) in the crankcase is a problem, vacuum is better but it's alll better than rising pressures.

That's all true but really i like a bit of tolerance with my engines... The winning combo for them both is the relatively low RPM limits. With the 3litre being quite a bit longer in the stroke it suffers far greater piston speeds than the likes off the rb26 at the same RPM. Apparently even 450kw is fine for the stock rods in regards to combustion pressures. With that said the true benefit of the RB30 is getting higher torque @ lower RPM often proving a more reliable engine due to everything else operating in a more 'comfortable' zone for the target HP in comparison to a 26. Given them figures unless you're chasing after a massive HP engine i can't see the need to go over 7200rpm... I was thinking about just new pistons to get the higher cr but for the price of rods and the piece of mind and potential progression of the engine in the future it's hard to resist!

Had a good look at some pictures and looks like i assumed the wrong way. i'v imposed the block on the engine to show the connection location better. Note that the two large lines are just hung there, i'v drawn where they connect to the engine bay. Going by there setup the oil at the back of the head must be fairly heavy and not aerated so it is allowed to flow direct in to the sump well under surface oil level. Acting ONLY as a drain. The attachment on the block however (image is deceiving, look at bare block. the attachment sits in the lowest point of the block). It connects to under the oil/air separator, if that's what we think it is... I'm unsure because due to it's location, crank windage would be firing straight at this pipe... Maybe it acts primarily as a vent from the block and the oil/air is caught in the next large catch can and disposed off. However under low rpm any oil that may have accumulated in here could drain back in to the block, id really love to see inside that small oil/air separator. As for the whole re-circ, i don't think anyone can prove either way. both have a positive effect but vacuum would still be the best option providing you can clean the air adequately... this is how it can be setup, no reason why m-speed has not got the same out of view in them images straight to the cold air box they have. I liked reading your post BB with your trip to japan, looked great fun. I think the GT500 cars may have taken a simplistic approach to oil problems? Them little cam covers wouldn't have too much space for lazy oil?

When you post info like that it makes me wonder why i'm bothering to build my setup with forgies... i'm going for <400kw... o well. better safe than sorry... i don't have a book of secret tricks that you guys do...

Bit of work but looks the goods.

Full throttle, full vacuum. Half throttle, half vacuum. The Manifold PCV valve only operates at idle. it is only there because it is within a sealed atmosphere and thus is able to pull stronger vacuum. It is not needed. The vacuum pipe that connects to the airbox also operates at idle, however this pipe operates when boosting also. Whenever the engine is running there is always vacuum within the airbox. As RPM increases the vacuum becomes stronger which is why it works so well (positively increasing blow-by pressure,positively increasing vacuum pressure). Because the airbox is directly connected to the atmospheric pressure of 15psi any positively pressured air that was to come through the turbo would instantly become de-pressurised. Air does choose the path of lease resistance. Air would most definently flow through the airbox filter rather than attempt to pressurise the crankcase. Neither would air inertia be a problem as the vacuum pipe would be connected at a right angle to the mainstream of air. (hence why the factory pipe from the crankcase to the airbox does not have a PCV valve, not really required). But would have no trouble operating here as no large boost pressures would be present, would not hurt to fit one. Considering our problems only happen at higher RPM the idling PCV valve is not really required which is why i suggesed earlier to connect it directly to between the turbo/filter. So with a connection to ATMO you have a crankcase pressure of >15psi and with the vacuum attachment you will always be <15psi. The lower the pressure in the crankcase the easier oil will return from the head, helping with them big corners. Aswell as the other advantages associated with less resisticance for the rotating assembly and pistons, ring seal etc.

Never saw this post before. which puts forward a good point. What does connecting it to the brake booster improve?