**RB2530**

Hey dude, Any luck on this price...I haven't seen a PM..mailbox is not full...

If your a newby on the track, running lower boost will get you quicker times anyway....

IMO at the moment you don't have enough information to lay blame or not lay blame...You know a turbo has failed but you don't know why. 1. Was it due to normal wear and tear? or 2. Was it due to an error of the mechanic?...ie did he dropped a nut/washer or something down the intake piping...This has been done before... I would suggest you get the turbos removed and inspected by someone who knows what they are looking at. Tell the mechanic you are going to do this and gauge his reaction... Even suggest to him that he can pull it apart in the presence of yourself or someone who you nominate... good luck with it....

I have one I bought from Caz Racing...It pretty good...Cant remember the name though? The ability to turn cylinders off is a good feature. Its intent (or what I use it for anyway) is to detect differences in cylinder performance and indentifying problems cylinders etc. I haven't used it for a while but from memory what it does is turns each cyclinder off then back on in a sequence and measure drop in rpm for each cylinder dropped. If all cylinders are even in compression, fuel addition and spark then the drop in rpm for each cylinder should be approximately equal. If you drop a cylinder and idle doesn't change as much you know there is problem with that cylinder...The software I have displays rpm drop for each cylinder on the screen so you can record it.. Also if idle timing jumps around you may find your idle is a little too high as from memory the ecu jumps from 15degbtdc to a 5degbtdc as soon as engine comes off idle without load...So ecu is toggling between 15 and 5 deg...I think??

Hey mate, Can I get pricing (delivered to Newcastle) for all brands in 255/40/17 when you get a chance.... 2 req'd only many thanks...

My front brakes have 8 cylinders....so at least my brakes are not fake...They produce raw stopping power!!!! But I run a brake booster so I must be cheating!!!

Oh and 3 more tips... 1. Never ever use a bolt in place of a stud +nut. Studs are better because you get full thread engagement in the hole plus when you are tightening a nut on studs the sliding surfaces are steel-steel as opposed to steel-alloy. 2. When you put the new studs in but before you place the manifold over them, measure the length of the non-threaded or blank section on the stud. Make sure that this length is at least 1-2mm shorter than the thickness of the manifold flange. Some studs have a longer blank section and if the nut bottoms out or runs out of thread before it bears hard on the flange, its the same as a loose nut. Its been done before... 3. Make sure you re-tension the nuts after say 500kms then every 20,000km. Its a pain to do but worth it...The gasket compresses a small amount over time... cheers

Just thought I would give you a couple more tips.....Last manifold I put on still going strong at 60,000km. 1. Make sure exhaust manifold is not deformed or warped. Check that all flange faces are flat by placing a steel ruler or straight edge along face that bolts to head. If it is warped it will always break the stud and end up leaking. 2. Always use Nissan genuine gasket. Worth the $120. 3. Always use new nuts. Use steel or inconel (spelling??). Never ever ever use brass. (I had a guy working at Peps once tell me brass nuts were ok to use.) 4. If a stud looks just a little bit suss, replace it. You are anyway. 5. Always use correct tightening sequence. This is in the workshop manual. Generally you tighten from centre of manifold outwards. Try and get good even tension in all nuts and do it in 2-3 passes. 6. Always use a good ring spanner. Never use a cheapy!! 7. Always use heaps of anti seize. 8. Never try and rush it... 9. Have your first beer AFTER its done.... cheers

Dude, Save yourself a lot of pontential grief and get a mobile guy to do it. If it is in a hard spot they can be easy to get wrong then you have a bigger problem. The mobile guys have all the good tools as well...Also dont try and start it yourself because inserts like helicoils have non standard size drills and taps... Its always good to learn so you can do it yourself but learn on something thats less critical, cheaper and has easy access..

Apologies in advance if I am off the mark here but I detect some inuendo this post?? You ask simple questions about complicated issues and expect simple answers?? If you substitute your actual numbers (water / methanol flow rate) into my way of approximating what your drop in afr may be you will find I am actually pretty close to the mark... I 'may' have some ideas about how much extra timing you can run...But since you are the 'Thread starter' I will leave it to you to find 'someone with knowledge' GOOD LUCK!!!

Drilling into the compressor wheel housing and spraying onto the blades would be BAD!!! Guaranteed damage to comp wheel....Its like this...The further along the blade you go from the turbo shaft, the faster that part of the blade is moving. Damage / wear on the blade is cause by the collision of the blade and the water droplet. So to minimise the collision you want as slow as possible blade velocity (towards centre of comp wheel and not the outer) and very small water droplets. So very finely atomised water directed towards the centre of the compressor wheel is the best setup. Getting the atomisation right is the big thing.. Don't try it unless you really understand this as guaranteed you'll be after a new comp wheel and maybe more in no time...WI after compressor is safer IMO...

Yeah I have seen those nozzles. I think they are featured in an Autospeed article somewhere. These nozzles work on the same principle as a paint spray gun. Also the comp wheel blade velocity reduces as you get closer to the centre shaft so if you are going to add atomised water pre-compressor you would try and aim the spary towards the centre of the comp wheel. BUT any water that hits the shaft /nut would bounce back and you would lose atomisation. Also adding methanol would reduce the surface tension of the water and there atomisation would be better however menthanol may attack compressor wheel material after a while....interesting

Yep I agree with point 1. Compressor maps would be or should be based on dry inlet air at standard temperature and pressure which is 25degC at 1atm. So as soon as you add WI the evaporative cooling effect would drop the air temp and increase the air density and viscosity etc etc. Damage to turbine blades will always occur (even dry air will cause a bit of wear over a long period). Its all about the rate of wear or damage. Really fine droplets will have minimal impact on the blades. The only problem is that the most common failure mode of a nozzle is that it gets partially blocked and the water does not atomise as it should. Good atomising nozzles run at very high water pressure. So if your pump fails partially or completely you will end up in scenario where the atomisation won't be right. When you switch your pump on or off the pressure wont rise instantly so you will always get situations where your atomisation wont be 100%. So IMO there still is a reasonable risk in adding water pre-compressor. It will largely depend on your WI setup.

What you have to do initially is work out what the overall change in fuel entering the engine is when the Water/methanol injection is switched on... When the WI is switched off you just have petrol entering...so rate of fuel flow will be 'very roughly' determined by injector duty cycle % x full flow number of injector (for standard fuel pressure). ie for stock RB25 fuel system = 375cc/min 43psi FP at 100% duty x 6 cylinders. At say 70% duty cycles this will be 375x6x0.7=1575cc/min. This = 1.16kg/min petrol. If you are running 50/50 water / methanol by volume this = 60/40 water/methanol by mass and your WI nozzle is supplying the water/methanol mix at 200mL / min (for example) then the mass of methanol entering engine will be 0.2x0.4 = 0.08kg/min. So the amount of fuel increase is not much at all. = 1.24 kg/min which is a 6% increase in overall fuel.. Now there are many assumptions made here. One main one is that all of the petrol and methanol burns...In reality it doesn't. Stoich for petrol is 14.7 afr so if you are running in the 12's not all petrol will burn. Also the methanol is soluble in water and i dont know if it burn when mixed with water... So based on this my 'best guess' is that your afrs would change no more than 5%. Depending on what you are using to measure this change will be too small to measure.. Any chemistry gurus please feel free to comment...

If you fed the receiver / water tank with pre-throttle body air the tank would never be under vacuum....And yeah the air over water idea is a good one too...I thought of using exhaust manifold pressure to pressurise a tank but don't know if the pressure difference would be big enough...It would depnd on turbo and exhaust design. Plus it could be very disastrous if water somehow got drawn into the exhaust mainifold...

Yep this is a known problem and thats why the WI kits use at least a 100psi pump. Another way of dealing with it is to use a sealed water tank and pressurise it with boost pressure. The obvious problem is that your water tank must be able to withstand boost pressure, otherwise you will pop your tank apart... I have tested a couple of those plastic red jerry can tanks. They must meet and an Australian Standard designated hydrostatic test. They must withstand 2.5bar for 30mins 2x or something like that. The trouble is in a WI application is the loading on the tank will be many, many more cycles and even if its only 1.5bar, after 1000s of cycles they may fatigue... A fix may be to fabricate a decent stainless steel strap that holds the tank together...or get a decent fabricater to make a tank out of aluminium 3 or 4mm plate. I considered using an air receiver off the brakes on a truck but I think they are mild steel and may corrode due to the water..

Just want to clear this up... 1. Water technically doesn't burn and aid in the combustion but there is a theory that the water 'may' dissociates producing Oxygen and Hydrogen which will aid in the combustion. 2. RON or Research Octane Number is a 'relative' number that decribes how the fuel behaves (with respect to pre-ignition) in comparison to reference fuels that are made up of different ratios of iso-octane and heptane. The test or reference fuel is put through a test engine with varible compression ratio. Pre-ignition vs comp ratio is characterised. If a commercial fuel is placed in the engine and it performs the same it is said to have the RON of the test fuel. So 98RON is called 98RON if it has the same resistance to pinging as the 98RON test fuel. Commercial fuels may not contain any Octane but can still have a RON. So it follows that, if water even on its own has the ability to 'reduce' pre-ignition, it therefore increases the RON of the fuel. This is by definition and not opinion. I would recommend trying WI. You wont get much power increase without changing ignition timing although after a while your combustion chamber and valve seat should be cleaner which may help. The big advantage with higher RON is the fact that you can run a fair bit more ignition timing. So on a stocker you advance the CAS... I am currently working on a tunable WI unit that can be mapped to engine load via the afm voltage. The water will recirculate back to a tank via a cooler so it won't be heated by engine bay temp. A bit like how the fuel system works. Also as someone else said, getting the atomisation of the water right makes a big difference. The reason for this is that the smaller water droplets, the more exposed water surface area you have and the more effective the water will be...It will cool much more effectively and also inhabit the combustion chamber much more evenly...

Hey dude, What time did you see the black GTSt at Sandgate yesterday? Around 3:30ish? Did it have silver AVS rims?

Just for interest sake, the following is a good way of testing the accuracy of a boost gauges is as follows. Go to the chemist and ask for a 15 or 20mL syringe. Even larger ones are fine. The bigger the syringe the harder you have to push the plunger. The syringe is plumbed up to the boost gauge and when you press the plunger the boost gauge will register what pressure is in the syringe. To check the calibration there are three ways: 1. If you have a gauge that you know is accurate, plumb this gauge up with the other gauge and then to the syringe all at the same time. They will see exactly the same pressure as each other so you can compare the two readings. 2. If you don't have another good gauge, you can calculate the pressure exerted by the syringe by doing the following. Measure very accurately the diameter of the bore od the syringe. Calculate the area. Measure the very accurately the force exterted on the plunger. This can be done by placing the syringe in vice and placing a weight of known mass on the syringe. Put some light oil (vegetable oil etc) in the syringe. Don't fill the syringe. The oil is just to reduce the friction of the plunger in the bore. The pressure out of the syringe will be the 'force on the plunger' divided by the 'area of the plunger'. It is reasonably accurate. The main source of error is in the physical measurement of the area and force plus the friction of the rubber plunger on the bore. You will need to know a bit about physics to get the units right. If anyone is interested in doing this I can work it out for you... 3. Use a proper gauge calibration tool. Don't know how much these cost but they basically use the same principle as option 2 but are a lot more precise. These methods beat trying to do road tests and are better for your licence.

Also the stock boost gauge is not very accurate and is scaled in mmHG... Cheap aftermarket gauges too are worth every dollar you pay for them...ie not very accurate either...

You will get a pressure drop throughout your intake system. ie pressure in plenum will be lower than at the outlet of compressor. How big the drop is depends on a quite a few things...btw a drop from 10 to 7psi is pretty poor.... The implication of this is that with a fixed WG actuator, the boost pressure at the plenum will change depending on where the feedback for the actuator is taken..ie whether it is taken from the plenum, intake pipework or directly after the compressor...

Sorry dude but I just have to point out the irony here...Isn't making a modification just to acheive a cosmetic outcome, 'rice' in itself...

Yep...It may not be a percentage of power. It probably won't be purely a %..In the diff you have sliding friction (pinion to crown wheel) which 'will' be a percentage but the loss at the front tyres for example will be varied more by strap down load, tyre pressure, rubber compound etc etc. Even front wheel toe-in/toe-out will consume power as soon as it deviates from "0 deg". It may be that with an average power output with an average front driveline, the number is 10% or there abouts. Another point is that if the front driveline loss is 4%, and you assume that the rear driveline loss would be similar, the gearset loss is 20-25%. That is 'very high' when you consider the dyno run is done in 4th 1:1 ratio where the load goes straight through the g/box and bypassing the gears (although they are still spinning and would consume 'some' power).

There will be a difference between 2WD and 4WD readings on a dyno... Its simple physics..In 4WD mode you have an extra driveline (minus g/box) running the front wheels. The transfer case, prop shaft, front diff and front drive shafts all exhibit frictional loss and therefore when they are moving, consume power. When they are not moving (2WD mode) they are not consuming power. There is also a fair amount of power loss between the tyres and the dyno rollers...So an extra pair of tyres spinning an extra two rollers...you guessed it more friction. So there WILL be a difference between 2WD and 4WD mode on a Dyno...I would guess around 10-15%... On the road however it is a completely different story... the front driveline is either being rotated by the transfer case (when torque is being directed to the front) or in 2WD mode, by the road itself turning the front wheels. Irrespective of what is turning what, the front driveline is rotating so it is still consuming power. So in my mind looking at GTR dyno figures in 2WD mode and comparing to RWD figures is not a useful comparison because it is not considering 100% of the driveline loss. Even with a RWD on a dyno you are neglecting to measure the loss from the front wheels and bearings as well. It all gets down to what do you really want to find out...If you want to know how quick your car really is take it to the strip..If you like seeing big (slightly exaggerated) HP numbers on a screen, put it in 2WD mode and take it to the dyno... If you are looking for a simple correlation between the 2, stop looking because it is not as simple as that. (PS I know you weren't asking this but I know it will come up...) cheers

I would try turning the engine over by hand. You will very quickly confirm if it does have comp or the comp tester is RS.