**RB2530**

Hey guys I am in!!! I will transfer some cash tonight... Whats the go with accomodation? I will be overnighting on Friday (maybe) and Saturday night. Is anyone else staying down there?

Hey guys, just wondering if there are any spots left...I forgot about this event...I am liken' the sound of it though so if there is room put me on the list and i will organise some cash...

Stock ECU has both 'Rich and Retard' PLUS 'air flow cut'. 1. Rich and retard is triggered by excessive cylinder knock only. When knock level threshold is exceeded the ECU richens AFR and retards igntion. Once R&R has been triggered the ECU then will attempt to reinstate AFR and ignition advance back to normal until it detects knock again. It is designed to protect engine against bad or incorrect fuel and internet mechanics. 2. Air flow cut is triggered when AFM voltage exceeding threshold voltage. Air flow cut starts at 4000rpm and threshold increases as a function of rpm up to about 5000 rpm. When it triggers, it cuts fuel and ignition...It is designed to protect against boost control failure...overboosting from broken WG actuator etc...also provides protection against internet mechanics... So there you go...a bit of truth for you amongst the fog...

Left leg and left foot... (you did say everything)

Shit...never heard of anything like that before....when you start the engine with the WG off does it feel like you are getting a lot of exhaust flow out of the WG flange...(just wondering if they may have f**ked up somewhere in the fabrication. ie not drilled where the WG pipe is welded onto the manifold...remote possibility but you never know...

Dood, make sure the WG piston is free to travel...take the spring out and physically pull the centre of the diaphragm... it should travel atleast 10mm...make sure the stem is not damaged...also make sure the diaphragm itself doesnt have a hole in it as well...connect a tube to the bottom port and blow into it and listen for leaks...apologies if this has already been covered...

From an acceleration point of view lightening the flywheel has a similar effect to lightening your car...It reduces the rotational inertia of your engine. lightening your car reduces the mass of the car and therefore inertia will reduce..therefore faster acceleration...effect from flywheel lightening is more pronounced in lower gears as previosuly stated.. Have used the stock flywheel and now have a 6kg FW and the 6kg definately more responsive...BUT +1 on the driveability comments...carparks etc are trickier but in my mind a small price to pay...

Yep...re-read your post after I replied...Cant help out with any Melb info...

There is a guy at Windsor called Stuart Wilkins that I have heard of....I haven't used him but have heard his name mentioned very positively a few times by different acquaintances of mine in Syd...He trades as Stuart Wilkins motorsport..I think they specialise in Datsun / Nissan racegear and rally prep and have done so for many years...At least give him a call...Dont have his number but Google should help you out... If you are in Newcastle PM me and I will tell you who NOT to go with... PS welcome to the forums...

Ok just looked it up...Ummm if thats what you reckon so be it....The arguments presented to me were very technically inert. ...I must have the wrong idea about this forum I think...I hoped for intelligent discussion regarding this topic.... dont think I'm gonna find it... regards....

Sorry buddy I come from the generation that uses English to communicate...maybe you could translate this for me....

..how about we stick to the technical stuff.. Anyway I have been thinking about the stock plenum some more have some more comments on the factory plenum... Fluid flow is terribly non-linear...From this it follows that any balancing of air flow between cylinders by design would most likely change once the factory air flows are exceeded...So variations between cylinders at factory airflow may be ok but at twice the airflow the variation may be unacceptable...

Mate I haven't highjacked 'your' thread!! Read back a bit...My comments are on topic..I make no apology to you... Also I cant convince you because you are not thinking about it!! This is evidenced by the fact that you are not giving any alternative explanations or reasons or questioning anything...You are just accussing me of commercial bias... Now I am asking myself how have i mis-quoted this guy because he doesn't appreciate it?? Maybe you could point out where I have...instead of just mentioning it without detail or facts...... anyway I hope others got something out of my posts...I have spent a fair amount of time thinking about it..cheers

No!! I am basing my opinion on my knowledge of 'Fluid Mechanics'!!

That only means the stock plenum would be crap if its job was transferring light...But its not...I can't see my exhaust valves from my muffler so does that mean my exhaust is crap?? Plus I dont believe I am saying that home made plenums kill engines...please read carefully...I am saying that you may lose horsepower (in comparison to a well designed plenum) due to unequal cylinder performance...

Sorry...maybe you did cover it...I dont think snow dogs would have a very high RON though:blink:

Nissan provides 100,000km warranty based on their design!! Greddy plenum resembles shape of GTR plenum...And at WOT the TB position is largely irrelevant...So in my mind the Greddy shape is valid... I am more than happy that people use the modified rb25 plenums but I never will...And I dont believe they produce reasonable results either... And as I have said many times before, dont quote me figures of cars using the modded rb25 plenums that make x rwkW (and stating they work well) unless you have data from the same car with a Greddy plenum and associated data that shows the Greddy is worse, the same or better...

Yep good luck with selling it...It looks good overall but that collector fabrication looks awesome...

Sorry mate not interested in buying it cause I dont need one atm...Just curious cos I have unfinished business with a guy who makes them in Maitland area...

Is this guy in Maitland NSW area by any chance??

My take on hump hose is it for fabricators who get it wrong and need a straight joiner that has more flex in it to overcome stuff ups in pipework fabrications I wouldn't use hump hose unless you had to because the hump changes the cross section of the pipe work though the join...this induces turbulence...you should aim for pipe work that has the smoothest, most consistent ID as possible...

If you take the black cover off the CAS (I think for S2) you should see the actual chopper disc itself. Make sure that when it rotates it is not making contact with the optical sensor that it runs in... I have seen one instance where a CAS was installed without the spacers that go between the CAS and the bracket on the engine...These spacers are brass from memory and are fitted into the rubber grommet that fits around the CAS. If the spacers are not used, the coupling on the end of the CAS shaft bottoms out where it goes inside the CAM gear. This will have the effect of pushing the CAS shaft through the CAS bearing and cause the chopper wheel to scrape on the optical sensor..

I am gonna try and explain in lamans terms why the Greddy and other plenums are shaped the way they are and a better option... Btw way i would not use any other plenum for a foward facing TB!! I know I am going to get quoted back to me that person x, y and z use a modified rb25 manifold and make x, y and z rwkW so they do work, BUT consider this Just because an engine doesn't suffer detonation or hasn't blown up yet doesn't mean it is running perfectly...It just may be that the tuning is overly rich and the leanest cylinder is still rich enough to keep EGTs respectable...It also may just be that the variation of between cylinders is just under the precipice of being acceptible and the engine 'is' holding together ...only just!! Dont forget that the standard way of tuning is by using one O2 sensor that gives an averaged reading and for turbo cars target AFRs used by tuners are always conservative when compared to NA tuning... The aim of any engine design is to have as much eveness between cylinder as possible...It is a known fact that multi cylinder engines that have even perfomance in each cylinder will make more power than those that don't...all else being equal... This why we go to the trouble of cc ing combustion chambers etc etc to ensure the comp ratio is even...Now I doubt any engine deign would be perfect as real life is never perfect...But factory setups would be designed, prototyped and bench tested to ensure variations are within fairly tight limits... So unless you do everything you can attain eveness throughout the cylinders, even if the engine is holding together and making decent power, you are still leaving horsepower on the table.. As far as the Greddy plenum shape is concerned.... Consider that: Airflow into manifold = airflow out of manifold.. Gas flowing through any enclosure expereinces friction so you get pressure drop between inlet and outlets..AND pressure drop is proportional to cross section area and volumetric flow.. Volumetric airflow is proportional to flow velocity x flow cross sectional area.. at constant pressure...so for the same pressure if you reduce the cross sectional area by 50% flow velocity will roughly double... Now if air enters the plenum at 6 volumetric units per second it needs to be divided up 6 ways...To do this you need the pressure at each outlet to be even...If you had a parallel plenum 6 units of air would enter, some would exit to cyl number 1 and the rest would continure to along the plenum...The air continuing throught the plenum would be 6 units minus air that exited through cyl number 1... Due to friction in plenum you would have pressure drop...due to reduced volumetric flow (some air has gone to cyl number 1) you would also have lower flow velocity (dont forget plenum is parallel at this stage) which also changes friction which changes pressure drop as well...BUT If after cylinder number 1 you reduced the cross section of the plenum to so that the air velocity is increased again, the pressure would be reinstated..This repeats for each cylinder until number 6 is reached... I think this is nearly correct....please feel free to pull it too pieces..

Yep thats the one. (hate getting in to work early)..I was talking to a guy a while ago who had a sprint car and thats what he uses...He just had a case where an engine he had built had a cracked piston ring from assembly...It wasn't making expected power and there was a slight miss...they did a static comp test and all cylinders were within specs...They ended up getting hold of an infra red temp gun and 1 cyl was down in temp...they pulled the engine down and found they had a broken piston ring in the colder cylinder... If you get one I would get a good one...I also wouldn't expect it to work as well on the stock manifold because it is cast iron (higher thermal conductivity) and thick walled so the temperature gradients due to different EGTs would be lower..Although if you had another rb25 with similar exhaust setup you could comapre the two...