zebra

Thats intersting Bris - I always though the GT-RS might have been a bit better response wise compared to the TD06

I would be weary of slicks on a surface like that dave, most runways are grooved and covered in dirt/gravel etc I cant find any info that says if it is grooved or not though

Looks tricky to drive with that much grunt, also was it missing a bit? or was it just a bit of distortion in the video? Yeah it sounds like a Hi-Po inline six should!

i hear rebuild #4 will start in September

Damn lol Should be good

6 seconds is huge! Much different with the setup?

You have a lot to learn my friend the A/R is just that, an Area Ratio...means nothing when comparing differnt turbos..only relevance it has is when comparing different hosuings of the same type of turbo, eg GT3582R has 3 turbine options, .63, .82 and 1.06 Have a look at a GT35 and a GT28 side by side. You will see why there will be a difference in response

What are you doing with the 3040 when the 26/30 goes in? Hint hint

http://www.topgear.com/uk/photos/lambo-aventador-2011-04-21?imageNo=0 Some more Top Gear test next week apparently....so we might see it in 2015

Jzz30 Soarer. So no go with just cutting wires Its only abot 2 hours from Canberra, So i will more than likely come out for a look.

You can run whatever turbo you want...whether its useable or not is another matter, as said above have a look at the TD-06SL2-20G if you want a good top end rush but still be useable. if if you want response the HKS2530..or even a GT-RS would be a good in betweener.

I agree here, this topic should be limited to Engine work

Indeed, Supercharged Ls1's (and I mean properly superchaged...not those ghey Votech/powerdyne things) Love big radical NA type race cams over the more traditional "blower grinds"

Yes they should be matched, Risking on these forums is the guru on all things handling, he recomends +2mm over the standard Anti-Roll bar sizes on Sylines. Spring weights and shock dampings depends on many things such as CoG weight split, intended use etc. So very hard to give a good idea on what to get.

In short no, the car will run yes, but wont net any real gains without a decent exhaust at the very least. Also Cams for turbo engines differ greatly to NA engines. So while you can have a 260deg 8.8mm lift cam for a turbo engine and an NA engine, things like the LSA and the ramp rate of the cam lobe are quite different. So while the Poncams etc would work ok, there would be better results had by getting a custom set done specificly for your NA engine.

http://www.cranecams.com/268-269.pdf This is one of the best cam catalogues I could find relating to Import performace motors, You can see what I was talking about regarding what the cams require. There is other info in there, Such as lobe separation angles etc, I deliberatley left that out, but I will touch on it briefly the Lobe separation Angle or LSA is the angle between the Intake and exhaust lobe (which is the lumpy bit on the cam that makes the valves open) This can be altered on RB engines by the use of adjustable cam gears (which is why I didnt mention it) But plays a bit part of older Engine cam engines (eg Rb30 or American V8s) But the closer the angle eg 110degrees in the case of the EVO motor above means the engine will produce more top end power than say having them set at 114degrees. It is effectivly the amount the valves overlap, eg the intake valve opening while still on the exhaust stroke, or vice versa, and you can see that info where it says Open/Close @ .050” Valve Lift Int/Exh That tells you when in the 4 stroke cycle the vavles are open or closed.

Heathcote is VERY slippery when the weather is cold, So big 2nd gear skids are the order of the day

Camshafts - Difficult topic but i'll do my best. The job of the Cam(s) is to open and close the valves, they are the true power maker in a Natmo engine Altering when the valves open and close has a marked effect on power/torque peak rpm etc In simple terms, Production cams are designed with a broad torque curve and smooth delivery in mind, and are generally quite mild, with low lift and a short duration. Now if we want more air to enter the combustion chamber we can do many things, we can increase the amount the valve lifts off the valve seat, we can lenghten the aamount of time the valve is open for (duration) and we can alter the cam timing (advance or retard) Now I have never seen an aftermarket Cam that only increases lift or only increases duration, it is a combination of both that nets the best result..... ....But at a cost, larger cams require more RPM to work, and move the power band further up the rev range the more lift and more duration means the engine loses low speed efficiancy (no doubt you have all heard a lumpy idle on a hot rod or drag car) This in the case of very large race cams, requires stronger/lighter conrods/crank shafts/valve train etc that can withstand the higher RPM needed. Larger cams also bleed off more cylinder pressure out the exhaust valves during the compression stroke (due to the valves being open for longer) So you effectivly lose compression (this is called dynamic compression) , so higher compression pistons are required to mantain the same dynamic compression ratio. They also need modifications to the ports (commonly called port and polish) , there is no quicker way to kill the performace of a car than to stick huge cams in the motor and leave the ports and compression ratio as is. So the heads need to be ported to match the cams, usually focusing on gas velocity (bigger ports are not always better, and in some cases the ports are filled with epoxy to make them smaller and therefore increase velocity) I wont go into to how to choose a cam as there are too many variables. But there are two different way to measure a Cams duration, there is Total duration, and duration a .050" lift, what that means is they count the duration from when the valve has actually lifted off the valve seat and can start flowing air. All the Japanese cams are listed as Total duration, so while a 280degree cam sounds huge for a small motor (like an RB) the actual effective lift is closer to 235degrees depending one which brand of cam it is (some are more some are less) I think I should also mention this - The more duration the further the powerband moves up the rev range, so you will often see something like this. In - .513 236deg @ 050 Ext .530 240deg @ 050 ^^ that there is a basic performance V8 camshaft (I just made it up btw) the duration as you can see is at .050" lift and would give a 5L V8 good power upto around 6000rpm Along side those details you will see something like 4000-6500 That is to give you an indication of where the powerband will be. May also give info like Rough idle, needs high compression pistons, 4000rpm stall or manual gearbox Now if I saw something like that, I could make a choice, I would look at my current engine and think, "can it rev to 6500rpm without falling apart" "can I live with the rough idle and limited power below 4000rpm or do I need something smaller/larger" "Is my Stall converter large enough to get the car into the powerband at the drag strip?" Things like that are what you need to think about, most street cars Dont need huge cams, just makes them a pig to drive and use heaps of fuel. Also notice that in the cam specs they DO NOT give an estimated power or torque figure, that is because there are WAY too many variables to give an accurate figure. I hope this helps. Any questions let me know. Andrew

Thanks for the thread, I will now fill with my long and boring stories On this Good Headers/Extractors cost thousands, the ebay/other cheap ones are rubbish. If I ever get the time I will nut out a decent design for some and have a set made, because I am sick of seeing crap products being passed off as good. Also Primary pipe length/size will vary depending on where you want peak torque/power, factory cams or aftermarket, Port work/valve sizes, whether you run mufflers or not, Exhaust pipe size and lenght all play a part in the design of the headers/extractors So yeah, as an Eg, an old mate of mine who is an engineer has an XA falcon with a 383 cleveland that was putting out 430rwhp, It had a set of generic 1 7/8" 4 into 1 extractors. We decided one day to nut out a new set with the aim of making bulk torque in the mid range to get the car off the line at the strip. So many many beers (re: weeks) later we had the design (went shorter in the primary pipe length and increased the angle of the collector) he made them up at his shop, fitted them and went back to the dyno, the car picked up 10hp peak, but made 40 yes 40hp more at 4500rpm, just by changing the headers and altering the jets in the carb to suit.

Like has been said heaps...a GT35 is WAAAAAYYYY to bloody big for an RB20.....its a 700hp(ish) turbo and you want to use it on the highway?

Might as well keep going, being that im home alone and bored. To get a RB25DE to lets say 150rwks (a bit over 200rwhp in the old money) then engine will need to make around 180kws at the flywheel (a bit under 250hp) the Engine will have to Produce 100hp per litre, which is asking a lot from a production engine with factory heads To put in perspective if using a V8 (whether it be a 302/308/428 etc), to get 100hp/L you would need aftermarket alloy heads, a big angry cam, well designed headers etc The stock RB25DE does 80hp/L which is pretty good for a factory motor, When Honda's Highly strung Type R motors do only a tiny bit over 100hp/L and they need to rev to 9000rpm to do it. So I hope this clears a few things up for people.

Its more down to the NA RB giving nearly all it can in Standard form. They are no understressed big cube bent 8 where its easy to make big gains easily. It appears that Nissan Gave no shit about the NA Twin cam RBs, why would they spend the money delveloping the head etc when they already have Turbo versions Without major port re-shaping and trialing 11ty different cam profles there are no real big gains to be had. I think the best ive seen was ~150rwkws from an NA RB25/30 which is about what a dead standard RB25DET produces

No point taping up panel gaps etc, you wont be going fast enough to have to worry about that But yeah, you will need to find the best way to launch I used 4500rpm and rode the clutch to stop wheel spin (before I got a 2-step) Everyone has a different way of doing it, you will just need to find what works for you

Go through the threads in here, you will see that both Myself and Marc help out a lot in here...but we then end up tearing our hair out because no one listens when we say a car back and a pod filter WILL NOT give you another 50hp. Or when people say they want to build a super powerful NA RB20 and we say that they could spend 20K on the motor alone and it would still be slower than a Stock R32 GTST etc

LOL yeah that too