Roy

You are an engineers engineer He said the wheel spins backwards, it doesnt. As you point out it effectively chops the air and all sorts of harmonics are going on as the low pressure high flow (ie fans with big tolerances) compressor basically cavitates. The KE in the wheels along with the engine running as an air pump means that the air on the hot side is still directional and going to keep spinning the turbine. Case in point put your foot over my tailpipe when I am running on the dyno and lift off at 6,000rpm.

Bonnet struts. How lardy dah

Are you sure? Have you witnessed the compressor actually spin backwards? I would be amazed if that were true. You have god knows how much cfm pumping out the exhaust spinning the turbine which I think would stop the compressor ever stopping and reversing . There is nothing to actually cause the compressor to spin backwards What will happen is it will be trying to compress air into a fixed volume and with a turbo effectively being a low pressure high flow pump the clearances will mean the air will be "chopped" vs compressed and you may get reversion of air pulsing back out the air filter but cant see the compressor wheel rotating backwards

I have no idea. Risking got it right I suppose you need to read as much as you can and decide for yourself. Jack ran Alcon kits and not many go as quick or punt a car as well sorted and as fast as his was He ran the Alcons for a few years. He upgraded to Supercar brakes but that was mostly because he could and they were brake porn rather than needed And this is a bonkers fast track car that runs Alcon fronts , though is a bout 300kgs lighter then many track GTRs but then again has over 400rwkws...you get the idea

Further to what others have said calling a caliper a street caliper is not a criticism. Look at cars like 997 GT3s that dont have the ceramic brake option. They can pound around tracks like Spa lap after lap with no brake problems just with some Pagid or Performance Friction pads (talking to owners that's what they tend to use) These are cars beign driven hard often on slicks. So street calipers are not inferior per say. What they are is generally heavier and constructed from more durable materials. Race calipers can often be similar in physical size, often identical in piston sizes but are often lighter and made from material that makes them stiffer and lighter. This sometimes means due to their duty they are lifed more frequently as they are designed for performance, not durability. They also often run titanium pistons and bridge ducts or water lines for added cooling and performance. Short of people actually racing their GTR where they are running for 6+ laps at full speed with sufficient engine cooling etc to permit such use....the Alcon etc kits will be fine for your application. Many people complain about certain AP its and I have heard the same complaint about Alcon Evo guys saying they still use loads of pads and eat rotors. If/when you need to replace a rotor forget about weight and unsprung weight and get a rotor with 70-72 vanes. Dont go running 24, 36, 42 vanes as you will run out of pad pretty quick. Of the people I know who run setups that run a 35mm thick 72 vane rotor they have never had a problem with brakes, had an appetite for rotors or calipers with them running nice and cool. Thats the main reason I like the AP CP5555 over the Alcon, simply because they take a 375/378/380 35/36mm thk rotors where as the Alcons must run a 32mm and typically 365mm. It just means that 1 in 10 person may exceed the Alcons ability where as 1 in 50 will exceed the AP setup with thicker rotor. Also if you are sourcing Alcons then it may pay to check local pricing now that PWR have relinquished distributorship as the pricing is a load better. If you get stung for customs/GST then I think it could well be cheaper to get locally, but if you send the front brakes to your mate at work and the rears to your home address you will probably get away with it

racegtst...gutted to see it end like that. Light damage is still a pain in the ass and timely to fix....Hope repairs are not painful Silkgoid aka bonkers fast guy. You heading down to PI for the PIARC sprint?

PHENOMENAL!

I am still chasing Mobil for where I can get Mobil 1 Racing 0W50. Will have a read of that link tonight

I am hoping to make it and there is a maybe 1/3 chance. Tune didnt go to plan on Saturday and cam gears, cams and another turbo being tried over the next few days. If its all healthy will be bringing it for a run. Otherwise PI at the end of month for me.

Regs are up. http://www.piarc.com.au/files/2013%20April%20Sprint%20Regs.pdf

More proof that Vettel is a farking idiot... The best actor in the world is… SV: John Travolta.

So from interwebs chat the pick of cams are Tomei then HKS, I had Apexi cams that were similar to HKS cams with my 20G and they sucked. Remember that the RB20 std has the same sized cams as the RB25s. That despite 500cc less and half a point of compression. So beauty of RB20s are you have to be pressing them pretty hard to justify new cams. I am of the thought unless you are flat out curious dont bother with cams as I think the money would be wasted. Unless you are pushing over 330rwkws I dont think cams are going to do anything for you. I have a spare throttle body that is getting bored out but I am packing more cc these days so my results are more representative of RB25 results then RB20 and I am hoping for something over 330rwkws

Just keep in mind that Risking has posted a cross flow radiator. If you are running a traditional radiator its probably a good idea to run a non pressure cap and bleed to the top tank to your header tank. The wide top tank vs narrow cross flow tank means the raised section for the radiator cap is a pretty opportunistic place to bleed to your header tank

Want to but some alloy to hard pipe it and need to know what id the hose is for R32 radiators

One thing I noticed when I was going from my car with the gate plumbed in to atmo. I used to shift earlier with the atmo gate as it sounds like you are ragging on it so much harder when you are not. With it plumbed back I would hit the limiter more often. Strange but I suspect based on where its cracking gate in 1st gear that you are shifting somewhere well under 7,500rpm and depending on your curve you could be starting off in the next gear with 60rwkws less then if you used an extra 500rpm before shifting. You really need to look at your power curve and gearing and work out the optimum revs for average spread of power. I know I had to rev my RB20 about 1,000rpm harger to have a real difference in power with the Plazmaman as under 5,000rpm it was generally lazier. So I used to hit about 9,0000rpm in 1st and every other gear about 8,300-8,500rpm to make sure it stayed on the boil

Cant agree with that statement for a second. The RB20 needs all the effeciency it can get on the exhaust side and a nice tubular exhaust manifold, preferably 6-2-1 style rather than a 6-1 type will give you more grunt everywhere then the same turbo on the std manifold. Thats assuming the same turbo being internal gate. If you go a high mount manifold and external gate you will 90% of the time get better top end as the boost control generally works a lot better. I also found out what yesterday what everyone already knew. No matter how big the rear housing you try on a 20G, how much boost you run...the compressor calls it quits at about 310-315rwkws. The real interesting thing is for a road car you shoudl run an 8cm housing. Hits 18si at about 3,500rpm and pulls 300rwks then boost falls over to about 15psi. There is no point reving it over 6,750rpm as the thing has no top end and is choking on exhaust gas with the little 8cm housing. But if you are running E85 it really lets you get away with a less then efficient setup with such a choked hot side of the turbo. Running so little boost, running so few revs and being so damn punchy with the 8cm housing would give you a good reliable street setup on an RB25. Now for the Poncams and the 73HTA. Should know by Wed. But safe to say the 8cm vs 12cm on the TD06-20G is a waste of time. It just moved the whole power band almost 1,000rpm for no gain in max power or torque curve. It may have helped traction that's about it. So if its a street car 8cm. Track car 10cm housing as it will trade a few rpm of response but allow you to run more ignition and boost up top and give you a better spread of power rather then the more peaky 8cm result.

Looks like Alcon have changed the production of the calipers the past 18 months. Those that I have see lately, seem to be a slightly tattier casting. They used to be a far better quality casting over the likes of the Brembos but now they look similar. They also seem to paint on the Alcon logo vs having the Alcon logo machined into the caliper face with paint filling the machined relief

Well thats shit. Good street tyres are drug money and I only run other people's uses semis. Oh well will stick with running aroubf with EA Falcons and E30s at PIARC

Mint 32...I think I saw that on Pistonheads Was only a matter of time until those rear spoilers caught on. Awesome looking pieces of kit. Amongst all these pretty cars ai recently trie dto rpetty up my engine bay of my track 32...its a bit blingy but blowby will soon dull everything down

Cool. So my car would fit with street. All of a sudden interested in running at Wakefield:) ... lol and finishing behind you

Is there a link to the regs for street class. A street class that can run semis is appealing to me

12 runs!...Sheesh I think i have done less than that my entire life. Good luck with getting it sorted. I can understand your frustration but provided the car is fun and reliable. SO moving on to a question for Stao. What is the best Mitsubishi based turbo you can come up with for an RB25 that wants more power then a T67-25G but not quite T78 domain

That video is no different to how I ran my car when at the drags as I didnt want to break anything. Still did a 12.9 @113mp with 2.2 60ft and 234rwkws of TD06 RB20. I will just question, are you sure you are not rolling forward a smidge and braking the light. I remember doing an awesome run and got a 15.4 or something. I was waiting for a loud V8 to launch and piss off so I could hear what my car was doing and I must have just broken the light.

LOL Trust goodness!