Roy

But even then tyres are all different sizes so cheat the truth a little. Road speed is road speed is road speed. At the end of the day you go through corners at a certain speed not rpm...so understanding what the car is doing at that road speed makes it easy to work back from (IMO) Sav, real interested to see how you go with your plenum...before tuning your car I would be going back to the std plenum if i were you. No way an RB26 throttle body with its bigger bore etc is going to be a good thing on an RB20 (pure speculation but just a feeling i have) And since you are racing your bus...throw the 26 throttle bodies in the bin. Ideally grab something with a smaller diameter and use the phenolic gasket etc to try and get some runner length back

You cant even race me for fastest RB20 anymore

Have you checked the valve stem length differences and whether you can use the GTR lifters in a 20? I have two sets of Tomei solid lifters for VG30, RB20/RB25 and they are different to RB26s and RB25 Neos, to the point that the RB26s obviously have longer valves ?!?!?! Intersting to see how you go

So, as you can see it kills response but does help flow at the very top end. But the combination of the plenum and other recent changes now means I have lost about 30rwkws through the mid range :( :( Will see how we go with a few more trials and erros, may as well throw the 10cm housing on it now and see if we can break 295rwkws...fark knows it needs way more top end now it has lost the response that made it pretty damn quick for a 2L As you can see at 116km/h i used to have 20psi and 185rwkws. Long live std cams, plenum and a full Greddy setup rather then 6boost and Turbosmart mani-gate setup

Truck turbos rule yo!

Apexi cams seem to use ramp rates different to others and can be tricky to get results from...well so the story goes. Here is my dyno sheet of an internally std RB20 with full Greddy TD06-20G setup before and after Apexi 260/9mm cams. I dont need to explain which colour is what...the std cams went back in so should tell the story What dobz said, the Rb20 runs a fair bit of cam for a 2L. Remember that the 2L is spread accross 6 cylinders and not 4 so the air to each cylinder and combustion chamber is different to a 4 cylinder and its easy to over cam a 2L six and lose all velocity and cylinder filling...or so it seems.

Well, how much farking around has it taken over the years for the RB26 guys to learn the best combo of head, exhaust, cams and turbos? Nobody is playing with RB20s so it is taking me a long while. If i can get about 280-290rwkws with about the same response as I have now out of a $600 wrecker engine then the experimenation has been worth it...still well under the cost of a built RB26 with the -5/-7/-9 setup I would actually look at running std RB26 cams before anything else. The R34 runs a difference CAS so ot sure if it talks to the ecu you are running?!?!?!?!

Actually, the 20G was the more responsive and powerful. Even allowing for the extra few psi I was running. Cars had the same HKS Type S intercooler, i think we even had the same HKS Hyper exhaust, both internally std RB20s. The GT-RS GTSt was actually a GTS4 running in rwd and it did not have cam gears where as mine did. Dyno runs were done on the same day minutes apart So all things considered, with adjustable cam gears, and a bit more boost the GT-RS in my eyes is a pretty good option if you dont want to mess around with manifolds etc and want the engine bay to look pretty std. Mind you this was a ways ago and my setup now makes 40rwks more with only a bit more boost and leaning in the tune a little more. So the gap would be a bit bigger, but then the GT-RS could be leaned on more for perhaps a similar response

Ok, so the quest continues. Bought a new turbo this week. So the plan is the 10cm housing goes on next week. Thinking is that the plenum seems to have lost a little in the middle but seems to be a bit happier up top. But just wont make any more power so guessing its the lil 8cm housing. Will see what the 10cm housing does... So along with that I am taking off the ARC 100mm thick cooler and installing an R34 GTR cooler. Hopefully being a bit smaller in volume we may get a bit of punch. I am a sceptic so will be interesting to see the result of that back to back. When the RB24 goes back in I may throw the ARC cooler back in, but perhaps 100mm cooler is simply too much core for a lil 2L. So, after the cooler nad 10cm housing and tune it will be decision time. If the 8cm housing looks to have bene the culprit for holding back the bolt ons the cams will go in....but meanwhile. The kinder surprise bitsa motor will have the following turbo setups to trial: - TD06-20G with 8cm and 10cm housing - T67-25G with 8cm and 10cm housing - TD06-25G with 10cm housing and if i can get a minute with working this weekend will try to fit the Stoptechs this weekend

On an RB20? More details such as turbo setup, what ecu and whether you have cam gears etc. Was the car tuned by the same person before and after? Real curious to know why i have had the opposite experience and have had to chase other things and lean on the tune harder to try and get the response i lost. There is perhaps some merit to how it hangs in at the top end, but ...still trying to get the car sorted with my Plazmaman plenum

So with AFMs being the nightmare they are, the radiator/intake beunbg reasonable solid mounted to the car, the AFM solid mounted to the radiator/intake...is there any concern over vibration and failing AFM? Given its on the inlet side i would be trying to throw some silicon either side to dampen any vibration it may be seeing

260/10.25 would be interesting. I am going to use Jun RB26 cams in mine

Well i have aset of 256 Poncams and if the 10cm housing has a hint of being able to make more power at the expense of response I may throw them in...but only if we see enough improvement to think that all the other bolt ons were all ebing limited by the little 8cm housing on the 20G. The whole thing will only flow as well as the shitiest part and that looks like it could be my small A/R exhaust turbine. But I will say I think the std cams are just fine. There are all sorts of schools of thought, headwork and cams give power and response....small camas, big cams....everyone thinks they are right. I look at race cars taht still run turbos, and you need to consider they all run restrictors or boost regiulators etc so that messes with things,and who wants to go to that expense only to find they are no better off, or worse off?

Whatever you decide, do us all a favour and do an accurate back to back comparison. ie have it tuned and run on the same dyno before installing the plenum and give it another tune by the same tuner and run on the same dyno post install I am real curious to see how the RB26 plenum will go

Such a nice car. Good luck with the sale. I thought long and hard about buying this car from its last owner

Not going to go into the debate of RB25, everyone has different views and I can see the merit in both schools of thoughts. What I will say is sadly, Russman has just stripped his RB20 with Poncams, HKS 2530 and 230rwkws so we will never get any footage of DECA side by side rolls with my TD06-20G powered RB20 with std cams making about 250-260rwkws etc... But seat of pants, Russman having driven my car and I have driven his on the street and track ....there really isnt that much differnce in lag between the cars. His car does have more drivability with about 10-15rwkws more at 3,600-3,800rpm, but at 4,200rpm they are making the same power and from 4,500rpm I am making about 30-50rwkws more in the top end as the 2530 really falls over at about 6,500rpm and the TD06-20G keeps pulling to about 7,600-8,000rpm. So the 20G does make for the quicker car when you are opening up the taps and going through the gears. If you are in the same 3rd and 4th gear sections of blipping up a gear then braking and start stopping the 2530 would probably get the better of it. the 20G is clearly quicker over the qtr mile and on a track, with a clearer advantage once you need to start accelerating over 180km/h. At Winton the merits of each setup probably end up about equal. At places like Winton and Sandown the 20G is probably the better setup. So , thats as detailed an example as i can really give. For me the take away is that no matter what turbo you throw on an RB20, they will not come on cam and make power until after 4,000rpm so trying to overcome the short stroke rev nature of the engine with a small turbo is counter productive. I think your car with the std plenum, std head and cams, with the HKS manifold with a 3071 with a twin scroll rear T4 housing would be a good thing. It would make about as much power as the 20G with probably better response or there abouts. Throw 19psi at it and a healthy RB20 will last a long time with a good tune. Stick with the std head and cams. I have played with a 6boost manifold as Ash has said and its no better then the Greddy manifold it replaced, evidence suggest it could be worse then the Greddy manifold. I have been there and done that with cams and lost power with Apexi 260/9mm cams so back in went the stds. Plenum, i currently have a Plazmaman on and after more tuning and playing around we have now almost got the same power and almost the same response as i had with std. I would have had far more money in my pocket and as good, a tad better performance with the std plenum. I am so far down this road I am going to try a bigger exhaust housing now to see if the 6boost manifold and Plazmaman manifolds are being held back by the restrictive hot side of the 8cm housing on the 20G...so this hasnt been economical but i find the trialling and understanding for myself half the fun...but also a lot of the frustration So stick with the basics of a well selected turbo setup that is well tuned...3071 gets my vote...will come on nicely just as the short stroke RB20 gets enough air in its lungs. My car will be up in Brisbane in a few weeks so if you havent been for a ride in a 250rwkws Rb20 then you are welcome to get a feel for it. I wont be surprised if you decide to go Rb25, but it will at least serve to help with your expectations

I am on a project in Virginia and looking at bringing my car up in March to do some track work up in QLD...do you have any plans of doing any track days in the coming 4-6 weeks?

Doesnt really matter a whole lot, i expect Nissan if interested would go with a model that isnt sold in Aus and call it a Mazimia or jsut use the Maxima look etc. The appeal of being able to go racign without the massive expense of developing chassis and components means I think manufacturers could be more readily drawn into a class like Supercar. But can also think of reasons why they wouldnt be interested and this is Cockgrain being a dill trying to talk up the series and its international appeal!

Well, don't want to jinx myself...but with these late night ass bleeding hours, provided Fri, Mon & Tues go to plan i should be good for taking thu/Fri off which means I am good to go. Will call PIARC when i get a minute to confirm space on Friday this week.

You realise that the JGTC R35 GTR is a V8? Well at least the GTR running around GT1 in Europe is a big V8. For Nissan to be let in it would need to be their four door Skyline platform wkth R35 V8. Unfer the skin can almost be a control chassis, but 4df Skyline panels and homologated v8 All for it as the racing is quiet close and entertaining, but thede days can do with more variety

Its only natural that the setup find s it's way onto another black R32