rev210

Put a motor bike engine in the car that revs to 15,000. It won't go very fast though. Ask a stupid question as they say

I got an email from James Martin the product manager at ACPT regarding some of the questions and rumours raised in this thread.. He very kindly responded in the email as follows; We have 2 applications for all the Skyline models. The smaller application will handle up to 800hp, and the bigger application will handle over 2000hp. So if you order a shaft we will need to know what size you want. Also, the bigger shaft is about $200.00 more than the price that I quoted you earlier. ACPT has been making the Skyline shafts for years and we do not require the stock shafts. We have been making the driveshafts for Nismo and Trust for a while now and this is why we don't need your stock measurements (unless you have a different rear end or transmission than the stock application.) The person claming to have broken 2 of our shafts bought the smaller shaft because it was cheaper and was hoping that it would work. This is why we have 2 applications, if you have under 800hp and you do not plan on exceeding this much horsepower, than the smaller application is for you. If you know that you will exceed 800hp, then you will need to use the larger application. If he had something rubbing on the shaft like an exhaust bracket or a sway bar, that would have caused it to break as well. ACPT is the original maker of the carbon driveshaft over 20 years ago. Also, ACPT is not a driveline shop; we are an aerospace company that typically builds parts for rockets, space shuttles, government assault vehicles, ECT... The same engineers that develop the parts for the aerospace companies are the same engineers that work on the driveshafts. All ACPT deals with is composites and all of our driveshafts are built in house including the winding of the driveshaft tubing. I do not know much about the UK company making a carbon shaft other than it looks really pretty (but you will never see it underneath you car) and it is really expensive. If I am not mistaken, I believe our driveshaft is about half the price of their shaft and is proven to handle what ever kind of horsepower you can get out of your car.

ok. Back on topic then.

ahhh jokes. No worries then

The wheel is a 'driven' rotational mass that is connected to the engine/drivetrain.Engine -flywheel-gearbox-tailshaft-diff-wheels. Weight reductions in this area reduce inertia significantly. This is why it is not just 'unsprung weight'. This is why race cars like light wheels. The extra inertia you have sought in the heavier flywheel was often used to assist overcoming issues of rev matching and bogging down with low amounts of power and large amounts of grip. I would lean towards turfing the cast iron (read very weak by comparison to chromemolly) flywheel and trying launch control, if off the line horsepower is the issue. Or turfing it in favour of very heavy steel rims (if you really must increase the weight which I don't agree with) ,the rolling intertia and extra weight potential is better than the slightly heavier RB30de flywheel. Contrary to old wives tales there is no loss of torque going lighter. It would suprise me very greatly if you didn't improve your accelleration times by approaching the issue of reducing the rotational inertia. So far it is only my humble opinion that you might have gone the wrong way here? (and perhaps only here) I hope that adds some usefull info for you, please feel fee to PM if you would like to question things a little more, I am very happy to try and help

No one wants to see you dead 'if', knock on wood, you ever need the roll cage. Because the way you have set everthing up is dodgy and you may as well rip the cage and the harness out for all the good it's not going to do you in a crash. 3lit3 32, The gas is known to sometimes leak out of the thread on the bottle. Even when you have checked it and properly thread taped it. You don't want to have taken a few lung fulls of gas before rampaging off down the track at 150mph it's not good for thinking straight if something should happen, thats racing. It's an anesthetic and thats why the manufacturers of every kit say put it in the boot with outside ventilation. You also don't want nitrous or fuel lines running inside the cabin for obvious reasons. If the reasons aren't obvious to you ask a manufacturer of the kits any one of them will tell you the same thing.

xr8eater, It's not a problem, just measure and then they make.

No room in the boot for the bottles? Although they may look 'cool' you really ought to move them, unless you already have the fuel cell strapped to the drivers seat in which case I say go hard or go home.

I'll make some more inquiries with ACPT but, they indicated a supplied shaft to my door without any measuring, they have already done R32,33 and 34 shafts so they don't need to remeasure them. As for duty is the US free trade agreement is good for anything? DiRTgarage, You didn't just have a few beers before you typed that one? Keith, Sounds interesting.

I know and I understand what you are saying. Sorry I do need to clarify; 1) IF you own an RB powered skyline 2) IF your flywheel is heavier than 3kg, My friends and I have had one a good kilo lighter than yours and it's traffic behaviour is like stock. 3) IF it has been correctly balanced from manufacturing Satisfy these and generally what I said is absolutely true. Your 'puck' clutch is your problem it has nothing to do with the flywheel weight of 5.5kg. They (puck cltuches) are always either 'on' or 'off' with the slight exeption being if they have a sprung center.

Thats $2100 aussie dollars delivered to your front door step.

xr8 eater, I believe the shaft lengths are probably the same between the R33 GTR and GTST if they aren't I am sure they can make one up. Given the lengths are the similar I'd say the price would be the same.

Ok mate. No one asked you to prove anything. Just when people talk about something as though its a fact it's reasonable to think they can back up a claim? I thought you would like to add some constructive information thats all. In the interest of trying to back up what you were talking about I took the liberty of doing some reading of various sites containing information on Nickel cast iron engine block metalurgy and the use of magnesium.In searching google I was unable to find any information regarding the importance of it in that specific application, nor any info regarding the specific differences between the Rb30 and Rb26 blocks. All that proves perhaps is I was looking in the wrong places?

Hi Mik, Hate to say it but without the magazine article being able to reffer you to an actual primary source fact I would doubt the validity. As it is you don't know what magazine you saw and can't reffer us to it. I am afraid without that we are still in 'rumour land'.

Also if the RB30 high powered blocks are prone to letting go so readily in R32GTR's what is the count on those? I only seem to hear about ones with 700hp+ in GTR's and none of those have let go yet. It's the old story of if its a problem for 1 person he tells 100, as opposed to 1 other if things go well. Seems to be more myths albeit backed by some decent ideas than facts?

Someone mentioned different metalurgy on the RB26 to the RB30. Call me skeptical but, I would have thought that the Nickel casting process used by all nissan 'B' blocks (from the B in RB) would be fine for all of them. The differences in the regular and N1 blocks is ribbing and no mention of metalurgy? If there is more Mg then tell us what the concentration is in each block and where the source of information is?

I have just got info back from Jame Martin the product manager at ACPT. They have off the shelf designs for R33, R33 & R34 GTR tail shafts. The price including shipping to Australia is $2,160 Aussie dollars for just one, I am sure we can get it a tad cheaper again if we group buy. This makes it half the price of the jap units and more than attractive enough as a modification when you consider that there aren't too many mods for $2k that are as good as the accelleration you are going to pick up from one of these bad boys. I shouldn't go on but the mines R34 is equiped with carbon tail shaft and it is quite a big reason behind the 'response' of the car. Here is one test of a rotational mass reduction on a V8 setup, the big thing to note is the massive reduction in time taken to achieve both maximum horsepower and torque once weight is taken out, that boys is accelleration increases. Note this is taken in 4th gear under load. http://www.vetteweb.com/tech/0407vet_flywheel/ Group buy anyone ?

I see there are a few people commenting who actually don't have any experience with either a lightweight flywheel or tail shaft. Neither the lightweight flywheel nor the tail shaft cause drivabillity issues. Thats from experience. Keep thinking about it. and then ask someone who builds race cars.

Considering the dollars people end up spending on modifications to acheive the same accelleration advantage they may well be reasonably priced considering the ongoing savings you get on the advantages listed above. Keith was apparently getting much keener prices than nismo and mines stuff.

The don't 'gain kw' at all. What they do is massively reduce inertia, allowing for faster accelleration. Accellerating faster without extra power is GOLD. NO extra wear NO extra heat NO loss of economy NO spending money on upgrading parts to cope with more power. The carbon tail shafts are very strong too. There is a guy Keith Cowie who I think made mention of getting them made up fairly cheaply for his R32GTR, if your around Keith please feel free to drop the name of the place

appart from the extra weight and difficulty in getting decent size pipe diameters to fit it is going to allow more head room for flow potentially. As for sound? who cares. The sound of power is an easy one to get used to. It will sound different to a single if it makes more power then it sounds better in my opinion. For those hung up on sound why not get rid of the turbo and go NA with a set of extractors (thats where your logic will end up).

Talk to Ant at X-speed about the D-jetro, he is good at both PFC's when it comes to tuning but his recent experience with the D-jetro is worth listening to.

I used to think that too. However. I am going to the D-jetro for no other reason than it just works better on the GTR's full stop. I know of three cars now with more than 600rwhp that have upgraded to the d-jetro and have light years better fuel ecconomy than even a standardish GTR on either the factory or standard PFC could ever dream of. How does 600kms to a tank sound? I can only guess that the two AFM's suffer from issues relating to the different flows that they always incur as a result of factory pipework, an the fact that the ecu must calcualte be it ever so small or large an allow for the different amounts of air. Perhaps on a single AFM this might not be the case but, I have seen nothing to compare to what the D-jetro in the right hands is capable of. Topaz, If you want 500rwhp easy peazy then bolt up a single TO4z or go the garret 2860rs With a set of 260 tomei poncams. The engine will need rebuilding for the task to be reliable, and a whole host of high km standard things that will wear out faster than you can blink. However you can always lower the boost and make a bit less power till you are ready for the rebuild and have fun with it for longer. 400rwhp on either of these turbo setups still makes for alot of fun with potential left to tune into.Mine is sitting at 370rwhp odd with very little boost, I still have standard dump pipes and I suppose replacing those at the same tune level and boost would put me at 400hp or so, it's nice to know there is more if you want it when you can actually pay for it. You might also consider why 500rwhp? Have you been in something with a snick over 400rwhp? It's pretty good and the extra 100rwhp pushes the issue of breaking things. Namely the gearbox. you ought to think about an application you want to put your car to.

PRICE DROP $6000 ono!

Hi Sydneykid, I was chatting with RIPS a while back about nitrous and we got onto the plugs setup and at the time he wasn't ready to give his indexing secret up. In the instances I have done this it has always been of benifit. If there isn't any one out there with data perhaps we can start with people visiting the dyno who would like the chance of maybe upto 5% more power? The chev example sounds right but, not knowing where/which way the squish/quench is when looking down at the bolted down head is my handicap at this stage. If I had the head off it might give me something to go by.