Dale FZ1

Try Chapman's Dyno at Cooroy.

That's what can happen sometimes. At least you're not pressurizing yourself. It WILL arrive in the workshop...

Yep, that's what it's about. Really, it comes down to the application the car is being put to. If you have a bent for circuit work, drags, sporting road driving, hill climb, or motorkhana, there is a difference of priorities. The relative lack of power in those naturally aspirated rear engined hairdressers cars, combined with the sort of grip and chassis balance they offer is what can make them shine in certain situations. But for most use, the 2wd Skyline has a certain appeal and suits my purposes. Given more $$ available, I'd probably have more than one car in the shed.

Excellent work, and the efforts at making a pictorial are commendable. Many thanks, because my own fit-up is currently being planned. The fuel rail mod looks good too. I will be interested to see the on-road results. Did you de-dag the plenum inlet, or the runners? What about facing the mounting flange? And any cleanup work on the injector mounts to get a good seal?

Sounds like a really worthwhile build Cubes - nice work. If you have it delivering bulk grunt in a driveable, tractable manner then that to me is what makes a car work. Getting it to the ground is always the key, so it sounds like you're on the edge of "too much" As Mafia said - you'd nearly be wishing it had 4wd. My question is - did you run into any knock problems during the tuning process?

I have a Blitz Nur spec rear muffler, with removeable baffle. Baffle in = 279 rwhp Baffle out = 302 rwhp No other changes, and back to back dyno runs. More grunt everywhere through the entire range. The top end does not die off either. More noise everywhere too, and an annoying drone on cruise with it de-restricted. So yes, restriction costs power.

I agree. The point all through this thread has been that compromise is part of the equation. Technical solutions cost real money, and the smart punter has to know where/when to accept compromise. Know if they'd rather have a couple of G left untouched, or know whether having that potential for a slightly fatter curve is going to make a REAL difference to them. Again, the dyno sheets only show full load behaviour and don't say much about transient response. We've said it earlier on this thread and others about the value of "feel" ie what happens with 1/4, 1/2 and 3/4 throttle, and driveability. It may be that by the time someone fits up a turbo (any of those discussed) with 500 crank hp potential, cams the engine (if desired/needed), plays with porting etc that they've got a far more lightswitch style delivery than expected. Again, that's part of the compromise that goes with their target while running a smallish capacity RB25. So for me, there are many facets to the whole deal. cheers

Looks like something that belongs in that Split Pulse Turbochargers thread. I've no probs with the technical aspects, just the expense of the extras (namely a properly setup manifold + external gate) to make it work. Cost:benefit analysis still has this particular style of bolt-on upgrade particularly effective. There are other variations like Dangeman4 has with his GT3582, and the 7 bladed GT30 but the concept and expense are much the same. Bolt-on, no internal parts or porting; just some careful tuning with the advantages of WI. A 3071 like Albert's, or a split pulse could hit close to the 300rwkW that Mafia did, but on an RB25 you've just spent a lot more money to make it happen. I'm still waiting patiently for Full Race Geoff to complete those back to back tests. Still we're only getting an idea of who won the dyno race, which isn't the most important thing as Lithium pointed out. Results on the road or track, and impact on the bank balance are what I'd focus on.

I tend to agree with your views here. Sure, the turbine efficiency is a major moderator of overall performance, but the compressor MUST be able to efficiently supply the mass-flow in the first instance. That drop in efficiency and rapid rise in shaft speed for the 71mm GT35 comp family tells against it if someone was shooting for 300rwkW. It could get somewhere near the 275 mark but no more on a R33 Skyline. Other cars with lighter drivelines and lower power losses, who knows? I think this helps heaps. Good info. Makes me wonder how this setup would perform with a manual box. Standard bottom end, but what about top end work? Go right to the start of this thread and you'll see Mafia is running an internally STANDARD engine. An SR20 can liven right up, but cams are the key to making it work. Conventional stuff, same as the RB series. Still, I suspect the reading might be slightly "happy" given your boost and engine capacity. Good work and the information is good but not quite on-thread. See above comments about different powertrain efficiencies and compressor mass-flow abilities.

Agreed. Unless you target AFR and ignition strategies different from a conventional (non-water/meth injected) tune you definitely won't see the full advantage of your system. With a correctly sized nozzle and rising rate delivery you should be able to achieve higher power with lower specific fuel consumption and retain VERY effective knock control. Keep at it and let us know how it progresses.

An overlay would be good to help with analysis. Wheel slip/spin on the rollers as it ramped up could be part of the answer. You are running a largish turbo and when it's coming on there, I'd think it is coming on hard? Given your gearbox is "recently" modded, and there is no indicator of poor or inconsistent operation you may ignore it as a probable factor. And have you ever seen what happens if the air-con clutch engages during a dyno run? Believe me, the dip is massive. Surely your tuner had some suggestions?

Are the two dyno runs directly comparable? ie. is there NOTHING else changed other than the manifold and dump? Is there any chance of tyre or gearbox slippage, and/or did you play with the VCT change-over rpm? Do you have any pics of the installed setup, or the manifold just for interest?

Assuming you were prepared to upgrade valve springs while doing head work, why limit yourself to Poncams which are advertised as the "drop-in" upgrade? You have the ability at that stage to increase the relief areas to accomodate higher lift cam specs. Other manufacturers are also out there, and there are different spec cams available. For higher rpm work, why not look at something in the 260-264 deg duration, and around 9.0mm lift? R33racer should have some valuable experience in this area, with a fairly serious build or two under his belt. And I will stand corrected by Guilt Toy re: the AFM.

Frankly, I don't believe either is over-rated. They both work well. As does a GT2871 Garrett cartridge into OE housings. They may share similar max power capabilities but I'd say their characteristics in operation would be slightly different. The HKS GT-RS should be slightly more progressive and easier to drive in its delivery. Whether the average driver would notice or care is a moot point. The extra cost in the HKS kit comes in the lines, fittings, shields etc that make it a complete kit. The main attraction of a GCG style unit is true bolt-on / bolt-off re-using all oil and water connections, no obvious change from stock appearance. And the difference is around $400. Just a matter of determining your priorities and lay down the $$. But back to the original question posed, and my opinion GT-RS is still a small step ahead for street use and internally stock engines compared to the 2835 Pro-S for virtually the same price.

Examine every part as working together in an inter-related system. That will get you closest to the “ideal” specification. As briefed, you intend this to be a track-only machine. This means little/no need for a smooth stable idle of a road car engine, and the useable engine speed range is likely to be up somewhere between 4500-8000rpm. More aggressive camshafts, allied with at least some tidy-up work in the head would assist hit the target with efficient airflow. Accurate and reliable valve control at extended high engine speeds and boost should dictate upgraded valve springs and collets. Not sure why not go the route of a 26 or Neo head and get the benefit of solid lifters? Using a 26 head would automatically permit easy fitment of the multiple throttles. Run with a GT3582, and be prepared to try both a 0.82 and 1.06 housing. The smaller size may meet your needs but you should consult with your supplier. 550cc injectors would be running out of puff, and raised fuel pressure is really a band-aid fix. Get the next size up. Nothing intrinsically wrong with Walbro pumps, you just need the correct spec. PM The Mafia for further detail on which one is good if you really want that brand. If you have the option of AFM, go for the physically larger Q45. More voltage headroom, and the physically larger body size will be a closer match to the inlet trunking required for your turbo. It’s a balance between fine control and the sheer ability to measure what mass-flow is going through without maxing out. Given you have new pistons (assuming different crowns to OE?), you really need to determine the desired compression ratio, and do a dummy fitup then cc the chamber. Slightly decreased static compression will not overly hinder performance, given you’re going to pump a good slug of boost into it. But until you’ve done some measuring you won’t be entirely sure which head gasket is the one you want. Rather than merely looking at the durability of the stock gearbox, suggest you look at the effective speed ranges of the gearing against the power and expected delivery of the engine. The final drive should be considered in this equation, but you may require a closer spread of gears to meet your needs. Hollinger or Albans could help. Bottom line for me is you will need to take the time (or pay for someone’s time) to assemble all the good bits properly. eg. just balancing the crank is of limited value unless you consider the rotating assembly of pistons and rods, and check for cracks in your crank. I hope you’ll post up your final specs and the results of the final build? This should be one potent machine!!

Did you blokes happen to take a pic or two? I understand what's being described, but you could save 1000 words

Post up a picture or two. Details provided are scant. Why would you buy something without knowing what it is or was previously used on?

The GT-RS is a hard act to beat. A Garrett cartridge that would go close to the target using OE housings would be 446179-5032 - The 56T GT2871R. But you'd want a good idea of the costs of oil + water lines for the total cost vs HKS product. Try a search on cams. There is plenty of comment about whether cams are justifiable at the power level you're targeting. I'd say the overall efficiency would lift with them but the raw numbers not show a large improvement from stock. At $700-$1000 fitted and installed you'd have to ask whether a changed exhaust note is justification enough.

KKK is part of the Borg Warner conglomerate. They include others such as Schwitzer. High quality gear but I think some of the technical info that Honeywell (Garrett) provides to the aftermarket/enthusiast is difficult to get. Very OEM focused.

Nothing is ever as simple as it seems. You'd have to consider the size and specs of each impeller, and the size of the housings they are fitted to before trying a mix & match approach. Might work, might not. Might find a R34 / VG30 housing will help to keep that surge prone cartridge in a happy zone. I have PM'd you Ben cheers

Very impressive looking graphs, possibly a little high-end biased for the torque curve. Table-flat from 4800-6300 is a great achievement. Given what is on the original thread, I'd like to see the results from a GT28RS for an earlier serving of torque down in the mid 3000s. Depending on the mass of one of those Audis it should still be quite lively though.

The interesting thing in having a look at the flow maps side by side for a 6 blade vs 7 blade configuration is that the 7 blade pushes more air at virtually any shaft speed. That's just because there is another blade (primary + don't forget the smaller secondary) getting a "grab" on what is coming into the inducer. An example is that the 56T 6 blade can push 53lb/min @ 2.5PR @ 130000rpm, while the 56T 7 blade can do 53lb/min @ 2.5PR @ 111000rpm. (rider: that is only one point on the map) But what goes with that is extra turbine grunt required at any given shaft speed to push that extra air mass. It's a bit like throwing a few extra bricks into a wheelbarrow. Alright to do, but you need the grunt to shift it efficiently. So the turbine must have enough "headroom" to handle the load and make it all work together. When you upsize the turbine A/R you effectively introduce a reduction in gas velocity and inlet pressure through the snail at lower engine speeds and loads. This directly impacts on your transient response and lag. If you were to get the spec suggested, you may well find that the bigger flowing compressor will need extra drive, but not get it until higher rpm. I'd still say that the internally gated turbine exactly as used by Mafia is a pretty good unit, and would mate pretty well with a 7 bladed comp to possibly give a more punchy mid rpm torque. It may however be a bit more abrupt in its sign-in delivery.

http://www.skylinesaustralia.com/forums/in...howtopic=172985 Check this thread.

I spectated the Belli Creek Rd stage today. The GTR sounded dreadful. There was some VERY loud whistle under throttle, but not a turbo whistle or leaky IC piping whistle either. More like a badly made muffler design whistle that I encountered years ago with a Nelson truck muffler. Nice to see it running, but my opinion it wasn't quick in the section I saw it running. My pick was a blue XR8 Falcon, a GTV6, an Escort, and Siddins Z-car. A few of the 911s were worth a look/listen, and a few of the Evo/STi runners were obviously fast too. Vandersee's Skelta must have an exceptionally low centre of gravity and runs like its on rails. Bring on Peachester tomorrow.

Easy. Take a 33 for a drive. If you like it and the price suits, then buy it. If not, then don't buy one. Any R31 owner/fan who reckoned you were weak/poseur would surely jump at the chance to be owning/driving your GTS-X; right? If not then they're talking crap and you should ask yourself some questions about listening too hard to other people's views.