Simon C

Pay attention to some aerodynamics and you might learn how it decreases drag and increases the downforce that the rear wing can make. Hey Koomsie, wont this particular 'aero' part increase the drag coefficient, if by only increasing the effectiveness of the wing? Probably depends on how much flow separation there is off the rear edge of the roof? [quote name='pedro said: At what speed do these aerodynamic devices show an improved performance over a standard model. /quote] ~160kph at a guess? Could get that driving at 90kph with a 70kph headwind..... 70kph headwind, easy in Wellington!

They won't. http://forums.nasioc.com/forums/showthread.php?t=448097 Need 17x8 + 47.

People doing turbo conversions to Nissan SR20DE engines follow the same principle. High compression NA engines + small turbos running low boost (~0.5bar) give really good throttle response and midrange, even if the dyno numbers aren't as impressive as a laggier, harder hitting factory SR20DET with mild tuning.

DPI would be furious, you adding all this extra weight to his old Spec C Looks nice.

There was a thread on one of the overseas Silvia forums. A guy wanted to know how to weld up his rear diff. So all the guys on the forums told him to weld the internal gears together so everything was solid and couldn't turn. The guy actually went and did it, and posted back wondering why his car was rooted. Even posted photos of the welded up diff so people could look and see what he'd done wrong!

Use superglue instead of the adhesive backing they come with. I'm on my second set because my first set peeled off in the Wellington rain and wind.

If you're around this weekend, I can show you what a TD05-18G feels like. A TD06 is probably too big for your application. You don't want lots of top end that takes a long time to spool. You want a fast spooling turbo with a big fat torque band so you have power all over the rev range.

You're right, there are certain biases in the testing. What would be really interesting is if they'd measured the pipe diameters and other quantitative aspects of the headers, not just listed the brands and the obvious design characteristics (4-2-1 vs 4-1, etc). There are a lot of other factors involved with how a header will perform, it would have been a great opportunity to get some further insight into it.

Yeah, that's the one. I don't have the URL for it, just a copy of the PDF. Took me ages to find it last time. If anyone knows the URL, feel free to post it up. From memory, the stock system spools very quickly but loses out at the top end. Most of the headers designs are within ballpark of each other, with various design features accounting for the differences.

PM me your e-mail slystiguy. I have an article from a US magazine directly comparing lots of different header designs from major tuning houses, back to back with dyno runs and in different stages of engine tune.

Hard to find wheels that will clear Brembos in NZ unless you're prepared to shell out for new ones. Offset will depend on the wheel width and spoke design. The best resource on the internet is the NASIOC forums. They're down for daily maintenance at the moment, so I can't get you a direct URL. But it's in their technical subsection, under tire and wheels. There's a sticky at the top, "Brakes that fit the STi". It's really annoying how many nice wheels on TM won't fit over the front Brembos without spacers.

Bollocks. Equal length is the most efficient, it will create more power and spool the turbo faster because there is not turbulence with the exhaust pulses from each cylinder interfering with each other. Also, there is a pressure wave effect which increases scavenging from each cylinder when the lengths are properly tuned. Quite simply, the laws of physics are firmly on the side of the EL headers. But it's nothing to do with heat transfer or reliability. The only advantage of unequal length is that it will generate the characteristic boxer rumble exhaust note. This is because of the exhaust pulses interfering with each other. Essentially, you're sacrificing power for a funky exhaust note. Some people value this highly enough that they will swap back to UEL from EL. Me, you'll have to prise my EL headers from my cold dead hands.

NSX. Especially the Type S Zero and Type R variants.

Pretty certain not, as the side indicators can't be easily seen from the front of the vehicle.

No it isn't, you've got gold wheels now

Measuring them lets you know the flow, so you can pick the four closest matching out of a large batch of them. If they're not well matched, you need to run your tune rich so that once of your cylinders doesn't lean out.

Decap = cheapest (do it at home!), but may not be precisely flow matched. Mine put out over 900cc.

He has carbon fibre side markers with the STi logo, like mine.

Definately need to heat wrap it. Those headers get bloody hot. I went overboard and wrapped everything individually, was a PITA but now I know that every square inch of metal has heat wrap in contact with it. Most people would just wrap adjacent pipes as one, you save a lot of money in heat wrap that way. Also wrap the first part of the downpipe, but not the horizontal bit at the exhaust end, otherwise water will splash up into your wrap and rot your downpipe. You need enough lift to swing the headers lengthwise under your car, to rotate them 180 degrees. So your front crossmember has to be as high off the ground as the headers are wide. Can be done with a big jack. 40cm won't be enough. I had drunkenmonkey come around with his big jack and give me a hand. Recommend you invest in some six-point sockets. Much less risk of rounding off your nuts. If you have a stock uppipe with the Subaru heatshields on it, AFAIK you have to get it out from underneath, and jack up the engine off its engine mounts to do so. It's actually much easier to put a heatwrapped aftermarket uppipe in than it is to take the stocker out. Here's a photo of my SYMS ones for comparison. You can see the ones you're interested in are different. The weld work is not as tidy, and the O2 sensor bung is just below the turbo flange. Not sure if the pipe diameters enlarge after each 2-1 join like mine do. Longevity aside though, I'd imagine they'd perform similarly.

At work right now, can't see TradeMe, but if they're a replica of SYMS headers then I can speak for them vs stock. Basically, no boxer rumble, much smoother harder edged note. My turbo spools about 300 RPM faster, car is much more responsive off boost, and more rev happy everywhere. Since I can't see the photos right now, I'm going to assume that they're an integrated uppipe like mine? If not, then you have nothing to fear. If so, then they will be a PITA to install, as you'll need to jack the car up really high to rotate them in, and undo the engine mounts too.

VF30/34 both run out of puff around 6500RPM and power noticeably falls off, so I disagree about them being the perfect match. Upgrade your injectors, fuel pump, fit a electronic boost controller, new turbo, and ECU remap. 250kw of fast spooling torque.

Wheel adaptor will throw your offset off, will wear your wheel bearings out faster, and yes you'll need a cert. Changing the hubs to V9/10 hubs means you also have to change your suspension, as the V7/8 stuff won't bolt up to the new hub design.

Best thing is to learn how to read and plot engine characteristics on turbo compressor maps. That'll clear up a lot of the confusion.

Headers made a huge difference to off-boost and on-boost with my car (spooled several hundred RPM sooner), but mine are 4-2-1 design rather than 4-1, so more bottom end gains in the design. The factory ones aren't actually all that bad. The cast iron, once it heats up, is actually quite good at holding heat. They're a bit restrictive for top end flow, but the benefit is bottom end torque and driveability. Some people recommend just port-matching the cross pipe on the factory headers, rather than going all out and replacing the whole lot. Certainly cheaper, and nothing to lose. The other major drawback to the factory headers is that they weight a freakin' tonne compared to aftermarket. It's actually a significant weight reduction ahead of the front axle going to aftermarket. Don't get crap cheap ones. If they leak at the slip joints, you can weld them up, but it won't stop them cracking at the flanges. I got my ones used off a race car in the US, cost me $900NZD landed, but then you have to get them coated or heat wrapped too.

Both of them outflow the VF30 by a large margin, so you can make a lot more power. The TD06 will spool slower, and I don't think you'd make full use out of it on the setup you've described. The TD05 would be my pick, I'd imagine it'd spool up similarly or slightly slower to the VF30. There are lots of cheap made-in-China turbos on TradeMe at the moment. More likely to crap out on you. If you're into spending money, you could go with a well made off-the-shelf like a Trust ARMS M7760 or an American built unit from Blouch or Forced Performance. I think Blouch make a variant now which has a lighter billet compressor wheel. All of these can be found second hand via the NASIOC forums, budget around $150USD shipping via USPS (it's how I got my GReddy, but mine's a TD0518G, which I love). Another alternative is to give Steve Murch at Motorsport Engineering a call and see what he can sort out for you, may well work out cheaper.