Gav

This guy used a LHD Z32 rack with the original R32 tie rods in his conversion. Click here

I've got my old rims available if you need (won't clear my 355mm rotors and 4 pot CSC brakes ). Tyres need replacing. See Ant at X-Speed, slide him $600 fold and all will be good!

I use Pauter rods and have absolutely no complaints. Light, tight manufacturing tolerences and will custom make at no extra charge. see: pauter.com Cheers Gav

I've been through 3 (well 4 if you count the Mines modded) ECUs on my R. First version was a "3.08" version that had the intermittent miss at cruise loads. Second was a Wolf 4 (MAP sensors) that had NO miss. Third is the D-Jetro PFC and the "cruise miss" returned. Now the strange thing is that I recently (before buggering off overseas again) installed an HKS "Twin Power" CDI unit and the miss is gone for good! I covered a good 1,000 kms with it installed and it's definately not a "placebo effect" My gut feeling is that the miss is ignition related.

Actually BOBBO is being a bit coy here. The tuning shop where he works has a very interesting graph overlaying most of the terbs described here fitted to GT-Rs. I think he's also been in most of them (I know I have). My thoughts for what they're worth: I have GT-RS terbs fitted to a well built RB28 (HKS kit) with big cams and head work. Click for dyno graph Having driven an almost identically specced RB27 (JUN kit) with 25/30s, I can certainly vouch that this car has a bunch more torque lower in the rev range and sacrifices very little top end to me (I reckon I'll have 30 more peak hp max). Also, having been in 2 TO4Z GT-Rs with standard cranks, again these sacrifice little low down torque but have an absolute phenomenal top end to boot! So whilst I would dearly love to defend my investment in the GT-RS terbs, I can honestly say that for most of the GT-R owners that are looking to upgrade terbs, BOBBO's advice is spot on: 25/30s TO4Z BOBBO see if you can get the dyno graphs as an overlay as discussed!

I have one of these fitted and it performs exceptionally well. Have a look at my gallery to see what it looks like fitted. Good luck with the sale.

No - I've got an HKS stroker crank fitted giving just on 2.8L displacement (87mm bore). The hardware should permit the engine to venture north of 9000 rpm, so I imagine overall airflow should not be too dissimilar. Good luck and keep us informed.

Paul do you think that the PFC has an "auto learn" function as well. I'm also a little sceptical of this.

Your logic is correct - I can't think of a solid reason why the D-Jetro should provide more power over a standard PFC. But I've seen the same tuner achieve just that. Perhaps he's just better at tuning D-Jetro's?? My main reason for going to D-Jetro was that I wasn't happy with the Wolf ecu I had (couldn't get the ATTESSA reliably working) and I didn't want to fork out the bucks for new AFMs, adaptors etc.

Hi Paul An interesting discussion. I guess firstly, I can't explain why the D-Jetro does show a consistent gain in power over the std PFC, however as I have said, I've seen this first hand on 3 GT-Rs now. I don't think there is any magic involved in this, however. With regards to MAP sensors "guessing" air quantity, I disagree. It simply uses basic gas laws to determine the quantity of air: PV=nRT, where P = pressure (i.e. map sensor), V = volume (known from the engine displacement and the rpm), n = the quantity of air (what we need to know), R is the Universal Gas Constant (the "magic" number) and T is the air temperature (taken from inlet manifold temperature probe). You can see that there is an inherent problem now with the fact that it is assumed that volume is related directly to engine revs only. For NA motors, this isn't a particularly good assumption as volumentric efficiency changes significantly across the rev range (indeed this is one reason for going to big lift and longer duration cams). For forced induction motors, the proportonal change in volumentric efficiency is comparitively much less, and therefore the equation hold much better. In your example above, you assume that the y axis (or load axis) is actually pressure on the D-Jetro rather than a calculated quantity of air ("n") in this case. I am sure that this isn't the case as (to use your example again) when target boost is reached well before the RPM redline, I've seen that the map trace doesn't go horizontally across the x (rev) axis, but rather continues diagonally down. This shows that additional load is being calculated by the D-Jetro and fuel/timing changes made to suit. There are certainly inherrant problems at low rpm and idle situations. Here the volumetric efficiency variations have a much greater effect and the manifold pressure jumps all over the place (particularly with "aggressive" cams!). For this reason the D-Jetro cross references against TPS and uses an average of the 2 MAP sensors in the manifold. With regards to MAF determination of air quantity (i.e. factory ECUs and std PFC), this is also a "guess" if you want to put it that way. Just about all of these systems use what is known as a "hot wire" AFM that relies on the fact that electrical resistance of a wire changes with temperature. The amount of air passing the wire is calculated by the change in electrical resistance. Generally a very reliable and cheap to produce system. I suppose that this (and the fact that most cars produced are NA) may be a reason for OEMs turning away from MAP to MAF based systems of measuing load). Some well known downsides of MAF systems are: * when air that has been measured doesn't go into the engine (i.e. blow off valves venting to atmosphere) * when the hot wire gets fouled by oil that may insulate the wire from the air * the delay between measuring on the inlet side of a compressor and actually entering the engine (especially on big intercooler volumes) * the fact that generally there is no account (or even measurement) of manifold air pressure or temperature. Both of these properties can vary even at a given AFM output.

Good advice. I've got a lot of hardware installed along with my GT-RS terbs. I'm changing the inlet cam to a longer duration 272 item, but I really doubt I'll crack the 600 rwhp level. I think 570 to 570 rwhp is a more realistic maximum for these terbs.

Why do you think so? I've seen a number of GT-Rs gain power when converting to D-Jetro from std PFC. Again - why? The D-Jetro has 20x20 load points that are configurable.

Good advice by Slippery, but a dyno tune/remap really is good value these days with the high fuel price. Not only will you gain power, but you should gain cuising economy also. Depending on the kms you travel I wouldn't be suprised if you paid back the cost of the tune within a couple of months due to fuel savings (assuming you can keep your right foot off the floor that is )

I agree, it all sounds normal to me. There is a slight possibility that the G sensor(s) are playing up and are too sensitive. Duncan's ATTESSA controller intercepts and modifies these signals so you can increase this sensitivity to what you want. I don't think that it can DEcrease sensitivity, however.

I believe it's for a "Step 2" crank and I believe fully counter weighted (unless someone can say otherwise?) as shown here: HKS website states these are good for 9,000 rpm and 588 engine kw, but I suspect this is somewhat conservative.

Mark99 I take my hat off to you for going down this route and sharing the experiences - as Cubes says, an interesting alternative and certainly has the potential for a good streetable GT-R. I'm not convinced of the cost benefits, however as I have a similar power curve with more headroom potential (i.e. rpm) using an HKS stroker crank and offset pin pistons. This crank has the advantage of being counterweighted and less prone to inducing destructive harmonics at high rpm. A good aftermarket damper is obviously part of the package. The HKS "entry level" stroker cranks and pistons are now in the order of $6k to $6.5k in Australia. It would be interesting to see what the true cost of modifying the RB30 crank and making custom pistons is compared to the HKS kit. Again, not meant to be a critisism but just some personal experience I'd like to add to the discussion. Will certainly watch your progress with interest!

This post has most (if not all) of the info you need: Click Here As Duncan says, a straight forward swap (very effective however for bigger/laggier terbs, however!)

I swapped out a std set of HKS terb manifolds with the balance pipe style on mt GT-RS units and it made a huge reduction to shuffle.

Nice result, but as per the above posts I agree that you have more power to come as the curve is still rising. You have a similar setup to me Gav's Dyno Graph, however note that I have shorter final gears from a GTS4, so a direct km/h comparison isn't possible. I still have some mixed emotions over the GT-RS terbs, however it is apparent (to me at least) that to get the best from these turbs on a 2.8L you still need to get some serious airflow through the engine. Big revs, high lift/long duration cams (I'm changing my Step 2 264 IN to a 270 duration) and head porting really makes a difference. Good luck and drop me a PM if you want to chat. Cheers Gav

400+ rwkw through my HKS 80mm (3-and-a-bit inches) exhaust. I can't see a problem for 300kw on 3" system.

If you want to remain "true to the marque", what about dropping in a VH45 V8? If you really have some spare coin and time, you may find that the Pathfinder will also have enough room to squeeze in twin terbs? Just a thought. Stop the press!!! Just looked up an article in Autospeed and quote: The VK56DE employs a massive 98mm bore and 92mm stroke for a total displacement of 5552cc. This engine is built in the US and, as far as we’re aware, is not sold outside of the country. Fitted to the ’04 Nissan Pathfinder Armada and Titan pick-up, this engine makes 305 bhp (227kW) at a low 4900 rpm and more than 500Nm of torque at 3600 rpm. In the Infiniti QF56 SUV it makes an extra 10 bhp (7kW). I wouldn't be suprised if this is a straight "bolt in" arrangement! Only thing is you would need to source the parts from the US, however cost wise it may not be such a bad proposition.

It's interesting that the material of choice for aftermarket manifolds seems to be stainless steel. This expands/contracts much more than plain old mild steel and tends to crack at the welds more often. Cosmetically there is bugger all difference if you are going to coat/wrap them anyway as well!

Nah - Space Shuttle is "Old Skool" and uses plain old Chemical Accelerant (liquid oxygen) - no turbos on those Bad Boys

We agree with the concept - the amount of loss is where we differ. You claim 30% pressure difference due to heat loss? This means that 30% the exhaust gas must be 30% cooler due to the tubular manifold (i.e. from 1000k to 700k - or from 727C to 427C) - it just can't be so - sorry.