GTRNUR

The modified twin turbo pipe has helped the shuffle situation, but it hasnt eliminated it. It no longer shuffles at low speeds like 60km/h in 4th, where teh MAF voltage are generally within 0.2V maximum variation of each other. But in 5th at 80 and 6th at 100 it still gets progressively worse as speed increases while at light load. Still seeing 1+ volts of variation. Im guessing nismo maf sensors with their increased load range and resulting reduced resolution would also help make the shuffle situation less evident. If I get off the throttle and then stand on it hard and both maf sensor voltages equalise and remain nearly the same as boost builds. So the next thing to try will be a HKS exhaust manifold with a balance pipe. Since they are rare as hens teeth and swapping the manifolds out is a prick of a job though I will probably just switch to MAP sensor based tuning and just ignore the light shuffle issue. Boost response has improved. 0.4 bar by 3000 and .6-.7 by 3500, where i shift. It doesnt feel like the turbos are fighting eachother anymore. The car used to surge and falter when the shuffle was happening though a big part of that would have been the ecu freaking out about vastly differing maf sensor voltages.. Oil cooler still hasnt arrived yet. On the bright side ive got the aircon gassed up again now, which is desperately needed up here this time of the year. So Steve, does this mean your achieving full boost by 5100 rpm?

Steve, I'll be interested in hearing how your pipe goes, and how it affects/improves low speed stability, spool up time etc. I recall you telling me that you had your actuators set at 1.1 bar at lift off too. I presume you run some kind of boost controller to crank that up to 1.4 bar. Im interested in knowing how quickly your setup makes boost and at what RPM wastegate boost is achieved without the controller turned off. Looks like you have enough pipe there to make me a system too. I wouldnt mind a nice 4" system. Being somewhat sick of fabrication though I'll probably just wait for a 4" racepace or some jap titanium system to come up for grabs. I do like sounding legal though.

Went for a long drive today. The car continues to go well although driving around the shuffling issue is painful. Just under 600km on the engine now. While driving up the range the oil temps got up to around 95 which is getting pretty hot, water stayed on 75. Back on level ground oil drops back to 90. My components for a complete earls based oil cooling system should hopefully be here before the weekend. 19 row cooler, -10 fittings, etc. I am loving the torque of the engine. Found a sweet spot that didnt shuffle to be around 2100 rpm in 6th, crusing at 100km/h. 14.7 afr's, 28 degress igniton and 1.00 on the knock gauge. The engine is still pulling a light vacuum at that load too. And lean on it a little and its immediatly into boost, and then mad shuffling . Drove the whole nearby range (now reduce to 60km/h thanks to the tourists crashing), in 4th gear at around 2000 rpm. Hills dont phase it at all. The same car with the stock 2.6 had to drop back to 3rd for the slow corners. Ive re-set the wastegate opening point on the actuators to 1 bar though I still haven't leaned on it to experience that level of boost yet. I want to sort out the shuffle issue first. Speaking of which I picked up my modified twin turbo pipe today too. They estimated 2 weeks before they could get to do the job, but instead they had it done in 3 days. I swear the fabrication shop that does my alloy work just likes messing with me. I'd be testing it now but tonight is the night that the cops like confiscating imports, so i'll get to find out tomorrow instead. That is all.

I was also thinking a twin entry intercooler might do the trick as well as keeping the pipes divided from the compressor housing to the intercooler allows more air velocity to build, and as a result more stable and balanced airflow at the maf sensors. Of course that would I'd lose my stock apeparance engine bay too, not to mention that most of the twin entry cores are designed for drag and not the street and are way too big for my application.

Thats the plan. I spent a good few hours reading the 10 page "shuffle" thread on gtr.co.uk and came across that guide yesterday. I'll be dropping off a spare pipe to be modded tomorrow morning.

Here's a few pics of mine after a recent photo shoot.

Even with the dual mass flywheel the getrag's still rattle. Its normal.

Update. The engine still continues to go well and has a little over 500k's on it now. Ive been working on the tune a little in the response zone around 2000-3500 rpm, still keeping boost below .5 bar. Its a hoot to drive, but now its more responsive Ive encountered the next issue. At light load around 2000 rpm in 6th the turbo's start to shuffle wildly. As in 1 to 1.6 volts variation between the two maf sensors, and they do this see-saw thing back and fourth. This does not help the tuning process at all! The problem is less noticable if I start to load the engine up above 2400 rpm. Im hoping that the shuffling is being made worse by the fact that ive got the wastegate actuators set pretty loose at the moment, so im going to re-calibrate and tighten them up to 1.1 bar tomorrow. I suspect i'll have to do the twin turbo pipe modification as well to help control the shuffle, or alternatively invest in the sexy nismo intake piping... time will tell.

Perhaps if your building an F1 engine but seriously the materials being used in F1 are vastly different than an offset ground Rb25 crank with a set of cheap rods and pistons that are still based on a conventional RB design. You cannot compare an F1 engine to an RB. There only common ground is that they are both 4 stroke engines. And you cannot hope to rev an Rb24 anywhere near whats needed to get any benefit from the rod ratio change. Yes longer ratios reduce some forms of internal stress on internal components. Specifically acceleration rates from BDC and TDC are less, and overall piston velocities are reduced, and inertia loading on the rod journels is reduced. Standard Rb25 stroke is 71.7mm with a 48mm rod journel and a 1.7:1 ratio. Presuming you go for an RB20 rod you can reduce the journel to 45mm and at the same time reduce the stroke 2.8mm to about 68.9mm. The ratio would then be 1.77. I dare say that with such a small stroke and only a tiny increase in ratio you would barely pickup a 2-3m/s^2 benefit in piston acceleration reduction at the top end of 9-10K rpm. At those engine speeds your well into requiring all kinds of radical forged parts, good oil system and most importantly a bullet proof valve train.

PFC & injectors still for sale

The upholstery looks great on the seats and the inserts in the back seats look very nice. Something the GTR interiors have always lacked a little is that feel of luxury. I'd rather have leather than all that carbon trim though. That probably makes me old right? Its not as though you really need the weight reduction... after all. 800PS!

Lowering the capacity to achieve a "better" rod ratio is a step in the wrong direction. People stroke engines to increase displacement at the expense of rod ratio for a very good reason. Displacement increases make a larger overall improvement to engine performance than any mythical and ideal rod ratio. Eg... 2.7 and 2.8 stroker cranks. Both add displacement at the expense of a little rod ratio. There are production engines out there with ratios ranging from 1.44 to 2.1. Whoever said 1.75 is perfect for an Rb engine has never also said precicely what it is perfect for. Did Nissan get it wrong? In reality there is no such thing as a perfect rod ratio. It comes down to 1. What will fit, and 2. What will work well for the given application and survive with reliability. The only reason you would chase the "perfect" rod ratio is if you are after that ultimate tuned package, which you can not ever hope to achieve with a bitsa engine and especially a limited budget. If budget comes into the equation even slightly the goal should be as much displacement as you can cram into the block as you can, and everything else is secondary. That being rod ratio, squish efficency, compresion ratio etc. In the end raw displacement makes the biggest overall difference. So in the RB world this means an RB30 bottom end.

Spacers Sold. Also, the map sensor can be unplugged from the D-jetro if you wanted to run the convetional twin Apexi map sensors instead. You'd just have to source the twin apexi/tomei sensors and a map sensor harness.

Spacers sold pending payment clearing.

Mark99 off the forum? He was quite helpful and fourthcoming with information for me when I initially started with this project. That is a rare thing considering everyone in "the industry" keep their secrets to themselves. Of course that is perfectly understandable really... Its the only way one has a chance of earning some money back after all thats spent on R&D.

Minor update. Solve the issues I was having with idle stability. Turned out to be a leaking gasket on the throttle bodies... of course the one at the back not that it made any difference to fix. I must say, removing and re-fitting the plenum on a gtr engine is a right prick of a job. But its all sorted now and pressure tested to 30psi with no leaks! Note to self: Pressure test the next engine on the floor BEFORE installing it in the car. Note 2: Use HYLOMAR on EVERYTHING! Fricken tomei rubber coated metal BS gaskets wont seal reliably without it. With that issue solved ive started to put some KM on the engine. Just over 200k's now, and have used 1/2 a tank. All in round town (in traffic) driving between 60-80k's, as well as up and down the tallest hills I can find. The engine has no noticable blow-by at all. I havent pulled the plugs and compression tested for a week but im pretty sure its getting close to being bedded in nicely. Oil samples are continuing to come up clean touch wood. Ive got quite a collection of samples on the shelf in my loungeroom now . Thats all for now.

1 x R34 GTR Power FC D-Jetro version. With a single GM 3 bar map sensor mounted on the ecu and directly wired to the ecu. No need to alter the engine bay wiring and splice MAP sensors into the MAF sensor wiring. Includes hand controller $1000 or will negotiate swaps for other parts. 6 x R34 GTR Vspec 2 injectors. Approx 35,000km on them $300 4 x Rays's 20mm hub-centric wheel spacers. Suit R34 GTR. Allows the factory guards to be filled out a little better. See Pic to see what they do for the look of the car. $120 Will accept swaps as part of full payment for parts. See my signature for the list of things Im still chasing for my car. PM me or phone 0434 147 478. Cheers.

And a current picture.

Update! Today I finally got motivated again and re-installed my re-sleeved master and slave cylinders. 2 hours of stuffing around bleeding and adjusting later and the clutch works like a treat! Thanks to a little tech support from Paul at red R racing diagnosing an adjustment issue with my throttle stop switch, the car now idles much better (as its not hunting on the map sensors), and also it doesnt flood the engine after a rev. The corrections for the larger injectors dont seem to match the requirements of the engine though, so Im still tweaking those a little. Not that it will matter as the new ecu arrives next week which will change everything. I put about 80km on the engine this evening, just cruising around town and up and down the tallest hills I could find in the tallest gears and keeping the revs low. It runs awesome and I think it will come close to meeting all my goals based on what ive seen today. The engine makes positive manifold pressure of around .15 bar at 2500 rpm and is at .4 bar at 3000. This is with a doey as hell ignition curve and 13:1 afr's too. Engine temps topped out at 71 degrees when driving, and oil temps at 89 as it was last time. External oil cooler is going to have to be installed before the first dyno session. From 2500-3000 the engine has that same urgency that the 26 had from around 3000-3500 as it just begins to surge onto boost. Driving and short shifting at 3000 rpm still feels quite zippy. You get to hear that all familiar slow and deep sounding spool of the large turbo's happening from around 2500. No aparrent choo-choo train noises so I think there is no shuffle issue there to deal with. Low end torque is nice too. The engine happily cruises at 60km/h in 5th gear at 1650 rpm, and at 80 in 6th at 1800 rpm, with 200mmHG of vacuuum. Oil sample and plug check tomorrow morning, then the testing continues. That is all for now.

The engine is one factor too. How do the engineers feel about spacers under the cross member to lower the RB30's so they actually fit the cars? Because technically it does interfere with steering and suspension geometry at little...

I'll have one up for sale in a week or so once my new ecu arrives. L-Jetro ECU and hand controller. Owes me $1k.

The rules are a lot more relaxed in qld than they are in the southern states from what I understand. You wouldnt believe what you can do up here if you have a good engineer on side. All this talk ive heard about the inter state rules being all bought into line will change things. Weather its for the worse or better who can say. They cant revoke cars that are already approved in QLD, but they can certainly stop new cars from being re-engined. They did that a few years ago with VW's and the old Myers Manx rebody conversions. It used to be classed as a re-bodied 1968 vehicle which meant it just had to meet the emissions of that era. Now to do the same conversion its done under ICV rules, so you have to somehow get a 1940's designed engine to pass emissions. In a sense its the governments way of 1. preventing vehicle modifications, and 2. getting old vehicles off the road.

After Vik. The main goal is to supply power to the coils. The ignitor module operates from earth to the +5v signal supplied to the unit from the ecu (when the coils are fired). There should be 6 inputs and 6 outputs, plus a single earth. The conneciton for that earth is the next most important thing. Always make sure that earth is good, and solidly bolted to the engine, and adding a 2nd earth strap from the chassis to the engine or gearbox isnt a bad idea too.

Get yourself a good 30A plus fused automotive relay and cut the +12V supply to the coils and connect it to a relay on pin 87. Run a high current wire from your alternator terminal and connect it to pin 30 on the relay. Ground pin 86, and connect pin 85 to where the coils used to get their +12V from (the loom). This allows much more current flow at the coil as there is less voltage drop across the length of the wiring in the loom.

I think cam choice is more about the applicaiton you have in mind for the car too. In reality I drive on the street, and on occasion on short sprint tracks (gocart tracks with tight corners), so low end response is what im after. I'd love to get to drive around some of the decent tracks you guys have access to in Sydney and Melb (and get to hold 3rd gear for more than 2 seconds), but thats a long way from where I live. So there is no point in setting up for that sort of track. While I have a power goal in mind which is easier to achieve with bigger duration cams, from what Im told I can achieve that figure with just the turbo's im using, so the additions i'll be making will be focused on building more low end torque instead. Given the choice I'd have gone with -5's or 2530's but the GTRS's were too good an offer to pass up at the time as I was able to get rid of a lot of my old R33 GTR parts in trade as part of the deal.