the phantom

Hey discopotato, How does the Garrett guru align his opinions on compressor/turbine relative sizing, considering the radically differing conditions each are operating in, i.e gas velocity/density? Would the more sizeable turbine with its inherently costlier inertial energy requirements not lead to losses of its own, i.e. slip? I am also considering this turbo for my next '30DET build but am unsure what to pick between the .82/1.06 tubine housing. What does he think? Intreresting thread.

So if I had a GTS25t box and a GTR box, its possible to make the GTR box into a GTS box by interchanging parts? Or are custom parts needed, Steve-SST?

can you share the part number of your turbo, cameron?

Hi discopotato33, I think a list of ACTUAL GARRETT PART NUMBERS is a great idea. Way to much confusion is causes by the several local turbo suppliers who insist on creating their own HKS type nomenclature for the sake of sales, with a hodge podge of different wheels and housings and horspower ratings, with subtle and confusing variations between the makers. These names mean absolutely FA to Garrett, seemingly only part numbers are recognised on the database. In my case the turbo does haves ball bearings, and is called a GT30, but has a TO4S compressor!!!??? Yes the TO4S is old school, thats why I would have liked to try the newer wheels, just to get a feel for the supposed newer technology and improved response. The boost control is good all the way, but you have to have a wastegate spring that is close to what you want to run, not just winding up a 5 PSI spring to 15 PSI and expecting good control. Also even though it seems to be at 90 degrees to the exhaust flow, look at the name brand manifolds out there, HKS et al. They too seem to have the wastegate tubes at 90 degrees to the flow. Seeminlgy ANY mods here in SA are deemed illegal, with little recourse or mechanism for engineering approval. We're in the dark ages down here, with government entities that rule with an iron fist and little intelligence. Bl4ck32, if I was going to get another I'd get what your getting but still go for the 1.06 housing. I feel that if the boost response is anything sharper than with the old TO4S wheel it would be difficult to control smoothly, and with a .86 one would think it much more abrupt. However this is my personal opinion, and I cant back it up with actual results. What you are about to do will certainly be an interesting comparison, and very important information. What are the part numbers and components for what you have in store, and where are you getting it from? Please keep us informed. Worst case scenario is a new housing for you, so it wont cost that much, relativey speaking. Bl4ck32....new response in light of your typo! This is now up a rung to what I thought we were talking about. In this case, I agree with your choice to start with a .86, but again, only your road impressions will tell the story...

Hey Joel, She's still running strong and now approaching 70000 km, but the button clutch is starting to show signs of slippage in the midrange on occasion. Not bad really, I didn't expect it to last that long, although I have tended to be gentle on it by avoiding high rpm clutch dumps! Work is precluding me from undertaking the next phase, although slow progress is being made. This should be a real rip snorter, and something unusual. As for the setup, it has remained essentally the same since day one, other than an intercooler change, and minor incremental improvements. The bottom end was fully reconditioned, balanced and carfully rebuilt with completely standard parts. Nissan gasket kit, ACL pistons and rings, and RB30ET oil pump. The head had some mild porting done; basically just a good clean up. Everything else is standard, bar some piping mods to adapt the new turbo's huge inlet to the AFM piping and BOV. The fun factor comes in the form of a Garret GT30 series, part number SB8005, with a 1.06 exhaust housing. An external 45mm Turbosmart Progate, fitted on an adaptor block, is sandwitched between the standard exhaust manifold and the new turbo. The intercooler is the largest I could fit without resorting to more bumper mods...about 600 X 300 from memory. Exhaust is a 3 inch straight through with two mufflers. Fueling and control mods just consist of a Malpassi regulator, a PowerFC, and Finer Filter air filter element in the standard air box. The standard AFM piping does implode so I made some flat alloy donuts that I squeezed into the convolutions within the rubber. Other than the wastegate, popping the bonnet reveals an almost completely standard looking thing. In hindsight I should have installed the wastgate pointing down and out of view, particularly with todays draconian policing attitudes. Boost sits at 15 PSI with what was originally a simple bleed valve. This was subsequently replaced with a Blitz ID II boost controller, with significant improvement in boost response as a result. Boost starts at about 2500, and increases linearly before peaking at about 3,800-4000 rpm, with a huge surge in power. It certainly isn't as responsive down low as with the stockie turbo, but the capacity more than makes up for it, and, given its unholy desire to reach for the redline, its quite entertaining to say the least. Given another choice and further development with this setup, I wonder how a GT30R with its GT series wheel rather than the old school TO4S in the one I have would perform. All up its nothing special really, but has delivered strongly and reliably, considering it gets flogged every day. I think the key to longevity is GOOD CONSERVATIVE TUNING. For those so inclined, I would suggest NOT skimping on this part, or reaching for ultimate dyno numbers, which will cause a meltdown as soon as the weather changes. I know this probably doesn't sound like much power to a lot of people, with everyone nowdays quoting obscene power levels, but for the road, it is by far the fastest and most entertaining vehicle I've ever owned, and can light up the tires with consumate ease irrespective of speed!! PS: Citroen DS....very funny!

I managed to get 245 rwkw with the standard injectors with a malpassi rising rate regulator. With the original '25 it spat out about 145 rwkw on the same dyno from memory. So if you disregard absolutes thats quite a hefty amount of headroom you have available. Yes...the RB30DET is a wonderful idea!!!

I have to agree with Joel on the rev happy nature of the RB30DET. There is absolutely no hint of reluctance to build revs whatsoever. I have to ALWAYS keep one eye on the redline whenever I feel the calling. The additional power has made it rev even better than the original '25 in my opinion. More torque will accelerate the car faster and in turn allow the engine revs to rise faster in unison. Provided of coarse you dont loose traction, which is almost an impossibility!!! Just a note on the water jacket mods...I used a die grinder on the block to match the head gallery as closely as possible. Then I got a hole punch and trimmed the standard Nissan head gasket to match around that area, so as to limit the water flow obstruction leaving it intact would have caused. In the end there was probably about 6mm or so of steel left to squeeze the gasket. I had concerns initially but figured that even with such a thin clamping area the gasket still ought to seal, it is only a water gallery after all, no large cylinder pressures to deal with. In the end it turned out to be just fine. My clutch is now begining to slip after a long arduous life. That may be the impetous I need to kick start the next angrier conversion from its hiatus, and allow me to take photos of everything I've done to clarify it for everyone. If only work didn't interfere with play

That's a sad sad tale, Browny_R31 :hellpisd: Is there an ombudsman able to examine this and no doubt countless other such stories?

Hey Roy, I got about 245 rwKW out of my RB30/25DET hybrid with a stock GTS25t airbox and a Finer Filter foam filter insert. I'd be more concerned with the air box to turbo pipe collapsing on itself though.

Hey B-Man, A dashpot is a mechanical damping device like a shock absorber. The type I mean here usually resembles a vacuum diaphragm, with a rod comming out the end. The rod is free to move out one way, but when you try to push it back in, it resists. Its pretty much like a 90/10 shock except its more like 100/0. The idea is to position the unit so some part of the throttle linkage pushes against the rod just before throttle closure. When you lift off the throttle, the linkage hits the rod, stopping the throttle from instantly hitting the stop screw, and only allowing it to slowly creap towards closed over maybe a couple of seconds....just long enough for the reversion to have subsided.

I also had an issue with the ECU plug with an intermittant connection to the AAC pin no less!!. Another thing...I have tested two different Power FC's with a CRO and had a look at the AAC waveform in comparison to the standard ECU. Quite suprisingly, the PFC idle control strategy on throttle lift off is INFERIOR to the standard ECU.... Standard ECU: When you open the throttle, the AAC valve opens in unison. When you release suddenly, the AAC valve SLOWLY closes back towards the idle target value. POWER FC: same except when you release the throttle, the AAC valve closes to the idle target value INSTANTLY. This obviously causes a much larger reversion effect as the turbo cant repond instantly to changes due to its inherent rotational inertia, a situation made worse with bigger turbos. Suddenly the now excess air has nowhere to go except out the AFM. Contrast that with the stock ECU which allows an additional bleed path through the throttle, thus reducing the impact. My solution: Install a dashpot on the throttle linkage to slowly close the throttle when you lift off. This has been extremely effective, to the point that I can say my issues are solved. Whats more, the dashpot only cost $5 from the local UPullIt. An veritable automotive nirvana when you're on the prowl for some odd tidbit and want to take your time to look around for something suitable from different manufacturers. My dashpot came out of a Mazda 121....

Joel, oops sorry...Yes your right, the new holes in the plate are ABOUT 25 mm HIGHER thus lowering the engine assembly by that amount. You cant go much lower than that because the sump will hit the sway bar. When I was working it out I had the engine bolted to the gearbox but supported on a jack from below on the sump rather than the mounts. I lowered it enough to clear everything ensuring normal movement room, then marked out the hole positions on the plates through the original engine-side holes in the mounts, which were placed in the elongated crossmember-side slots so they could move outwards as required.

Hi Joel, After about 70000 very hard km now, I have not noticed any ill effects with the engine lowering. I too initially thought this may cause universal joint issues, but there have been none...no vibrations...ever. The effect on the drive shaft angle is very minimal, and the lowering of the centre of gravity can only do good things.

Hi, I couldn't close my bonnet with the standard setup and Rb30 conversion. I probably could have but didn't try forcing it. I didn't want to disturb the hood liner let alone the bonnet with the natural engine movement. Doing the mods to lower the engine is quite straightforward...i.e. cheap. You dont need to modify plenums or anything that drastic. You simply get a 10mm plate that sits between each mount and engine. The plate has eight holes. Four countersunk in the standard position to bolt the plate to the block, and 4 threaded, about 25mm lower to bolt the mount to the plate. Then you extend the mount slots on the crossmember as the mounts will naturally stick out a bit further due to the plate width. Remember to also trim the radiator shroud slightly to allow for the slightly lower position of the fan. The engine to gearbox braces also need minor relieving to clear some lines. Its all quite simple and easy, and will not look obvious.

Yeah RIPS can do it and arrange all shipping. They are in New Zealand. Dont know if they will do it without a short motor however, give them a hoy...

To the dickheads who completely debadged my Skyline parked on the road in front of a mates house in a quiet Walkerville street, last night...... CONSIDER YOURSELVES VERY LUCKY YOU DIDN'T GET CAUGHT. TODAY WOULD HAVE BEEN A VERY DIFFERENT DAY FOR ALL OF YOU....

Based on JasonO's measurements, and if haven't missunderstood the description, a single restrictor would then have to be < 1.7 mm diameter to be actually restricting anything, based on the surface area of two 1.2 mm holes. Sydneykid, I cant see anythign wrong with your logic. So are you assuming that the GT's would be designed for a 'low pressure' engine and that RB's may need the restrictor? Do you run one on your cars with your custom turbo setups? Does anyone have published Garrett specs on the oil requirement of GT series turbos?

A NEW AAC costs about $450 new from Nissan unfortunately. I assume the $40 was for a used one? If not please share and I'll take a couple! I once had the AAC wire pin in the ECU plug somehow loosen and make an intermitant connection. I only found it accidently whilst fiddling around with the associated plug wiring and noticing the revs change when I nudged the wire. Cleaning out the AAC thoroughly may restore it to working order unless the spool is worn and it's leaking. You cant take it completely apart unless your really keen though. O2 sensors cannot be restored by any type of cleaning. They age chemically and once expired you need a new one. Typically they only last 45-50000 km.

What would you say is the diameter of the restrictor hole seen in your photo?

Putting a resistor in series with an injector will lower the voltage across the injector. If the injector drive circuitry hasn't been designed WITH THIS IN MIND as opposed to other systems, i.e GTR, would it not upset the operating characteristics of the injector?

I've been wondering this also for a very long time but have no definite answers. The standard R33 turbo runs a restrictor however....

Trimatics can be successfully modified to handle substantial power outputs without the trauma.

Can the Skyline autos be modified to take serious power outputs reliably? Does anyone have first hand practical experience on the results of any mods done by any particular shop? Everyone seems to just go the trimatic/powerglide route.

I dont think that anyone in this vast thread has specified what year SII began and SI ended. If it is SII then yes provisions are there...

The current highest bid is 2750. They will not fit on an R33 GTSt unless you like them sticking out past the guards by 25mm!