Dale FZ1

After checking out the amount of adjustment I needed to make in the air bypass, I was satisfied there must have been an air leak somewhere/somehow. Note that there was NO noticeable loss of boost, or any hissing to indicate such, nor was the vacuum at idle lower than normal, nor was the idle rough. Suggested method of tracing an air leak is to run the engine, then get a fine misting spray bottle of water to mist water around the manifold and injectors. If the engine stumbles while doing this, it's a fair indicator of a leak. Alternative is to spray some ether (sold as Aerostart or Start Ya Bastard) in the same areas, and watch for the idle speed to lift higher. Be careful using ether because it ignites easily. No good having an engine bay fire. I re-split the manifold, and though the gasket seal looked perfect, I did find something: The circled areas show where the inside bolts go. Note that one has a rubberised locator/isolator missing? It came out with the bolt upon disassembly. When I had originally put it in, things had not gone "home" properly. I must have been in a little rush just to finish the job and failed to see this. Then when I went to check the tension on all bolts, I gave it a little tweak with the spanner and felt it suddenly seat home. I presumed the seating was in fact yours truly stripping the thread and got very cranky. I had expected to need a thread repair job while redoing my work. (thankfully there seems to be steel thread inserts used by Nissan, so it would take one hell of a lot of tension to strip things out). When I reassembled the manifold, I did it with perfect daylight, checking things 3 times. Result: final adjustment of the AAC ultimately returned the bypass screw close to where it had originally been. Stable idle, about 700rpm at operating temp, about 900 - 950 from stone cold. Also I haven't gained any additional boost or vacuum. That leak must have been very very small. There has been a lesson in this one, shows why some of us are mechanics and some aren't. cheers Dale

Looks like I have fixed it. Got a couple of pics for posterity too. I'm going to run it for another day, then post up the outcome. Looks like it was related to attention to detail rather than any glitches.

Are they OE Nissan gear, or aftermarket ie. Garrett? Got any pics to share?

Rob - didn't touch/adjust/bump the TPS. I will check my throttle closed voltage to be sure though. And yes, I am concerned that giving the AAC a thorough cleanout and adjustment is only a gloss over whatever the real problem is. At least it seemed to work. Blind Elk - yes, as per original thread starter, I entered appropriate correction factors for the larger squirters. If not, it would be richer everywhere by a factor of about 18% Cubes - although it was only the vacuum ports, AAC and TPS that were effectively disconnected, I will have a go at a full idle reset / ECU re-learn. I find it odd because there was no mechanical changes done other than installing bigger injectors, and no electronic changes other than specifying the injector correction factors. The ECU was not disconnected or power source removed. I will firstly run it for a few days with the current AAC clean/adjust, then have a go at full idle reset and post up any results during the week. Paul - the hand controller has been disconnected at all times other than for a short run to see the difference in duty cycle. As expected, it was reduced by a factor of slightly less than 1/5 for similar running as with the original injectors. The whole situation has been a bit odd but I reckon not something that has to be tolerated. Thanks guys, the input/feedback has been helpful. cheers

I removed the AAC valve assembly from the plenum today. There was some carbon deposited through the air channels, but not caked in or excessive (that I could tell). Used a fair bit of carby cleaner to loosen up anything, then blew it out with compressed air. Also removed the AAC solenoid from the assembly, cleaned up everything I could realistically get to. Result: no significant change. Given what I saw, I didn't expect much different. The idle quality DID change, but inconsistently. Coming to a halt and engaging the clutch, revs would go down to about 800, climb to 1200, then hunt for about 10-15 seconds between 500-1000. Typically this seems to be related to a crappy carboned up AAC. Not sure on that one given that I had just put a reasonable effort into cleaning it out. Further effort put into reading the engine service manual, and I found there is a manual adjustment on the AAC. Pic below shows it circled, viewed from the drivers side: Following the manual, a clockwise adjustment of the screw did pull the idle revs down. A test drive showed the engine would come back to an idle within spec. Will have to drive the thing for a few days and see if the fix is satisfactory. Has anybody found this sort of fix useful/workable in the past?

No problems controlling boost as yet. At this stage I am limited to 10psi; waiting on a chance to run it up on the dyno and get the chance to lean on it a bit. My calculations suggest the 48T will start to run out of puff at 16psi tops on the RB25, and I should hit the power target @ 14psi or so. With luck the turbine housing and wastegate won't be a limiting factor. What is interesting in my case is that boost is fairly controllable by throttle position. I did have some concerns about the ability to bypass sufficient gas through the stock wastegate valve, but had to trial it and see. Anybody looking at this sort of high flow job should really insist on having the valve and port upsized. I 'm not a big supporter of using the VG30/R34 turbine housing on a stock-ish R33 spec engine or the RB20. Too much lost mid range response in the pursuit of high end power for my liking. cheers

Mike Warner Wheels on the Sunny Coast. Premier Circuit, Warana. Good quality work.

Thanks Brett; appreciate your thought. Self learn idle really only applies if the ECU has been removed (my understanding). In this case, all I did was disconnect the sensors that feed info to the ECU, laid them aside, and continued with the removal of plenum and fuel rail. At the end of the procedure the plugs were reconnected. I don't think that it (ECU memory wiped) would be the cause, because my idle is stable - it is just a couple of hundred rpm higher than previous.

Depends on how you want to approach the job. Check the link to the GT2871 based highflow into my RB25. There are a couple of fiddly bits to deal with when going that way (ie stock comp and turbine housings onto Garrett core). At least all the air in/out ducting bolted back up. There may be some power/efficiency benefit in using the RB20/25 turbine housing and Garrett comp cover; but this means more fabrication work for ducting. There is even more fabrication / purchases needed if you run the stock Garrett turbine housing and use adaptors. Remember there is a 5 bolt dump you need to marry up to that housing - different from the Skyline 6 bolt. Overall the HKS is the best option if you just want to have something that fits up without any issues. It MAY work better. It DOES cost more. Consider what funds you have available, and whether you are interested/able to deal with the fiddly bits that go with fitting a custom turbo. A primary issue to consider though, is which comp trim you reckon is best suited to your engine and driving habits/needs. A 2mm difference in the inducer size does make a difference. Obviously the HKS is only available in 52T. cheers

Didn't disconnect battery for the job - didn't need to. And yes - I know the manual says to do so, and the potential issues with sparks when the fuel rail is disconnected. Working in a well ventilated area, and I had control over the keys at all times. To do this job, the manifold has to be split. It is the only way to access the fuel rail and injectors. All connections put back together and double checked for proper attachment.

BUMP I made a slight change to injector lag, with no effective change to idle. Then I went into idle control, altered the FC1 / FC2 values and got a hunting idle (rolling up/down between 500-1000). Made me remember that I had used carby cleaner in the plenum to purge oily film from the PCV feed. The AAC valve was left in-situ, and I suspect it may have got a coating of the oily crap. Going to have a look at cleaning it tomorrow. Surely someone has some idea here?

BUMP Are there any opinions or experiences amongst you? I'm looking to fix this one myself. Many guys have reported doing injector upgrades, so have there been problems like this one? I can't identify any loss of boost, or decreased vacuum @ idle. I've been considering that my correction factor was incorrect, leading to a rich mixture similar to cold-start correction. Going to do a short test by altering the correction slightly. First test I will do is alter idle speed setting in the ECU and see how that impacts things. comments?

Here's a problem I may need opinions on, while I look for a fix. Car: ECR33, runs Apexi PFC and FC Datalogit. High flow turbo, stock manifolding. Injector upgrade to S15 Silvia spec. I installed the injectors yesterday, entered the correction factors via Datalogit and car started straight up, no issues with running that I could tell. Took it for a short run this morning to check for fuel/water/air leaks. All nice and tight that I can tell. Problem came up when I stop and engage clutch. Revs drop down to about 900 (normal), and then come up to a stable 1250-1300. This happens when a/c is OFF. When a/c is ON, revs drop to about 900-950 (stable). I'd considered a few potential causes. Vacuum leak. Inlet manifold has to be split to access injectors, and throttle body removed. Machined faces were all cleaned up spotless prior to reassembly, I used copper spray gasket to further aid sealing, and the manifold bolts were all torqued down in sequence (and a bastard of a job it is too). There is no obvious hissing under vacuum or under boost. The car also responds to a throttle lift, so I think (hope) I can discount air leaks. TPS adjustment. Didn't touch it. Should be operating same as before. Idle adjustment. Didn't touch the throttle body other than use some carby cleaner around the butterfly. Didn't do any electronic adjustments via Datalogit. Should all be operating same as before. ATM, I'm going to have a second look at the inlet manifold bolts for tension, similar for throttle body bolts. Any ideas on where else to look? cheers Dale

I think you have got the difference in characteristics nailed: top end flow, at the expense of low end/mid range. Depending on what you actually want the car to do, that ski jump mid range can make it tiresome, if exciting to drive. I agree, it will be interesting to see the extent of the differences. Bear in mind the first upgrade Interloper was running shared the same spec VG30/R34 housing you want to use. FWIW, I suspect the 56T cartridge is just a little too large for a responsive match to RB25, let alone an RB20. While the RB20/25 spec turbine housing would keep the results biased towards mid range, the larger A/R R34 unit wouldn't allow the assembly to respond quickly. Keen to see your results though. cheers

CAMS affiliated clubs are around here, good to be taking part in events run by your own club. Try also Northern Districts Sporting Car Club there's a list of clubs found on the CAMS web page.

A clear demonstration of the benefits of increasing area under the curve, even if the max figure is not greatly changed in percentage terms. The thing that is prominent to me is the shape of curve difference between 90-120km/h. Gone from concave (ski jump) section, to convex (hump) section. It looks like a big indicator of response, possibly related to the size of the turbine housing (R34 vs HKS)? The full load dyno curve might show the difference in power, but I get the impression that power is only a small portion of the story. Transient response is where it's at for me!! Proof is in the driving no doubt. Looks like it was money well spent. cheers Dale

That's nothing to sneeze at; knocking on the door of 300hp (sounds bigger). I bet it hauls... FWIW, remember absolute numbers mean little in a lot of instances. The shape of the graph indicates plenty. Do you have a graph to add? Maybe post it up on the stickies section. cheers Dale

Likewise, mine are all braided. It was more the routing I was interested in. Fitup shouldn't be any different, given they are pretty much the same engine and style of high flow. Pics would be good, mainly for interest of all. Here is the thread on mine: http://www.skylinesaustralia.com/forums/in...p;#entry2359870 And yes, ATM I'm very pleased with its performance. Lag is not something I would associate with this combination. Starting to get used to the extra grunt, and I'm looking forward to having it tuned to the potential I aimed for. cheers Dale

Looking at it overall, I could/should have considered the .60 A/R comp cover. Not a lot more stuffing around, but I would have had a bit of pipe work to have fabricated. HKS turbine housing would be a handy pick-up but I haven't seen any recently. I feel this cartridge shouldn't upset the flow dynamics of the stock housings too much, due to the incremental impeller dimension changes. The HKS/Garrett housings meant for the cartridge should probably add to overall efficiency, but this setup seems to be working well. Would be great to do a back-to-back, but this upgrade is about as far as finances allow. I run a pyrometer, thermocouple located in the dump pipe. With the stock turbo under high load/rpm I could see temps @ 720 C max. Backing off from a run like that, temps quickly drop back. On cruise it typically ranges between 560 - 640. I also run an inlet charge temp gauge, just prior to throttle body. Like to monitor what is happening there. At the moment I haven't seen any significant change in temps but will see what transpires after a tuning session to lean on it a bit.

Any pics? Your upgrade is very similar to mine, just being used on RB20 instead of RB25. Interested to see much/any different from how I routed my oil/water lines.

I was initially a little disappointed to find that Turbo Australia had fitted an RB20 wastegate actuator, so that I had 10psi of boost straight up. The disappointment was in not knowing just what sort of improvement or change (if any!) would come from changing the CHRA (rotating assembly) within the OE housings. That did not last long, as the difference at stock boost was only going to be academic. Noise has changed a little, much more obvious induction sucking and a bit more of the F1-111 jet engine whistle under load,. The stock blow-off valve may be having a harder time coping with the extra pressure; at full throttle I get a totally different noise on lifting off, or changing gears. The noise I can identify is best described as a quick, single chirp. There is little discernable difference at the rpm when it starts to get boost (ie the gauge will start to rise @ 1600rpm in 3rd or 4th gear in roll-on acceleration). The full 10psi arrives by 2500 if the engine is loaded up, and by 2800 in moderate roll-on driving. There is no obvious power "step" when the turbo starts to work. ie. no firecracker effect. It feels much like a stocker, but just punching quite a bit harder. Running through a couple of my favourite bends it's just smooth response, hard acceleration, and linear power build. Oversteer on exiting tight corners is easy - dial about 2500rpm and squeeze the throttle in 2nd. Running off large roundabouts at the same low-middle rpm in 3rd or 4th gear is satisfying as it just drives smooth and hard – the feeling is like it has gained a litre of engine capacity. Higher in the rpm range it builds linearly and probably still plateaus around 62-6300. I say “probably” because it is now building speed quick enough beyond 5000rpm that you are watching the road more than analysing power delivery. This will change as I get used to the extra amount of stick it has. On a highway run, the feeling is that the turbo makes the car respond to load on hills by accelerating – but staying under the boost threshold. It is an odd sensation to feather the throttle to avoid picking up 10km/h going up a hill. This is different response from standard, which I attribute to the comparatively aggressive upgrade from stock in turbine spec. Overall, the match is meeting my expectations. The existing tune is very rich, and logging a few runs is not showing any knock issues. I'm satisfied there is no risk of engine damage running the current maps. Can't wait for my dyno session next week to get the final tune and boost setting sorted.

These were my modification parameters, documented to keep focus on the whole objective: Power capped through boost and engine rpm limits. Conservative fuel and spark strategies. Partial throttle response and minimum lag is the means to maximising chassis balance + response, driveability, and vehicle speed over all conditions. Boost response, and overall engine response should be smooth and without a discernable torque “step” or cut-in point. Monster top end power to be rejected in favour of smooth, linear, lag free delivery. Engine power increase to be achieved primarily through improved compressor and turbine efficiency without introducing undue restriction (inlet pressure) in the turbine. Standard gearing is being retained, so the speed range of the engine cannot vary significantly from stock. To remove all doubt about the best fitment to meet my requirements, a post-mortem was conducted of OEM turbos fitted to both RB20 and RB25, specifically to check the measurements and impeller trims used by Nissan. Using a set of vernier calipers, the outcome was somewhat surprising, and confirmed that the GT2871R was going to form the basis of my upgrade. Some basic calculations following Garrett’s literature, and plotting them on published maps also helped give a feel for what would work. This process was useful for estimation only, since the OEM housings were to be used with a Garrett cartridge. Note the wider cross-section on RB25 housing gives a larger A/R. Comparison of the available cartridges showed the 48T version CHRA 446179-31 likely to best meet my objective. Plots @ 320, 340, 360 hp (@crank) show maximum compressor efficiency is being hit right in the mid-range, only running out of puff (ie hitting choke zone) @ 360hp. Plots run equally either side of the median line, suggesting high overall levels of efficiency and hopefully minimal drive requirements for low-lag. Conclusion: Highest realistic output for this upgrade probably 350hp @ 15psi. Very comfortable @ 340-350hp. The comparatively high shaft speeds (vs the larger 52-56 trim sizes) for given outputs means this unit would be a little out of depth for a dedicated track car. Should be very nice match on a mild road-focused engine. Don't know if everyone goes into the detail like this, but it helped me to understand what the upgrade was going to produce, and choose a unit that meets my target. Bit more to come on initial driving impressions. cheers Dale

Actually, it is only marginally larger than stock. Have more pics and commentary on selection of this particular unit. Out of time, more tomorrow.

I acquired a Hi Flow upgrade based on 48T GT2871R, using stock RB25 housings. Selection was based on fairly honest appraisal of usage and needs: daily driven to work + runabout. 70% some sporting driving on-road 25% some motorsport events. circuit sprints, motorkhana, touring road events. anything where risk of run-off damage is low. 5%. Low rpm boost threshold; big-engine style response between 2000 – 4500rpm, also looking for strong power up to 6000rpm Decided to fit it myself, sharing the experience with the SAU community. The process of fitting is fairly straightforward, but time consuming given the relatively tight space constraints about the engine bay of an R33 Skyline. I would recommend the job be undertaken only if you have a reasonable mechanical knowledge, patience and methodical approach to work, access to a range of tools, ramps, stands (or a hoist) and a dry, lockable working area. Do not expect the job to be completed in a single day if you are a home-mechanic and want to double check each stage of your work. Two very full days should be set aside. The Garrett-style high flow is NOT a straight bolt-up fitment and did take some extra effort to get it finished and running. The oil feed required a nipple fitted to the turbocharger core, to take an elbow fitting for the pressure line. The more compact dimensions of the Garrett core compared with the Hitachi OE core effectively closed the clearance between the turbine housing and the oil fitting. The nipple was screwed in as firmly as clearances for spanners would allow, leaving me to hope my work was good enough and the tapered thread was going to seal effectively. Tight clearances about the turbine housing gave a bit of grief when doing up one of the four manifold flange nuts. Not impossible, but best approached by placing the spanner on from between the engine block and manifold. Remember to reinstall the locking tabs and fold them up hard against the nuts. The oil dump tube was not satisfactory, and required modification. The Garrett core is drilled/tapped for 6mm retaining bolts, but the supplied fitting was drilled undersize – should not have been an issue. The big one was that the angle and length of the tube did not lend itself to satisfactory hook-up with the return-to-sump nipple. The tube was sweated off the flange, a new length of tube with suitable bends and orientation was cut/bent and TIG welded in place. Good if you have access to friends in trade-work, but a problem if not. The changes in overall dimensions meant the OEM heat shielding over the turbo no longer fitted satisfactorily. Mounting bolt holes did not align properly, and I did not believe the shield design lent itself to simple redrilling. On top of that, it needed a hole cut in it to allow the oil feed line to pass through. Assistance from MR Sheetmetal saw a new one fabricated and fitted. Advice from Turbo Australia was to fit an oil supply hose with 4mm ID. Nissan engineers heavily restricted the volume of oil supply to the turbo by using a 1mm orifice in the banjo bolt and banjo fitting at the engine block. Failure to integrate a restriction would lead to problems with oil sealing in the turbo at the minimum, and possibly an issue with oil pressure in the engine. Given a parallel (ie. non-tapered) metric thread in the engine block, it was decided to integrate the OEM fitting into the feed line than to source a suitable fitting and restriction. This will be an area to monitor for vibration cracking, even though the length of steel piping used is quite short. Water lines were a much lesser challenge, though the steel line running behind the block towards the inlet manifold was dealt with by cutting and attaching a fitting that the braided line could be screwed into. It also needed a little bending to get suitable clearance of the braided line from the turbine dump pipe. The other water line attached to the side of the engine block with banjo fittings. Overall, special care was needed with the “set” of all fluid connections, and also to ensure there was no contact with other metal components that would result in hose failure due to abrasion. This needs an eye for detail, and an attitude of “fix it properly, once”. The OEM metal gaskets are by far the best quality when compared with what Garrett can supply. Get new ones if you are worried about the integrity of the used ones, or else buy a can of copper spray gasket material. This will fill any small pores in the surface and give a better seal when reusing the originals. It is cost effective too. Priming the turbo with oil prior to the first start-up is strongly advised. To do this, disconnect the igniter, and disable the fuel pump by removing the fuse (found in the boot compartment beside the battery). This ensures the engine will not fire when cranking, and nor will the exhaust system be loaded with raw fuel vapours that can damage the catalytic converter. I cranked the engine for 15 second intervals, 6 times and deemed that satisfactory. I have heard of another approach whereby the oil drain hose is left open while an assistant cranks the engine. Once oil runs from the drain hose, reinstall and clean up the mess before starting the engine. Overall, would I do the job again? Yes. It was challenging first time around, but another would be comparatively much less difficult. Hope the pics give a bit of an idea to anyone else wanting to have a go. I will give comment later about how this particular hi-flow runs on the road. cheers Dale

The 48T would be a better match for sure. It is actually very responsive on a RB25, and the power available from it is adequate for most uses. It's a case of area under the curve, or that "average power" concept. The issue with the 56T is not so much the ability of the turbine to flow, but to drive into boost. The extra blade area on the larger trim just needs a bit more to get going. As Rob32T indicated, it's not lacking for grunt once into boost, but the rpm where it starts to come together is a little higher than I would find desirable. It may suit his needs, however.