Dale FZ1

These two little articles put things in perspective regarding Danish petrol. http://www.mex.dk/uk/vis_nyhed_uk.asp?id=5...yhedsbrev_id=74 http://www.rec.org/REC/Publications/LeadOut/chapter61.html I’m not sure if we still get MTBE in Australian produced fuels. It seems that the stuff was to be severely limited by pressuring the fuel companies. There was evidence of it being present 4-5 years ago thanks to Woolworths penetrating the fuel market http://www.waterquality.crc.org.au/hsarch/HS23a.htm http://www.abc.net.au/science/news/stories/s715002.htm http://www.smh.com.au/articles/2002/07/10/1026185062263.html A bit more quick research shows that the Danes use the same standard of octane measurement (RON) as we do. And if 98 is not readily available, then I’d be doing what it takes to eliminate knock that you’d come up against with 95RON and the sort of tune required to deliver the power he’s already got. Water injection sounds good to me. FWIW, best results should be had by integrating WI into the tuning strategy, rather than as an add-on. If you are prepared to give it a go, best results would come from running full load AFR up near 13:1 and give it the ignition timing that it will take. But it will require a properly engineered system to get the results.

Not a brilliant pic, but gives an idea of my efforts. Running an inlet temp probe just prior to the throttle, I found inlet temps skyrocketed with slow speed, low load, stop start driving. The exit air temp from the radiator is 80 degrees +, and heat transfer through those alloy pipes is very rapid. Basically you'd have to expect degraded engine performance and an increased tendency to knock with higher inlet temps. I changed to a custom fabricated steel pipe, HPC coated, then used a ceramic wool and covered with sticky backed refrigeration tape. Result was much reduced heat soak effect IN THOSE CONDITIONS nominated. Running at higher speeds (80km/h and above) + loads the differential effect was much less pronounced. Not an indicator of anything other than the higher mass flow of air being less affected by the radiator discharge in those conditions.

There was no indicator of the standard of measurement. Could be RON, MON, or (RON+MON)/2. Indicators are that he is still working on the tune, and the fuel may not be the limiting factor that you think. It may be that the only requirement to making more grunt is give it more timing. Let's see what he comes back with.

Rough guess, I'd say the ignition curve could be cranked up (advanced) in that area - dependent on knock. It looks like your results are similar to The Mafia and Lithium who also run GT3076 on RB25, though I'd like to compare the shape of the curves. Given your AFR might be a little rich, you might find a good bit of extra power there for the taking with extra time tuning. What sort of ECU did you choose? Did you go with internal gate, or external? I take it that the top graph is boost, in bar (absolute)? The line from 4000rpm is a bit up/down. Maybe your boost controller needs a little adjustment to smooth that out too?

It does look very tidy overall. Good effort, and I'm especially interested in the work done to control/contain heat. I'd think the cable ties are very temporary, and we'd see either tie wire or a clamp of some description take its place before installation. Looks like you're going to be aiming for some fairly serious output there Dave; no longer a daily drive proposition? What are you doing with management systems?

That'd have to be at least partly due to the difference in mass between an R33 and R31 chassis though? Weight counts for a lot. That said, having a little less power spread over a wide range - rather than concentrated over a narrow range will make for a better thing all round. Matter of interest type question: what sort of useable rpm range does the 26 with GT-SS work over? While the 26 is definitely spec'd overall better than a 25, depending on the power level I think there's a good argument for having something with VVT. Not flaming something up, just commenting that the 25 isn't a dog by any means. The 26 though, is a better base platform.

Locally delivered - Falcon

After a while, it becomes clearer that minor changes in spec will deliver relatively minor changes in characteristics. Relative being the operative word. Basically if you have a 48, 52 or 56T version of the 2871 cartridge, you will end up with higher potential power capacity from successively larger trim, within limitations of the housings they are slotted into. More power potential across that range will give slightly slower response. Not much, and for some probably not enough to worry about, and for some barely enough to notice. The 56T would be my third choice, but not something to avoid by a long stretch. It is quite possible to use very different specifications in turbos intended for the same application, and get very similar results. Case in point from people who've experienced it. FWIW, both impeller size and number of blades on the rotors is nothing like similar when you have a look at a GCG unit vs. the Garrett 2871 and a HKS 2535. But the end result isn't vastly different. Yep, a good choice. The newer 2530 KAI with its ported shroud compressor housing has a bit of bling (and extra noise) associated with it, and the response above idle should be close to immediate. Definitely give the car a big-engined feel, and probably run out of puff (read: power tapering) above 5500rpm or so (my guess). Something to remember is that you are dealing with a turbocharger. It is a speed machine that needs to be accelerated up to certain rpm before it will effectively pump extra air into the engine and develop more power. If you stomp on the throttle from idle, EVERY turbo that is reasonably matched to the engine will still take SOME time to get up to speed. Try squeezing the throttle, and remember that until the turbo is up to speed that you have effectively a 2.5 litre N/A engine. After that, it's all honey. And FWIW, all of the units being nominated have a ball bearing core, so it's not a ball vs plain bearing issue. Internal specification can (does) play a part, but so too does stuff like suitable boost control and setup (including preload) of the wastegate. The beauty of an auto is that with a torque converter and rpm flare you should be able to get away with a slightly larger turbocharger and still get quite good engine response. If you needed any convincing there, drop a PM to dangerman4 or search for his threads. Availability of a 2535 might be something of an issue, and FWIW, that 48T version of 2871 hybrid like mine also has only slightly different transient response than stock. Barely enough to notice, but I do know it's different from stock if I'm driving under 2000rpm. Once on-boost when the car has more power everywhere, and you have to ask when/where/how often you'd deliberately run around under 2 grand. With an auto, not very often I'd say. Not a lot more I can add. Basically there are some good options out there, with a few very similar in driving characteristics. Provided you've got proper boost control and suitable tuning there should be little cause for complaint. Price/availability and stock appearance might be some of the more pressing issues to resolve. cheers

Minor correction. GT-RS has a 52 trim compressor, mid-size in the 71mm compressor range. For my hybrid, the only two options when purchasing a bare cartridge to slot between the housings was 48T and 56T. I went with the smallest size.

Check here: http://www.skylinesaustralia.com/forums/Gt...l&hl=gt2871 This spec is under-rated, mainly because it doesn't aim for huge power. But it achieved 225rwkW for me with ease, and remains a very driveable road-spec turbo. Running a turbotech bleed, it peaks at 14psi delivered @ 2800rpm and tapers to ~ 12.5psi @ 6000. That's probably due to the simple boost control method, and I'd say it would deliver another 5-10kW with an EBC. I don't think it would do as well with an R34/Stagea spec OP6 turbine housing, as it would take longer to wake up and respond down low. If you've run a GT3071 hybrid, then all the water and oil fittings would be a straight fit onto this GT28 core. Just another option but for bolt-on ease, the GT-RS is a hard thing to beat. Wolverine is running one on his Stagea from memory, and prior to that had a GCG high flow - so try a PM to him for comment/advice.

Dave have a look at the diagram below, sourced from http://www.turbobygarrett.com/turbobygarre...bo_tech102.html You can see that the A/R is a mathematical representation of the physical layout of the snail. It's the relationship between the size of the air passage within the volute, and how open the scroll is. Usually unless you are comparing two housings from the same family, it's not a legitimate comparison because the A/R is a ratio only, not a measure of absolute size. The Garrett info suggests that for a compressor, A/R size does not significantly affect compressor performance, though a larger A/R housing may be specified to optimise a low boost application, while a smaller A/R may be used to optimise higher boost applications. Note that the rider is for housings from the same family. I'll take a stab and suggest that you will see some subtle differences in characteristics between your setup and (for example) Lithium's with his 0.60 A/R. The 0.70 housing is physically larger, and I'd say will take a little more turbine effort (and time) to give you full boost. The freer flowing housing should remain efficient at the higher end of your RPM scale, and may give a few more hp (not many though) because the air isn't being forced through so tight a radius within the scroll. So in summary, take away a couple hp + response down lower, pick up a few higher up. Not a massive difference, but back to back you'd probably pick it without resorting to dyno sheets. My opinion only.

Concrete?? Try an event on dirt/grass. Either way, be prepared for a Skyline to be bigger than optimum, overpowered and unable to put power down compared to some machines out there. But be prepared for it to be a ton of fun. Besides car preparation, speak with club officials who run the event. If it's a CAMS sanctioned event you will need the appropriate licensing too.

Simon you may find that the EBC can now go about its job of allowing boost to ramp earlier, so sounds like the efforts have paid off to a degree. The right sort of preload would probably help further. It would be nice to get it perfect, but Trent has obviously seen some issues with various combinations. Have you called GCG or HPinabox to check if there are similar experiences with your spec 3071, and if so what is the fix (if any)? I guess if you can get it to the point that it is "satisfactory" then all ok - go and DRIVE it Just to clarify Phil, I wasn't actually concentrating on nutting out the issue your GT-RS has. My comments were directed solely to Simon's setup, and no, I have no opinion as to the cause of your overboosting. I hope you can get it right. Suggestion: If you believe your timing is retarded, then assuming you have a programmable ECU why not try progressively advancing the thing to see what happens? I can confirm that retarded timing DOES result in elevated exhaust temps. While tuning my PFC, I had the whole map retarded by about 6-7 degrees due to the position of the CAS. Pyrometer read +150 degrees C on cruise, and the car ran like a dog. Would not pull. Believe me, if you have retarded ignition you will know about it.

This is something I agree with - double check the spec of your actuator. Secondly, while the pics of your turbine housing show the wastegate arm moved through a big arc, have you checked to see how widely a wastegate normally opens? Basically it moves enough to unseat the valve, and then enough to vent excess gas. Probably 8-10mm or so, but no more from the observations I've made. Which makes me ask - how/where is the actuator mounted on the turbo? Main point of interest here is the angle that the actuator rod has to work on. If it is a dicky angle, then the actuator might push to its maximum extent but not really enough to vent the main turbine flow and control boost effectively. I did read your comment about disconnecting the wastegate and getting 17psi, but you're getting 20psi. A revision of the actuator mounting bracket and actuator rod position might be in order? If it gets a fairly straight push onto the bell crank then you're getting the valve moved through the maximum available travel. Hope that makes sense.

Being a carb'd engine, I'm presuming it is the TRX850 or an earlier TDM900? Good fun machines both, in the right environment. The wear on those cam journals is a bit of an issue I think. What condition are the mains and big ends in? What sort of mileage and service schedule on the engine? And what was the reason for the pull-down? The different colour of exhaust valve deposits indicates a difference in mixtures (to my eyes anyway). It might be worth checking to see if Yamaha plated the bores with Nicasil in those things too.

Post copied across from linked thread: http://www.skylinesaustralia.com/forums/Re...20&start=20 Looking at the graph, it seems to me that boost isn't "spiking" as much as taking a leisurely ramp up to 20psi where it's holding steady over a fairly wide band at higher rpm. The initial knee is pretty much the same shape as a stocker, which points to good/easy/quick response. That it is holding so steady at 20psi (once it gets there) makes me think it's not necessarily "creeping" either - if there was a problem with adequate venting of waste gases then you'd be more likely to see it steadily running higher and higher. It makes me think that the control of turbine speed at that level is actually quite effective. All of which leads me to ask: what is the actuator rated at; and what (if any) additional system are you using ie. turbotech pneumatic bleed, EBC, etc? Maybe there's some change necessary in that area? Like BHDave said - sort out that mid range area and it'd be hard to knock. BTW, top result - the peak number is about 15 - 20kW higher than I'd have expected one of these units to achieve. I'd had comments from GCG that your specs should yield somewhere near 280ish, but I wasn't convinced it could. Thanks for sharing the results. Now all I want to see is how Gary Dawson gets on with his, and for you to sort out that boost control with further feedback of on-road and on-track experiences. Looking here, I can see sense in checking over that wastegate valve, if it's not correctly located then that could be causing an issue. Adding a bit of extra weld on that disc:shaft union could be worthwhile. But the thing that is jumping out at me is to ask WHY is the preload backed off so severely? If that valve is not seated correctly (read: very firm), then you are getting too much leakage at lower turbine speeds. To me that seems to be the reason why your mid range is climbing lazily - the wastegate is wasting earlier than desired. Can you explain why the preload was backed off, and what your boost target actually is? That might put us better in the picture. cheers

Looking at the graph, it seems to me that boost isn't "spiking" as much as taking a leisurely ramp up to 20psi where it's holding steady over a fairly wide band at higher rpm. The initial knee is pretty much the same shape as a stocker, which points to good/easy/quick response. That it is holding so steady at 20psi (once it gets there) makes me think it's not necessarily "creeping" either - if there was a problem with adequate venting of waste gases then you'd be more likely to see it steadily running higher and higher. It makes me think that the control of turbine speed at that level is actually quite effective. All of which leads me to ask: what is the actuator rated at; and what (if any) additional system are you using ie. turbotech pneumatic bleed, EBC, etc? Maybe there's some change necessary in that area? Like BHDave said - sort out that mid range area and it'd be hard to knock. BTW, top result - the peak number is about 15 - 20kW higher than I'd have expected one of these units to achieve. I'd had comments from GCG that your specs should yield somewhere near 280ish, but I wasn't convinced it could. Thanks for sharing the results. Now all I want to see is how Gary Dawson gets on with his, and for you to sort out that boost control with further feedback of on-road and on-track experiences. cheers

Looking good. I noticed the boost @ 1.2bar tapered off after peak torque, and then had a bit of a rise at the end. Might be calibration of your controller? Also the scale on your plots indicates crank hp. Given your spec, I'd think that power delivered should be at the wheels. The 0.8 bar plot @ 367hp has a very nice, smooth shape - I like it. Should be very driveable and I notice that the high rpm torque does not drop off. There's the turbine efficiency working for you, not choking the engine. Very nice overall, and give us a drive report once you've done a few miles. cheers

My understanding is that the casting is a copy of the OP6 housing. And that was from the source. A photo of the dump flange area including the wastegate should assist. Either way, you won't have a dog. Interested to see how it goes.

Does it look something like this? If so then that's quite normal. Two rows of blades, one higher and larger than the second set. If you had a two stage compressor, with two completely separate rotors then it would indeed be something special. Keep us posted, and show a pic or two. cheers

Do you have the housing? If so good find. Everything I see in the Garrett master sheet with the cropped 56.5mm version of a 3071 ~ 2835 is shown with a 56T compressor. Not to say they don't do a 48 or 52T but you might have more luck finding rocking horse sh_t. As a side issue, you know my 48T 2871 hybrid makes 300 rwhp. Garrett rate the real thing ~ 380 odd hp, and working on Sydneykid's drivetrain loss of approximately 80hp it's within spitting distance of getting there. So basically those OEM housings haven't really held it back. If for some reason you spec'd a 48T version then there might be no net gain. I would concede the potential extra efficiency of a HKS housing might make the engine breathe easier up top, but there's not a lot of extra to be had. I acquired an OP6 housing (A/R ~ 0.7x) to try the theory, but it's currently sitting untouched in the shed. After a few calculations I concluded that I would have needed the extra capacity of a 52T or 56T to make the whole effort worthwhile. And then I'd have a whole new hybrid. Hopefully someone can confirm or reject whether you could get an off the shelf cartridge, or have to get a custom one built up. Off-track, but I'd hoped you'd go down the route of the split pulse. At least it would put a certainty to all the discussion in that area. cheers

Great find, if it is what you suspect. Is it a GCG type, or a Garrett core into stock housings, or something else? What power it will support is dependent on the exact specification of its internals. Once you know that, there is heaps of information to be found in the stickies.

Whether it's applied internally or externally, I don't think it matters. They both should result in a reduction of transfer of heat from/through the item being coated. For the difficulty (and extra cost they may want to charge) of applying the internal coating, I can't think of a reason why I would do anything other than external application for the items mentioned.

Yes, that CHRA number = 56T GT2871 cartridge. With the larger (compared to 48T version) inducer size on the compressor, it should provide a responsive 240kW (maybe a bit more) on an RB25. Compared to the 48T version, it won't offer quite the same transient response (ie very close to stock-feel) but pretty good. Any idea why your mate pulled it off the RB20, and/or what it drove like with that turbo fitted?

You could get the turbine housing HPC coated. Depending on finances, look at doing the manifold and dump pipe(s) too. Not cheap but it is good stuff. ACL do some funky looking sheeting that can be shaped into a good heat shield. Same stuff used in the Ford XR6T, and it is not terribly expensive. Done right it will look something like a factory job, though it might depend on how much bling you want from exposed bits n pieces.