Dale FZ1

Toyota aren't the only Japanese manufacturer of a well engineered V8. Soarer reminds me of an old Jag - big on the outside, small on the inside. Goes well in a gentlemen's express kind of way. Not for me, but good to see someone having a play with them.

Install looked tidy. Power number was very good if it was running something like a GT35 (I read 363kW) and should move that lardy Soarer pretty well when the revs are up. If it was one of those T88 units, at that power level it's seriously under employed. I don't know if it was the scaling of the dyno graph, but it looked to have a fairly late/steep rise in the torque curve which then did not hold for long before it ran out of rpm. I wonder how stock the internals are, and how much $$ was required for the external bolt ons? There should be a reasonable supply of off the shelf speed gear available ex-US.

Sorry, mine did hit R&R with exactly the same mods as Peter described, and running stock boost. There was absolutely no doubt that I had hit it either. And it is a Series 1 R33 also... As an aside, the coils in a vehicle that age would be getting a tad tired.

Hi Peter you are most likely experiencing the rich/retard syndrome. It is a failsafe threshold in the factory ECU, designed to not let you exceed a certain power limit. Search "rich + retard" and you'll come up with plenty of reading on the topic. By installing the less restrictive FMIC and pod, you are effectively allowing the engine to swallow a larger MASS of air at the same boost pressure. Then when you increased the boost, well it is just trying to exceed that boundary by a larger amount. The ECU responds as it is programmed to do, and your car stutters and stammers as described. There are ways around it, either by fooling the factory ECU (use a piggyback interceptor), or using a different ECU. With the mods you are running, there is no sound reason to be running smaller plug gaps IMO. cheers

Come on, don't be shy... Actually I'm just interested in how you've gone about doing the inlet trunking, and any heat shielding. I'd say with certainty it's in the tune. And going by own experiences and the above comments, would it be reasonable to suggest this happens at relatively low rpm and WOT? I struck this situation with mine on a test hill known to Mafia. Basically hit the hill around 2000rpm in 4th gear, steady throttle, and feed the throttle heavily into it. The hill is about 500 metres long and top rpm is about 4500. In that 2000-3000 bracket, the engine is loaded much heavier than can be achieved on a dyno. Basically you access cells in the map not normally hit, and if the ignition is too far advanced, it will knock. What makes it more noticeable is that the steepness of the hill keeps the engine operating within those cells for seconds at a time, rather than just flashing straight past them. On more level ground, the rpm picks up too fast for that load area to count for anything significant. Mine was sorted with adjustments to about 5 cells in total.

I've seen some epoxy-type filler that might work, but sounds like you really need someone to look at it in-situ, and then on the bench. Was there any signs of weakness or porosity, or did anyone look at it with/for you prior to installation?

It's not only wind resistance, but the terrain being travelled too. Loading an engine up a long, long climb is way different to what can be achieved on a dyno. Any tuner worth their salt would (should) be running Datalogit, with wide band input. Really takes the guess work out of things. At that power level, your fuel system shouldn't be under strain, but why run with a non-standard FPR? Provided the fuel delivery and mapping is working as needed, it should be a matter of tweaking the ignition map. Off thread, but can you post up some pics of your engine bay?

The Chinese copies (or mine at least) are finished poorly when it comes to matching. I made quite a few adjustments with die grinder to both the runners and water passages. The end result was worth it.

Marvellous how sometimes you can answer your own questions. Did a dummy fit on each manifold. No problem - they are both recessed in much the same manner. The OE manifold probably moreso. I was just concerned that the fuel spray pattern might be affected by way they were recessed. So it's all good.

Does anyone have a pic of their rail/injectors bolted in place before installation? I'm looking for a view of how the nozzles sit when viewed backwards from the inlet valves. Mine seem to be recessed quite a long way into the bore and don't know if it is right. The original manifold has them pretty well flush with the surface of that shrouded area they discharge into. If there's confusion about what I'm asking I will get some pics posted up.

I'd be interested to see the write up and get an idea of what's involved. Specs sheets from ACL shows the VG30DE has a 87mm bore (+1mm on the RB), and different gudgeon height and diameter. That engine spec shows a 10.5:1 compression. Looking at the 25DE piston, it appears that it achieves the lift from 9:1 (of the 25DET) to 10:1 compression by an extra couple of mm on the height of the crown, gauging by the valve relief cut outs that the 25DET forgies typically don't seem to have. Perhaps someone with pics of the different pistons can post some up. I will get one of the 25DE to start it.

I didn't expect to find forged slugs available, but felt there may have been a market for cast replacement 25DE. Nissan do them, available ex Japan. Going rate seems around $110. Anybody else with experience here who can tip in their knowledge please? I've seen the general design used by BMW in the S50 I6 engine they used, and wondered if the piston design matches that of the RB. Combustion chamber and bore size is essentially the same - a German Nissan??

I'm the bloke with the 48T 2871 hybrid. It runs in R33 spec housings, and runs pretty well. No, it probably won't go past 230rwkW. Yes, it is quite responsive. Yes, I would recommend it to anyone who wants a mild upgrade. No, I wouldn't recommend that hybrid to be run with the OP6 housing. There are other cartridges better suited to the use of that housing - see paragraph 3. The T25 flanged Garrett 2871 could probably be fitted with a flange adapter plate, but I'd find it difficult to understand why you'd go that way. Wolverine is right, and he has good experience with the HKS GT-RS. Bolt up, and good to go. Worth the money, and you'll find not a great deal of difference in price between the HKS kit, and the Garrett turbo with all the fittings and lines you'll need to make it work. The HKS 2835 Pro S and a hybrid version of the 3071 with OP6 copy turbine housing available from GCG and HP InaBox are broadly similar in specification, and in characteristic of operation too, I would say. Both will be slightly tamer delivery under 3500rpm, and hold torque longer as the rpm goes over 6000, so more power. Each turbo above will require the same supporting mods, though I have got away with a stock AFM. Cost differential across those turbos is not great, though the 2835 Pro S would weigh in heaviest $$ wise. I would not expect a 270kW turbo to respond down low like a 230kW one, and I would not expect the 230kW to have the freer breathing delivery of the 270kW. Hope that helps, and best of luck. Update this thread with your eventual selection, and opinion of its operation. cheers

I've got to replace a piston that's seen contact with a foreign body (screw) that was dropped into the combustion chamber. It seems that genuine Nissan is the only option. I don't want/need the forged low(er) 9:1 and 8.5:1 compression items offered for the 25DET. A lengthy search of the SAU forum hasn't come up with any other information. Do any of you guys who've actually replaced pistons have ideas and/or sources for the 10:1 DE spec items?

"Everybody else" still seems to be Birnie and myself. I haven't changed any of the corrections, and it's still running just fine. In the absence of information from any of the experts regarding what latency or lag time actually is, it seems that it is not a critical figure. The correction for flow rates, is.

Could be worn rings or valve stem seals. Get it to a reputable workshop for some kind of diagnosis.

I'd say there are two important factors in achieving the fuel range Paul is getting: 1. engine output. I think he is running under 200rwkW. "Normal" driving even with change ups under 4000rpm and not running big throttle settings will probably put through less mass air flow, requiring less fuel usage. That difference would be marked against your powerhouse. If Paul put up a chart showing AFM voltage output vs rpm for a typical city run it would show some good info. 2. whether the 460km is "with" city driving, or "predominantly" city driving. I can pull that sort of range with a little (lot) of luck, but have to be right out of the throttle. There is some interpretation in describing the use there. My fuel logs have been maintained meticulously over 30000km, and have an arithmetic average of 7.9km/l over that distance. So 400-410km per tank is the norm, with a fill being 50 litres plus/minus 2 litres.

That is some pretty serious monitoring equipment you have there Ronni. It looks like you have a range of skills that will see you get the optimum out of that RB If you are into data acquisition, could I suggest looking at pressure within the exhaust manifold (ie. backpressure), and exhaust temps pre-turbine. Temperature drop across the turbine is an area of interest, and backpressure has been a topic of discussion over some time. If you have the gear and time to work on those two, you'd be streets ahead of most of us. cheers

So does this second ECU control only fuel, or fuel + ignition? I'd have thought that while you can get optimal fuel mapping, to get the best from a fuel that has extra anti-knock properties and aids in charge cooling, the ignition map would be advanced quite a bit further? I find this interesting, would like to hear more.

There's been talk on and off about running LPG in a Skyline but you're the first bloke I've seen who's done it. The results look quite good. Congratulations Couple of things I have to ask- running stock turbo and boost? the AFR settings on petrol and LPG look no different. I'd have thought you would need different fueling strategies to get the best from gas? why not ditch the petrol system and run dedicated gas? cheers

I'm after a 25DET bottom end, basically the leftovers from somebody's conversion to a 3 litre bottom end. A serviceable block and crank will do fine for a freshen up rebuild. Can pick up from Gympie to Brisbane if you have a bottom end gathering dust after chasing cubes .

Did you have them do the job, or bought off someone who did? Do you have any detailed pics of the unit prior to installation that might show the ID tag, or are you able to read them in-situ? It'd be interesting to know what spec you have. A fairly common MTQ high flow for RB seems to be the BB GT2876 cartridge into stock housings. Despite some commentary about that spec being laggy, I know of a couple of people who ran it using OP6 housing and were very happy with the response and output (on an RB25 though). I'm with the idea of getting the tune sorted. Provided the fueling is reasonable, get some ignition timing into it and watch things spark up.

I believe dangerman4 may have some words based on good experiences with the 6boost.

Yes, all true. The manifold and turbo is all heat shielded. The big silver box in my pic is a sealed pod enclosure with silver faced neoprene for insulation, and a direct external air feed. I couldn't afford/justify the down time or expense of removing and sending the manifold or turbine + dump for HPC coating. It was as far as I was prepared to go, but I proved to myself the value of the changes through the inlet temp probe.

Yeah, it does look a bit like wrapped garlic bread HPC probably was a bit over the top but I decided to give it the best chance of success. Then the cast alloy pipe is affected by heat radiating from the manifold and top of the engine. Correct to some extent. It's also about the mass flow through the inlet tract, with a reasonable velocity preventing the heat penetrating and affecting the air within. I'd have to dig out some old notes I made while testing, but basically I was achieving Summertime inlet temps of 80+ degrees in stop/start traffic, idling at lights etc. With the piping setup as pictured, it came down to ~ 60 degrees at an ambient 35-38 degrees. Clearing the traffic light runs, with about 3km of constant running ~ 80km/h and a bit of throttle, it would come down to somewhere around 50 degrees or slightly under. I ran some temp probes at different points under the bonnet, and on hot days the heat buildup under bonnet is significant. Those 270 degree pipe bends aren't a bad idea but you'll still get radiated heat affecting the air within them too. I take it that the reflective stick on stuff is the tape you're looking at in my photo? It is basically a heavy grade alfoil with sticky back. Good, but I wouldn't use it by itself as a long term solution. The Greddy style manifold may offer significant improvement over stock RB25 if trying to reduce heat soak. out of info, but that's my experience and opinion. cheers Dale