Dale FZ1

If they're running less than 11:1 I see it as a bandaid attempt to address exhaust temps. The fuel is acting as a cooling medium - for anyone who watched the F1 cars of the turbo era, on qualifying trim they would blow plumes of black smoke, bit like when you watch a jet plane on takeoff. Same approach just to try and avoid a mechanical failure. But you're then putting so much fuel into the cylinder that it HAS to be super advanced just to try and burn the fuel load. I've seen a car on the dyno just ramping up to full load with 10.5:1 AFR and the engine was just hesitating like all get-out. With conventional ignition map the poor thing just wouldn't run right. The other issue would be a tendency to wash down the bores and promote rapid/excessive wear. If they have money to burn for pull-downs and its all about that last tenth on the track I can understand but not otherwise.

Looking good. I'd like to see the boost and AFR overlays. What sort of muffler setup did you have fitted? And how is the noise level? Just had a 3.5 inch system fitted to my R33, not droney or anti social so pretty good for every day use. Hurricane mufflers.

Don't know about an N1 pump, I used stock. The shims in that setup offers a slight increase in pressure. The RB25 block has 3 feeds - rear, middle, and front. The front does the VCT. I used the 1.6mm restrictors in the rear and middle. I wouldn't go any smaller than that when using hydraulic lifters or else face bleed out problems and noisy lifters at idle and when cold.

Insert a grub screw into the VCT feed in the top of the cylinder block. Eliminate the VCT solenoid in the head, and use a bung. Tape the solenoid connector out of the way on the main harness. Run 1.6mm restrictors in the front and middle oil feeds, and install 2mm shim (2 washers will do) under your oil pump relief spring. Forget the extra external drain, and drill out the internal drains in the head and block. Worked for me with doing a 30DET build using fixed cams.

System in good nick, complete with silencer. Stainless steel, sounds good. 1 minor rash mark. Should also suit R32. Pickup preferred. Reason for Sale: changing system Price: $250 Contact: via PM Location: Sunshine Coast

Both appropriate responses so far, but specs are still a bit sketchy including perhaps an overlay of before/after. With that turbo (unknown turbine A/R?), and those cams (exact spec not really known?), and comments over the years from Roy about his RB20 exploits, you'd have to be thinking it wouldn't peak - with proper setup on everything - until somewhere well over 8000rpm. So besides seting cam timing, how fast was the engine spun during tuning? I recall a couple of lads fitting a GT3582 sourced off an XR6T, onto a stock RB20. Pulled maximum power around 9000rpm, but I have no idea how long it ran like that...

Agreed. And that has been the thrust of comments - get the setup right, and THEN tune to suit what he is running. Not likely. The GT30 0.63 IW combination is restrictive at higher mass-flow rates. If you had the opportunity to sit one beside a 0.82 or 1.06 A/R housing from the same family it's easy to see why. To have a realistic chance of hitting 300kW with a reliable tune would likely require either E85 or WI.

Put a GT3071 and GT3082 both with the same turbine housing side by side on a bench. Doesn't matter if it's 0.63, 0.82 or 1.06. Turbine specs will be identical. Airflow capability through the turbine will be identical. Getting a visual makes it easy to understand that using the same rotor, housing, and wastegate configuration/size will result in the same total flow capacity. My earlier comments about the Mafia related to how he got the best from that turbine spec, achieved very stout results but needed WI as insurance against knock. Provided Bond can check/rectify issues with any exhaust restriction or whatever other problems exist, he should be able to make strong torque through the range by tuning that capitalises on the characteristics of E85. In my view that is done by using lots more igition timing than is used for tuning with only pump petrol (no WI) But I agree there is something wrong.

Agreed. As I suggested, there is at least a couple of things requiring a check over to diagnose what's going on. I wonder what his tuner suggests?

Alcohol fuel has lower calorific value per gram of fuel. Changing the fuel type and adding the right quantity won't make significantly extra power just by that change alone. The extra stick will come from making appropriate ignition timing changes that capitalise on the knock resistance of the fuel. Same process as tuning for racing fuel or avgas really. It would be interesting to see what the ignition map for this particular car looks like, just to quell any back/forth about this aspect of his tune.

I didn't see any mention of making changes other than to E85 and the quieter muffler. Still, not hard to check cam timing without wasting time and money before returning to the dyno. Then I'd go and drop the quiet muffler and see just how much it picked up. Injector duty cycle beyond calculated/expected values for the power output to me says setup issues with the fuel system ie. pump. Is the wiring allowing the pump to work to its rated capacity? Check with the multimeter to remove doubt. The GT30 0.63 A/R housing should prove restrictive in terms of max airflow capacity (compared to the 0.82), but the E85 should allow bags of extra ignition timing as per Mafia's expoits running WI. That's how he made power from that turbine setup. Sure this thing's been fuelled up (but I wonder about that lambda value not being rich enough, given it's essentially an alcohol fuel), but has the ignition timing been cranked up to take advantage of the knock resistance E85 offers?

I tend to agree with Adrian's comments. Spend $$ to obtain/maintain chassis integrity first. Seeing Richard Galley's Z car at Rally Queensland, they can/do carry good speed. Power:weight is where you'll get the performance, and recognising the much lower weight factor should help identify areas where the spending can be contained. L series can be made to go, but it's going to cost so I'd go with the modern engine combination. You'll hit the power ceiling easily with a GT3071, but use a 0.82 turbine housing so it can continue to rev. I'd think you could target usable power from 3500-7500 without really doing much/anything to the head. Perhaps valve springs and a tidy up, run stock cams. Bottom end, find some RB26 rods with decent bolts, forged pistons, and put the crank in for weight reduction. That would be what makes the whole package rev quickly and give some extra reliability. Yes I can see it will cost, but it would also make the package come together nicely with a 4.6:1 rear end.

Depending on how you plumbed the pump into the system, you may have eliminated the non return valve. Best approach for full flow, but you need to crank the engine once or twice (sometimes?) to prime the fuel system. Once the engine is shut down the pressure bleeds off again, requiring the priming crank. Highly recommend that you check the voltage your pump is seeing too. An 044 likes/requires higher voltage than stock wiring provides in an R33, and I can't see things being any different with an R34.

Didn't the person/s you bought them from know what the specs were? Send them to a cam specialist and have them measured. Exhaust cam has the CAS drive.

So it is running the stock ECU? With those same mods I struck the failsafe "rich and retard" that the stock ECU is programmed to run. Same symptoms were observed.

That's equating to ~ 8% water:fuel at the cited injector duty cycle which isn't heaps but is heading in the right direction. Ask your tuner for overlay of AFR. Be nice to see that. I'm not 100% convinced that even brand new coil packs (Splitfire or any other brand to suit RB) have enough spark energy to deal with water injection, hence the comments about CDI. What is your tuner's view?

Points of interest from original post bolded, looking to clarify your situation and even the approach to tuning. Are you running stock fuel pressure? Assuming so, then with injector duty cycle 70% then total fuel flow should support approx 380 hp @ the crank, not the wheels. Or has your tuner significantly leaned off the full load/high rpm fuelling to match W/M delivery? Might be worth reviewing any datalogs you may have acquired during the tune. Another issue to consider is that if you are introducing a significant proportion of W/M then the std ignition system may not be coping that well. There may be a lack of grunt in the spark department - time for a CDI? Have you discussed with your tuner how aggressive the W/M delivery is? I'd be thinking the lack of response to ignition timing could be that the total tune (fuel, W/M, spark) and mechanical spec gives very high knock resistance but there is a factor holding it back a touch. I'd lean towards spark energy rather than static C.R. Assuming your inlet and exhaust pipework is all decent free flowing ie. you're not stuffing 20psi boost in against a large amount of back pressure - then you'd probably expect to achieve up to 430rwhp +/- 10hp. That turbo probably won't push much/any greater air mass, but with W/M the engine should be nearly bomb proof. 500rwhp is a lot to chase from an RB25, you might send Fineline a PM for his views. Do you have a dyno sheet to help with this thread?

Suggest having a trawl around on this site: http://www.waterinjection.info/ Sponsored by Aquamist, but there is not a demand that all discussions be centred around that product. There is even a longish thread with pics on a Pommy GTR using WI.

For the airflow (ie power) potential of that turbo, your injector size would be probably best up around the 740cc mark, and also look at an 044 pump. And depending on your planned max engine speeds, consider whether to install upgraded rod bolts, or just go to beefier rods.

CHRA = complete turbocharger assembly, less housings. So it includes both impellers.

Comp housings definitely are different sizes. Didn't pick any easily measurable difference on the turbine side for either housing or rotor between RB20 and 25. Also RB20 comp impeller is smaller inducer + exducer. Just a smaller unit, flows less. Later series 2 RB25 also went to a nylon/composite impeller. Lighter weight.

Doing a service on the lifters is a good idea if/when the engine is out, or head off and you have/make time to do it. Gum/varnish buildup happens normally, and I agree with the oil spec and servicing regime as to when/if the lifters become a problem. There are a few parts that make up a hydraulic lifter, and servicing them isn't much more than getting them disassembled, using a bit of solvent and manual scrubbing, then reassembling them. When you do 24 lifters if just becomes a matter of keeping things in order, and I agree reinstall them onto the same cam lobes. Just be sure not to lose anything during the process.

If you've still got all the stock gear, spend an hour or two reinstalling it and let us know. Now I'm interested to find out.

There's no doubting it's a cracking result, though I'd be interested to see it run on the rollers again after that screamer is given the heave-ho. Every time I see an EW setup and results of boost control, it's pretty clear that the effort and expense is well justified. It's a real bugger that you had to go away from the original plan, but if it won't fit, it won't fit. Grafting a pipe onto the housing obviously works, just doesn't look that elegant and makes it difficult to swap housings if the need/want arises. Couple of comments about the DE+T spec: I've got a set of those 25DE pistons, not a bad thing but they do have sharp edges around the valve cutouts. Can be knock-inducers so keep that in mind. Also the DE block does not have under piston oil squirters. The oil jets take temps out of your pistons, so be aware if you intend taking this thing to a track and running consistent high rpm/load. Given you're powering a GTS4, this engine/turbo spec would be quite satisfying on the street, vs a GTR which would work in a different rev range.

That's my point exactly. I get the feeling that the turbine housing is choking, so bigger cross sectional area may have a minor effect on what is an absolutely stonking bottom end, and allow the top end to flow. Speculation only, and I'm sure Stao has/is considering it all.