joshuaho96

Massive thread necro here but has anyone considered doing a complete revamp of the FPCM to use a buck converter instead of just increasing the ground resistance? I figure reducing load on the alternator for other items + no resistor heat dissipation to worry about would be a decent benefit for the 6V/10V modes.

That's some neat info. I have seen cases where aftermarket intakes cause immense amounts of noise on the sensor and all kinds of other issues when not designed with MAF in mind which is why I'm reluctant to blindly have a go at it without any real aero/mech background.

Even with a single AFM I haven't really seen single turbo builds that try to avoid turbulent flow into and out of the AFM, most seem to assume speed density instead which doesn't really struggle with these issues. 4D tuning is basically what I described, a blending of MAP and TPS based on throttle position. As you reach something like 20% throttle you go from a filtered MAP signal to TPS as the primary load source with a blending method to make sure the transition isn't noticeable. MAP sensor with a normal single throttle body setup has lots of intake vacuum so you can clearly see what engine load is doing, I don't dispute that speed density works very well in that application. However with ITBs there's so little vacuum volume that the signal is going to be extremely noisy from the intake valve opening events and because all the cylinders are linked there's a big "vacuum leak" from the other cylinders that makes it really difficult to get good load signal from MAP past small throttle openings. I do wonder if you could make speed density and ITBs work without TPS blending if you had a MAP sensor for each runner and only fed the ECU the lowest pressure of the 6 signals being sampled. That could work even better than AFMs. Banking on WB02 isn't a great strategy IMO, my experience with O2 closed loop is that unless you're within ~5% before O2 fuel trim on the dyno it can cause the ECU to start chasing its own tail. California smog tests thankfully exempt AWD vehicles from the IM240 drive cycle dyno test but RWD/FWD cars can be required to do a proper smog test instead of just revving in neutral at 2500 RPM.

The problem with most single turbo setups is that the intake piping isn’t really figured out very well, AFMs are sensitive to turbulence and reversion so I’m skeptical that a Y-pipe on the turbo inlet as a mount for AFMs and then some pods strapped to that makes for a good AFM signal.

I'm questionable on your statement regarding AFMs vs MAP with ITBs. From what I have seen the resolution of the sensor is for a small portion of the total engine load scale which then requires the remaining portion of the map to be reliant on the throttle position sensor. I just don't buy that throttle position is a reliable load signal, there are way too many factors that can change and throw it off. Admittedly AFMs don't have the best transient response characteristics. The MAP could be used within the range that it works as an accurate load signal but after that the only thing that works would be the throttle position signal anyways.

Ceramic coating can be done on low mount manifolds as well, I've just never seen anyone make a single EFR low mount manifold. There's also the problem of retaining MAFs, which I'd prefer due to the ITBs of the stock engine. Speed density blended with TPS can work but it impacts emissions which is a relevant problem for me.

I think the problem there is more like I've never seen a single turbo build where they targeted a power goal of something like 290-300 kW at the wheels. I believe Hypergear tried with the sst thread but I wasn't too impressed with the results. High mount manifolds that I usually see on single turbo RB26s also greatly increases the amount of heat radiating into the engine bay instead of out the exhaust. Not a fan of the extra volume from exhaust valve to turbine inlet either. It's all relative to though, to me -9s are as big as I'd go. Street manners are a very big deal to me, it's definitely never going to be a V8 but I want the powerband to start as close to 3000 RPM as possible and hold out until ~7000-7500 RPM if I can help it.

The GT-SS might be the best balance, I've noticed the compressor efficiency seems to be better in the expected regime of operation vs R34 N1, but it definitely gives something up in response compared to stock turbos. I waffle regularly on what is the best turbo for a 2.6 street car with driveability as a primary concern.

Are your high flow G1 profile dyno comparisons between stock ceramic vs inconel high flow? I would be very surprised if you've managed to maintain stock response.

-7s are going to just barely break 300kw at the wheels, probably high 200s if you have exhaust restriction/wastegate control isn't ideal. They're a good street turbo though. If you want more power -9s will get you there without too much difference in turbo lag, mostly at that 3000-4000 rpm region where you'll notice the difference back to back.

I guess they're normally referred to as steel turbines, but regardless the point is my power goals are basically maxing out stock turbos rebuilt with steel. Another option would be -7s or -9s but whatever the case this is primarily a street car, it needs to be well mannered and pass California's emissions testing every 2 years. Good turbo response in that high 2000 to low 3000 RPM range is important to me.

Stock the R32 GT-R made 10 PSI of boost with the restrictor, 14 psi without. If you aren't making 10 psi definitely start asking why. While we're on the subject of turbo selection, is there anything out there that replicates the response of the stock ceramic turbos but with an inconel exhaust wheel? -7s and -9s seem to be about on par or slightly better than ceramic turbos rebuilt with inconel exhaust turbines which means boost comes in a little later. I'm shooting for high 200 to low 300 kW.

For a street car would you guys recommend the 3 gear set instead of 5 gears? I don't like how the 5th gear is shorter, as-is the engine turns ~3000 RPM around 130 kph.

Curious to know how the Autowatch works out. I've seen positive reviews but no real personal experience. I know the trackmate works, an importer in the US puts them on all of their inventory and has used it to recover stolen cars before.

Any reason to necro this thread? Also, do you have proof that the design is a direct copy? If Younes bought a spool spline drive and used it as a reference to make improvements I don't really see that as a big problem. Competitive analysis is an important part of making good products.

I would avoid the short shifter, reducing the shifter travel just makes it easier to burn up your synchros. The solid shifter might help with tightening up the feel but will increase noise and vibration transmitted through the shifter. If you're worried about the NVH I would just replacing some bushings in the shifter and call it good.

Alarms don't do much other than maybe something psychological. Install a GPS tracker in the dash and a transponder immobilizer to deter easy theft. Something like the Autowatch 573PPi will work well enough. GPS trackers are tougher to figure out as they are often region dependent. Trackmate makes one that hides well in the dash but they have an extra monthly surcharge for Australia so that affects the pricing.

I'm pretty sure your understanding is correct, S2 + S3 R33 GTRs relocated the airbag controller to the center console, R33 S1 puts the airbag controller on the wheel itself so the swap is not as simple as it seems.

A remap is not magic, it will not solve your idle issues. Any GTS-T ECU will not be compatible with an NA motor, the timing curves are completely different due to differing compression ratios. An RB25DE makes about as much power as a modern economy car, the only way to change that appreciably is forced induction. Or if your engine is really in bad shape and needs a rebuild.

This is pretty much it. I would also make sure that your grounds are properly set up, if you used stock harness and PnP adapter for the ECU you should not have problems but any noise on the coil trigger will cause spark to go off continuously which will manifest as a no-start condition. You should also verify power to all components like ECU, ignitor, etc are sufficient during cranking. Some ECUs are exceptionally finicky about power supply and will lose ignition sync, etc when when cranking pulls the battery voltage too low.

A proper tune will never take ~3-4 hours unless your tuner already has a canned map, your car is perfect, and they just need to verify that everything is running properly + maybe small tweaks here and there. It will take a few days to do it right even though Link or whatever ECU manufacturer of choice is providing the base map which shouldn't be too far off in the first place. OEMs take months of engineering time to do the factory calibration. It's a full time job. Even then sometimes they run out of time and it's too late to get another calibration emissions certified and you end up with a factory tune that breaks engines. Subaru has done this before. With a turbo engine especially the dyno cannot do everything for you, some road testing is needed to tune for real-world IATs. Engine calibration is not for kids. If you don't trust your tuner to not crash/abuse your car they have no business doing an ECU calibration. Some logging is needed to diagnose why your car is running wrong on the base map, if you can screenshot a trace of the behavior people can probably help.