joshuaho96

You have to convert to LHD, not RHD. The headlights are RHD/LHT from the factory. Here's a pdf guide for the conversion, pdf warning: https://wardiz.org/blog/wp-content/uploads/2011/04/R33-Projector-Headlamps-Tutorial.pdf For those that are not bound by issues like TUV compliance you can have the series 3 HIDs modified to produce an LHD beam pattern like this:

https://clubgrandtouring.wordpress.com/2020/08/11/what-do-the-f40-and-the-bcnr33-have-in-common/ It's normal.

Look at the spectrograph view, if turning down the timing has no visible change in the knock sensor (and you know the knock sensor signal is good) then it's probably calibrated wrong.

R34 VSpec 1 and VSpec 2 do not have the same part number for headlight housings. Not sure where you got that. "Housing assembly" is the part you're talking about, "Headlight Assembly" includes things like the HID ballast, bulb caps, bulbs, etc. Whether you need a housing assembly or a headlight assembly depends on what's wrong with the headlight. You may not even need a housing assembly if your problem is just that the lens is damaged. If you want to swap to Xenon from Halogen then you will want an entire headlight assembly. I believe the difference between the 1999-2000 headlight assembly vs 2000+ headlight assembly is this: "Xenon headlamps change from Series 1 cars to Series 2 cars. Series 2 cars (lense code 1618) have shadow chrome inserts as opposed to champagne accents on the Series 1 (lense code 1601) cars. Series 2 cars lost the light level actuator motors from housings activated via cabin switch." Source: http://gtr-registry.com/en-bnr34-specs.php There may be smaller differences though. I suspect this is why the some housings are half the price of others.

https://prestigemotorsport.com.au/import-early-build-r35-gtr-from-2019/?fbclid=IwAR0jNtvFhRqoKozqtkl4CIHATNoiNRaASE4HF045jPAFqGFz7-F3sr344Ew Looks like early builds can be done, but those aren't as desirable as the DBAs.

Haltech seems to have automatic transmission support now, it's noted for the Y60/Y61 Elite adapter harness: https://www.haltech.com/overview-plugnplay-adaptor-nissan-patrol-y6061-tb4245/ They have online documentation here: https://support.haltech.com/portal/en/kb/articles/transmission-control

Maybe, but load is measured based on a completely arbitrary MAF VQ. I’m manually doing the VQ to grams per second unit conversion. Even if you don’t bother with that there’s still a huge delta between deriving TP via VQ, Kconst, and RPM and what the ECU reports as TP. I suspect that much like how the MAF VQ units are arbitrary to fit the size of the ADC output, Nissan was likely doing some internal rescaling to get the load index to be an 8 bit integer and TP to fit in a 16 bit integer. Internal tooling could easily handle this weirdness while still showing sane units to anyone working on the engine calibration. Talking to Matt at Nistune he also suspects that this is just some bit twiddling done to make the scaling fit. It’s not documented in Nissan’s patent on their ECUs of the era which makes me think it’s an implementation detail.

For those that are interested in the original problem, I found some logs of a stock R32 GTR running Nistune and concluded that it's a roughly 23.5 or 23.6x factor that is hidden in the TP calculations. So instead of this: TP = (Kconst * VQ) / RPM It's actually something like this: TP = (Kconst * VQ * 23.6) / RPM Here's my work, gathered by going through this Nistune post: https://forum.nistune.com/viewtopic.php?f=8&t=3655 The header is not quite as helpful as I would hope but basically the first 4 columns are straight from the logs and TP less K is effectively the expected VQ/RPM value, while VQ and VQ/RPM headers are the interpolated VQ value measured from MAF voltage and VQ/RPM is that VQ value divided by the RPM in that part of the log. The two methods arrive at vastly different numbers, so the ~23.6x factor I mentioned is how I reconcile the two. Edit: What's remarkable about this is actually how close the TP index is to the total airflow to the engine, in grams per cylinder, just with fewer significant digits.

My understanding was that if you adjust K at all or changed the MAFs you've effectively rescaled the ignition and fuel maps, even if the math still works out such that the ECU stays within the OEM load scale. I really just want to ensure that I keep the factory fuel targets/ignition timing in real load + RPM, so that the behavior is going to be the same as stock if I don't modify them. Maybe pointless but I'm trying to make sure that I don't change too many variables all at the same time.

I’m aware that general practice is to not bother with trying to do this, I just want to make sure that messing with K and VQ that I rescale the maps correctly. Getting down to raw physical units helps because the VQ scale is not a linear factor.

I'm trying to understand how a stock BNR32 ECU calculates TP load on the primary fuel/ignition maps. I read through the Nistune manual to find the following equation: TP = (VQ * Kconst) / RPM TP load index = TP / 256 I looked up the MAF VQ (voltage quantifier) curve in the base BNR32 ECU's MAF table and referenced it against Haltech's RB26 stock MAF curve. From this I concluded that the VQ curve is such that 1 VQ unit is equal to roughly 0.005152 grams per second of mass flow. This constant produces a curve that makes the Nistune and Haltech curves agree almost perfectly. The only error I see with this method is below 1 g/s, so with two MAFs at roughly the same flow rate that's likely below the minimum airflow at idle: From there I tried to reverse the TP load index equation to get some sort of estimate for grams per cylinder. Something I noticed reading the tables is that there is a fuel cut that occurs above a load index of 160, which suggests to me that the load index of the OEM tables should never exceed 80 and the final load row of 88 is just a failsafe. I tried the following to convert this TP load index into grams of air per cylinder: TP_load * 256 * Kconst * 60 = VQ/RPS Where TP_load is 80, Kconst is 233 (defined by the ECU), and 60 is a constant to convert RPM to RPS. From there we can convert VQ into a grams per second value like this: TP_load * 256 * Kconst * 60 * 0.005152 = (g/s) / RPS The seconds cancel out, so this is actually a grams of air per revolution value. Every revolution half of the cylinders are intaking air because it's a 4 stroke engine, so we can divide this number by 3 to get grams of air per cylinder. The problem is that when I do this math I get a figure of ~27 grams of air per revolution. At the power peak of ~6800 rpm stock that implies the "peak load" limit corresponds to roughly 3000 grams per second of air mass metered by a single MAF. A single MAF can only meter about 150 grams of air per second before it maxes out. So I'm off by a factor of 20 which is definitely wrong. Anyone know if I just suck at math? Or if I'm missing a bunch of extra bits to how TP is calculated? If anyone has a Nistune log of MAF VQ, RPM, and TP on a stock RB26 + stock tune I would really love to see it.

Step one is probably sell the car and get an AWD variant because you need a big divot in the floor pan to fit the transfercase.

I flipped it backwards, -5s are too big, correct. But GT3-SS turbos are tiny, 0.54 a/r exhaust turbine which is tighter than any other turbo out there. They nose over hard on 2.6, so the concern is that a 2.8 will just shift everything down a few hundred RPM and make the engine feel like a Mazda 2.5T where the power falls off a cliff well before redline. The HKS turbos may be a waste of time/money but it's already too late, the turbos are bought for and installed so I'm just going to see how they go. The engine isn't at the point where the bottom end is going to be taken apart yet so it's going to just be a 2.6 for now. I have a VCAM step 1 sitting in the garage so that can be a first attempt to try and get the VE up earlier to spool the turbos. If that doesn't get the desired powerband then I'll think about a stroker or RB26/30. I'll post dyno charts and data logs as I work through this, if it sucks you guys can have some fun pointing and laughing.

No, but I'd rather not spend 5000 USD on a stroker kit only to discover that the engine peaks in power undesirably early. -5s are too small for 2.6L, but the GT3-SS is so small that it has trouble holding boost out to 7000 RPM even with 2.6L. I have a feeling that if you stroke it out to 2.8L it's going to be even worse in that regard.

Gran Turismo Sport seems to do a pretty good job of simulating the R32/R33/R34 GT-Rs.

I was under the impression that if a turbo is already choking the engine above a certain RPM, additional displacement would just shift the power curve down some amount of RPM. Is this not the case?

Yes, if you're going to go past a 2.8L stroker on an RB26 block it definitely makes sense to go to an RB30 bottom end instead, which has a much longer 152.7mm conrod. Even with a 3.4L, 94mm stroker kit on an RB30 you're still at 1.62 rod ratio which is roughly what the RB26 is at stock. More cubes is better for performance no doubt, my concern is that going to a 2.8L stroker on the RB26 means you might increase piston side pressure to unfavorable levels, and that going to a 121.5mm rod means you compromise the piston design. Shorter compression height means there's less room for the piston rings, either the top ring gets closer to the crown, the oil control rings get closer to the piston pin bore, or the rings have less spacing. Personally, I'm really hoping the turbo I selected is small enough to not require agonizing over this issue any further.

Stroker kits are either 119.5mm or 121.5mm, but the stroke in both cases increase to 77.7mm. So you're picking between a 1.56 rod ratio or 1.54 rod ratio. Either way it's on par with the B18 used in the Integra Type R, which seems to be pretty close to the edge of what is considered safe. The longer conrod length kits use a different piston design to get everything to work. Anyways, my plan has always been to target low power and focus on balance. I expect with the HKS GT3-SS turbos I selected it will already nose over well before 7000 RPM even with 2.6L displacement.

Is 2.8L stroker on the RB26 really a wise move to go for in a rebuild? I get the impression that the RB26 was already a stroker motor from the factory and was originally intended to be a 2.4L. 2.8L would cause the conrod/stroke ratio to get even more unfavorable. I'm currently planning out an RB26 build and this issue has made me go back and forth on whether a stroker kit is really wise.

doublepost

Base timing on an RB26 is 20 degrees BTDC. If you actually have your base timing at 10 deg BTDC then commanding 26-28 degrees means you're actually commanding 16-18 degrees of timing. As others have said, it's also possible that you're knocking and not hearing it. Is the OEM knock sensor particularly insensitive or something? I was under the impression that a properly set up knock sensing setup (bandpass set up with correct bandwidth + peak, crank window appropriately set) is on par with what human ears can do.

What kinds of compromises are involved in fitting an RB30 into the R32?

45M yen price tag. Well outside the budget of anyone that would be posting here I presume.

Are they ever getting around to the double VCAM setup they claimed to be working on?

The question is really more why do you want a billet block? They're designed for 1200+ hp builds. The liners are extremely thick and the water jacket doesn't do as much as it does in the stock block which is a closed deck that reduces coolant flow. You should really consider what this car is going to be used for. If it's going to be idling in traffic all day that means keep the power relatively low to reduce cooling load on the engine, keep the OEM water pump, big radiator, stock clutch fan with fan shroud, proper radiator ducting. All of those requirements point towards either OEM or N1 block. It would be cool to have some billet aluminum block tailored for say 600 whp max as a "street oriented" block but the people willing to put down 10-13k USD on a billet block usually want big power, not just removing ~30 kg from the front of the car.