Stock rb25det neo questions

[Kinkstaah]

I mean it's probably likely that people overestimate their skills in dialling in a setup and noticing the changes.

I had SK shocks and springs, and added heavier springs and got them revalved by Sydney Shocks to suit based upon what I told them I wanted the car to handle like. I got back a completely different feeling set of shocks, which probably (?) feel great on track but holy hell are they rough on tram tracks and the like. The shock dyno actually looks pretty similar to Shockworks (from what I can surmise from a screenshot of a youtube video - and my dyno printout...)

Truth be told I doubt I'd be any faster or slower with either setup, or camber/castor combination. I also had whiteline eccentric castor bushes up front of my R34. I removed them and put in poly non-adjustable ones to soothe my OCD (nobody ever set the castor the same side to side, and it'd be near impossible to do) and be happy the wheel is centered in the well now for clearance reasons. Yes I wanted it to move 1mm 'back' :p

I've effectively set my castor back to stock, negating all the benefits of that which is supposedly massive. I've probably also altered toe and camber in a negative (detrimental) way. I can't tell any difference steering the car.

[tsuokun]

On 1/6/2025 at 8:19 AM, GTSBoy said:

Sadly, it is a non-trivial exercise to set up to measure and correct bump steer. I am happy to show my rig, which involves nasty chunks of wood bolted to the hub, mirrors, lasers, graph paper targets and other horrors. Just in case anyone wants to see how it is done. I'll just have to set it up to take the photos.

I for one would love to see this. Save the HICAS locker and subframe inserts, I haven't done anything to the rear suspension. Factory camber adjustment is dialed all the way out though.

[Murray_Calavera]

32 minutes ago, tsuokun said:

I for one would love to see this

Jump on youtube, search for bump steer gauge and enjoy the show. 

[GTSBoy]

Yeah, my offer was more to show exactly how rough and ready the rig can be and still be useful. Youtube vids will definitely show cleaner setups. Same concept though.

[Wazmond]

Update 24/01/2025:
   Bought a GReddy/Trust Intercooler (crossflow spec-LS) that was meant for a R33 GTST $871 AUD shipped, and a GReddy Profec boost controller $483 AUD, both brand new from Japan. Being honest, I would've thought the intercooler kit was discontinued but I guess not yet.

Decided due to funds + time, I'll stick with a nistune on this stock-ish setup ( stock turbo set to probably 10-12psi ) and have it run cleaner ( suspect the 3" turbo back etc has sh*tted on my economy ) for my trip down south soon for the WSBK. Hopefully I can get it all installed and tuned by then.

As for who I am getting it tuned with, I will be going with Toshi, (not hearing back from DVS so scratch that). There is also Birrong Auto but not sure if they do nistune installations and if they even tune it...

Otherwise, anyone know where I can get my hands on an aluminium intake/suction pipe for an RB25DET NEO?

[Dose Pipe Sutututu]

6 hours ago, Wazmond said:

Birrong Auto but not sure if they do nistune installations and if they even tune

Haha watch Alex's eye twitch when you mention Nistune to him in person lol.

He's not a fan, then again it's quite a niche product. I personally don't mind them, but most usually steer clear from it.

Word of advice, do not ground the AFM to the chassis, there are heaps of incorrect guides on the interwebs. Send both GND on the AFM back to Sensor GND on the harness.

[joshuaho96]

11 hours ago, Dose Pipe Sutututu said:

Haha watch Alex's eye twitch when you mention Nistune to him in person lol.

He's not a fan, then again it's quite a niche product. I personally don't mind them, but most usually steer clear from it.

Word of advice, do not ground the AFM to the chassis, there are heaps of incorrect guides on the interwebs. Send both GND on the AFM back to Sensor GND on the harness.

Nistune needs something like an entire excel spreadsheet in which you build an abstraction layer that converts everything from real units you can actually measure into all of the various tables. The number of unexpected dependencies hiding in how the Nissan ECUs do math is a pretty impressive optimization trick for 8-bit MCUs but good god is it awful to actually work with in practice. 

[GTSBoy]

1 hour ago, joshuaho96 said:

Nistune needs something like an entire excel spreadsheet in which you build an abstraction layer that converts everything from real units you can actually measure into all of the various tables. The number of unexpected dependencies hiding in how the Nissan ECUs do math is a pretty impressive optimization trick for 8-bit MCUs but good god is it awful to actually work with in practice. 

Um. No.

Since Matt introduced the TIM it has become a lot easier to deal with the consequences of changing K for AFM and injector swaps.

Then, tuning is a f**king doddle. No-one needs to know or care how many grams of air are flowing or any other bullshit. Need more fuel in a cell? Add more fuel. Need more timing in a cell. Add more timing. Need to adjust any of the other tables for warm up and so on? No harder than anything else.

Sure - it's not an ECU system for starting from scratch on an arbitrary engine. But then.....it was never supposed to be, not recommended for, and almost never used that way. So....

On your engine, in particular, Nistune/Nissan OEM is about as sophisticated and difficult as banging 2 rocks together. Those ECUs are primitive and simple. There is nothing difficult there. I learnt Nistune from scratch, created new maps with extended axes, interpolated/extrapolated the original maps onto them and tuned my RB20 (basically the same ECU as your 26 ECU) all by myself, more than 20 years ago. And that was long before even TIM.

[MBS206]

2 hours ago, GTSBoy said:

Um. No.

Since Matt introduced the TIM it has become a lot easier to deal with the consequences of changing K for AFM and injector swaps.

Then, tuning is a f**king doddle. No-one needs to know or care how many grams of air are flowing or any other bullshit. Need more fuel in a cell? Add more fuel. Need more timing in a cell. Add more timing. Need to adjust any of the other tables for warm up and so on? No harder than anything else.

Sure - it's not an ECU system for starting from scratch on an arbitrary engine. But then.....it was never supposed to be, not recommended for, and almost never used that way. So....

On your engine, in particular, Nistune/Nissan OEM is about as sophisticated and difficult as banging 2 rocks together. Those ECUs are primitive and simple. There is nothing difficult there. I learnt Nistune from scratch, created new maps with extended axes, interpolated/extrapolated the original maps onto them and tuned my RB20 (basically the same ECU as your 26 ECU) all by myself, more than 20 years ago. And that was long before even TIM.

Everyone is too used to learning from places like HPA "how to tune" and what to expect at what point, rather than being able to see "The computer says I'm in cell with Row = 8, column =4, and I can see my fuel is lean, so lets add more"
Everyone wants "real units", which helps for someone picking it up for the first time and seeing how bad the tune is if they're not used to touching it.

 

However, I think for most of us who want to play with it, you're 100% right, we're only needing to learn about it for OUR CAR. Which makes it great, and we don't need to care what the real values are, we just need to know which cell it is, that's causing the lean or rich point, or that we want more ignition timing or less. But again, everyone wants everything super you beaut and nearly self tuning, with VE maps, and a billion compensations...

 

Though then there's me over here when I'm doing reverse engineering work just reading data in hex format that most people couldn't work anything out from. Yet I can see what's going on.

[Dose Pipe Sutututu]

4 hours ago, GTSBoy said:

No-one needs to know or care how many grams of air are flowing or any other bullshit. Need more fuel in a cell? Add more fuel. Need more timing in a cell. Add more timing. Need to adjust any of the other tables for warm up and so on? No harder than anything else.

That's right, simple but works.

Run out of load? Rescale the table lol.

Want to be lazy and not rescale? Drag the K

[joshuaho96]

11 hours ago, GTSBoy said:

Um. No.

Since Matt introduced the TIM it has become a lot easier to deal with the consequences of changing K for AFM and injector swaps.

Then, tuning is a f**king doddle. No-one needs to know or care how many grams of air are flowing or any other bullshit. Need more fuel in a cell? Add more fuel. Need more timing in a cell. Add more timing. Need to adjust any of the other tables for warm up and so on? No harder than anything else.

Sure - it's not an ECU system for starting from scratch on an arbitrary engine. But then.....it was never supposed to be, not recommended for, and almost never used that way. So....

On your engine, in particular, Nistune/Nissan OEM is about as sophisticated and difficult as banging 2 rocks together. Those ECUs are primitive and simple. There is nothing difficult there. I learnt Nistune from scratch, created new maps with extended axes, interpolated/extrapolated the original maps onto them and tuned my RB20 (basically the same ECU as your 26 ECU) all by myself, more than 20 years ago. And that was long before even TIM.

I mean yes, if you're starting from scratch on an unknown engine yes you don't need to be doing all kinds of math in the background but if you're doing relatively minor changes like AFM + injectors + boost up with some aftermarket turbos it takes quite a bit of math if you want to do something like maintain OEM fuel + timing tables but compressed and then a bit more load scale up top.

I think I've spent too much time working on big engineering nightmares though so I'm a big fan of trying to constrain the scope of whatever work I'm doing as much as possible and trying to get it right before moving on. For example, a local owner just did the usual E85 + single turbo conversion to his R32 GTR and nearly burned his car to the ground doing some spirited driving up the local mountains. Turbine is unshielded and too close to the hood insulation. It's tough to balance "just get the project done" and "seemingly small details can cause massive setbacks I'm not willing to deal with".

[Wazmond]

On 24/01/2025 at 9:02 PM, Dose Pipe Sutututu said:

Haha watch Alex's eye twitch when you mention Nistune to him in person lol.

He's not a fan, then again it's quite a niche product. I personally don't mind them, but most usually steer clear from it.

Word of advice, do not ground the AFM to the chassis, there are heaps of incorrect guides on the interwebs. Send both GND on the AFM back to Sensor GND on the harness.

Was planning on getting an R35 MAF and the adapter, should this be okay?

Also any idea where I could get my hands on an intake pipe?

[GTSBoy]

44 minutes ago, Wazmond said:

Also any idea where I could get my hands on an intake pipe?

They usually get made by hand as part of any such swap.

[Dose Pipe Sutututu]

10 hours ago, Wazmond said:

Was planning on getting an R35 MAF and the adapter, should this be okay?

Also any idea where I could get my hands on an intake pipe?

R35 card MAFs are great, not a fan of the Z32

[Wazmond]

A question for tuning awd, is it possible to disable the AWD? The stagea is an EA/T AWD, Toshi had said on a GTR, he was able to disable it and make it 2wd. Just wanted to double check if this was possible

[GTSBoy]

Yes, but it's not as easy as pulling a fuse on anything other than an R32.

There's a routine you have to do, involving disconnecting a loom plug and bleeding down the preload.

[Wazmond]

@Dose Pipe Sutututu I read your replies RE: R35 GTR MAFs, any ideal spots to put on? Obviously will need the adapter plate.
Will be having a cross over intercooler fitted shortly, would putting it a bit before the TB be okay?

[GTSBoy]

1 hour ago, Wazmond said:

any ideal spots to put on?

Will be having a cross over intercooler fitted shortly, would putting it a bit before the TB be okay?

While it is a very nice idea to put card style AFMs into the charge pipe (post intercooler, obviously), the position of the AFM and the recirc valve relative to each other starts to become something that you really have to consider.

The situation:

• The stock AFM is located upstream the turbo, and the recirc valve return is located between the AFM and the turbo inlet, aimed at the turbo inlet, so that it flows away from and not through the AFM. Thus, once metered air is not metered again, neither flowing forwards, or backwards, when vented out of the charge pipe.
• When you put the AFM between the turbo outlet and the TB, there is a volume of pressurised charge pipe upstream of the AFM and there is a volume of pressurised pipe downstream of the AFM. When the recirc valve opens and vents the charge pipe, air is going to flow from both ends of the charge pipe towards the recirc valve.
  • If the recirc valve is in the stock location, then the section between it and the TB doesn't really matter here - you're not going to try to put the AFM in that piece of pipe.
  • But the AFM will likely be somewhere between the intercooler and the recirc valve, So the entire charge pipe volume from that position (upstream of the AFM, back through the intercooler, to the turbo outlet) is going to flow through the AFM, get registered as combustion air, cause the ECU to fuel for it, but get dumped out of the recirc valve and you will end up with a typical BOV related rich spike.

So ideally you want to put the AFM as close to the TB as possible (so, just upstream of the crossover pipe, assuming that the stock crossover is still in use, or, just before the TB if an FFP is being used) and locate the recirc valve at the turbo outlet. Recirc valve at the turbo outlet is the new normal for things like EFRs anyway.

In the even of a recirc valve opening dumping all the air in the charge pipe, pretty much all of it is going to go backwards, from the TB to the recirc valve near the turbo outlet. But only a small portion of it (that between the TB and the AFM) will pass through the AFM, and it will pass through going backwards. The card style AFMs are somewhat more immune to reading flow that passes through them in reverse than older AFMs are, so you should absolutely minimise the rich pulse behaviour associated with the unavoidable outcome of having both a recirc valve and an AFM in the charge pipe.

[Wazmond]

So to summarise, the best thing to do is to move recirc to between turbo and IC, and maf on the crossover pipe.
Meaning I'd need a recirc flange, drill a hole in the piping on turbo outlet area. And drill hole on crossover to fit/weld maf sensor?

Either that or put the MAF on the turbo inlet right? 

Is an aftermarket recirc/blowoff valve recommended? Do currently have family in Japan so could probably bring something back with maybe a cheeky lil SuperAutobacs run?

[GTSBoy]

7 hours ago, Wazmond said:

Either that or put the MAF on the turbo inlet right?

Essentially, yes. Although I wouldn't put the AFM on the crossover pipe. I'd want to put it into what amounts to the correct size tube, which is more easily done in the intercooler pipework.

I bought a mount tube for card style AFM that replaces the stock AFM - although being a cheap AliExpress knockoff, it had no flange and I had to make and weld my own. But it is the same length and diameter as the stock RB AFM, goes on my airbox, etc etc. I don't have a sick enough rig to warrant anything different, and the swap will take 5 minutes (when I finally get around to it and the injectors & the dyno tune).