Tuning the NSX 3.0L Using the OEM ECU

Honcho · 19 October 2020

RYU said:
I'm caught up somewhat with this thread. I'm not sure I can help directly as I'm not modifying my factory ECU. I went straight to a HKS F-Con VPro which is quite frankly pretty old by today's standards but still quite good for our 30yr old car. I can share some of my findings that might help some of you on your tuning adventures.

Welcome to the party, Regan! First off, I'm SO pleased you decided to go back to NA for your car. It's the soul and drama of the NSX.

The HKS unit is still the gold standard for NA NSX tuning in Japan and it should say something that all of the major NSX tuning houses are still using it on customer cars in 2020. It might be old, but it works well.

My main question: Why is there no talk of timing advance on the C motors here? Is this because it's common knowledge (which I'm not privy to) that added timing doesn't do much? Or is it because no one has tried? What are the current assumptions around this? Please share your opinions. I've heard here and there through general NSX chatter that this engine likes a lot of timing from tuners. I can verify some of that (see point 2 below)

I can add my information here for help. Hopefully others will chime in too. First, Mark Johnson told me many, many years ago that the NA1 NSX-R "hot chip" tune was identical to the regular NSX, but just with "a little more timing." While it might have yielded a few extra HP on that 100RON Japanese Super-Premium gas, it did nothing on US cars running US fuel. Chris W just dynoed a real R and found it identical to the US cars. Now that we have access to the factory tunes via TunerPro, we can check the NSX-R differences, but the SOS dyno test seems to validate the idea that adding timing on the NSX 3.0 liter doesn't translate to more power. Brian at Prospeed also advised me when I was considering a chip for my old 91 that adding timing does nothing for power- any gains are within the margin of error on a dyno. Finally, I follow the blogs of two serious NSX tuning houses (RFY and T3TEC) and, when discussing tuning timing, they leave it mostly stock, choosing to focus on fueling. Setting these points aside, it also seems that eating into the safety margin on timing isn't worth the small gains you get, if any. But, all of this advice is for a stock 3.0. Once you start changing the system (compression, RPM, cams, ITB, etc.) the old advice may not hold. In my opinion, once you change compression and/or cams, you're altering the fundamental nature of the fuel charge in the cylinder and timing might need to be addressed to restore ideal combustion.

* I'm using 1000cc Injector Dynamics (based off the Bosch EV14) with these ITBs and idle is not smooth at 800rpm but amazingly smooth at 1000-1100rpm. I'm considering trying RDX injectors but I find no need as i'm preparing for the 3.5L. Here's the eye opening part in terms of duty cycle... at idle i'm using 0.9% at redline WOT i'm at only 31%. 1000cc is too big for the 3.5L but it's the smallest Injector Dynamics sells these days. I bet that's because of the amazingly good low duty cycle performance.

I'd seriously consider moving to the RDX. They are going to deliver that low-rpm stability you get from Honda Genuine injectors and have more than enough headroom for safe duty cycles even with a 3.5 ITB car. Everyone on this thread is using them in their cars, so we will have a lot of field data as tuning gets underway. I would go with Brad's RDX fitment kit too.

* In regards to ignition timing advance. I've been lucky to be mentored by one of the best tuners to be involved in the NSX community. He was also an owner and was part of a team that set world records. Anyway, he shared with me his timing table. He's quite the conservative tuner and would gladly give up some power for added longevity and overall well being of the engine. Even on crap California gasoline at WOT redline his timing table is 9 degrees advance. I've personally used his map as a guideline and can go an added 3-5 degrees on top of that before noticing knock but added power is negligible so it's not worth being so close to the edge like that IMO. ITBs need to use Alpha N with MAP vacuum only useful as compensation during low load conditions so it's not quite appropriate to copy his map (nor the OEM for that matter) during the partial throttle cells.

[MENTION=33247]MotorMouth93[/MENTION] is working on an Alpha-N tuning patch for the ECU that will permit stable ITB tuning. You should reach out to him. Since you are changing compression and cams, I'd mess around with timing a bit, but be careful. Based on the complicated knock routines in the OEM ECU, Honda was very, very concerned about knock in this engine. I'd probably start at stock timing on a dyno and then advance until either gains dropped off or I started to see knock. If I saw knock, I'd dial back by 10% just for safety margin. You'll find the sweet spot for your cams/pistons that way.

* I'm tuning WOT to 12.8. I like a little bit of cushion. Pretty much everywhere else in the map, from low load to medium load i'm anywhere from 15.5-13 AFR.

It looks like 12.7 to 13.0 is the sweet sport for WOT fuel on the 3.0. I'm street tuning to 12.9 myself, but will likely correct on the dyno if there is a small adjustment needed. I don't know if the HKS can run closed loop, but we're keeping it active for everyday cruising and linking it to throttle position (25% or less, for example).

* I've recently driven a Prospeed "custom tune" NSX. I have to admit.. I was quite impressed with the bottom end TQ. It was that noticeable. Because it was a "custom tune" I don't know which version of the chip it's closest to or is based off. I also recently drove a stock ECU NSX to compare to. What I was not impressed with the Prospeed was the roughness (for a lack of a better term). It was like comparing an 8bit to a 64bit, it was that rough.. even jerky in mid throttle low rpm parts of the map. The WOT TQ was impressive for just a reflash of sorts...

To be honest, now that we've had a chance to look at some of the various Prospeed tune versions, we weren't impressed. He never disabled or even changed closed loop operation, so the NSX ended up tuning out most of his fuel adjustments back to 14.7, except at WOT. The timing was not touched and the fuel changes were not smooth. We are aiming to be much more thorough. Now that we can control closed loop, there is a ton of torque to be unlocked in the midrange. One goal for this project is to have some really solid community tunes available based on hundreds of hours of tune time.

* Lastly, I also mentioned in the linked thread above... While I totally commend and support the research into the OEM ECU, I do believe a higher resolution tune from a modern ECU is worth it. Hell, i've been able to get ITBs to have driveability nearly like stock (98%'ish) - that's unheard of. It's actually noticeably smoother than the OEM ECU NSX I drove in many aspects like startup and high res control over AFR to name a couple. I know it's daunting to tune a fresh ECU (trust me.. I know) but if you have the time, it's worth it to have control over everything (tip in, decel, pressure compesators, speed compensators, barometer, nearly everything you can think of, even per cylinder AFR and timing if you want to get into the weeds). I know the cost might be prohibitive but I know some folks on here are spending mucho dinero on their cars and adding a standalone is not being considered... why?

My reason is that Honda spent more time and money than I will ever be able to muster getting the car starting and running smoothly in all conceivable driving conditions. All of that stability is baked into the programming and while we can tweak a lot of the parameters to dial in the car, there is a lot of stuff that is hard-coded into the ECU (the way that the ECU arrives at a final fuel pulsewidth, for example). I want to take advantage of that stability and just use my ECU to maximize the performance potential of the engine, which is about maybe 10% of the ECU definition.

EDIT: Something fun maybe you can helps me with. Let's assume I was able to dial in my fuel table with the 1000cc injectors on the stock 3.0L. As a baseline starting point for the 3.5L with higher lift cams and high CR on the same gas - might you add... say 15% more fuel globally as a starting point? I haven't thought of the math yet.. but eager to hear your suggestions. If cams are going in so will cam gears. That will be a whole other ball of wax...

My rule of thumb is the mathematical % increase plus another 5% for safety. It's better to be wrong rich than wrong lean.

EDIT 2: I was looking through the old Prospeed threads and found this interesting. I never looked into this before because I just wasn't interested. Have you seen his AFR plot? It's kind of all over the place, but what's more interesting is he's inheriting the OEM AFR curve. This lends me to believe he doesn't have control over the actual fuel map individual cells? I'm not quite sure honestly... but my question is.. why not try to flatten those peaks and valleys? That's probably why the car I drove had some roughness.

As noted above, the Prospeed tunes left a lot to be desired.

mskrotzki · 19 October 2020

Thanks for your response. Here are my thoughts in orange.

RYU said:
I'm caught up somewhat with this thread. I'm not sure I can help directly as I'm not modifying my factory ECU. I went straight to a HKS F-Con VPro which is quite frankly pretty old by today's standards but still quite good for our 30yr old car. I can share some of my findings that might help some of you on your tuning adventures.

Some background as to what I'm currently doing of which I eluded to on this thread http://www.nsxprime.com/forum/showthread.php/214979-Need-help-with-IGNITION-TIMING-ADVANCE . I removed my stock CTSC (on the same HKS) and installed a custom built ITB kit. I'm working out the bugs of the ITB kit on the stock 91 3.0L engine (over 100k miles). I'm fairly close on the ITB and now building my high CR 3.5L, with headwork, maybe cams and cam gears.

My main question: Why is there no talk of timing advance on the C motors here? Is this because it's common knowledge (which I'm not privy to) that added timing doesn't do much? Or is it because no one has tried? What are the current assumptions around this? Please share your opinions. I've heard here and there through general NSX chatter that this engine likes a lot of timing from tuners. I can verify some of that (see point 2 below)

The Denver contingent certainly will look into ignition timing as time goes on. I do want to get familiar with the Demon II, TunerPro and data logging. I plan to take it a step at a time.

A few things I can share thus far.

* I'm using 1000cc Injector Dynamics (based off the Bosch EV14) with these ITBs and idle is not smooth at 800rpm but amazingly smooth at 1000-1100rpm. I'm considering trying RDX injectors but I find no need as i'm preparing for the 3.5L. Here's the eye opening part in terms of duty cycle... at idle i'm using 0.9% at redline WOT i'm at only 31%. 1000cc is too big for the 3.5L but it's the smallest Injector Dynamics sells these days. I bet that's because of the amazingly good low duty cycle performance.

* In regards to ignition timing advance. I've been lucky to be mentored by one of the best tuners to be involved in the NSX community. He was also an owner and was part of a team that set world records. Anyway, he shared with me his timing table. He's quite the conservative tuner and would gladly give up some power for added longevity and overall well being of the engine. Even on crap California gasoline at WOT redline his timing table is 9 degrees advance. I've personally used his map as a guideline and can go an added 3-5 degrees on top of that before noticing knock but added power is negligible so it's not worth being so close to the edge like that IMO. ITBs need to use Alpha N with MAP vacuum only useful as compensation during low load conditions so it's not quite appropriate to copy his map (nor the OEM for that matter) during the partial throttle cells.

Before I'm done getting back on the road I'll have $16 K into this engine. You can bet your bottom dollar I too "will gladly give up some power for added longevity and the well being of the engine." At least part of the rebuild is new knock sensors.

* I'm tuning WOT to 12.8. I like a little bit of cushion. Pretty much everywhere else in the map, from low load to medium load i'm anywhere from 15.5-13 AFR.

Sounds like a good plan to me. With the long distance driving I'm prone to do, a little extra fuel mileage is a good thing.

* I've recently driven a Prospeed "custom tune" NSX. I have to admit.. I was quite impressed with the bottom end TQ. It was that noticeable. Because it was a "custom tune" I don't know which version of the chip it's closest to or is based off. I also recently drove a stock ECU NSX to compare to. What I was not impressed with the Prospeed was the roughness (for a lack of a better term). It was like comparing an 8bit to a 64bit, it was that rough.. even jerky in mid throttle low rpm parts of the map. The WOT TQ was impressive for just a reflash of sorts...

Rather than "roughness" I call it tremendous non-linearity. The stock NSX has two noticeable ranges; when the intake runner lengths change and when VTEC kicks in. My one-off chip has three distinct ranges, with an additional shift around 7000RPM. That one scares me a little bit. Jeremiah has posted the tables on that chip on Google Docs; I've downloaded them but I haven't looked closely at them yet.

* Lastly, I also mentioned in the linked thread above... While I totally commend and support the research into the OEM ECU, I do believe a higher resolution tune from a modern ECU is worth it. Hell, i've been able to get ITBs to have drivability nearly like stock (98%'ish) - that's unheard of. It's actually noticeably smoother than the OEM ECU NSX I drove in many aspects like startup and high res control over AFR to name a couple. I know it's daunting to tune a fresh ECU (trust me.. I know) but if you have the time, it's worth it to have control over everything (tip in, decel, pressure compesators, speed compensators, barometer, nearly everything you can think of, even per cylinder AFR and timing if you want to get into the weeds). I know the cost might be prohibitive but I know some folks on here are spending mucho dinero on their cars and adding a standalone is not being considered... why?

Welcome to the group -- I personally enjoy working with something that already exists as opposed to throwing it out and starting with something new. I think both approaches are fine. No right or wrong here.

EDIT: Something fun maybe you can helps me with. Let's assume I was able to dial in my fuel table with the 1000cc injectors on the stock 3.0L. As a baseline starting point for the 3.5L with higher lift cams and high CR on the same gas - might you add... say 15% more fuel globally as a starting point? I haven't thought of the math yet.. but eager to hear your suggestions. If cams are going in so will cam gears. That will be a whole other ball of wax...

Certainly a reasonable starting point. When I was planning going to 3.2 L I was going to add about 8% and go from there.

EDIT 2: I was looking through the old Prospeed threads and found this interesting. I never looked into this before because I just wasn't interested. Have you seen his AFR plot? It's kind of all over the place, but what's more interesting is he's inheriting the OEM AFR curve. This lends me to believe he doesn't have control over the actual fuel map individual cells? I'm not quite sure honestly... but my question is.. why not try to flatten those peaks and valleys? That's probably why the car I drove had some roughness.

With TunerPro RT I certainly intend to smooth out the peaks and valleys and see what happens.

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RYU · 19 October 2020

Thanks gents for your replies. Lots to unpack here. Will do so little by little. Just a few that come to mind immediately.

Regarding the benefit of an aftermarket ECU - IMHO it's better everywhere except in cost and time. If you don't have enough of both to spare, I'd 100% stick with the OEM as you are now. The reason I say this is because I've now driven 2 bone stock ECU driven 3.0Ls and one Prospeed 3.0L and the resolution in the tune of a stock ECU can be improved. It's been over 10 years since my car has been on a stock ECU so I have forgotten what mine was like :biggrin: Honestly, if I was looking at a near bone stock 3.0L engine rebuild.. the stock ECU would be appealing and I would jump into Demon II head first... however now that my eyes have been opened to the world of aftermarket ECUs, knowing what I know and already having sunk the cost... after a I/H/E i'd go straight to a standalone. The time investment is HUGE though (i've already spent $500 in dyno time alone and nearly 20hrs of street tuning time)... I'm still torn if it's all worth it. I sort of don't have a choice. I only trust 2 people to work on my ECU and one of them is me. I can give it to the local go-to tuners but I'm not willing to pay them the thousands of dollars for the hours and hours of tuning required to get everything right. I just can't imagine you can do that in a 3hr dyno session. With this in mind, I can totally 100% understand keeping as much of the OEM strategies intact. I'll happily admit part of my lack of fondness for the OEM ECU is my ignorance of kind of elegance exists in the code. I trust what you're saying here Paul!

Regarding the benefit of added timing. While I have yet to confirm on the dyno.. my seat of the pants / butt dyno feeling shows quite a bit of improvement in the TQ department with 5-10 degs of added timing bled at certain areas of the map. Given the OEM has to account for multiple shitty conditions (like crap gasoline) i'm sure this is why they were so overly conservative. Engine response is probably the biggest improvement but I can't say that for sure #becauseITBs . I have gone back to back with loading my extrapolated OEM timing table (Thanks @Honcho!!!) and my current street tuned timing table which has timing advanced baked in. There is absolutely a difference (probably ~10-20lb/ft, ~20-30wHP). Now if the dyno shows only a little improvement and does not confirm what my butt dyno is telling me, i'll revert back to the OEM because a little bit of added safety is worth it. Though, I feel i'm about 3-5 degrees retarded still before I reach the edge of knock threshold. It should be easy to load the maps and perform a couple of ramp runs with OEM vs. RYU timing maps. As a side note: I am worried about my own personal ability to detect knock in the C30. So i'll gladly admit that. I'm going easy on my car until I can verify all the numbers with the relatively safety of a dyno.

RDX vs. 1000cc injectors - I had RDX injectors on my CTSC and pretty much maxed them out but still surprised I didn't need more. Then again.. I ran my fuel rail pressure at 50-60psi as well. It was this way for nearly 10yrs. I was quite happy with them (except that shitty NSX multiple crankover starting cycle, more on this later if anyone is interested. I don't have this problem with the ITBs & 1000cc's). FWIW I still think the RDX injectors will idle poorly at 800rpm on my car because ITBs are oversized for this motor and air flow at such a low RPM is at such a low velocity. The idle quality at 1000-1100 rpm is super impressive though - she seriously hums here even with the 1000cc so since I already have them I'll likely just keep them. If I could do it over again, i'd have gone with the RDXs for sure. If they're enough for a ~350wHP/250lb-ft CTSC, it's enough for the 3.5L. I sold those with my CTSC kit. I may still go with the RDX because my interest might take the best of me during this crazy pandemic! I'm not looking forward to all the hours of more tuning though just to get to where i'm at now.

I'll be on my stock 3.0L for a while (albeit with ITBs sized for a 3.5L) so i'm happy to try a few things for you guys if you'd like.

[MENTION=7151]mskrotzki[/MENTION] - is the resolution in the stock tables enough to smooth out those peaks and valleys? it would be great if so. if so, i'm surprised Prospeed didn't do so. Seems like such a basic thing to do.

Sorry, I rambled on on this post. This is such an interesting topic!!!

jvtec95 · 22 October 2020

Just a couple thoughts on RDX injectors:

I don't think you can mathematically scale between injector sizes because the injector latency is different between the OEM (peak and hold) and RDX (saturated) injectors, the injector latency in the prospeed chips is changed to account for this (although there's some questions about how these values were found). I think there could be some improvement on the prospeed tunes once some of these things are better understood and messed with.

The injector pulsewidth (value on the fuel table) is a "signal time" of how long to send voltage to the injector. The RDX injectors have a longer latency, which means there is more "dead time" before the injector actually opens and allows fuel to flow.

I do think the prospeed tunes could be improved upon, they seem excessively rich and the map doesn't seem as smooth as the OEM maps. This seems supported by the "bumpy" torque curve above. The resolution of the OEM tables should be fine, I think it's the values in the tables that could be improved!

I'd like to get my car on the dyno (I work with someone who is a very good dyno tuner), but that most likely won't be until next summer. I'd like to see how much I can personally improve things before taking up dyno time (hoping to get the fuel tables where I'm happy with them, then see what ignition timing can add or change).

By the way, does anyone have the JDM .bin files? or the type-r?? I'd also be interested in any other "hot chips" people may have just to see what things have been tried in the past. I'd be willing to scan and load any .bin files from any chips and return them. Just to build the library of info and tuning examples to reference.

jvtec95 · 22 October 2020

One more thought, if the spray is better/finer on the RDX injectors then the rate of burn should increase which would mean you would have to retard timing to have the same peak pressure as the OEM injectors. Maybe the benefit of the RDX injectors with the OEM timing map is this "artificial" advance due to the fuel burning faster and having peak cylinder pressure earlier.

MotorMouth93 · 22 October 2020

Scaling will generally get you in the ballpark for changing injectors so you'd want to add some safety margin and then fine tune from there.

The way the ECU works is the injector latency is added to the final pulsewidth. The fuel maps are not just "signal time", they are "theoretical injector on time". I say theoretical because that depends on the injector latency tables being correct, and in our case, they are not. RDX injector latency (easily found by searching) is wildly different from what's in the RDX tune, I suspect some tricks were done with the latency tables to get the car to idle better with the RDX injectors.

I've seen some discussion revolving around this indicating that you can play with the dead times to make large injectors idle better but cause issues elsewhere in the tune since injectors tend to be non-linear at very low duty cycles, if this is what's actually happening in our case I could patch the binary to have separate "idle latency" and "run latency" tables that switch over at, say, 1200rpm to have the best of both worlds. The code would be simple to implement, but I need to do more reading on this subject first.

MotorMouth93 · 22 October 2020

RYU said:
* Lastly, I also mentioned in the linked thread above... While I totally commend and support the research into the OEM ECU, I do believe a higher resolution tune from a modern ECU is worth it. Hell, i've been able to get ITBs to have driveability nearly like stock (98%'ish) - that's unheard of. It's actually noticeably smoother than the OEM ECU NSX I drove in many aspects like startup and high res control over AFR to name a couple. I know it's daunting to tune a fresh ECU (trust me.. I know) but if you have the time, it's worth it to have control over everything (tip in, decel, pressure compesators, speed compensators, barometer, nearly everything you can think of, even per cylinder AFR and timing if you want to get into the weeds). I know the cost might be prohibitive but I know some folks on here are spending mucho dinero on their cars and adding a standalone is not being considered... why?

To answer your question why, it's simply because I can. Buying a standalone would be the easy way out in this case, it’s a challenge that I want to see if I can figure out. OEM engineers aside, you can probably count on your hands the number of guys in this country who can say their car runs on code they wrote themselves. If I succeed, I'll be the only guy on the planet running ITBs on an OEM NSX ECU.

Also, all of those compensations except for the per cylinder stuff you list are already present and tunable in the stock ECU.

I'd say there's a fairly decent chance that I'll end up with a standalone at some point if I can't get it running in a way I'm completely happy with, but I'm going to avoid that if at all possible.

Edit: I also believe that for most people who just want to get the most out of their basic modifications that there is absolutely no reason to buy a standalone when the stock ECU is perfectly capable of being tuned and will ultimately run better in most cases. Getting a perfect from scratch tune for a car like an NSX is not something most tuners are capable of within a reasonable amount of tuning time, but just tweaking some already running maps is fairly straightforward. Don’t get me wrong though, when you mix it up by adding forced induction or ITBs or other finicky engine builds where the enhanced resolution of a standalone can really shine it makes perfect sense to switch.

NSX_n00b · 22 October 2020

jvtec95 said:
By the way, does anyone have the JDM .bin files? or the type-r?? I'd also be interested in any other "hot chips" people may have just to see what things have been tried in the past. I'd be willing to scan and load any .bin files from any chips and return them. Just to build the library of info and tuning examples to reference.

I can send you the Dali Hot Chip out of my ECU to scan when I pull my car apart this winter

mskrotzki · 7 November 2020

I got my car back yesterday and quickly remembered why I waited so long (~4 months) and spent so much cash (~$16.5K) It is a FULLY rebuild SOS build with just about everything new -- every sensor, every seal, every hose, everything.

The ECU has the Demon II emulator installed with the, I think, original ProSpeed Stage III tune. It is as good as I recalled, especially since I'll be in break-in mode for the next 1000 miles or so. The mid-range torque and responsiveness is marvelous.

While wasting the whole day with CenturyLink trying (unsuccessfully so far) for an upgrade to FiberOptic Gigabite service -- they disconnected my DSL but did not connect the Fiber -- I looked into the fueling tables in TunerPro. Here is what I found:

RYU · 7 November 2020

mskrotzki said:
I got my car back yesterday and quickly remembered why I waited so long (~4 months) and spent so much cash (~$16.5K) It is a FULLY rebuild SOS build with just about everything new -- every sensor, every seal, every hose, everything.

The ECU has the Demon II emulator installed with the, I think, original ProSpeed Stage III tune. It is as good as I recalled, especially since I'll be in break-in mode for the next 1000 miles or so. The mid-range torque and responsiveness is marvelous.

While wasting the whole day with CenturyLink trying (unsuccessfully so far) for an upgrade to FiberOptic Gigabite service -- they disconnected my DSL but did not connect the Fiber -- I looked into the fueling tables in TunerPro. Here is what I found:

That's really interesting but it doesn't make sense to me. I'm probably reading it wrong but why is the OEM table richer than the Prospeed? Or rather, the later or leaner.

RYU · 7 November 2020

Also, is there any reason to believe the OEM ECU uses a target AFR table? I suppose it has to for Long and Short fuel trims? Is that target table viewable?

mskrotzki · 7 November 2020

RYU said:
That's really interesting but it doesn't make sense to me. I'm probably reading it wrong but why is the OEM table richer than the Prospeed? Or rather, the later or leaner.

My understanding is the entries in the chart are the foundation of the pulse width or time the injectors are open. The in PWs in these charts are functions of RPM (the vertical columns) and the engine load measured by throttle position (horizontal rows). I also understand that in the NSX case the final signal to the injectors determining the pulse width is further massaged by other factors, Intake Air Temp, Coolant Temperature Barometric Pressure, knock sensor return, etc, etc.

If the RDX injectors flow more fuel than the original injectors I think it makes sense they would have a lower pulse width than the originals to get similar AFRs or Lambdas. This is complicated by the fact that the RDX injectors apparently have greater latencies, which has to be taken into account.

What I don't understand, is why the Prospeed maps are so jagged. I understand that the ECU does smooth the signals it sends to the injectors, so they don't receive quite as jerky a signal as one might expect from the map. Part of my plan will be to take this in small increments to try and separate the many variables and get the best performance for my new engine in my 5300' above sea level environment. I am anticipating getting together with Paul, Sebastian and Spencer several times in the near future, COVID 19 permitting. [Cases here are spiking with >10% test positivity and I'm afraid we will be getting locked down in the near future.]

An additional complication is my car registration is woefully out of date since I couldn't get an air test in March and April (all the stations were shut down) and then my car was off the road. I'm concerned with the bas...... impounding my car at the test station unless I get a 15 day waiver, which is maddingly elusive.

Wish me luck.

RYU · 8 November 2020

Ah, bigger injectors. Of course. I had a brain fart moment

jvtec95 · 14 November 2020

So I got sick of trying to "fix" the ProSpeed tune and decided to just try from scratch. I changed the injector latency values from what was in the ProSpeed tune to some values based on actual latency measurements of the RDX injectors provided by sparky & greenberet in this thread:

http://www.nsxprime.com/forum/showt...unning-anything-OTHER-than-OEM-fuel-injectors

Then I took the OEM fuel tables and created a spreadsheet to scale them by injector flow difference (240 / 410 cc) and added a safety factor. Last weekend I went out and drove and datalogged for a while and scaled all tables by % until I was reading ~13:1 AFR on WOT. This turned out to be +8% on the safety factor, then I drove for a while with O2 sensor correction turned off (no fuel trim) and datalogged while keeping an eye on AFR values. Idle was pretty close to stoich or a bit leaner, no issues with stumbling or poor idle. I'm pretty happy with the results and I think it feels closer to "OEM" without any weirdness in power delivery or overly rich areas.

MotorMouth93 - Thanks for the info on how the ECU uses the latency value, I've got the PW value recorded in your datalogging file. Do you know if the datalog value is "final" (with corrections)? The reason I ask is when I look at the datalogging values, the PW is higher than what would be read off of the fuel tables. I'm guessing this is the value sent to the injectors?

Based on recent weather I probably won't be doing much further testing, the only other part of the ECU I think could use some attention is a group of TPS Delta % values for Accel Enrichment. They are also listed as PW based, so I'm guessing these are going to be artificially high for the RDX injectors. Not a big deal and didn't seem to affect driveability, but it would be nice to correct any PW based values to get things as close to OEM operation as possible. MotorMouth93 may know of some other areas to look into as well (or maybe he'll be running ITBs by then!)

RYU · 14 November 2020

Side question please, does the stock NSX idle at stoic 14.7? I've found the smoothest idle quality at around the high 13s. Granted I'm on ITBs.

Creasian21 · 15 November 2020

i just hooked up my wideband, running stock 91 ecu and injectors. im getting 14.5 -15.3 when warmed up and idling

MotorMouth93 · 15 November 2020

jvtec95 said:
So I got sick of trying to "fix" the ProSpeed tune and decided to just try from scratch. I changed the injector latency values from what was in the ProSpeed tune to some values based on actual latency measurements of the RDX injectors provided by sparky & greenberet in this thread:

http://www.nsxprime.com/forum/showt...unning-anything-OTHER-than-OEM-fuel-injectors

Then I took the OEM fuel tables and created a spreadsheet to scale them by injector flow difference (240 / 410 cc) and added a safety factor. Last weekend I went out and drove and datalogged for a while and scaled all tables by % until I was reading ~13:1 AFR on WOT. This turned out to be +8% on the safety factor, then I drove for a while with O2 sensor correction turned off (no fuel trim) and datalogged while keeping an eye on AFR values. Idle was pretty close to stoich or a bit leaner, no issues with stumbling or poor idle. I'm pretty happy with the results and I think it feels closer to "OEM" without any weirdness in power delivery or overly rich areas.

MotorMouth93 - Thanks for the info on how the ECU uses the latency value, I've got the PW value recorded in your datalogging file. Do you know if the datalog value is "final" (with corrections)? The reason I ask is when I look at the datalogging values, the PW is higher than what would be read off of the fuel tables. I'm guessing this is the value sent to the injectors?

Based on recent weather I probably won't be doing much further testing, the only other part of the ECU I think could use some attention is a group of TPS Delta % values for Accel Enrichment. They are also listed as PW based, so I'm guessing these are going to be artificially high for the RDX injectors. Not a big deal and didn't seem to affect driveability, but it would be nice to correct any PW based values to get things as close to OEM operation as possible. MotorMouth93 may know of some other areas to look into as well (or maybe he'll be running ITBs by then!)

The pulsewidth value in the logger has a variety of corrections (barometric pressure, IAT, etc.) applied so it won't match what's in the fuel tables, I don't remember if the injector dead time correction is included in that value though so I'll check on that next time I'm digging around in the assembly.

Can you share your current binary? I'd like to try it out and feed some data into the AFR chart generator script.

jvtec95 · 15 November 2020

Warm-up will always be richer than stoich due to coolant temp correction. Once up to operating temp, OEM ecu will always be stoich because it is running closed-loop and will cycle between slight rich and slight lean based on narrow-band O2 output (above values are same as I've seen). This is driven off of fuel trims, so even if the tables are off, the fuel trim will correct based on O2 sensor.

The info I don't have is what the OEM tables would put AFR at during idle with O2 correction turned off. I believe sometimes this is used to set new injector latency values when no other info is known.

Awesome work on the ITB setup RYU! I would think for stability a little on the rich side would be better for load fluctuation at idle, I'm sure its a tricky balance with ITBs. I have a set of Hayabusa 50mm throttle bodies I've yet to install on my Integra, if I get that figured out I may try to work on a similar NSX version (more fab work for a V formation). If I don't skip to forced induction on the NSX first... too many projects!

jvtec95 · 15 November 2020

Ok, thanks for the info on the PW, good to know.

Yeah, I'll upload it for you to take a look at, it will be good to get some others weighing in on it. Note, it was pretty cool out last weekend so hoping no idle issues pop up in warmer weather. It had no trouble starting or on warm-up for me, so I was glad the CTS corrections seemed to work well.

mskrotzki · 16 November 2020

This is becoming a very interesting ride. I got my car back, running on the Demon II with, IIRC, Jeremiah’s Stage III ProSpeed tune. The car ran great on the 90 mile drive home. I also drove to the Air Inspection Station and passed with flying colors. (Now I just have to wait for my registration tags to arrive in the mail.)

Coming home from passing Air Test, I got the laptop out and started fooling with TunerPro. At first I could not connect with the Demon II. The emulator has rather sketchy attachment to the ECU socket, and can easily become dislodged when plugging in the USB cable. I fooled with the case and inserted two screws through the side to positively hold the Demon into the socket by having them firmly hold the top of the Demon board, but carefully not distorting it in anyway or touching any components. The board was stable, but the connection to TunerPro was not. Wiggling the cable caused the Demon to attach and detach. I tracked that down to a bad cable from Moates and replaced it.

Then it got really interesting. I put the, at that time, the latest bin, xdf, adx and patch files into TunerPro, patched and uploaded the files to the emulator – and the engine basically wouldn’t run. It started hard, threw CEL and TCS lights, barely idled --- and smoked like crazy. Poor running could certainly be attributed to the ECU, but smoke? All the worst ran through my mind. Brand new engine, not taken above 4500 RPM, oil changed at 130 miles: Broken ring, bad valve guide, who knows?

Just before calling Paul Z, I removed the Demon and put my ProSpeed chip in, expecting no change, but low and behold, it runs fine. Starts easily, idles properly, no dash lights, no smoke, plenty of power: all is well with the world.

So I am stumped. The Demon ran fine for 130 miles before uploading new files. After uploading the car would not run at all, no matter what files I uploaded. Am I missing something running the Demon? Did I mechanically damage the Demon? What would cause all the smoke from an obvious bad tune? Later I’ll ask [MENTION=18194]Honcho[/MENTION] if I can briefly install his Demon to check out the damaged Demon theory. I should be able to come to a conclusion pretty quickly on that score.

I’m look forward to trying [MENTION=21305]jvtec95[/MENTION]’s new bin. I’ve downloaded it from the Google Docs site and will give it a try at my first opportunity. I’ll assume one needs the same xdf and adx files for logging as the previous bin file.

Could someone give me guidance in attaching the wide band O2 sensor into TunerPro and where the best place is for hooking up the heater power source? I just have the cable from the sensor behind my passenger’s seat so I’ll need a connector and a place to plug it in.

Thanks for everyone’s help.

Mark

MotorMouth93 · 16 November 2020

Sounds like the ECU isn't happy with the data it's receiving from the Demon so is going into failsafe mode which is hard coded to run the stock injectors, so will run stupid rich with the RDX injectors hence the smoke. A quick check to make sure the ECU is happy with the tune is to make sure the fuel pump primes when you turn the ignition on, if not then it's likely in failsafe mode. Once you get a bad tune on the Demon, it can be finicky to get it working again. Pull the ECU fuse so it's completely powered down, flash a known good file on the Demon, and try again. Don't try to start it unless you hear the fuel pump prime.

Also you shouldn't need screws to hold the demon in place, are you sure its seated in the socket properly?

The most likely issue is that the checksum is bad, the checksum is automatically updated when you save the bin so after applying a patch make sure to save it before uploading.

Or you might have applied the wrong patch.

You can send me your bin file and I can look at it if you want.

The easiest way to hook up the wideband is to connect the data signal from the wideband controller to the first analog input on the Demon. For powering it, I'd run a wire from the aux power port in the fuse box over the driver footwell.

mskrotzki · 16 November 2020

Thanks for the quick response. I’ll get on it tomorrow and ensure I hear the fuel pump prime.

The socket on my ECU is from the old ProSpeed Chip I had (and still have running right now). I just looked in my Demon box and see two different sockets with two different pin receptors. Perhaps changing to one of those would seat the Demon better. What I have right now seems to be OK.

I was ignorant of the checksum issue. I ran the 90 miles home and passed the air test on Jeremiah’s Stage III ProSpeed bin – NSXProSpeed.bin with the NSX.XDF from the Google Docs collection.

I tried the NSXProSpeed-09-20p with the tunerpro_nsx_work_in_progress_prospeed_patch_v2.xdf and the tunerpro_demon_datalogging_work_in_progress.adx. I used the tunerpro_nsx_work_in_progress_ prospeed_patch.xdf patch by opening it in TunerPro and applying the patch. This is the only patch I'm aware of. I did not save it – which sounds like the root of my problems. The demon is sitting on my workbench and the ECU is functioning perfectly with the old ProSpeed Chip installed. Is pulling the clock fuse after reinstalling the Demon still necessary?

Thanks for the tip on powering the O2 sensor. Is there a schematic to locate the first analog input on the Demon? How would I find this?

It’s supposed to be warm here for the next few days, so it will be a good time to get this sorted out.

MotorMouth93 · 16 November 2020

If the socket looks like this then yeah that could cause issues with the Demon staying in place. These sockets are intended to hold ROM chips which have a different pin design than the Demon board.

You need to use the logging patch from tunerpro_nsx_work_in_progress_prospeed_patch_v2.xdf. The one from tunerpro_nsx_work_in_progress_ prospeed_patch.xdf does not work and will cause the failsafe mode like you're seeing (hence the DOESNT_WORK part of the folder name), jvtec encountered this issue a couple months ago.

There is a green screw terminal block on the Demon board with labels GND, AI_0, AI_1, AI_2, and AI_3. The ADX assumes an LC2 wideband signal is connected to AI_0 but you could use any other wideband controller if you set the conversion equation up properly. You also need to ground the GND terminal. You could also connect other things like oil pressure or oil temp sensors to the other analog inputs.

@jvtec95 Have you seen any differences in AFR between the front and rear banks with your setup?

mskrotzki · 17 November 2020

I reinstalled the Demon II this morning, loaded [MENTION=21305]jvtec95[/MENTION]’s ProSpeed NSXRDXNOV2020.bin to the emulator, turned the key, listened for and heard the fuel prime, turned the key the rest of the way and all was well. I didn’t take the car out of the garage, as its registration expired in April. If I really needed to go somewhere with it, I would take a chance. Denver cops have lots more to do than watch license plate expirations. (I did drive it to get its air check.)

I do have the tunerpro_nsx_work_in_progress_prospeed_patch_v2.xdf and the tunerpro_demon_datalogging_work_in_progress.adx installed also – but I’m not yet able to get the dashboard responding. The Moates Demon II Logging Patches still show up in the Parameter Tree – but they have NOT been applied to the NSXRDXNOV2020.bin.

I’ll probably wire the O2 sensor tomorrow and try to get Data Acquisition going. Whenever I click the Acquire Data arrows I see the orange label “DA Connecting,” in the lower TunerPRo border but never anything more. Does the box turn green and say something like “Connected” when all is well?

Not being much of a solderer, I am disinclined to mess with the socket at this time. Later perhaps.

Thanks for all your help.

Mark

MotorMouth93 · 18 November 2020

The file NSXRDXNOV2020.bin already has the logging patches applied, if your TunerPro configuration is correct it should "just work". Make sure the port type is set to "Shared with Emulator" and also check the connections on the ECU to make sure they are routed properly.

Tuning the NSX 3.0L Using the OEM ECU

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