Honcho's Long Road to Imola Type-S Zero

[Honcho]

Seats, Upper Trim, etc.

The NSX-R belt buckles did not reach far enough to easily engage the belt tab. The driver's side was still serviceable, but the passenger side required the driver to unlatch the buckle. This was unacceptable to me from a safety standpoint. So, I sent some spare Honda buckles out to Safety Restore, who graciously lengthened then using new webbing and DOT-certified stitching. It's now easy for people to latch and unlatch. Of course, that meant the misery of pulling the seats out again.

The Wedge brackets cannot accommodate the steel tab in this configuration, so I had to make my own. These seat belt brackets are welded 1/8 steel.



Much better



A little vacuuming and it's back in. Now that the buckle no longer sits between the seat and the console, I was able to move the seat further away from the door panel. It still touches, but not as badly.



Whenever you pull the seats, you're rolling the dice on the trim. I covered the (brand new) sill piece with a cloth, but about 5mm was left exposed. Of course when I stumbled with the seat, the corner of the rail dug right into the unprotected portion. I'm trying not to rage about it and tell myself that the car is 30 years old and has some "patina". Grrrrr.



I also was able to hot glue the pins on the oil temp light control unit, which meant I could install the upper trim piece. Of course, I cracked the middle tab pin trying to pop into place. New ones will be ordered.

 

[v-tecpwr]

The new NSX has a side sill cover like our engine bay service mat that you can buy. That will save your side sills when taking your seats out. Part # is 07AAZ-T6NA700 It even has the NSX logo on it.

 

[Honcho]

Test Drive 6

VTEC, Power Enrichment, etc.



Today was a gorgeous sunny day and I decided to take the plunge and start using those Comptech cams. That meant it is time to tune VTEC! Johnny Tran would be proud. Now, for the three people who actually care about this stuff, it's time for charts!



What you see above is a 2nd-3rd WOT run starting at about 3,000 RPM. It revealed a lot about the car:

• The craziest result is that the NSX decided it was a good idea to go back into closed loop (red line above) between 3,904 RPM and 6432 RPM and start adding fuel like mad. This is with the throttle buried. It then re-entered open loop for the rest of 2nd gear and all of 3rd gear. From a pulsewidth standpoint, it exited closed loop at 7.542 ms, re-entered at 6.736 ms, and then exited again at 9.267 ms. @MotorMouth93's excellent work on the ECU shows us that there are three main triggers for open loop: throttle position, minimum PW for open loop, and maximum PW for closed loop. My NSX was way beyond the threshold on all three of these triggers, yet the car went back into closed loop. Clearly, there is something else playing a role. More research is needed.
• Next, the car entered VTEC normally. Thank God. My base level VTEC tune is pretty close- you can see that the VTEC AFR starts around 13.0 and slowly rises to about 13.7. All I did was take the 1994 OEM VTEC map and reduce it by 20%. It looks like I took a little too much fuel out of it. Using the chart, I adjusted the key cells on the map to add back between 2% and 5% fuel depending on the AFR. I ended up here:

You can see that I added a "hump" of fuel around the (VE)max area of the engine, which on the NSX is between 6,800 and 7,200 RPM. I added 5% fuel at 7,000 and 7,200 and 2% fuel at 6,800 and 7,400+. I'll do another pass in the future to see if this brought the AFR into the "ideal" range of 12.5-13.0.

• You'll also notice that the area selected is not at the max range of the fuel map. It's because here at 6,000 feet ASL, today's barometric pressure was 25.5 in/hg. This meant that the most Load the S Zero could generate was 75%. That's right, up here in the Rockies, my car is down 25% on power (at least today- we can see 26+ in/hg in Denver). Crazy part is it still feels quicker than a stock NSX would be at sea level. Unfortunately, the only way to tune the 80-100% area of the map is to bring the car to sea level- project for another day.
• Below are the same two pulls showing Load (green), Throttle (orange) and RPM (purple). Notice how the Load drops slightly as the car climbs to redline? The drop can be anywhere between 2% and 5%. John thinks it may be a restriction in the intake tract- my car is using the AT snorkel. More research needed here, since Load isn't just a straight line to manifold pressure. There may be other factors causing the drop.

• My tach needs a little calibration. The reason you see those rev limiter hits is that it was indicating about 7,500 RPM at the redline. At lower RPM, it is quite accurate though.
• There are some annoying rattles and buzzes. I know this is because I stripped out a lot of the sound deadening, so it's kind of a lame complaint. I may still try to chase them down and fix with a roll of felt tape.
• Finally, my driver's window alignment isn't perfect- there is an annoying whistle above 100 mph. I can't do much to change it until I address the stiffener beam in the door.

Overall the car is extremely strong and fast- the speed comes on urgently and it pulls hard all the way to redline. It's been over 10 years since I last drove a Comptech cam-equipped NSX and this reminds me why I liked it so much. I think CT did a really nice job with the profile- the VTEC crossover is is almost seamless. You just notice a slightly louder roar above 6,000. But the power band just grows and grows smoothly all the way to redline. It's definitely not the Johnny Tran slam-you-in-the-seat Civic style. Thanks to John, the logger and software is getting dialed in further. For now, the main task will be to uncover why the NSX is staying in closed loop so long and why it is dipping back in during max throttle acceleration.

 

[Zoom]

• Finally, my driver's window alignment isn't perfect- there is an annoying whistle above 100 mph. I can't do much to change it until I address the stiffener beam in the door.

Wait, aint that a feature of every NSX ? Thought that wind noise (100+ kph for me.. or about 60mph) was a given by those frameless windows. Aligning those looks like a huge PITA...

 

[Honcho]

ECU Tuning

Yesterday we solved a puzzling issue revealed by my VTEC logs: right before going into open loop, the fuel pw would spike and cause the AFR to go way rich (like 9 or 10). @MotorMouth93, who is now the guru of the NSX ECU code, noted that there is a delay before shutting off the closed loop system, where the ECU switches to the open loop map, but leaves the fuel trims on for a few milliseconds. You can see that here in the straight blue line:



Because the fuel trim was "locked" at +15% during the switch to the open loop map, this meant the car was adding 15% fuel to an already rich map. You can see the result in the green line. Injector PW is putting along at ~7000 and then spikes up to 10000! The red line is AFR- look how it drops at the same time. All the way down to 10.9 this time. You want a little of that to protect the engine and also to manage the VTEC (light blue line at the bottom) changeover, but this is too rich.



Basically, John figured out that the low cam open loop base maps are too rich in these regions, so the trim multiplier is adding fuel to an already rich condition. Reducing fuel in these zones will smooth out this transition, so that AFR only drops to 12.5-13.0.

I pointed out that this behavior may be a feature, not a bug of the OEM fueling logic. I assumed that the car would go into open loop once I stomped on the gas, but it appears that the car prefers to stay in closed loop until right about the VTEC crossover. Honda may have set it this way for emissions purposes, and the low cam open loop base map may just be a "transitionary" map to keep the fueling safe until the VTEC map takes over fully. In this case, the NSX waited until 5,682 RPM before it decided that it should exit closed loop and then exited at 6,082 RPM.

However, the above didn't solve the problem of the NSX going back into closed loop during the middle of the pull. Below is that curious situation. Orange line is throttle- you can see I sort of rolled on the gas at about 1,900 RPM an then stomped on it. In this case, the car made the right initial call: "I'm accelerating hard so I should go into open loop). But then, in the middle of a WOT acceleration, the NSX decides it would be a good idea to go back into closed loop! You can see the fuel trims (blue line) kick back on and the AFR (red line) shoots up to ~14.7.



The three factors that control the open/closed loop transition are:

• MaxPWForClosedLoop - Closed loop won't operate above this limit
• MinPWForOpenLoop - The car won't go into open loop below this limit
• Throttle Position - The car will enter open loop if the throttle is pressed over this limit

John explained it in detail here, but it's basically a truth table concept, where the ECU establishes certain conditions as true/false and makes the closed/open decision based on the matrix output.

So, I placed the cursor at the point where closed loop turned back on and used the data tracing function in TunerPro to see where I was on those three factors:



At the time the NSX decided to re-enter closed loop, FinalPW = 6736 and TPS = 101. Based on the chart, open loop should have stayed on because 6736 > 2500 (MinPW for open loop), 6736 > 4820 (MaxPW for closed loop) and 101 > 40.18 (TPS for open loop). The only thing I can think of is maybe the ECU doesn't compare the FinalPW to measure this, but some other PW (like the base map maybe?). However, this only occurred once. On all other pulls, the car went into open loop and stayed there. Maybe this was just a blip?

An interesting mystery.

 

[Ready2RetireAt21]

Amazing work! I’m guessing this is how the Acura Factory Refresh program would be……times 10.

 

[tucsonsx]

I doubt the factory refresh would approach this level of quality. This is a labor of love - the price would be astronomical if Honda put this kind of time and effort into a project. From what i have seen following this thread this car is better than anything that came off the line in Tochigi.

 

[Honcho]

I doubt the factory refresh would approach this level of quality. This is a labor of love - the price would be astronomical if Honda put this kind of time and effort into a project. From what i have seen following this thread this car is better than anything that came off the line in Tochigi.

Thanks! Yeah, if this was done at Honda, you'd be looking at $150,000 to $200,000, and they would not have changed it to a Type-S for you. I'm not sure that they would agree to color change either.

But, you would get all new components like the suspension members and stuff like that, so there is that...

 

[Honcho]

Engine Refresh 95

Time for the final verdict.




The fluid stayed blue. If there was a head gasket leak, it would turn bright yellow. I can now call the engine refresh process complete.

 

[Honcho]

Re-Assembly 114

A-pillars

Managed to get the black covering completed on the A-pillars. The fumes from the contact cement made my head dizzy. You can see my black ABS cement repair from where it cracked in half. I am ordering the Honda genuine parts just in case these crack again.

 

[MrHugo]

This car is one of a kind. I would be more scared to drive this than lets say a GT3RS since I know I can buy another GT3RS as long as I have money. Not something I can say about this car....

 

[Honcho]

This car is one of a kind. I would be more scared to drive this than lets say a GT3RS since I know I can buy another GT3RS as long as I have money. Not something I can say about this car....

Thanks, I've actually been driving it quite a bit, even without the PPF. It's just too fun to let it sit.

 

[RYU]

Thanks, I've actually been driving it quite a bit, even without the PPF. It's just too fun to let it sit.

I just did the PPF on the front end of my DD. It wasn't as hard as I thought but admittedly I rushed it and did a 8/10 job. Plenty fine for a DD since it's mostly for protection. On second thought.. a high dollar paint job like yours might cause me to think twice.

hey, do you know where one can buy that material you're using to cover the A pillars? Not sure if I missed that somewhere on your thread.

 

[Honcho]

I just did the PPF on the front end of my DD. It wasn't as hard as I thought but admittedly I rushed it and did a 8/10 job. Plenty fine for a DD since it's mostly for protection. On second thought.. a high dollar paint job like yours might cause me to think twice.

hey, do you know where one can buy that material you're using to cover the A pillars? Not sure if I missed that somewhere on your thread.

Yeah, I'm going to pay a professional- I want the paint to look perfect, and be able to track and drive on club events. My car is sort of famous at this point, so I feel like I have to keep it looking 100%. LOL

I found the fabric on some random China auction site I think. It was years ago, so let me see if I can dig up the receipt.

EDIT- It was ebay:

https://www.ebay.com/itm/2224991973...VQebQxs-wlE_1vUGZtPQCK6KdVJzS3fBoCigQQAvD_BwE

 

[RyanRA]

My car is sort of famous at this point, so I feel like I have to keep it looking 100%. LOL

Seeing your car in person may just nudge me to attend my first ever NSXPO. : )

 

[Honcho]

VTEC Tuning

Thought Prime would enjoy this. Gives you an idea of the car and my engine work.

 

[docjohn]

that sounds beautiful...so happy to see it out revving away..

 

[Honcho]

that sounds beautiful...so happy to see it out revving away..

Thanks- it shifts so lightly and directly too. The damper delete, LWFW and Kaz-style clutch job really make a big difference. It's racecar...ish but totally streetable. It's exactly what I was aiming for. The Bee's Comptech cams are pullin hard too!

 

[tdiggity]

Re-Assembly 113

Type-S Badge

I'm drilling holes in my freshly painted NSX...

The final milestone is here: Type-S Zero. There is some more tweaking and tuning to do, but the car is effectively done. I said 4 years ago that placing the badge would be the last step. And here were are.

Amazing attention to detail on the badge mounting!

I'm got a situation where I have an aftermarket front bumper without a honda/acura badge. Any tips on mounting the badge to the front bumper in the OEM location? Knowing me, it would be off by a few mm and annoy the hell out of me for all of time.

 

[Honcho]

Amazing attention to detail on the badge mounting!

I'm got a situation where I have an aftermarket front bumper without a honda/acura badge. Any tips on mounting the badge to the front bumper in the OEM location? Knowing me, it would be off by a few mm and annoy the hell out of me for all of time.

**EDIT** - I just realized you have an aftermarket bumper with no pin holes. You need to find the centerline of the bumper. Use painter's tape and find some control points on the bumper or hood that you can measure from. I used the tail lights on the rear bumper as my control point. Once you have the centerline indicated with a tape line, position the badge vertically on the line until it looks right. Mark the pin holes at that location and drill.

You can't mess it up- the front badge has two pins to align it and two push-nuts to hold it in place:

 

[tdiggity]

**EDIT** - I just realized you have an aftermarket bumper with no pin holes. You need to find the centerline of the bumper. Use painter's tape and find some control points on the bumper or hood that you can measure from. I used the tail lights on the rear bumper as my control point. Once you have the centerline indicated with a tape line, position the badge vertically on the line until it looks right. Mark the pin holes at that location and drill.

You can't mess it up- the front badge has two pins to align it and two push-nuts to hold it in place:

View attachment 178743

Yea, aftermarket Mode4 bumper. I don't have any good control/reference points because I don't have the OEM bumper either. Will need to hit up a local meet and take some measurements.

 

[jvtec95]

Honcho, I noticed your tuning questions and I went through some similar issues when I had upgraded to the RDX injectors. @MotorMouth93 is the expert, but I wanted to share some info that helped me when I was troubleshooting. I was also experiencing dropping out of the PE / open loop. I went through the ECU tables and found quite a few that deal with PE setting based on PW. Take a look at the attached screenshot from my TunerPro cal, and make sure you've adjusted all of the tables that reference PW.

 

[jvtec95]

Tables that reference PW that need to be re-scaled:
Max Pulsewidth for ClosedLoop Operation ClosedLoopMaxPw
PeReduc MinPulsewidth
TPS Delta % vs. AccelEnrichPw TableA - Under RPMThreshA
TPS Delta % vs. AccelEnrichPw TableB - Under RPMThreshA, PostCranking
TPS Delta % vs. AccelEnrichPw TableC - Over RPMThreshA
TPS Delta % vs. AccelEnrichPw TableD - Over RPMThreshA, PostCranking
TPS Delta % vs. AccelEnrichPw TableE - Over RPMThreshB
TPS Delta % vs. AccelEnrichPw TableF - Over RPMThreshB, PostCranking

Scalars:
Min PW for DynInj Timing
MinInjPw, PowerEnrichment

You can also monitor the status of PE, in the image above the green line is PE, purple is VTEC status (0 = off, 1 = on)

Also shown above is the changes I made to the Voltage vs. Injector Latency for the RDX injectors, which I'm assuming you've already changed (more of a reminder for anyone else reading this). ProSpeed chip had this messed up also.

For tuning, I believe you can disable the oxygen sensor system switch so it doesn't apply trim (I think that's what I did on the dyno, it was a couple years ago now). The image above is form street tuning datalog, so you can see the transition from trim applied to open loop when the throttle is WOT.

Hope this helps, I may be missing some things, but for the last 2 years my car has run like OEM+ and dyno tuning and datalogging haven't shown anything weird going on.

 

[Honcho]

@jvtec95 I was hoping you'd chime in here. I ended up on the same path as you, adjusted all of those tables and managed to eliminate the drop out issue. I'll post a screen of my adjustments tomorrow. Next up I'm going to use Johns tuning scripts to tune open loop.

**EDIT**

I noticed my accel enrich PW are bigger than yours, but they are still 20% below OEM.

 

[Honcho]

MCS Suspension, PPF

MCS reports that the shocks are revised and on their way back to Denver. Can't wait to get them on there!

In other news, the Zero is currently at PPF getting Xpel Ultimate wrap. It will be quite a relief to have the paint protected. Next step after that is to find a shop to extend the rear header adapter.