After completing my OBD2 BaschBoost supercharger (BBSC) install, tuning, and putting some miles on it, I thought I'd do a writeup on the process.
Details: I puchased a used Novi 1000 BBSC from a fellow Prime member some time ago, but it came with a first-gen Split Second (SS) box. I sent the box off to Mark Basch, and received a replacement after a bit of waiting. In the meantime, the kit sat in my garage, and I polished some parts by hand and got some other things taken care of. I obtained a 8lb pulley and Walbro 255 fuel pump from chudson1549.
My car is an almost stock '98, with a 3.2 engine, throttle-by-wire, and OBD2. I was made aware of the potential issues of the install from the beginning, but decided that the gains would be worth the time spent troubleshooting.
Installation: The installation was split over two days, due to some initial problems. The injector plugs on the OBD2 models are different than OBD1 models, for reasons I never tracked down. We were able to track down the OBD1 plugs from other honda harnesses that we had access to. I initially put the the older-style plugs on using in-line splices. After some problems with the cats overheating after the kit install, I cut all the original plugs off and soldered on the old-style plugs, alleviating the problem. I did a little bit of research into the injectors - it seems the 3.0 cars use peak/hold injectors, and 3.2 use saturated. Saturated can be used in place of peak/hold, but not the other way around. Fortunately, the 440 RC injectors that come with the kit appear to be saturated, as they test at 16ohms. More info can be found here.
RacerX-21 of DAL Motorsports did the installation of the kit itself. It took him about 12 hours. His expertise of the kit and the car in general was evident throughout the installation, although my expertise in handing tools to him was second to none. The difference in the headers on the 3.2 did slow the progress down a bit over a 3.0 installation. I drove off with the car under the stock fuel management system; very rich, and hardly drivable. Installation pictures can be found here.
We moved from a dual stage fuel system to a single stage. This required bypassing the large silver resistor on the front, right hand side of the engine. When the car is running at lower speeds, the fuel pump is throttled back by running through this resistor; at higher speeds, the resistor is bypassed. To ensure we had enough fuel always being delievered, we bypassed the resistor by shunting the wires leading to the resistor. Coincidently, there's a connector on the targa models that goes to the clamshell, but isn't plugged into anything once in the clamshell- it happens to have the same plug, so I used it so that I can switch back to a dual-stage system, if need. Having a single-stage system hurts fuel economy, but makes tuning easier, as the fuel delievery is constant.
I have since switched to a Gatorback belt, which has helped immensely with slippage. The part number for this belt is 4060672 / 6PK1705 ; I'm not sure if the last number is the 6-pack number - in any case, I got it from a local AutoZone.
Electronics: This was the most difficult part. I had the next-gen SS box, but no wiring diagram and no harness. I finally found that the EVO VII/VIII worked as a drop-in replacement, and got some wiring diagrams from AndyVecsey. It turns out that the connections for the OBD2 cars are electrically the same as the OBD1 cars, but the pinouts in the harnesses are different. I'll later post the wiring diagrams here for future reference. Also note that I had a harness that originally came from Mark Basch, but was missing 9 pins. It turns out that this harness won't work in OBD2 cars - you need a harness with all the pins- the one above does have all the pins. The SS box was loaded with all 10's in table A (fuel delivery) and all 0's in table B (timing) - no change from stock, so the SS box shouldn't be modifying any signals, and the car should run as if the SS box didn't exist.
We had several problems starting here. First, the engine had problems starting - it would turn over easily, but would never fire. Removing the harness (and thus taking the SS box out of the loop) would cause the engine to start up again without any issues. With the SS box in-line, we could start the car with a rolling start. I called and spoke to Mark at Split Second about the problem; I was first told that it was an issue with my car or that I had a bad battery. I suspected this was untrue, but replaced the battery anyway with a larger one - no difference. He then told me about a 100k ohm resistor inline on the yellow wire (CAM angle sensor) inside the black box, but not covered by the epoxy; this resistor was in place because some cars were sensitive to starting, and others sensitive in the 7-8k rpm range. His suggestion was to first remove the resistor to see if the car starts, then replace it with a smaller and smaller one until the car didn't start, and choose the next highest one up - this would supposedly solve the starting problem and minimize the high rpm problem. Removing the resistor didn't help.
I had called Larry Bastanza as well, although he was just as stumped as the rest of us. but gave me several other ideas to try.
Based on his recommendation, I tried bypassing the SS box one wire at a time. As luck would have it, the first wire I tried did the trick. It was a CAM angle sensor wire - one of the yellow or tan wires. At this point, we knew that a) the car would start fine with the supercharger on the stock ecu and b) the car would run fine on the SS box. So, after going back and forth with Split Second, I finally got the idea to use a relay and bypass the SS box on startup. A hack, but after my 10th resoldering of the harnesses, two harnesses @ $140/ea (too many times resoldering on one), and 10 days of trying, I was open to anything. I picked up a $4 DPDT relay from Radio Shack, wired it in, and it worked the first time. The resistor in the SS box was removed again, and the relay was soldered in position.
Check Engine Lights: The next problem I had was constant Check Engine Light (CEL) problems, and the car going into "limp home mode." I picked up an Auterra OBD2 -> Palm scan tool, which made diagnositcs much easier. I was getting engine misfire codes all the time. Finally, Kodiac, who had been there through the entire process, guessed that the vacuum hoses we were using to send the vacuum to the SS Box were too small. We replaced them with larger hoses (3/8" ?), and the problems went away.
Tuning: We finally scheduled some dyno time, and pulled 375rwhp on the first run, slobbering rich. I don't have a tap for an five-wire O2 / FJO sensor, so I'm just using the tail pipe sensor on these runs. Kodiac was very familiar with the SS box, and we had the map that the nsxnut was using on his 8lb BBSC setup with a 3.0. Within an hour, the car was tuned, showing 11.5 A/F's across the board (although probably slightly richer, given that we were using a tailpipe sniffer and not an FJO). We let it cool for a bit and did two final runs. The first was at 380rwhp. Kodiac remembered the VVIS was still enabled, so we pulled the VVIS vacuum line (effectively disabling VVIS) and put a screw in the end. The final run was 390rwhp / 267 ft-lbs.
My map, tuned for 3.2L engine, BBSC w/ 8lb pulley, Walbro 255 fuel pump, 440 injectors, single stage fuel system, 93 octane pump fuel, and ~70F temperatures can be found here. Obviously, I will gaurantee that this will not work as-is for you- it is only meant as a reference and starting point for work on a similar setup.
Dyno: The final dyno sheet is shown below. Keep in mind that this is a heat-soaked engine - I would imagine that the engine is pulling around 400-410rwhp on a good run; I'll post when I go back to the dyno.
For reference, the accepted drivetrain loss for the NSX is ~12%, so 400rwhp =~ 450 crank hp. I never dyno'd my car before the supercharger, but assuming a 290hp starting point, that's about 160hp and 80 ft-lbs of gain.
Vacuum Tuning: We had talked to Mark at Split Second about the best way to tune OBD2 cars. He suggested that, by using a scanner, the long-term fuel trim values can be monitors. The ECU constantly monitors the engine and sets both short and long term fuel trims for each range of RPMs. To make the engine happy (and to make it run well), we drove the car and held the engine in each column on Table A on the SS software, adjusting the fuel value as necessary until the scanner showed a long term fuel trim of +/- 3%.
History: I don't have a long history with the engine, but enough that I feel that I can say it was a success. I've driven it about 1000 highway miles (~23mpg) and 340 track miles @ VIR, including a solid hour of track time and holding 7950 rpm for almost a mile @ 125mph on consecutive laps. Not a single problem with overheating, CEL's, or any other issues. The car performed flawlessly. I'm not a very experienced track driver, but the engine was still run hard. As a side note, the intake air temp (as reported by the scan tool) was around 90F, or about 40 degrees over ambient. This was also true on highway driving - about 110F when the outside air was around 70F. I have no explanation as to why the IAT's are seemingly low to the other supercharger installs I've seen.
Current Issues: I call these "issues" because they're not really problems- just minor things that need to be worked out. The first is that the car sometimes wants to stall when falling back to low RPM, say when I hold the clutch from 4k rpm back to idle. It doesn't happen all the time, and I can catch it if I just pop the clutch back out, but it does make stop and go traffic tough.
The only other issue is that I sometimes (maybe once every 200 miles) get a CEL for an EGR sensor issue, only in constant throttle, highway conditions. This wasn't an issue in the city or the track, and doesn't impact performance, but is annoying. It's related to the vacuum system and "stealing" too much vacuum to run the SS box and the bypass valve. When I find a solution, I'll post. UPDATE: See post below. I now don't think this is related to the EGR at all, but to a possible blown cat earlier.
Special Thanks: I'd like to publicly thank the following people in their help in getting this running: Mike Daniel (Kodiac), Mark Hicks (the nsxnut), Rob Morrison (RacerX-21), Mark at Split Second (949-863-1359), Andy Vecsey (AndyVecsey), and Larry Bastanza (Larry Bastanza). I've also been honored with a direct call from Mark Basch (NSXTech) himself after he caught news of my success, and am happy that I was able to offer my $3 relay fix as a possible permanent fix for future SS boxes.
Final Notes: I'm very happy with the kit and the progress with my car. I would like to stress to everyone that the kit itself performs flawlessly - the majority of the issues are related to tuning the SS box, and the original SS box has been replaced with the second-gen version. An AEM or other high-end box may be a much easier (although more expensive) solution. I still plan on posting the complete wiring diagrams and part numbers of the items I used. I hope this helps someone, and I'll be happy to answer any questions I can.
Details: I puchased a used Novi 1000 BBSC from a fellow Prime member some time ago, but it came with a first-gen Split Second (SS) box. I sent the box off to Mark Basch, and received a replacement after a bit of waiting. In the meantime, the kit sat in my garage, and I polished some parts by hand and got some other things taken care of. I obtained a 8lb pulley and Walbro 255 fuel pump from chudson1549.
My car is an almost stock '98, with a 3.2 engine, throttle-by-wire, and OBD2. I was made aware of the potential issues of the install from the beginning, but decided that the gains would be worth the time spent troubleshooting.
Installation: The installation was split over two days, due to some initial problems. The injector plugs on the OBD2 models are different than OBD1 models, for reasons I never tracked down. We were able to track down the OBD1 plugs from other honda harnesses that we had access to. I initially put the the older-style plugs on using in-line splices. After some problems with the cats overheating after the kit install, I cut all the original plugs off and soldered on the old-style plugs, alleviating the problem. I did a little bit of research into the injectors - it seems the 3.0 cars use peak/hold injectors, and 3.2 use saturated. Saturated can be used in place of peak/hold, but not the other way around. Fortunately, the 440 RC injectors that come with the kit appear to be saturated, as they test at 16ohms. More info can be found here.
RacerX-21 of DAL Motorsports did the installation of the kit itself. It took him about 12 hours. His expertise of the kit and the car in general was evident throughout the installation, although my expertise in handing tools to him was second to none. The difference in the headers on the 3.2 did slow the progress down a bit over a 3.0 installation. I drove off with the car under the stock fuel management system; very rich, and hardly drivable. Installation pictures can be found here.
We moved from a dual stage fuel system to a single stage. This required bypassing the large silver resistor on the front, right hand side of the engine. When the car is running at lower speeds, the fuel pump is throttled back by running through this resistor; at higher speeds, the resistor is bypassed. To ensure we had enough fuel always being delievered, we bypassed the resistor by shunting the wires leading to the resistor. Coincidently, there's a connector on the targa models that goes to the clamshell, but isn't plugged into anything once in the clamshell- it happens to have the same plug, so I used it so that I can switch back to a dual-stage system, if need. Having a single-stage system hurts fuel economy, but makes tuning easier, as the fuel delievery is constant.
I have since switched to a Gatorback belt, which has helped immensely with slippage. The part number for this belt is 4060672 / 6PK1705 ; I'm not sure if the last number is the 6-pack number - in any case, I got it from a local AutoZone.
Electronics: This was the most difficult part. I had the next-gen SS box, but no wiring diagram and no harness. I finally found that the EVO VII/VIII worked as a drop-in replacement, and got some wiring diagrams from AndyVecsey. It turns out that the connections for the OBD2 cars are electrically the same as the OBD1 cars, but the pinouts in the harnesses are different. I'll later post the wiring diagrams here for future reference. Also note that I had a harness that originally came from Mark Basch, but was missing 9 pins. It turns out that this harness won't work in OBD2 cars - you need a harness with all the pins- the one above does have all the pins. The SS box was loaded with all 10's in table A (fuel delivery) and all 0's in table B (timing) - no change from stock, so the SS box shouldn't be modifying any signals, and the car should run as if the SS box didn't exist.
We had several problems starting here. First, the engine had problems starting - it would turn over easily, but would never fire. Removing the harness (and thus taking the SS box out of the loop) would cause the engine to start up again without any issues. With the SS box in-line, we could start the car with a rolling start. I called and spoke to Mark at Split Second about the problem; I was first told that it was an issue with my car or that I had a bad battery. I suspected this was untrue, but replaced the battery anyway with a larger one - no difference. He then told me about a 100k ohm resistor inline on the yellow wire (CAM angle sensor) inside the black box, but not covered by the epoxy; this resistor was in place because some cars were sensitive to starting, and others sensitive in the 7-8k rpm range. His suggestion was to first remove the resistor to see if the car starts, then replace it with a smaller and smaller one until the car didn't start, and choose the next highest one up - this would supposedly solve the starting problem and minimize the high rpm problem. Removing the resistor didn't help.
I had called Larry Bastanza as well, although he was just as stumped as the rest of us. but gave me several other ideas to try.
Based on his recommendation, I tried bypassing the SS box one wire at a time. As luck would have it, the first wire I tried did the trick. It was a CAM angle sensor wire - one of the yellow or tan wires. At this point, we knew that a) the car would start fine with the supercharger on the stock ecu and b) the car would run fine on the SS box. So, after going back and forth with Split Second, I finally got the idea to use a relay and bypass the SS box on startup. A hack, but after my 10th resoldering of the harnesses, two harnesses @ $140/ea (too many times resoldering on one), and 10 days of trying, I was open to anything. I picked up a $4 DPDT relay from Radio Shack, wired it in, and it worked the first time. The resistor in the SS box was removed again, and the relay was soldered in position.
Check Engine Lights: The next problem I had was constant Check Engine Light (CEL) problems, and the car going into "limp home mode." I picked up an Auterra OBD2 -> Palm scan tool, which made diagnositcs much easier. I was getting engine misfire codes all the time. Finally, Kodiac, who had been there through the entire process, guessed that the vacuum hoses we were using to send the vacuum to the SS Box were too small. We replaced them with larger hoses (3/8" ?), and the problems went away.
Tuning: We finally scheduled some dyno time, and pulled 375rwhp on the first run, slobbering rich. I don't have a tap for an five-wire O2 / FJO sensor, so I'm just using the tail pipe sensor on these runs. Kodiac was very familiar with the SS box, and we had the map that the nsxnut was using on his 8lb BBSC setup with a 3.0. Within an hour, the car was tuned, showing 11.5 A/F's across the board (although probably slightly richer, given that we were using a tailpipe sniffer and not an FJO). We let it cool for a bit and did two final runs. The first was at 380rwhp. Kodiac remembered the VVIS was still enabled, so we pulled the VVIS vacuum line (effectively disabling VVIS) and put a screw in the end. The final run was 390rwhp / 267 ft-lbs.
My map, tuned for 3.2L engine, BBSC w/ 8lb pulley, Walbro 255 fuel pump, 440 injectors, single stage fuel system, 93 octane pump fuel, and ~70F temperatures can be found here. Obviously, I will gaurantee that this will not work as-is for you- it is only meant as a reference and starting point for work on a similar setup.
Dyno: The final dyno sheet is shown below. Keep in mind that this is a heat-soaked engine - I would imagine that the engine is pulling around 400-410rwhp on a good run; I'll post when I go back to the dyno.
For reference, the accepted drivetrain loss for the NSX is ~12%, so 400rwhp =~ 450 crank hp. I never dyno'd my car before the supercharger, but assuming a 290hp starting point, that's about 160hp and 80 ft-lbs of gain.
Vacuum Tuning: We had talked to Mark at Split Second about the best way to tune OBD2 cars. He suggested that, by using a scanner, the long-term fuel trim values can be monitors. The ECU constantly monitors the engine and sets both short and long term fuel trims for each range of RPMs. To make the engine happy (and to make it run well), we drove the car and held the engine in each column on Table A on the SS software, adjusting the fuel value as necessary until the scanner showed a long term fuel trim of +/- 3%.
History: I don't have a long history with the engine, but enough that I feel that I can say it was a success. I've driven it about 1000 highway miles (~23mpg) and 340 track miles @ VIR, including a solid hour of track time and holding 7950 rpm for almost a mile @ 125mph on consecutive laps. Not a single problem with overheating, CEL's, or any other issues. The car performed flawlessly. I'm not a very experienced track driver, but the engine was still run hard. As a side note, the intake air temp (as reported by the scan tool) was around 90F, or about 40 degrees over ambient. This was also true on highway driving - about 110F when the outside air was around 70F. I have no explanation as to why the IAT's are seemingly low to the other supercharger installs I've seen.
Current Issues: I call these "issues" because they're not really problems- just minor things that need to be worked out. The first is that the car sometimes wants to stall when falling back to low RPM, say when I hold the clutch from 4k rpm back to idle. It doesn't happen all the time, and I can catch it if I just pop the clutch back out, but it does make stop and go traffic tough.
The only other issue is that I sometimes (maybe once every 200 miles) get a CEL for an EGR sensor issue, only in constant throttle, highway conditions. This wasn't an issue in the city or the track, and doesn't impact performance, but is annoying. It's related to the vacuum system and "stealing" too much vacuum to run the SS box and the bypass valve. When I find a solution, I'll post. UPDATE: See post below. I now don't think this is related to the EGR at all, but to a possible blown cat earlier.
Special Thanks: I'd like to publicly thank the following people in their help in getting this running: Mike Daniel (Kodiac), Mark Hicks (the nsxnut), Rob Morrison (RacerX-21), Mark at Split Second (949-863-1359), Andy Vecsey (AndyVecsey), and Larry Bastanza (Larry Bastanza). I've also been honored with a direct call from Mark Basch (NSXTech) himself after he caught news of my success, and am happy that I was able to offer my $3 relay fix as a possible permanent fix for future SS boxes.
Final Notes: I'm very happy with the kit and the progress with my car. I would like to stress to everyone that the kit itself performs flawlessly - the majority of the issues are related to tuning the SS box, and the original SS box has been replaced with the second-gen version. An AEM or other high-end box may be a much easier (although more expensive) solution. I still plan on posting the complete wiring diagrams and part numbers of the items I used. I hope this helps someone, and I'll be happy to answer any questions I can.
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