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So I recently installed a Knightsports ROM tuned JDM ECM in my 1995 and I wanted to share the results. I have tried a couple US ROM tunes before (Pettit, M2) that had been applied to 1993 ECMs, these had performed okay but the boost was too high for my taste at 13-14psi, particularly for the primary turbo, and there was a god-awful 3,000RPM hesitation with both of them. I ran them both for a short time and then passed them on. For both, I checked AFR's and they were both about a half point richer across the RPM range, mostly, compared to my OEM N3D8 (1995, Federal emissions) ECM at full boost. I think with either of them, I could have accepted the tune and done something to lower the boost a little if it were not for the heavy 3,000 RPM hesitation. My car with the N3D8 ECM has a slight hesitation when cold, but it goes away almost completely when the car is warmed up. Why the OE ECM and not a PFC? Well I own one but I have never been able to fully tune out a tip in hesitation and that really is annoying. Also, I am a fan of the OE safety guards, no problem with AC function, etc.
I have been watching for a RE Amemiya Type A ECM for awhile, but was not able to find one in decent condition that was built on a N3A7 C-version JDM ECM. I wanted to use the -C as that is the last iteration of the N3A7, so I was hoping that Mazda had learned a few things by that time and included them in the tune. I did not find a RE-A, but I did find the Knightsports and after some research I thought I would give it a try. The results far exceeded my expectations. The performance is a little stronger, boost is nicely maintained at a max 12psi on primary and between 11-12psi on the secondary, AFR's are really conservative, and there is absolutely NO 3,000 RPM hesitation. I was actually blown away by the improvement in powerband smoothness compared to the OEM ECM. It is very very smooth. Knightsports really did a good job on this tune.
My car is lightly modded, with Blitz SMIC, JDM OE downpipe, stock main cat, Apexi Noir catback.
When I cranked it for the first time, the car immediately fired up settled into a smooth idle. So far, so good. Idle AFR was about 17.1, just like the OE ECM.
I took it out and did some checks on the AF, and the results were good. Basically, richer than stock at most points and about the same as the other ROM tunes. Here are the findings:
I suspect this tune was set up for slightly more mods, like an aftermarket intake and less restrictive exhaust.
Measurements were taken with an ECM AFR-1200 meter. Here is idle
Other things I noticed were that the fans seem to come on earlier, there is clearly a different air pump engagement logic, and surprisingly the check engine light illuminates like before. I'm not sure what it does now but it will pass a visual inspection at smog check time, and as long as the tune works then there will not be any need to swap back the OE ECM. I am going to give it a try next time and see.
Here is the label on the Knightsports ECM, unfortunately I have no idea what the codes mean.
I know why banzai makes it (to make it easy to tap into things without messing with the stock harness). But are you using it just to make it easier to install and play around with?
So I recently installed a Knightsports ROM tuned JDM ECM in my 1995 and I wanted to share the results...
I took it out and did some checks on the AF, and the results were good. Basically, richer than stock at most points and about the same as the other ROM tunes. Here are the findings:
I suspect this tune was set up for slightly more mods, like an aftermarket intake and less restrictive exhaust.
Measurements were taken with an ECM AFR-1200 meter. Here is idle
Rich indeed, those AFR's are 1.0-1.5 richer @12psig than is the norm in the aftermarket ECU world... and that's with the de rigeur porting and more efficient single turbos. Definitely plenty of fueling overhead for the increased VE from modifications.
my car passed emissions last time with the RE-A ecu, which was a pleasant surprise. it wasn't quite as clean as the stock ecu, so the margin was pretty thin, but it passed.
i moved on to the PFC, if you wanna test my RE-A ecu, shoot me a PM?
I was also impressed by how much smoother my menu tuned Knightsports 4beat ecu made my FD run.
When I put in my wideband I was less surprised, since as you say it runs richer. In my standalone tuning on my FC 2001-20014 I noticed richer is the easy way to make a rotary run well.
However, my FD with Knightsports 4beat was very responsive to throttle input at low load as well.
I struggled to attain that in my own tuning. I wonder if Knightsports used more ignition advance at low load tha I was comfortable experimenting with.
Knightsports uses the same patch harness between the factory ECU and factory wiring for a "no-cut" installation of their electronic boost controllers.
On my Knightsports install, when I eliminated the electronic boost controller I kept the patch harness since I had cut the 3 wires you have to to run a JDM ECU or Power FC in a USDM FD.
Better than breaking the pins off the ECU for resale to JDM car owners and dont have to depin stock harness connector (another alternative).
It's too bad there isn't any widely disseminated info on what exactly has been changed inside these chipped ROMs vs the factory. Like what maps were changed etc. We're only speculating, based on final measured results.
The patch harness is from Banzai, I installed it to reduce the plug-in cycling on the OEM harness female pins. My car already has cut wires for a PFC on the original harness, if I ever replace it I will use the patch harness for the "cuts". I have the various wires disconnected for this ECM, same as would be the case for a PFC.
I tried to contact Knightsports to learn the details about this tune, I even offered to pay them just to let me know what the setup was...no response. This particular ECM came off a wrecked FD, so I figured since the vehicle it came off survived long enough to eventually crash then it might be okay for the engine. Since I am in CA and "Premium" fuel is 91 octane I added a bottle of Lucas octane booster to a fresh tank of fuel before the install. I figured the fuel economy would suffer, but it is so poor already that I really didn't figure it would make that much difference.
Anyway, I am very happy with the result. The ROM tune seems to have a 1997 date, I really have to hand it to the engineers at Knightsports, even way back then they had the FD tune dialed in. This particular setup must be pretty common, I see the exact same tune on YJ auction right now for a starting bid of JPY 4000.
Yeah. Japanese shops don't like to talk about their details and also don't like to sell replacement parts. Try buying a replacement bracket for a blitz FMIC and let me know how that goes hahaha
I went through Andy Utsumi of Auto Style USA to register my used Knightsports 4 beat in my name and reflash into my specs.
A bilingual 3rd party raised in Japanese culture is the the way most Japanese companies would like to deal with us.
I of course would have also liked to know how my ECU was initially flashed (and it is documented by Knightsports), but Knightsports is protecting customers personal information by not providing that information.
An alteration of the ECU is a crime there just like it is here...
It's too bad there isn't any widely disseminated info on what exactly has been changed inside these chipped ROMs vs the factory. Like what maps were changed etc. We're only speculating, based on final measured results.
in theory one could extract the code from say a stock ECU and then the aftermarket chipped ones and kind of figure it out.
i bought my RE A ecu not really expecting it to run as well as it did, but also because it was the easiest way to have a flashable ECU.
I went through Andy Utsumi of Auto Style USA to register my used Knightsports 4 beat in my name and reflash into my specs.
A bilingual 3rd party raised in Japanese culture is the the way most Japanese companies would like to deal with us.
I of course would have also liked to know how my ECU was initially flashed (and it is documented by Knightsports), but Knightsports is protecting customers personal information by not providing that information.
An alteration of the ECU is a crime there just like it is here...
That's kind of a bummer that it's not possible to get a spec sheet on the modifications.
For my case, I guess I could do some "tuning by mods" and verify A/F at each step to get the A/F a little less rich. I did have a cheap bastard-style modified airbox for awhile that I removed and sold off because I couldn't take the airpump noise (even with a silencer in the bypass hose), also having the silencer seemed to drive up NOx quite a bit at smog check so I think bypass air was leaking back into the cat or exhaust port area.
Now, with the JDM-style airpump clutch management the noise might not be so bad as the airpump clutch seems to be engaged less often. I actually looked to see if the autoexe-style intakes were still available but they seem to be discontinued now...
That's kind of a bummer that it's not possible to get a spec sheet on the modifications.
For my case, I guess I could do some "tuning by mods" and verify A/F at each step to get the A/F a little less rich. I did have a cheap bastard-style modified airbox for awhile that I removed and sold off because I couldn't take the airpump noise (even with a silencer in the bypass hose), also having the silencer seemed to drive up NOx quite a bit at smog check so I think bypass air was leaking back into the cat or exhaust port area.
Now, with the JDM-style airpump clutch management the noise might not be so bad as the airpump clutch seems to be engaged less often. I actually looked to see if the autoexe-style intakes were still available but they seem to be discontinued now...
You can still get the autoexe intakes. I bought mine from RHD Japan, they are just made to order so you have to wait 1-2 months.
Did you get the ECU from Banzai on Ebay? I was looking at it for myself. I even talked to BLUETII about it.
Yes, that is the one I have. We worked out an agreeable price, and the fact that there was some history about the car and its setup was why I tried it out. This exact same spec is on YJA right now, so if your car is mildly modified like mine, or even slightly more mods, you can install with confidence.
Hmm. Yes I see that now. Well I'll have to give that some more thought then.
Are you running an airpump on your car, and if so, how is the airpump noise level?
I have an air pump but I haven't installed the intake yet. I assume it's the same noise level as any other open filter intake. I'm considering picking up one of these ECUs like you grabbed as well. I only have a catback but plan to run a larger downpipe and the intake as well.
A little bit different, and I’m certainly not going to try it, but thought this was interesting. I wonder if its actually as advertised or if it’s just a different kind of patch harness.
02-25-23, 03:53 PM
