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After extensive frustration in tuning my 2002, I tried an aftermarket ECU to see if that would bring together and enhance the performance of the other mods I have installed -- with minimal performance gains. As I built up the car, I dyno'd each mod separately, with the exception of the ECU switch. I added the Injen intake prior to the ECU, and then dyno'd the engine with both modifications, introducing uncertainty as to the performance of each.
I was able today to compare the two ECUs back to back on the same day within minutes of each other, and the performance of the Mugen ECU was significantly superior to the stock ECU. That dyno plot follows:
However, I am still down from when I drove the car off the showroom floor, new and dyno'd it with about 1200 miles bone stock. I have not been able to repeat those values despite significant time and money expended. I show the stock dyno plot compared with the best run today with all the modifications I have made.
The only significant variable changed is the temperature, from 68 F to 81 F, a delta of 13 degrees. From the loss of HP at near peak RPMs, I am increasingly inclined to question if the aftermarket headpipe is flowing as efficiently as the stock piece. I doubt the Cat-back exhaust has any great role and the Injen intake clearly added bumps in both HP and torque. Now I have eliminated the aftermarket ECU as a source of power loss, I invite comment on the role of the aftermarket exhaust manifold in contributing to the loss of high RPM HP.
Thanks much, appreciate any input and tuning suggestions. cthree, hope this falls within "posting dyno plots in support of technical issues..."! dlk
Your dyno says VAFC tuning but there are no air/fuel ratios on it. How did you tune it? Did you have an outside source to get the a/f readings from? What a/f ratio did you try to tune it towards? The reason I ask is because I dynoed my car for the first time today and like your stock graph shows I got a lot of drop off over 8.5k. In your other graphs there is not as big of drop off so I am assuming your VAFC and/or Mugen ECU is leaning your ratio out some.
Originally posted by TypeSH In your other graphs there is not as big of drop off so I am assuming your VAFC and/or Mugen ECU is leaning your ratio out some.
The aftermarket ECU continues to make power after the stock item begins to shut spark and fuel down. Both major aftermarket ECUs advertise that they make power all the way to the redline. Not a function of the VAFC.
SH,
Yes, I believe that the stock ECU begins to shut down before the published 9000 RPM redline, based on multiple dyno runs with the stock ECU and an aftermarket ECU. I have no empirical data on either, however, the aftermarket ECU states that it has a 9000 RPM redline. You can clearly see in any of the dyno posts on this forum there is a drop off in power and torque well before 9000 with stock ECUs. I'm not claiming to know where the stock ECU begins to shut down, I'm just observing performance measured on an accurate dynomometer, and making assessments based on those observations. I can't tell you why your engine goes so rich at 8.3K and above, but if you have some form of engine management other than the stock ECU, you should be able to lean it out, right? If you're running the stock Honda ECU, I don't think you're dropping power because the mixture is rich, I think the ECU is cutting off ignition and fuel, typical ways of protecting the engine from over-revving. And, remember, at those RPMs, the engine is just running out of breath with the stock cam profile.
Going back to your first post, yes, I do know the Mugen ECU provides a leaner mixture at most RPMs than the stock ECU, as well as more ignition advance. Hope this helps. dlk
You paid a lot of money for a six hp loss! The older I get the more I question advertising claims. I've always asked for measured proof of results. You have provided i t. Like we always said (yes, even thirty years ago) When the green flag drops...
Sorry this didn't work out as planned for you. Please people, realize that 120 hp per litre is one heck of an amazing output. It just might be that is about all we're going to get currently, sales claims notwithstanding.
#1 - the comparison chart with the original runs vs. the new runs is not useful for comparison. That's because it uses actual hp numbers which are not corrected for conditions. The significantly cooler temperatures on the original run would have resulted in a correction factor of between 0.96-0.97 depending on humidity. This would move the original curve down by 4-8 hp. The dyno operator should have given you runs with a correction factor. Even then, the dynojet software would have probably flashed that a comparison over such wide temperature ranges may not be completely accurate (unless they have taken that out in the latest software)
#2 - The latest runs were undoubtedly made with the ECU's recently reset, correct? If so, there may be more power lurking in there as the ECU learns the engine. The immediate reset is the only quick way to do a legit comparison (otherwise you'd have to drive the car around awhile to let the ECU adapt between tests). Thus, IMO, the differences in hp will probably remain the same, but the actual numbers will go up.
#3 - Using the Mugen header (which I believe you have 9906) will result in a small loss of power after the power peak. This has been observed so many times that it should be considered factual by now :-). However, in return you gain significant torque below VTEC, and from 6000-7500 rpm. Leaning out the top end helps alleviate the problem (which the Mugen ECU does), but a car with something like the Spoon header will usually make more top end.
Plenty of gains to be had on this engine, but you just have to be sure you know which gains you want and where. I think that in this case 9906 you've shown that the Mugen ECU does provide some useful gains. Just gotta use really good gas to make it run well.
9906, the ECU does not "start to shut down". It richens the mixture, which is what in fact protects it, not leaning it. Leaning the mixture will not prevent overrevving, and this is not what the drop is from. The protection from overrevving is the fuel cutoff, which is abrupt when you don't shift at redline. That is the protection from overrevving.
08-31-2002, 02:41 PM
