First off, I'm glad to see that everyone has kept their heads, and are looking at this in a constructive and analytical way. It's also good to see that the 'dogs' haven't descended to point fingers and bash Mugen. There have been some very valid points about why the dyno numbers are the way they are, and they all seem plausible in one way or another. Here are my .02c from looking at the plots:

The baseline plots were done in 68 degree weather - ideal conditions for making power. I know the dyno runs are supposed to be corrected, but I've never felt that those correction factors do a good job of equalizing the conditions. The Plot with the Header and Exhaust was done on a 63 degree day, but no matter how big the fans are in front of the car, I think heat-soak is inevitable in a dyno situation. Then, the plot with the ECU was done on an 80 degree day. This is significant.

It sounds like you are willing to take the parts off and add them one-by-one; I hope you do this on a single day. That is the purpose of a dyno - to compare parts in similar conditions. There isn't much correlation between dyno charts from different days. If we are counting different days, our car got +7hp and +8lb-ft. from the Mugen Exhaust only - but the weather was totally different, and I know that we didn't get that much power from just an exhaust.

Again - I go back to the thing I've stated many times in the past. Dyno charts do not translate well into the real world. All of my real-world experience has shown that the Mugen H/E/ECU combo is WAY faster than stock in real-world conditions. Again, no matter how big the fan is sitting in front of your car at the dyno, it can't match the real airflow a car sees on the road. We've done 3rd gear pulls, 4th gear pulls and 5th gear pulls on the highway between several stock cars and Mugen equipped cars - and always the Mugen cars pull away HARD. That is the real test, IMO.

Not to mention the track manners that combination has. At laguna I could pull out of turn 2 with tons of meat in 3rd gear - whereas the stock cars I drove were anemic in that rev range.

I really hope you don't give up on these parts, 9906... their gains are real. They were not designed with peak numbers in mind, however you should definitely see peak increases when you take the parts off and add them one-by-one during a one-day dyno session.

Which brings me to more of a question than a comment - don't ECU's need to 'learn' changes? I know that on a friends Ford F150, it took a few days after adding a header for the power to really come in. It didn't feel any faster at first, then a couple days went by and it was really hauling. If the Honda ECU is this way also, then maybe it hadn't learned the 100 Octane fuel yet? Fuel can have a profound effect on ignition timing, and maybe the ECU hadn't optimized for that change yet? I don't know that this is true, but I wonder if anyone else knows about this?

If this is the case, then maybe even a one-day dyno session won't show the 'true' gains of the parts because after a few days the ECU will have optimized? Definitely keep us posted and keep Scott in the loop - I'm sure he's willing to help you in any way to get to the bottom of this.

 

Don't quote me, but I don't think the "learn mode" of the ECU will change "wide open throttle" ignition timing. Additionally, the higher octane fuel should require additional wide open throttle ignition timing. The higher octane fuel burns at a slower rate and you want to achieve maximum cylinder pressure at ~ 15 degrees after top dead center for maximum power. Since you haven't changed the compression ratio or the maximum operating RPM of the engine, the engine will likely make more power with 92 or 93 octane fuel than it will with 100 octane fuel. Another point when considering fuel is that, depending on what part of the country you live in, the fuel(s) change 4 to 5 times a year. The octane rating is ~ the same but things such as RVP (Reid Vapor Pressure) and other additives change. These can also affect power.

If I were dynoing, I'd try 2 or 3 different types/octane fuels. There might be ~ 3 - 5 HP sitting at the gas pump waiting for you.

If you're going to try the higher octane fuel try bumping up the timing in 1 degree increments until you make MBT (mean best torque).

 

At WOT the Mugen and the stock ECU do not read sensor inputs, rather they operate solely on a preset fuel/ignition curve. On the partial throttle maps, both ECU's do adjust their maps. The bad thing is that there is speculation that the stock ECU will tune itself to run near stock over time, negating any mods, aka OBD-IIb. Again, this is only at partial throttle and of course there's many opinions surrounding this.

Chris

 

yo jason s...u r not accounting for MUGEN wheels and HOOSIER TIRES on red car at LS, those alone are going to yield a considerable difference in the percieved/real accelerative force driving out of those turns......try not to neglect all the facts in your next pontification and when calling other peoples cars anemic.....

 

I have driven cars with the Mugen I/H/E/ECU on many occasions. They are just plain faster than a stock car. They are also much faster than they were in stock form. I have seen and done many real-life tests on the highway and the fully-equipped Mugen cars always pull significantly on lesser-equipped cars.

Please look to the lap-times that the King prepared S2000 was turning at Laguna back in December. This car was besting cars that no stock S2000 could compete with. Very impressive stuff. This is the strength of Mugen - lap times and driveability.

In any respect, the car in question here needs to be returned to stock and baselined for any important info to come of this discussion. Cars and engines change over time.

Please note that the S2000 engine is very different between examples. Some cars are much stronger than others.

Let us also not forget that Mugen does not tune for PEAK power numbers. They tune to produce outstanding lap times on road courses and improved driveability. If you want PEAK numbers go to another brand.

As always, I would suggest keeping Scott at King in the loop. He is a very fair and accomadating individual. I bet that he would pay for the baseline dynos if they were conducted in a manner that he sees fit (as others have indicated, when and how dyno runs are done can impact the result).

As a last note - Mugen is a world-class company. They tune F1 engines, they tune AMLS engines and the list goes on. I'm sure they know more than the guys at the local speed shop.

 

Couple things:

1. The consistency of dyno's and correction factors is quite good, but you have to make sure you equalize other things. The biggest variable that people do not pay attention to is coolant temperature. On the stock ECU this has a profound effect and a difference of even a few degrees, if its the right few degrees, can have a substantial effect on power. Things like the Mugen thermostat and rad cap do help the car to cool down quicker as well. If you monitor things and make sure you equalize the operating parameters of the car, you can be quite consistent, as the Society of Automotive Engineers didn't just pull the SAE correction factors out of their tailpipes. And if you do so, the results usually translate well to the road.

2. The one benefit that's hard to measure on the dyno is ram air. C&D tested a fully equipped Mugen S2K and knocked 0.3 seconds off their best previous 1/4 mile and gained 2 mph. Some of that was weight reduction thanks to the Mugen header, exhaust and wheels, but there were certainly power increases. However, you need some serious compressors and a sealed inlet to measure the gains of a ram air system like the Mugen setup on the dyno - I haven't seen anyone do it yet. But based upon the numbers C&D posted, I think that in the real world the Mugen I/H/E ECU combo is good for at least 5-7 lbs-ft across the critical acceleration range (6000-9000 rpm). That's very believable considering the torque gains the header provides from 5k-7k. You wouldn't see all of that on the dyno though because of ram air.

3. ECU's, at least stock ones, need time to learn. Fuel trim numbers change all the time in part throttle operation. And when you go to full throttle, the long term fuel trim is applied to the entire map (you can read it in the Helm's manual if you like). So what is learned at part throttle makes a difference. Swapping in the Mugen ECU on the dyno therefore is not necessarily representative of what you're going to see after even a few miles of driving. Hook up an OBDII reader after you plug it in (assuming the OBDII still functions) and watch the changes in short and long term fuel trim even at idle. As for ignition timing, usually that only changes with temperature or detonation, not necessarily driving style.

4. Race gasoline won't necessarily gain or cost you power, but it usually can help. Its funny that we always look at octane numbers. The only thing octane numbers tell you is how detonation resistant a fuel is compared to other fuels. What we really have to look at is energy content, burn speed, etc. Good race fuels often have a quicker, more controlled burn than regular gasoline, and this can help out power through both consistency and a more complete burn. Even if your ignition timing has remained the same (in fact, in some cars, with some fuels, we actually ran a bit less timing!). I've seen gains as high as 15 whp on a normally aspirated Toyota engine. Your mileage may vary, which is why I said in an earlier post that you have to see how a particular fuel affects your combo - to change it without testing throws a major unknown into your testing process.

5. SphinkterMC is right. You really can't look at the times of the red car at LS as solely indicative of the benefits of Mugen hp. There were many, many other variables in play including aerodynamics and weight. The car was fast because it was an integrated whole with improvements in virtually every area. And as we all know, handling usually trumps hp by a large margin when developing a race car from a production car.

UL

 

Here is my dyno with just the Mugen exhaust.

I think you should re run with all your mugen parts, and loose the injen intake. Just because they say makes power on a S2000 with just an injen intake, doesn't mean it makes power with you other mods. I've heard the ecu doesn't make power, but I am very surpised to see on your car that you aren't making power with the exhaust and headers. Something is wrong with your car or your configuration of mods. I would try putting the stock airbox back on and seeing what happens.

 

[QUOTE]Originally posted by ultimate lurker
[B]5.

 

Not neglecting anything, man... I know how handling effects acceleration - read my response to UL above. And don't forget about our highway runs at Asheville last year. Both the red and black Mugen cars next to my autocross car, a stock car and one with an HKS exhaust. The two Mugen cars consistently blew the doors off the others from 40-60, 60-80, 80-120 and so-on. It was a real eye opener for me, as I didn't think you could see that much real-world difference from those parts. In my opnion, Dynos can be more misleading than helpful sometimes - especially making runs on different days. I don't care about how good the SAE correction factors are, results from different days never tend to correlate well.

 

It's amazing how much mis-information is out there regarding race gas, and the $$$ people waste unnecessarily on it. Use race gas if you have a highly tuned engine that needs it, i.e. one w/ very high comp. ratio, or lots of boost. Gasoline's energy content is inversely correlated w/ octane, so you only benefit from higher octane to the extent your engine needs it to prevent detonation &/or the ECU will adjust to enhance power.