okay, I wouldn't have believed it but 3hp from spark plugs...
12-04-2001, 08:34 PM
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okay, I wouldn't have believed it but 3hp from spark plugs...
<center><img src="http://pictureposter.audiworld.com/4061/dyno_plot.jpg"></center><p>We got some Denso Irridium plugs for the Civic and put the car on a dyno last Thursday in order to get the fuel pressure correctly set for the engine. We're running a single cam 1600 and had it balanced and blueprinted but the fuel pressure hadn't been matched. We did the initial runs and tuning with the NGK plugs that we've been using and got the mixture as far as we could get it (which is basically by adding fuel pressure) and maxed out at 127hp at the wheels.
We threw the Denso Irridiums in and lost some power but started increasing fuel pressure and we were able to get MUCH higher pressure because initially, the mixture appeared suddenly too lean. When we were done, we got 130.6hp. The blue plot is the Densos and the red plot is the NGKs. Also the fuel mixture was MUCH more consistent with the Densos.(look at the plot at the bottom...this is where we were ABLE to set it with the Densos vs. the NGKs).
Not sure what this would do in a car with a sophisiticated ECU...possibly the mixture wouldn't adapt to take advantage of the difference in the spark but in the Civic we got real, measurable horsepower.
And yes, that is the stock intake/airbox and OEM filter though we are going to try a "CAI" once again just to convince ourselves what a waste of time they are. On a whim, Mike put one of those "Tornado" intake things and predictably, it lost 3 more HP.
We threw the Denso Irridiums in and lost some power but started increasing fuel pressure and we were able to get MUCH higher pressure because initially, the mixture appeared suddenly too lean. When we were done, we got 130.6hp. The blue plot is the Densos and the red plot is the NGKs. Also the fuel mixture was MUCH more consistent with the Densos.(look at the plot at the bottom...this is where we were ABLE to set it with the Densos vs. the NGKs).
Not sure what this would do in a car with a sophisiticated ECU...possibly the mixture wouldn't adapt to take advantage of the difference in the spark but in the Civic we got real, measurable horsepower.
And yes, that is the stock intake/airbox and OEM filter though we are going to try a "CAI" once again just to convince ourselves what a waste of time they are. On a whim, Mike put one of those "Tornado" intake things and predictably, it lost 3 more HP.
12-04-2001, 08:50 PM
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yes but...
the NGKs were run several times and the one plot is the absolute best we got and the Densos were run several times and that as the best we got. Consistently the Denso runs always had more HP/Torque than the NGK runs but in practical terms, this is probably one HP but we get benefits in endurance racing from having a consistent air/fuel mixture.
12-04-2001, 09:05 PM
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that's what I don't know...
I'm not sure if the Audi's would "know" enough to adjust the air/fuel ratio to benefit from these plugs. The HP difference is measureable but WAY too little to "feel" so you wouldn't know unless you could do a similar dyno test.
12-05-2001, 05:06 AM
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This makes me wonder if this is why MTM sells their stage three..
as a kit. I know it includes new plugs and fuel pressure regulator, so I'm thinking they probably optimize the ECU to take full advantage of the whole system.
Your testing verified for me what I've been wondering for a while, thanks.
Your testing verified for me what I've been wondering for a while, thanks.
12-05-2001, 05:42 AM
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CAI really work for honda's as long as it is AEM
but really it is all the intake baffleing on those cars that hurt them. On our ITR there was an amazing 3/10s decrease in the 1/4mi.
