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Best Dyno Run Is Usually Not The First Run... (archive)

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Posted by dpeete on September 17, 2000 at 23:38:52:

In Reply to: Don't agree posted by Luxo M3 on September 17, 2000 at 20:19:46:

I have been to DynoSpotRacing as well and have dynoed my car... every dyno I have ever seen for my car or other people from other shops doesn't have the first dyno as the best. The car usually peaks around the 3rd or 4th run on the dyno at which point the heat starts to bring the numbers back down.

The crappy Kalifornia gas would have as much to do with this as anything. Detonation usually incorporates the gas a factor... sombody should dyno a chipped car with octane booster to see if it will do better then a non-chipped car on octane booster.

My 2-cents, and I'm not a JC fan:

>Then we came up to the whole chip idea, and he said that it was worthless. I was quite suprised because I have heard many good things about all of them, but he then explained to me why.

Ok, well we have documentation and dyno to prove that chips work on 95/OBD1 cars. Otherwise we're talking some serious lawsuits against Dinan, Autothority, pretty much all the Honda aftermarket guys, etc.

>He stated that with obd2, the chip will choose whichever fuel map is optimal for each certain situation. What the chip upgrades do is put more radical fuel maps into the car. What happens then is your car will use these maps for a little bit, but not like them because your car will ping like crazy. so after a few runs, the horsepower will go back down. He said you could try and force your car to use more radical fuel maps, but it isn't good for the engine. He then stated that on all the 96+ m3's he's dynoed, after installing the chip there was an increase, but after about 5 dyno runs, they were back to stock. So basically chips are worthless.

What he'd referring to is the engine management system and the ability to retard timing to affect detonation issues. When the car does this to safeguard itself, it isn't "erasing" or reprogramming itself. It's simply retuning itself to stave off detonation. Once it senses that heat and detonation issues are gone, hey back to hi performance time.

My observations are:
Running a car on the dyno doesn't do much for heat exchange as a ton of people on this board will note. Most dyno runs are only good for a few runs as you don't have the cooling system on any car running up to snuff. You're best run will probably be the first.

I've yet to see a dyno run with a fan duct up to the front of the car pushing at least 25mph winds into the mouth of the car...

>He said that the 99 m3's usually have a little more bhp then previous m3's with anywhere from 209-213 at the wheels. He said that the best bang for the buck is the ECIS intake which usually bumps the hp at the wheels up to around 220.

Here's another tough one....observed MotorTrend, Car and Driver, etc. tests seem to say that the later the year M3, the slower it gets. No flames please, but seen it published in magazines.

>If you disagree with him, then I guess you can go on the dyno day. I think it is october 21.

Heck if it's free, I'll show up to watch.

>Another thing, has anyone tried his cams that he's developing? He claims 15 at the wheels for 1 grand.

15hp for adjustable cams? Ask him to see that power on an OBD2 car [ha, ha, ha]. If what he said was true about software, wouldn't using cams to affect intake/exhaust mix affect the mixture and also make case for detonation necessitating hte need for the engine management system to retune the engine?

-Luxo M3

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