The not-so-offical EVO 9 ECU tuning thread
The MIVEC took a dump or you forgot to tune the maps for the "outside of the MIVEC map" range? Isn't 6k right where the MIVEC stops working?
Terry S
Terry S
Last edited by Terry S; Nov 28, 2005 at 09:35 AM.
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Joined: Jul 2005
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From: Davis, California
Looks like what happens with the DCCD on STi's when the dyno rollers aren't synchronized properly and the center-diff suddenly locks the front and rear axles itself.
Happens to a lot of STi's on dynojets, but I could have sworn Dyno Dynamics were a bit better than that. Mustang dynos lock the front and rear rollers to avoid it.
Weird stuff.
Happens to a lot of STi's on dynojets, but I could have sworn Dyno Dynamics were a bit better than that. Mustang dynos lock the front and rear rollers to avoid it.
Weird stuff.
Thread Starter
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From: Danville/Blackhawk, California
Nice guess guys. No one got it right although Noize was the closest. What happened was a temporary loss of *rear* roller contact. The "problem" was the car's torque ramp up was so vertical and abrupt that the rear straps would stretch long enough for the car to literally pull itself up on the front rollers (the loading rollers which actually measure power). With the tires leaving contact with the rear lightweight passive rollers (you can spin them by hand), there is a slight bump in power (less roller mass to spin). Without contact with the tire, the rear roller slows down. But seconds later, torque starts to fall enough so that the tires falls back to where it started (contacting both the front and rear roller). Once the speeding tire makes contact with the slow rolling rear roller, it quickly spools it back up to wheel speed. This absorbs a lot of power and accounts for abrupt reduction on the graph 
Usually, we never run into this issue on pump gas. Even on big turbo'd cars. This is the first time we had to apply another strap at the front of the car pulling downwards towards the dyno.
-shiv
Usually, we never run into this issue on pump gas. Even on big turbo'd cars. This is the first time we had to apply another strap at the front of the car pulling downwards towards the dyno.
-shiv
Originally Posted by RedAustinIX
Shiv - are you hitting the rev limiter at 7600? I bought a IX a month ago and, despite redline being 7k, haven't hit fuel cut yet... I've gotten to about 7500-7600 RPM without hitting the limiter, and didn't want to find out the hard way whether this engine doesn't have a fuel cut!
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Joined: Sep 2004
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From: In my house
Originally Posted by shiv@vishnu
Below are two graphs. One of torque and one of whp. Each graph has three runs on it. The brown run is the stock EVO IX with just a remapped ECU. And the red and blue runs represent the addition of a full exhaust (dp, cat and cat-back) at various states of unfinished tune.
Can anyone guess what kinda happened on the red run and REALLY happened on the blue one? Hint: There was nothing inherently wrong with the tune (no det, knock retard, boost drop, etc,.)
-shiv
Can anyone guess what kinda happened on the red run and REALLY happened on the blue one? Hint: There was nothing inherently wrong with the tune (no det, knock retard, boost drop, etc,.)
-shiv
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Joined: Oct 2004
Posts: 254
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From: Edison New Jersey
Originally Posted by shiv@vishnu
Nice guess guys. No one got it right although Noize was the closest. What happened was a temporary loss of *rear* roller contact. The "problem" was the car's torque ramp up was so vertical and abrupt that the rear straps would stretch long enough for the car to literally pull itself up on the front rollers (the loading rollers which actually measure power). With the tires leaving contact with the rear lightweight passive rollers (you can spin them by hand), there is a slight bump in power (less roller mass to spin). Without contact with the tire, the rear roller slows down. But seconds later, torque starts to fall enough so that the tires falls back to where it started (contacting both the front and rear roller). Once the speeding tire makes contact with the slow rolling rear roller, it quickly spools it back up to wheel speed. This absorbs a lot of power and accounts for abrupt reduction on the graph
Usually, we never run into this issue on pump gas. Even on big turbo'd cars. This is the first time we had to apply another strap at the front of the car pulling downwards towards the dyno.
-shiv
Usually, we never run into this issue on pump gas. Even on big turbo'd cars. This is the first time we had to apply another strap at the front of the car pulling downwards towards the dyno.
-shiv
Great work Shiv!!