thanks for the info. man. 8)
I second that. :wink:Exhaust Depot said:Dan, go dyno your car again, this time disconnect the catback rught after the cat.
where did they put it? I left before they brought it up.hemidakota said:Seen your car at the show today...pic also.
I didn't dyno my car stock, but the TurboXS project car dyno'd at 230 stock, 265 with MBC. I agree that the delta is the important number. The June issue of Turbo Mag has an interesting article where they took a car to 5 different dyno's in one day and got very different results at each. Interestingly, the Dynapack they tested was right in the middle of the bunch.DODGETWEAKER said:P.S. - Looks like the dyno at TurboXS is running alittle high. Do you have a run with the car in total stock configuration? Maybe you should visit another dyno to see if the car puts out the same numbers. When is the last time the dyno was calibrated? The only thing I trust chassis dynos for is A - B comparisons. Focus on the delta in output not the abosolute value until you can back the numbers up with runs on a different dyno. My rule of thumb is +Delta=Good & -Delta=Bad. :lol:
We reset the ECU to let it "learn" with the new fuel and made quite a few runs on it. I don't know exactly how long that process takes, but after the first 3 runs we weren't seeing anymore changes.el_jefe said:How long does it take the ECU to adjust to a different grade of fuel? I was under the impression it took a while, it has always been a habit of mine to fill the tank with octane boost/race gas before I go to the track, so the ECU could adjust on the way there.
I'm sure you're right with regards to domestic cars. But what they were telling me was that Japanese cars often have their JDM maps still in them because they are tuned for higher octane gas in that market. So they can take advantage of higher octane fuel by advancing timing until the knock threshold is reached. We wanted to see if maybe PVO slipped something into the ECU. ;-)DODGETWEAKER said:Most all OEM engine management systems with a knock sensor do not advance spark when higher octane fuel is used. The engine is calibrated on the recommended fuel and the knock sensor is used to protect the engine if lower octane is mistakenly put into the car. If knock is detected, spark is retarded until knock is no longer detected. Over time, spark advance will increased back to the original level as long as there is no knock present. Until a octane sensor is invented for a vehicle, a car with stock hardware and stock calibration will not see any power gains using fuel with an octane higher than the recommended level.
If you are seeing a gain with race gas, it is because the increased boost was causing a leanout condition and your engine was retarding spark due to knock with pump gas.