This vehicle calved on me this winter: top gear went. I have first and second gear w/lock-up left. The engine only has about 30,000km on it, the rest is near 420,000 km. I was going to take out the engine and scrap the rest, but as it was just sitting here, decided to do a gadgetman groove on it as well.
Again, because of lack of traffic on these gravel backroads, to do a quick check on the mileage before and after in second gear, I did not want to use a full tank), I used a separate small gas tank (about 1 gal) with an in-tank high pressure fuel pump from a 98 Ford Windstar, fastened to a crude frame over the engine (hood off); I disconnected the stock fuel lines from the fuel rail and joined them (open loop system) and left the original pump run. I just plumbed in the lines from my Ford pump to the fuel rail, with the return going straight back into the small gas tank. I plumbed in the electrical to a switch, and it was done. I added a couple cups of gas to the tank, and with the return line in a gas can, ran the fuel pump till it was sucking air (the car was on the road where I was going to do my 'before' mileage test and here it is level, level, level (aka flat ). At this point I added a measured 1 litre of gas, reset the trip meter, started up the engine, and accelerated evenly, not too fast (very scientifically) up to 40 mpg (second gear) and maintained the speed until I lost power. At the moment I lost power, I checked the trip meter (accurate only to the tenth of a Km). I did the test twice before and twice after the groove.
I kept the speed at 40 mph because at about 45 mph in second, it switches to open loop mode as the rpm's are getting fairly high.
On this application, I tried the new angle, using the Panavice, and did a much better cut than my previous attempts. From the pictures you can see that the there were no modifications necessary for this engine on the IAC opening as it does not interfere with the groove at all, and enters under the throttle axle. I capped the PCV port at the intake manifold, and did no further vacuum checks.
Before the mod: @40mph on coarse gravel, with a 3mph diagonal tail wind: LTFT: -1; mileage: 8.1 km/litre (repeated twice with same result); 0-60: 16.4 to 16.0 secs
After the mod: @ 40mph on same stretch, with a 6 mph head wind: LTFT: -4; mileage: 9.7 km/l the first try (fuel trims were all over the place: got home and checked- Throttle body bolts were loose: Forgot to tighten them (a number of days lapsed between the groove and the test with other time sensitive things in progress: lesson: be methodical, and steady, and give yourself enough time) and so it had a vacuum leak. Tightened them and did my second test: 10.1 km/l, again with the 6mph head wind on gravel. 0-60: 15.5-15.4 secs.
This translates into an increase of power and milage: although a much better result would have been had with a full tank, an increase like this on 1 litre is very significant at a 24.7 % increase ( 22.8 Can mpg in 2nd gear to 28.5) with a head wind, albeit not a strong one.
You can see here that no re-routing of IAC is necessary.
Here is the groove with the new angle. notice that there is a factory groove, shallow, in the middle going parallel to the throttle bore. I would recommend filling this first with epoxy and then do the groove, as it is in the area of the groove where the most response should be, and it would certainly alter the effects if it were to stay, as it did in this case.
I plan on doing one more test with this, with all the vacuum lines checked and/or ports capped, and with the factory groove filled.
So guys, it does work!
Luke
Yes the groove Does work, huh! I have to give Kudos to you for not only improvisational skills but striving for Emperical measurements as well. You took a situation w/unusual variables and kept your eye on the ball. Ya even got wind speed data...I bet someone at Area 51 is reading this and thinking of recruiting you...
