VANAGON archives -- December 2001, week 3 (#351)

Date: Thu, 20 Dec 2001 10:25:10 -0500 Reply-To: Robert Donalds <bostneng@FCL-US.NET> Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com> From: Robert Donalds <bostneng@FCL-US.NET> Subject: Boston Bobs day at the dyno Content-Type: text/plain; charset="iso-8859-1"

fellow learkers and so forth mores

I spent the day testing vanagons on a chassis dyno with mixed results. The truth of the matter is that everything I thought I observed by the seat of the pants method was wrong. First on the dyno was the big valve engine in my 84 camper first run to warm the engine up made 50 hp at 3000 and a max reading of 77 hp at 4600 RPM thats a nice start but the air fuel ratio was a little lean second run fully warmed up 3000 RPM 41 hp and max power of 70 hp at 4500 RPM the fuel air ratio is now off the scale its way to lean. Thats huge loss of power amost 25 % at 3000 RPM from the one thing that nobody seems to check air fuel ratio. OK the day is young so we can take this in stride and I am sure this engine has the potental to make alot more power because the 20% increase in air flow threwout the valves lift . after checking the fuel pressure we desided temporarily boost the pressure used the adjustment screw on a pair of vise grips clamped to the return line and we got the gauge to read a steady 35 pds under load. (dont try this at home) and we did another run no differance in power or the air fuel ratio. OK I now have a problem that is more than I want to sort out on the $100 an hour chassis dyno and its time to move on to the next van. I brought out the family van blue bell with a stock 2.1engine it a stock 1984 7 passenger plan Jane quick as a bunnie and Im sure its not as fast or as powerful as my race camper. First run bang 3000 RPM 55 hp max hp of 74 hp at 4600 RPM air fuel ratio right on the money mid 13s same thing second try. thats not what I exspected but I keep repeting the things I am learning so far #1 fuel air ratio is VERY important #2 the meter is running when you are on the dyno. At this point the cars are stacking up behind me waiting to have a go on the dyno, turbo jettas and new beetles. Home I go to get the next van and when I pull back into the yard where they are testing and they signal me to get the van on the dyno for my next test. this next van is on a 89 carrat automatic this van has the ossy chip from Derek Drew and I have been driving it for a day. My seat of the pants told me that the chip gave the van a little more throttle responce maybe but not $250 worth. First run 52 HP and the air fuel ratio is almost as lean as my camper and the automatic uses more power so less gets to the rear wheel plus the engine has 118 K. next I replaced the ECU with the orignal one from the van next run the max power is 56 HP and the air fuel ratio is much better I gained 4 hp by going back to the stock chip. at this point more cars are behind me and I have double tested to confirm the results the daylight is fading and the temp is droping below 40 so its time to call it quits for the day. I do plan to do more testing with both the big valve engine and the rockers and chip but not for a couple of weeks In the mean time I am going to make myslf a little air fuel ratio meter using a heated oxy sensor and figure out some way to get a nice reading under load so I can sort out the lean conditions I found. The moral of the story is # 1 seat of the pants doesnt mean much if anything # 2 air fuel ratio is sooooo important to making good power # 3 tuning affects not only power but engiine life It has been my experiance that the air and watercooled Zamboni engines, the type 2 vans and aircooled vanagon engines just don't servive for long if the air fuel ratio or timing is off even a little. The reason I use these as an example is they are often pushed to and past ther limits. the ones that live have been set up correctly Derek wrote

Boy, that sounds frustrating to be under the clock like that and to need more time to test and fine tune.

I recall something about how the rockers alone can do an OK job of increasing the power but that for the health of the engine it is better to run the rockers with the chip and not to run the rockers without the chip.

I also recall the chip seller indicating that the chip alone is not going to do that much for people but this message was a little muted since, of course, it would impede sales of the chip.

You do not say that the ratio rockers were installed. So I assume they weren't?

Derek disappointing is the word I would use to describe the day. I learned allot about how critical the fuel mixture is. The other lesson is that fuel pressure made no change in richen up the mixture. That is not to say that in other conditions it might be helpful. I still have know idea why the big valve engine ran so lean. I mentioned this to Greg at Greg's repair he pointed out that just because I had checked each sensor as I installed them he thought that the pin test in the Bentley book had great value. The reason he gave was that the when checked this way you can observe the values the ECU gets not just the reading at the sensor. point well taken and I will check that out . The chip test was interesting I thought it felt good and It might give a like more throttle response but the fact is it made less power as a straight add on. that's not to say the chip does not have value. I had emailed Darrell in regards to the chip add on. he reported that with the digitool he observed the chip tended to run richer and go lean and the stock chip tended to be lean and go rich. There are many factors involved Darrel was driving around town and I was doing flat out pedal to the metal pulls on the chassis dyno going from 3000 RPM to 4700 RPM. It could be the rocker don't need the chip the chip needs the rockers to make any increase in power. some more testing is needed after a way is found to get the air fuel ratio dialed in on both vanagon injection systems. the next round of testing will include the ratio rockers I have not desided how to post the results and what to post the dyno only gives paper print outs the one thing I did not like about the system. The company that offers this service is called podium performance systems based in NH phone # 1 866 dynoguy. Roger the owner travels the up and down east coast and has testing days at tracks and shops. If there was enough interest it make it worth his time it would be no problem to set up a day of testing give him a call

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