Date:         Fri, 21 Dec 2001 09:48:40 -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:      Re: Boston Bobs day at the dyno
Content-Type: text/plain; charset="iso-8859-1"

Thanks to all who responded for your thoughtful replies 

following up on your many ideas 
I don't think at this point I have exceeded the ability of the fuel injection system but the thought had crossed my mind. The injectors are new 1500 miles ago as is the fuel filter. the gas tank is out of a newer 87 van and has the larger feed line to the pump. I have all the data plotted and the air fuel ratio is consistent threwout the rpm range and not leaner at the top as might be expected if the pump was running out of volume.The increased fuel pressure trick with the vise grips did hold a constant pressure according to my gauge threwout the power run with no change in power.  The injection system should be able to handle air fuel ratio even when the air flow was increased across the RPM range.  I have yet to recheck the values of the sensors and at the top of the list would NTC coolant sensor both cold and hot.  I shared the data despite the poor showing so far of my big valve engine so others would understand the importance of setting up the fuel injection by testing the exhaust gases. Its way to easy to say that the reason for poor performance or low fuel economy is the engine itself. This big valve engine I tested had been put on a gas analyzer and was lean around 1/2 percent CO when it was new as measured after the cat converter big mistake, I had given the cat credit for the lean readings. The fact that the engine lost 10 HP at 3000 RPM as it fully warmed up is big time news to me. I cant tell you how many times I have heard from my customers that this new engine doesn't have any more power than the old one. my next question to them is have you completed the tune up and they say almost every time yes. when asked if they have set the exhaust gases they say NO at that point I tend to loose interest in there problem. Lean engines are also more likely to preignite and detonate under high speed highway conditions and warmer weather. 

the osy Chip ran leaner at full throttle that doesn't mean the a day of tuning might not improve the out come but it did get the same signals from the engines sensors as the stock chip. You know sometimes the factory just gets it right.  I would say that getting the air fuel ratio is key to performance, economy and engine life. 
all rights reserved
B. Bob
http://www.bostonengine.com
  .