:skep: Ok it is a little on the cold side here to be running B99, 99% Biodiesel and 1% #2 diesel - Not B100 simply for a tax credit. B99 starts to cloud around 40 degrees that overnights have being going below out here. So I have been running B50 to prevent issues.
Interesting with the GM3 where I had to loose a lift pump or plug a filter to loose top end boost. Say from 14PSI falling to 12 PSI top gear WOT as the RPM went up and a fuel restriction starved the IP. More boost with 3rd gear and higher RPM though. In other words the GM3 is spooling with engine RPM and only lower RPM does a ‘lesser amount of fuel’ show up.
I removed the fuel sock, plugged, on my 1993 from nasty #2 I am getting somewhere. New tank just this summer and still has a brown scum... This was the cause of the recent boost falling off at the top end with my ATT. Like 15 PSI going down to 13. Peak of 18. Typical fuel restriction and the lift pump test showed little volume from the plugged sock.
Now after the repair I can’t get over 13 PSI. Not because of a lack of fuel as it is a steady 13 PSI so fuel isn’t falling off. The fuel just needs to be turned up more and the timing retarded a little. You see when I dropped the tank I emptied #2 out into the 275 gal B99 tank. So I put B90 or higher back in the tank. B99 has less power and lights quicker than #2 – these both reduce boost: the less power affecting boost more than the faster lighting. Faster lighting is in effect advancing the timing. 10% less MPG with B99 is the norm for me - on a GM3 as I have not yet measured MPG on B99 and the ATT. (Day is 70 degrees out so not a fuel gelling problem...)
In other words I am slightly reducing the fuel by going to B99 from #2 diesel. (fuel screw is unchanged.) The GM3 never noticed the fuel changes and kept the same boost - had I looked and measured the waste gate would not have been as open with B99. Yet the ATT driven more by heat does notice and drops off some boost due to less heat of B99. This means the ATT is the better turbo as it is boosting on heat not RPM and airflow alone. I can turn up the fuel more even with #2 as I am not getting any smoke after I wind up the ATT.
Even with B50 I am down on boost. So heads up if you do switch fuels or get some % of Bio and are wondering if your filter plugged etc. from a sudden reduction of peak boost - it is from the biodiesel.
Interesting with the GM3 where I had to loose a lift pump or plug a filter to loose top end boost. Say from 14PSI falling to 12 PSI top gear WOT as the RPM went up and a fuel restriction starved the IP. More boost with 3rd gear and higher RPM though. In other words the GM3 is spooling with engine RPM and only lower RPM does a ‘lesser amount of fuel’ show up.
I removed the fuel sock, plugged, on my 1993 from nasty #2 I am getting somewhere. New tank just this summer and still has a brown scum... This was the cause of the recent boost falling off at the top end with my ATT. Like 15 PSI going down to 13. Peak of 18. Typical fuel restriction and the lift pump test showed little volume from the plugged sock.
Now after the repair I can’t get over 13 PSI. Not because of a lack of fuel as it is a steady 13 PSI so fuel isn’t falling off. The fuel just needs to be turned up more and the timing retarded a little. You see when I dropped the tank I emptied #2 out into the 275 gal B99 tank. So I put B90 or higher back in the tank. B99 has less power and lights quicker than #2 – these both reduce boost: the less power affecting boost more than the faster lighting. Faster lighting is in effect advancing the timing. 10% less MPG with B99 is the norm for me - on a GM3 as I have not yet measured MPG on B99 and the ATT. (Day is 70 degrees out so not a fuel gelling problem...)
In other words I am slightly reducing the fuel by going to B99 from #2 diesel. (fuel screw is unchanged.) The GM3 never noticed the fuel changes and kept the same boost - had I looked and measured the waste gate would not have been as open with B99. Yet the ATT driven more by heat does notice and drops off some boost due to less heat of B99. This means the ATT is the better turbo as it is boosting on heat not RPM and airflow alone. I can turn up the fuel more even with #2 as I am not getting any smoke after I wind up the ATT.
Even with B50 I am down on boost. So heads up if you do switch fuels or get some % of Bio and are wondering if your filter plugged etc. from a sudden reduction of peak boost - it is from the biodiesel.
