Working on a project on an LS2 Corvette. (this is our 7th trail vehicle (we have had a few major failures) ).
The new method / design we are using eliminates Exhaust Gas reversion while increasing volumetric efficiency and effective compression ratio. This time it is working really well, so far (1000 miles).
We do it with newly designed intake valves. These intake valves, along with their normal functions, also act as check valves against reversion on the intake cycle (during valve overlap) and also compression reversion on the compression cycle.
On the Dyno @ stoichiometric (perhaps a bit richer) we have significant increase in low end torque. 300 ft.lbs at 1000 RPM and it goes up quickly at 1500 RPM to 400 ft. lbs of toque and stays there until 5250 and starts to peel off slowly , it does not fall off a cliff. These are significant increase in torque. Max spark advance 19 degrees. Exhaust temperatures 800 F range. 87 octane gasoline. The engine has a medium range after market cam.
We are playing with the Air Fuel ratios and today we have it running with very good performance at 24 to 1 A/F (that is as high as our wide band A/F meter goes), it idles at 300 RPM (not all that stable,needs more flyweight). At cruise, 70 MPH @1600 RPM up a 6 degree grade, with exhaust temps 1100 to 1150 degrees F. (these temps have turned the corner, they were hotter at about 19 to 1 AF) Throttle position is 45 percent, performance is acceptable.
Questions,
How can I check the NOX?
Is there any reason to believe that the NOX emission may be low?
We plan on going further lean until the exhaust temperatures drop to 800 or 900 degrees(if the performance continues to stay acceptable) , with the throttle pretty much open and then control speed with fuel, via fuel pressure. Why? Not sure just trying out some new things. I would love to hear comments as too what the NOX emission will be????
How about adding, diesel fuel 5% at a time, to see what effect that has on performance and NOX.
Thanks for any and all input!
The new method / design we are using eliminates Exhaust Gas reversion while increasing volumetric efficiency and effective compression ratio. This time it is working really well, so far (1000 miles).
We do it with newly designed intake valves. These intake valves, along with their normal functions, also act as check valves against reversion on the intake cycle (during valve overlap) and also compression reversion on the compression cycle.
On the Dyno @ stoichiometric (perhaps a bit richer) we have significant increase in low end torque. 300 ft.lbs at 1000 RPM and it goes up quickly at 1500 RPM to 400 ft. lbs of toque and stays there until 5250 and starts to peel off slowly , it does not fall off a cliff. These are significant increase in torque. Max spark advance 19 degrees. Exhaust temperatures 800 F range. 87 octane gasoline. The engine has a medium range after market cam.
We are playing with the Air Fuel ratios and today we have it running with very good performance at 24 to 1 A/F (that is as high as our wide band A/F meter goes), it idles at 300 RPM (not all that stable,needs more flyweight). At cruise, 70 MPH @1600 RPM up a 6 degree grade, with exhaust temps 1100 to 1150 degrees F. (these temps have turned the corner, they were hotter at about 19 to 1 AF) Throttle position is 45 percent, performance is acceptable.
Questions,
How can I check the NOX?
Is there any reason to believe that the NOX emission may be low?
We plan on going further lean until the exhaust temperatures drop to 800 or 900 degrees(if the performance continues to stay acceptable) , with the throttle pretty much open and then control speed with fuel, via fuel pressure. Why? Not sure just trying out some new things. I would love to hear comments as too what the NOX emission will be????
How about adding, diesel fuel 5% at a time, to see what effect that has on performance and NOX.
Thanks for any and all input!