E85 and photo shoot
07-14-2009, 11:02 AM
#31
Race Car
Duke,
Curious what you are targeting for AFR in different areas. Also what EGTS throughout the rpms/pressures??
Are you running very rich on the top end?? I am a little puzzled as to why you would be maxxing out the pump at such low pressures. I am not totally up on your current setup maybe you have a crazy head on there???
BTW I am using a HV pump (928 I think) feeding a 951 pump.
Curious what you are targeting for AFR in different areas. Also what EGTS throughout the rpms/pressures??
Are you running very rich on the top end?? I am a little puzzled as to why you would be maxxing out the pump at such low pressures. I am not totally up on your current setup maybe you have a crazy head on there???
BTW I am using a HV pump (928 I think) feeding a 951 pump.
07-14-2009, 06:59 PM
#32
Nordschleife Master
Thread Starter
holy crap haha
not sure about the specifics of ethanol vs gasoline (weight per volume, actual energy content per voilume) but with some extremely crude and most likely incorrect math i just did if you were burning gasoline at that rate itd put you around 750HP. is that accurate at all? lol
not sure about the specifics of ethanol vs gasoline (weight per volume, actual energy content per voilume) but with some extremely crude and most likely incorrect math i just did if you were burning gasoline at that rate itd put you around 750HP. is that accurate at all? lol
Duke,
Curious what you are targeting for AFR in different areas. Also what EGTS throughout the rpms/pressures??
Are you running very rich on the top end?? I am a little puzzled as to why you would be maxxing out the pump at such low pressures. I am not totally up on your current setup maybe you have a crazy head on there???
BTW I am using a HV pump (928 I think) feeding a 951 pump.
Curious what you are targeting for AFR in different areas. Also what EGTS throughout the rpms/pressures??
Are you running very rich on the top end?? I am a little puzzled as to why you would be maxxing out the pump at such low pressures. I am not totally up on your current setup maybe you have a crazy head on there???
BTW I am using a HV pump (928 I think) feeding a 951 pump.
I'm thinking about perhaps adding a Walbro (they're small) to my 044 pump. But 2x 044 would feel better.
My EGT sensor recently went crazy so no good readings there.
07-15-2009, 11:15 AM
#33
Race Car
So what AFR have you leaned it to?
Also FYI. I have found a little more MPH by dropping timing lead at higher rpms. One day I will get it back on a dyno to mess with timing to verify power output, but at this point the car seems to pull a little harder with the timing ~ 21-23 degrees at over 6k rpm. This also could be contributed to using a stock IC and higher AIT.
I haven't had the time to do the things I want right now, so it will have to wait a bit.
Also FYI. I have found a little more MPH by dropping timing lead at higher rpms. One day I will get it back on a dyno to mess with timing to verify power output, but at this point the car seems to pull a little harder with the timing ~ 21-23 degrees at over 6k rpm. This also could be contributed to using a stock IC and higher AIT.
I haven't had the time to do the things I want right now, so it will have to wait a bit.
07-16-2009, 06:18 AM
#35
Nordschleife Master
Thread Starter
So what AFR have you leaned it to?
Also FYI. I have found a little more MPH by dropping timing lead at higher rpms. One day I will get it back on a dyno to mess with timing to verify power output, but at this point the car seems to pull a little harder with the timing ~ 21-23 degrees at over 6k rpm. This also could be contributed to using a stock IC and higher AIT.
I haven't had the time to do the things I want right now, so it will have to wait a bit.
Also FYI. I have found a little more MPH by dropping timing lead at higher rpms. One day I will get it back on a dyno to mess with timing to verify power output, but at this point the car seems to pull a little harder with the timing ~ 21-23 degrees at over 6k rpm. This also could be contributed to using a stock IC and higher AIT.
I haven't had the time to do the things I want right now, so it will have to wait a bit.
So you mean you got better performance by lowering ignition advance? That sounds very strange to me?
At 1.2 bar I now run 25 deg at 4000 rpm, 28 deg at 6000 rpm and 30.5 at 7000 rpm.
At 7000 rpm, 1.2 bar, 11.7 AFR my 1000 cc injectors are at 100% duty cycle.
I don't those tires are still on the market. I would look for Toyo R888, they are pretty good priced.
07-16-2009, 06:47 AM
#36
Rennlist Member
I have also heard about people gaining by lowering the advance in some situations Duke.
07-16-2009, 08:09 AM
#37
Nordschleife Master
Thread Starter
Sure, but not we're talking about 40-50 degrees of advance here.
MBT (minimum best torque timing) is still above the degrees we're talking here.
But with E85 it won't necessarily start to detonate with more advance than (or at) best torque timing so the best way is to tune on the dyno and add advance until there's no more gain in torque. Or just add more ignition advance until the logs show you're not accelerating any faster
E85 burns much faster at richer mixtures so that affects timing too.
Maybe I'll drop in the 1600 cc injectors today and turn up the boost. It still isn't as fast as it was on pump fuel with 1.55 bar so it's almost boring
MBT (minimum best torque timing) is still above the degrees we're talking here.
But with E85 it won't necessarily start to detonate with more advance than (or at) best torque timing so the best way is to tune on the dyno and add advance until there's no more gain in torque. Or just add more ignition advance until the logs show you're not accelerating any faster
E85 burns much faster at richer mixtures so that affects timing too.
Maybe I'll drop in the 1600 cc injectors today and turn up the boost. It still isn't as fast as it was on pump fuel with 1.55 bar so it's almost boring
07-16-2009, 11:11 AM
#39
Race Car
Duke, I tend to go the other way, starting ~ 30 degrees at 4k and dropping down as the rpms go up .
Using the engines VE curve to determine BMT and also having the extra timing in the lower rpms seems to help spoolup.
I am in agreement that the most timing you can run will make the best power, but in the upper rpms it starts to fight itself due to the poor VE. I agree all should be done on a dyno to be absolute.
This has just been my experience overall with other engines too regarding timing curves.
Using the engines VE curve to determine BMT and also having the extra timing in the lower rpms seems to help spoolup.
I am in agreement that the most timing you can run will make the best power, but in the upper rpms it starts to fight itself due to the poor VE. I agree all should be done on a dyno to be absolute.
This has just been my experience overall with other engines too regarding timing curves.
07-16-2009, 12:08 PM
#41
Nordschleife Master
Thread Starter
Duke, I tend to go the other way, starting ~ 30 degrees at 4k and dropping down as the rpms go up .
Using the engines VE curve to determine BMT and also having the extra timing in the lower rpms seems to help spoolup.
I am in agreement that the most timing you can run will make the best power, but in the upper rpms it starts to fight itself due to the poor VE. I agree all should be done on a dyno to be absolute.
This has just been my experience overall with other engines too regarding timing curves.
Using the engines VE curve to determine BMT and also having the extra timing in the lower rpms seems to help spoolup.
I am in agreement that the most timing you can run will make the best power, but in the upper rpms it starts to fight itself due to the poor VE. I agree all should be done on a dyno to be absolute.
This has just been my experience overall with other engines too regarding timing curves.
I totally agree that agressive timing in the midrange is good (as long as it doesn't knock). In boosted cars MBT timing will always be knock limited so you tune for knock and then add a safety margin.
An engine is as most sensitive to knock at peak torque, which in turn means you can add advance as torque drops. Lower VE at higher rpms will also accept more advance without knocking. Plus the fact that the time frame for the combustion goes down as rpms go up.
My experiences both from a theoretical and practical standpoint shows that you need to add a lot of advance at higher rpms to keep the torque from skydiving.
That's also the reason why my torque curve doesn't drop with more than 30-50 nm between torque peak and 7000 rpm. This with a stock valved head, stock headers, stock intake.
My injector duty cycle at higher rpms also somewhat shows that I'm making good power up there. I can't see how other 951's could getaway boosting above 18 psi on E85 with 70-80 lbs injectors. IMHO that can only be done with low power at higher rpms.
07-16-2009, 02:29 PM
#42
Race Car
To me that sounds backwards but let's agree to disagree
I totally agree that agressive timing in the midrange is good (as long as it doesn't knock). In boosted cars MBT timing will always be knock limited so you tune for knock and then add a safety margin.
An engine is as most sensitive to knock at peak torque, which in turn means you can add advance as torque drops. Lower VE at higher rpms will also accept more advance without knocking. Plus the fact that the time frame for the combustion goes down as rpms go up.
My experiences both from a theoretical and practical standpoint shows that you need to add a lot of advance at higher rpms to keep the torque from skydiving.
That's also the reason why my torque curve doesn't drop with more than 30-50 nm between torque peak and 7000 rpm. This with a stock valved head, stock headers, stock intake.
My injector duty cycle at higher rpms also somewhat shows that I'm making good power up there. I can't see how other 951's could getaway boosting above 18 psi on E85 with 70-80 lbs injectors. IMHO that can only be done with low power at higher rpms.
I totally agree that agressive timing in the midrange is good (as long as it doesn't knock). In boosted cars MBT timing will always be knock limited so you tune for knock and then add a safety margin.
An engine is as most sensitive to knock at peak torque, which in turn means you can add advance as torque drops. Lower VE at higher rpms will also accept more advance without knocking. Plus the fact that the time frame for the combustion goes down as rpms go up.
My experiences both from a theoretical and practical standpoint shows that you need to add a lot of advance at higher rpms to keep the torque from skydiving.
That's also the reason why my torque curve doesn't drop with more than 30-50 nm between torque peak and 7000 rpm. This with a stock valved head, stock headers, stock intake.
My injector duty cycle at higher rpms also somewhat shows that I'm making good power up there. I can't see how other 951's could getaway boosting above 18 psi on E85 with 70-80 lbs injectors. IMHO that can only be done with low power at higher rpms.
I guess I can agree to dis agree. This is just the way I have done it for years in other applications and I didn't see that the 2v head 2.5 was much different. To truly find out one would have to dyno at your current timing setup and then swap down the timing and reduce fuel and see what happens. My past experiences have shown that a reduction in timing at high rpms and boost makes more mph in the quarter.
I am not sure what is going on with your IDC but IIRC Bruce was running the same size injectors and had dyno'd well over 400 hp at 24 psi before having any issues.
Personally I have to say that I am a little leary running the 76 pound injectors over 22 psi with a good pump. Without the added supplemental I have not ventured further.
07-16-2009, 06:02 PM
#43
Rennlist Member
MBT (minimum best torque timing) is still above the degrees we're talking here.
But with E85 it won't necessarily start to detonate with more advance than (or at) best torque timing so the best way is to tune on the dyno and add advance until there's no more gain in torque. Or just add more ignition advance until the logs show you're not accelerating any faster
E85 burns much faster at richer mixtures so that affects timing too.
But with E85 it won't necessarily start to detonate with more advance than (or at) best torque timing so the best way is to tune on the dyno and add advance until there's no more gain in torque. Or just add more ignition advance until the logs show you're not accelerating any faster
E85 burns much faster at richer mixtures so that affects timing too.
MBT is still above what degrees? The lower 20's or even higher than your upper 20's?
What do you think the MBT is on our engines with gasoline only (let's say race gas so that knock is out of the equation)?
Also, all the research that I've done indicates that rich mixtures with E85 burn slower than mixtures that are only 10% rich.
07-16-2009, 06:06 PM
#44
Rennlist Member
07-16-2009, 06:26 PM
#45
Nordschleife Master
Thread Starter
I dropped in the 1600 cc injectors today. Those are a bit painful to tune. Even with the correct injector dead times I had to redo most of the fuel map.
Boosting around 1.35 bar: 100-181 km/h 3rd gear in 5.44 sec. 100-200 km/h in 7.6 sec
Pretty decent for a mildly modified engine at this boost level
Boosting around 1.35 bar: 100-181 km/h 3rd gear in 5.44 sec. 100-200 km/h in 7.6 sec
Pretty decent for a mildly modified engine at this boost level