Well, I have the target. Now to just dial in the fuel table. It's close though.
Advancement of fuel delivery?
- Thread starter Alky V6
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Well, I have the target. Now to just dial in the fuel table. It's close though.
Found this after checking over the engine. Not sure when it happened. This is the CO2 line to the boost valve. The attachment arrangment will be corrected. This may be what caused the 22 kPa swing in the boost around the shift into 3rd in datalog 23d.
Never mind. Pressure in that line should have been 0 by that time. Hard to figure out when it popped out.
Never mind. Pressure in that line should have been 0 by that time. Hard to figure out when it popped out.
Attachments
Comparison of datalogs 22x and 23d
22x was the first run of the weekend, Friday night. I know the boost valve line was connected on that run. Let's see how the boost ramp compares with the last run of Saturday night, which turned out to be the best for the present combination.
The 22x run was aborted due to the boost being too high for the 1-2 shift and the tires going away. Nitrous was being used for .45 seconds to pre-spool the turbo.
Timestamp(time into run); rpm; map(kPa); timing:
41.42(-0.480); 2371; 93.48; 33.4. Staged at WOT.
41.44(-.460); 2369; 93.48; 19.3. Nitrous is activated.
41.84(-0.060); 3469; 94.71; 19.8. First sign of boost.
41.90(0.000); 3496; 93.48; 19.8. Assumed point of transbrake release.
42.24(0.340); 3826; 98.40; 19.8. 98 kPa tuning point reached. Obtaining 98 kPa by 3800 rpm has been an important target for me. The mixture at this point in the fuel table is very critical to reach this target. And, it's still not right.
42.44(0.540); 3872; 100.87; 19.8. 100 kPa tuning point reached. This is a very important threshold for the boost ramp up.
43.04(1.140); 4480; 110.72; 19.5. 110 kPa tuning point reached.
43.44(1.540); 5023; 126.73; 18.8. 126 kPa reached.
43.64(1.740); 5261; 137.82; 18.1. 137 kPa reached.
43.76(1.860); 5367; 145.21; 17.9. 145 kPa tuning point reached.
44.00(2.100); 5849; 166.15; 15.8. 166 kPa reached.
44.30(2.400); 6688; 199.40; 14.6. 200 kPa reached. Target 1-2 shift point reached. Nitrous turned off.
44.50(2.600); 7107; 226.50; 23.5. 226 kPa reached. Timing is back in.
44.60(2.700); 7315; 230.19; 0. 230 kPa reached, rev limiter, start of 1-2 shift.
44.76(2.860); 6354; 246.20; 25.4. Peak kPa reached and boost controller pulling it down. 1-2 shift in progress.
44.80(2.900); 6534; 244.97; 25.6. First sign of slippage. Run aborted soon after this point.
I need to reaccess my boost controller setting, rpm, and boost valve opening point for the 1-2 shift.
Either the pre-spooling makes a very big difference, or the boost valve line was off for the 23d run. I feel a new best for this combination is in the very near future.
The fuel maps of 22x and 23d have been carefully studied and compared. 23g is ready for testing.
22x was the first run of the weekend, Friday night. I know the boost valve line was connected on that run. Let's see how the boost ramp compares with the last run of Saturday night, which turned out to be the best for the present combination.
The 22x run was aborted due to the boost being too high for the 1-2 shift and the tires going away. Nitrous was being used for .45 seconds to pre-spool the turbo.
Timestamp(time into run); rpm; map(kPa); timing:
41.42(-0.480); 2371; 93.48; 33.4. Staged at WOT.
41.44(-.460); 2369; 93.48; 19.3. Nitrous is activated.
41.84(-0.060); 3469; 94.71; 19.8. First sign of boost.
41.90(0.000); 3496; 93.48; 19.8. Assumed point of transbrake release.
42.24(0.340); 3826; 98.40; 19.8. 98 kPa tuning point reached. Obtaining 98 kPa by 3800 rpm has been an important target for me. The mixture at this point in the fuel table is very critical to reach this target. And, it's still not right.
42.44(0.540); 3872; 100.87; 19.8. 100 kPa tuning point reached. This is a very important threshold for the boost ramp up.
43.04(1.140); 4480; 110.72; 19.5. 110 kPa tuning point reached.
43.44(1.540); 5023; 126.73; 18.8. 126 kPa reached.
43.64(1.740); 5261; 137.82; 18.1. 137 kPa reached.
43.76(1.860); 5367; 145.21; 17.9. 145 kPa tuning point reached.
44.00(2.100); 5849; 166.15; 15.8. 166 kPa reached.
44.30(2.400); 6688; 199.40; 14.6. 200 kPa reached. Target 1-2 shift point reached. Nitrous turned off.
44.50(2.600); 7107; 226.50; 23.5. 226 kPa reached. Timing is back in.
44.60(2.700); 7315; 230.19; 0. 230 kPa reached, rev limiter, start of 1-2 shift.
44.76(2.860); 6354; 246.20; 25.4. Peak kPa reached and boost controller pulling it down. 1-2 shift in progress.
44.80(2.900); 6534; 244.97; 25.6. First sign of slippage. Run aborted soon after this point.
I need to reaccess my boost controller setting, rpm, and boost valve opening point for the 1-2 shift.
Either the pre-spooling makes a very big difference, or the boost valve line was off for the 23d run. I feel a new best for this combination is in the very near future.
The fuel maps of 22x and 23d have been carefully studied and compared. 23g is ready for testing.
Reaching 145kPa by 5367rpm is about a 400 rpm decrease over what was occurring without the boost valve. The same goes for reaching 200kPa by 6688rpm.
The time from launch to the optimum 1-2 shift point dropped about 3 tenths of a second.
The time from launch to the optimum 1-2 shift point dropped about 3 tenths of a second.
More datalog analysis results.
I took the 22x and the 23d datalogs and compared the boost ramp up rates side by side.
A few conditions were different between the 2 tests, and they were:
22x(first run Friday evening) - .45 of a second pre-spooling on the nitrous before transbrake release.
Boost valve was in operation.
23d(last run Saturday evening) - no pre-spooling on the nitrous before transbrake release.
Questionable as to whether the boost valve was in operation or not. The CO2 line to the boost valve was discovered to have blown off after the pass.
22x and 23d - nitrous bottles were good.
After the launch and by this MAP (kPa) the difference in rpm was:
95 kPa - 320 rpm
98 kPa - 360 rpm
110 kPa - 450 rpm
146 kPa - 910 rpm!
I took the 22x and the 23d datalogs and compared the boost ramp up rates side by side.
A few conditions were different between the 2 tests, and they were:
22x(first run Friday evening) - .45 of a second pre-spooling on the nitrous before transbrake release.
Boost valve was in operation.
23d(last run Saturday evening) - no pre-spooling on the nitrous before transbrake release.
Questionable as to whether the boost valve was in operation or not. The CO2 line to the boost valve was discovered to have blown off after the pass.
22x and 23d - nitrous bottles were good.
After the launch and by this MAP (kPa) the difference in rpm was:
95 kPa - 320 rpm
98 kPa - 360 rpm
110 kPa - 450 rpm
146 kPa - 910 rpm!
Alky 3.2 23j.WT4T3
The a/f ratios are very close. Close enough that I started playing around with the ignition timing table. The ECM allows me a straight amount of nitrous retard which was causing too much nitrous retard by the end of the hit. I made changes to the timing table that would work together with the straight nitrous retard to allow the timing to climb through the nitrous hit, rather than ramp down.
A little more timing advance has been added to the basic timing table overall.
The a/f ratios are very close. Close enough that I started playing around with the ignition timing table. The ECM allows me a straight amount of nitrous retard which was causing too much nitrous retard by the end of the hit. I made changes to the timing table that would work together with the straight nitrous retard to allow the timing to climb through the nitrous hit, rather than ramp down.
A little more timing advance has been added to the basic timing table overall.
I have to wait 'till next weekend.At idle to 2100 rpm, I added in about 7 degrees of timing. The temperature of the engine is very cold now.
I have no radiator fan and with the timing I was using before, the engine temp would get up to around 210F after idling long enough.
With the new timing, I have a hard time obtaining 150F degrees. Even after some simple load testing, I'm lucky to see 180F.
The engine still likes around 32 degrees of advance at converter stall.
Ignition timing used for temperature control at idle of an alcohol engine.
If I find that in the staging lanes I have a hard time getting the engine up to correct running temp (target is 150F), then I'll retard the timing a little to put some heat into the engine. I could also pick an rpm zone in the timing table, just off idle to put in a retarded timing number. If I needed some heat fast, I could just bring the idle up a little into that retarded timing region.
Another thought on the engine temp. In sprint cars we lean the fuel out to warn our motor during warm up idle. If we turn the fuel on all the way you can see the engine temperature drop. It has a simple 90* off/on ball valve we set it to 45* or so. We don’t adjust the timing since we use magnetos.
P.S. this thread is full of great info thanks for sharing.
P.S. this thread is full of great info thanks for sharing.
Thanks for the input. It made me think a little about idle control using both fueling and timing.
As the engine warms, especially after a run down the track, the idle starts to get a little out of hand. With an alcohol engine, idle rises as the engine warms. This is because more of the alcohol is being processed due to better atomization and evaporization of the fuel in a warmed engine, especially when temps get to 180F and over. If the mixture is lean enough as this warming occurs, you can end up with what's called lean idle speed runaway.
By setting up the fuel table to richen the mixture as idle speed increases, starting out on the lean side at low rpm, and the timing table setup to retard timing as the engine warms and idle speed increases, starting at a high timing at low rpm, then the fuel and timing will be working together to keep idle and engine temp under control.
As you may guess, I'm not using IAC.
As the engine warms, especially after a run down the track, the idle starts to get a little out of hand. With an alcohol engine, idle rises as the engine warms. This is because more of the alcohol is being processed due to better atomization and evaporization of the fuel in a warmed engine, especially when temps get to 180F and over. If the mixture is lean enough as this warming occurs, you can end up with what's called lean idle speed runaway.
By setting up the fuel table to richen the mixture as idle speed increases, starting out on the lean side at low rpm, and the timing table setup to retard timing as the engine warms and idle speed increases, starting at a high timing at low rpm, then the fuel and timing will be working together to keep idle and engine temp under control.
As you may guess, I'm not using IAC.
Testing went good. The fuel map is within 1% for the most part. 3% in others.
The new timing strategy on the nitrous was a disaster. It doesn't like a lot of retard at the start of the hit. It does seem to like the timing I gave it at the end of the hit. I went back to the timing strategy I've used from the start for the beginning of the hit, plus a few degrees more, and ramped in quite a bit of timing into the back half of the hit. I don't have time to play with the basic timing table anymore because of an event that's coming up that I want to have the car consistent for. I'll get back to that tuning point later.
The aux fuel wall in the primary fuel table had to be extended because the boost ramp up rate has increased by quite a bit. Most likely due to the new boost valve. The boost ramp up was blowing past the wall and was seeing the drop off in pw before the aux fuel could start flowing from the nozzles, causing some nasty lean spikes. I had to change the wall cut back point from 161/163kPa to 171/173kPa. So now the total duration of the wall is from 148 kPa to 171kPa. The height of the wall has been decreased by 1%.
To make the aux fueling wall statement a little clearer, as the boost is rising and passes the 148kPa map point, the aux fueling solenoid opens and allows fuel to flow through the intake plenum internal plumbing to the fuel nozzles inside the plenum. By the time the fuel finally gets to the nozzles and begins flowing into the intake ports, the boost has already risen to a new level of 172kPa. If the electronic injectors are cut back before this 172kPa map point, a lean spike will occur because the fuel has still not begun flowing from the nozzles yet.
The 1-2 shift is coming up quicker. I had to move the rev limiter up a little because of the difference in how quickly that 1-2 shift is coming up. One pass, I just didn't catch it quick enough and ran into the rev limiter.
The rev limiter is usually set at 7300 for 1/8 mile runs. I'll be setting it to 7900 for the coming 1/4 mile runs. I'll need to check the timeout on the boost controller to make sure it's set long enough for the 1/4.
The new timing strategy on the nitrous was a disaster. It doesn't like a lot of retard at the start of the hit. It does seem to like the timing I gave it at the end of the hit. I went back to the timing strategy I've used from the start for the beginning of the hit, plus a few degrees more, and ramped in quite a bit of timing into the back half of the hit. I don't have time to play with the basic timing table anymore because of an event that's coming up that I want to have the car consistent for. I'll get back to that tuning point later.
The aux fuel wall in the primary fuel table had to be extended because the boost ramp up rate has increased by quite a bit. Most likely due to the new boost valve. The boost ramp up was blowing past the wall and was seeing the drop off in pw before the aux fuel could start flowing from the nozzles, causing some nasty lean spikes. I had to change the wall cut back point from 161/163kPa to 171/173kPa. So now the total duration of the wall is from 148 kPa to 171kPa. The height of the wall has been decreased by 1%.
To make the aux fueling wall statement a little clearer, as the boost is rising and passes the 148kPa map point, the aux fueling solenoid opens and allows fuel to flow through the intake plenum internal plumbing to the fuel nozzles inside the plenum. By the time the fuel finally gets to the nozzles and begins flowing into the intake ports, the boost has already risen to a new level of 172kPa. If the electronic injectors are cut back before this 172kPa map point, a lean spike will occur because the fuel has still not begun flowing from the nozzles yet.
The 1-2 shift is coming up quicker. I had to move the rev limiter up a little because of the difference in how quickly that 1-2 shift is coming up. One pass, I just didn't catch it quick enough and ran into the rev limiter.
The rev limiter is usually set at 7300 for 1/8 mile runs. I'll be setting it to 7900 for the coming 1/4 mile runs. I'll need to check the timeout on the boost controller to make sure it's set long enough for the 1/4.
I just went back and checked the boost ramp up rate I had with the T76 in the area of 'the wall' in the fuel map. The internal plumbing space volume of the aux system back then was larger, so more time was needed before fuel would finally begin flowing from the nozzles. The duration of the wall was 148kPa to 172kPa.
The internal space volume of the new plumbing configuration is less, so less time is needed before fuel begins to flow from the nozzles. The wall duration is 148kPa to 171kPa.
1 kPa difference plus the difference in the space volumes.
The internal space volume of the new plumbing configuration is less, so less time is needed before fuel begins to flow from the nozzles. The wall duration is 148kPa to 171kPa.
1 kPa difference plus the difference in the space volumes.
Sounds like that valve you designed is doing what you hoped for and more. A little agrivation to get you where you need to be I guess. When's the event and where is it. Do you know of they're going to do a web cast or not? I'd love to watch if they do.
23w datalog
Timestamp; (time into run); rpm; map;
39.48 (.000) 2344rpm@93.5kPa. Start of run. TB released and nitrous started.
39.82 (.34) 3469@94.7. 95kPa tuning point reached.
40.22 (.74) 3811@98.4. 3800 and 98kPa tuning points reached.
40.34 (.86)3948@99.6. 100kPa tuning point reached.
40.42 (.94) 3994@100.9. 4000 and 100kPa tuning points reached.
40.88 (1.40) 4371@108.3. 110kPa tuning point reached.
40.94 (1.46) 4464@112. 4500rpm tuning point reached.
41.28 (1.80) 5000@ 124.3.
41.62 (2.14) 5766@144. 5780 and 146kPa tuning points reached. Start of 'the wall'.
41.98 (2.50) 6686@174.8. End of 'the wall'.
42.18 (2.70) 6992@199.4. Nitrous shut down.
42.38 (2.90) 7343@230.2. Rev limiter hit.
42.54 (3.06) 7493@245. Rev limiter hit again.
42.68 (3.20) 6937@257.3. 1-2 shift initiated.
42.94 (3.46) 6132@270.8. 1-2 shift finished.
The 1-2 shift should have occurred at timestamp 42.18.
Time from 144 to 244kPa: .86 second.
Timestamp; (time into run); rpm; map;
39.48 (.000) 2344rpm@93.5kPa. Start of run. TB released and nitrous started.
39.82 (.34) 3469@94.7. 95kPa tuning point reached.
40.22 (.74) 3811@98.4. 3800 and 98kPa tuning points reached.
40.34 (.86)3948@99.6. 100kPa tuning point reached.
40.42 (.94) 3994@100.9. 4000 and 100kPa tuning points reached.
40.88 (1.40) 4371@108.3. 110kPa tuning point reached.
40.94 (1.46) 4464@112. 4500rpm tuning point reached.
41.28 (1.80) 5000@ 124.3.
41.62 (2.14) 5766@144. 5780 and 146kPa tuning points reached. Start of 'the wall'.
41.98 (2.50) 6686@174.8. End of 'the wall'.
42.18 (2.70) 6992@199.4. Nitrous shut down.
42.38 (2.90) 7343@230.2. Rev limiter hit.
42.54 (3.06) 7493@245. Rev limiter hit again.
42.68 (3.20) 6937@257.3. 1-2 shift initiated.
42.94 (3.46) 6132@270.8. 1-2 shift finished.
The 1-2 shift should have occurred at timestamp 42.18.
Time from 144 to 244kPa: .86 second.
Pinks All Out at Bakerfield Sept. 11-12.
Totally cool Donnie. Good luck.
How did you do at the event ?
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