Advancement of fuel delivery?
- Thread starter Alky V6
- Start date
What about precision controlled EGR!!!
EGR also has the added benefit of controlling detonation, preignition, combustion temperature as a whole.
That may be the way to go Donnie. You could even run a tube through the intake to heat up the chage some. That may be the best way to get a little more heat into the engine.
You need to check out some of the electronic ones Donnie. Maybe one off of a 3800? I've never had a problem out of the one on my car so it should be adjustable to some degree.
It uses external tubing and you should be able to get one in a salvage yard for cheap.
It uses external tubing and you should be able to get one in a salvage yard for cheap.
You could introduce it before the turbo but it might make for issues on setting up the mix. Running a 1/2" tube through the plenum will also allow you to heat the air to some degree. Just a few off the top of my head Donnie.
Last night I revisited the auxiliary rev control (2-step rev control) feature of the ECM that I use. Since the last upgrade of the ECM and software, this feature now works reliably.
There are various features to the aux rev control, but I simply picked timing retard to 0 degrees to control the limit. No fuel or coil output reducing, dropping or cuttoff.
I set the aux rev control to 2100 rpm as a test, with a 'rev limit approach retard setting' of 500 rpm. The rev limit approach retard setting is the amount of rpm before the actual rev limit rpm where the ecm begins to ramp the timing out. With a 500 rpm setting, half of the timing will have been taken out by 250 rpm before the rev limit rpm. This along with a 15 rpm hysteresis makes for a softer aux rev control (2-step).
One thing I noticed was that when coming off the aux rev limiter, the converter stall was higher and the a/f mixture was leaner. The aux rev limiter feature also allows for more or less fuel during the limiting, so I added 5% more fuel. I also added 4% more fuel to the fuel table at the new T/C stall speed. The result was a very slight change if any in the a/f mixture while on the rev limiter.
Also, the stall increased slightly. I was obviously netting more hp from the additional fuel that I was adding.
Another item noted. The exhaust temp gauge would rise very quickly while on the aux rev limiter. That's understandable with the timing going to zero. The burn is later in the power stroke and some is still burning when the exhaust valve opens, heating the exhaust system.
So my conclusion at this time is, the zero timing brought on by the aux rev limiter is heating more surface area of the cylinder and exhaust system to higher than normal temps. The higher cylinder temp is preheating the new incoming a/f charge to a higher temp where more of the fuel is vaporizing by the time the ignition fires off the charge. The increased vaporization is allowing more of the charge to be burned and hence the leaner than expected a/f ratio readings. She wants more fuel, Jim!
I wonder how much fuel I can put to it before the charge is overcooled by the excessive fuel or before the a/f mixture reading will start moving towards richer.
One more note. While on the aux rev limiter, there is a very noticeable climb in the amount of exhaust energy exiting the exhaust pipe. A box that I put at the exhaust pipe to catch fumes and pump them outside, would be moved back by the force of the exhaust energy.
Interesting stuff.
Oh. I should add. I'm performing the aux rev limiting without a distributor. If you have the right waste spark system, you can have 2-step rev control.
There are various features to the aux rev control, but I simply picked timing retard to 0 degrees to control the limit. No fuel or coil output reducing, dropping or cuttoff.
I set the aux rev control to 2100 rpm as a test, with a 'rev limit approach retard setting' of 500 rpm. The rev limit approach retard setting is the amount of rpm before the actual rev limit rpm where the ecm begins to ramp the timing out. With a 500 rpm setting, half of the timing will have been taken out by 250 rpm before the rev limit rpm. This along with a 15 rpm hysteresis makes for a softer aux rev control (2-step).
One thing I noticed was that when coming off the aux rev limiter, the converter stall was higher and the a/f mixture was leaner. The aux rev limiter feature also allows for more or less fuel during the limiting, so I added 5% more fuel. I also added 4% more fuel to the fuel table at the new T/C stall speed. The result was a very slight change if any in the a/f mixture while on the rev limiter.
Also, the stall increased slightly. I was obviously netting more hp from the additional fuel that I was adding.Another item noted. The exhaust temp gauge would rise very quickly while on the aux rev limiter. That's understandable with the timing going to zero. The burn is later in the power stroke and some is still burning when the exhaust valve opens, heating the exhaust system.
So my conclusion at this time is, the zero timing brought on by the aux rev limiter is heating more surface area of the cylinder and exhaust system to higher than normal temps. The higher cylinder temp is preheating the new incoming a/f charge to a higher temp where more of the fuel is vaporizing by the time the ignition fires off the charge. The increased vaporization is allowing more of the charge to be burned and hence the leaner than expected a/f ratio readings. She wants more fuel, Jim!
I wonder how much fuel I can put to it before the charge is overcooled by the excessive fuel or before the a/f mixture reading will start moving towards richer.
One more note. While on the aux rev limiter, there is a very noticeable climb in the amount of exhaust energy exiting the exhaust pipe. A box that I put at the exhaust pipe to catch fumes and pump them outside, would be moved back by the force of the exhaust energy.
Interesting stuff.
Oh. I should add. I'm performing the aux rev limiting without a distributor. If you have the right waste spark system, you can have 2-step rev control.
- Joined
- May 28, 2001
So does this translate into more boost for the launch off the line?
Last night I revisited the auxiliary rev control (2-step rev control) feature of the ECM that I use. Since the last upgrade of the ECM and software, this feature now works reliably.
There are various features to the aux rev control, but I simply picked timing retard to 0 degrees to control the limit. No fuel or coil output reducing, dropping or cuttoff.
I set the aux rev control to 2100 rpm as a test, with a 'rev limit approach retard setting' of 500 rpm. The rev limit approach retard setting is the amount of rpm before the actual rev limit rpm where the ecm begins to ramp the timing out. With a 500 rpm setting, half of the timing will have been taken out by 250 rpm before the rev limit rpm. This along with a 15 rpm hysteresis makes for a softer aux rev control (2-step).
One thing I noticed was that when coming off the aux rev limiter, the converter stall was higher and the a/f mixture was leaner. The aux rev limiter feature also allows for more or less fuel during the limiting, so I added 5% more fuel. I also added 4% more fuel to the fuel table at the new T/C stall speed. The result was a very slight change if any in the a/f mixture while on the rev limiter.
Another item noted. The exhaust temp gauge would rise very quickly while on the aux rev limiter. That's understandable with the timing going to zero. The burn is later in the power stroke and some is still burning when the exhaust valve opens, heating the exhaust system.
So my conclusion at this time is, the zero timing brought on by the aux rev limiter is heating more surface area of the cylinder and exhaust system to higher than normal temps. The higher cylinder temp is preheating the new incoming a/f charge to a higher temp where more of the fuel is vaporizing by the time the ignition fires off the charge. The increased vaporization is allowing more of the charge to be burned and hence the leaner than expected a/f ratio readings. She wants more fuel, Jim!
I wonder how much fuel I can put to it before the charge is overcooled by the excessive fuel or before the a/f mixture reading will start moving towards richer.
One more note. While on the aux rev limiter, there is a very noticeable climb in the amount of exhaust energy exiting the exhaust pipe. A box that I put at the exhaust pipe to catch fumes and pump them outside, would be moved back by the force of the exhaust energy.
Interesting stuff.
Oh. I should add. I'm performing the aux rev limiting without a distributor. If you have the right waste spark system, you can have 2-step rev control.
Dusty Bradford
Well-Known Member
- Joined
- May 24, 2001
Last night I revisited the auxiliary rev control (2-step rev control) feature of the ECM that I use. Since the last upgrade of the ECM and software, this feature now works reliably.
There are various features to the aux rev control, but I simply picked timing retard to 0 degrees to control the limit. No fuel or coil output reducing, dropping or cuttoff.
I set the aux rev control to 2100 rpm as a test, with a 'rev limit approach retard setting' of 500 rpm. The rev limit approach retard setting is the amount of rpm before the actual rev limit rpm where the ecm begins to ramp the timing out. With a 500 rpm setting, half of the timing will have been taken out by 250 rpm before the rev limit rpm. This along with a 15 rpm hysteresis makes for a softer aux rev control (2-step).
One thing I noticed was that when coming off the aux rev limiter, the converter stall was higher and the a/f mixture was leaner. The aux rev limiter feature also allows for more or less fuel during the limiting, so I added 5% more fuel. I also added 4% more fuel to the fuel table at the new T/C stall speed. The result was a very slight change if any in the a/f mixture while on the rev limiter.
Another item noted. The exhaust temp gauge would rise very quickly while on the aux rev limiter. That's understandable with the timing going to zero. The burn is later in the power stroke and some is still burning when the exhaust valve opens, heating the exhaust system.
So my conclusion at this time is, the zero timing brought on by the aux rev limiter is heating more surface area of the cylinder and exhaust system to higher than normal temps. The higher cylinder temp is preheating the new incoming a/f charge to a higher temp where more of the fuel is vaporizing by the time the ignition fires off the charge. The increased vaporization is allowing more of the charge to be burned and hence the leaner than expected a/f ratio readings. She wants more fuel, Jim!
I wonder how much fuel I can put to it before the charge is overcooled by the excessive fuel or before the a/f mixture reading will start moving towards richer.
One more note. While on the aux rev limiter, there is a very noticeable climb in the amount of exhaust energy exiting the exhaust pipe. A box that I put at the exhaust pipe to catch fumes and pump them outside, would be moved back by the force of the exhaust energy.
Interesting stuff.
Oh. I should add. I'm performing the aux rev limiting without a distributor. If you have the right waste spark system, you can have 2-step rev control.
This is what the clutch racers refer to as "anti-lag".
Your a/f should not respond to the changes because the fuel is burning in the exhaust before the 02 sensor. A dead cylinder, which is what a 2-step is, will cause the a/f to read leaner than it actually is. Adding more fuel, with no timing puts even more fuel into the exhaust, the fuel then explodes in the exhaust and puts heat and energy into the exhaust system. You should have seen an increase in MAP as well. I'm guessing the extra boost the engine is seeing is what caused your stall speed to raise.
What you are doing is what the turbo racers with clutch transmissions do to get launch boost. Timing can even be set at -5 to -10 BTDC and a ton of fuel thrown at it. This is what causes the clutch cars to have the violent backfiring sound on the starting line.
I doubt it will, due to my extremely low stall T/C and the amount of exhaust energy that is needed to spool this 91mm.
It's time to work on the T/C.
Marty's got some new technology and is working on a new CNC billet stator to hopefully allow a little more stall and a little less rpm drop during shifts. He seems to think I won't have to give up any of the top end too.
Marty's got some new technology and is working on a new CNC billet stator to hopefully allow a little more stall and a little less rpm drop during shifts. He seems to think I won't have to give up any of the top end too.
Don, on the second page of this thread you have some new Electromotive converts you need to school:wink: http://www.turbobuick.com/forums/performance-ecm-upgrades/244452-c-n-p-coil-near-plug-coil-plug.html
That's OK Scott. Either people will discover how superior the TEC system is and change over to it, or the other brands will finally catch up to the ignition accuracy and power of the TEC system. I'm not here to champion a product.
At present, the aux rev limiter is not setup to drop fuel or spark. The system does have those options however. I presently have it setup to only retard to 0 degrees advance.
A rich alcohol mixture will add its own extra oxygen to the a/f mixture as a whole. Half of the methanol molecule by mass is oxygen. If the right circumstances exist, all the methanol will disassociate and extra oxygen will be present to burn with any extra fuel. I wonder if this has anything to do with the fact that at certain rich mixtures and ignition timing settings during the nitrous hit, the O2 sensor flatlines at 14.64:1 throughout the hit.
Am I getting a COMPLETE burn of all the fuel in the exhaust system by the time it hits the O2 sensor after the turbo?Don't know yet. I'll be taking a closer look at it tomorrow.
Don I don't recall, but what EFI ystem are you running? And are you using the stock Buick ref angle of 10 deg BTDC, or do you have a new crank sensor at about 50 deg BTDC? I suspect the latter, but am asking because generally with a narrow ref angle predictive spark setup you can't get any less timing than ~ 10 deg BTDC (the ref angle). Maybe yours can, but just wondering if you are certain it can achieve the programmed 0 deg advance? Could be important here with all the stuff you're doin'
I was down to about 12 deg total advance on mine at full load with the boost + the hose. But I have the stock CRS and an old FAST system, so to add more hose power from there (and thus more retard), was going to have to move the crank sensor back some more, or switch to a delayed spark setup.
TurboTR
I was down to about 12 deg total advance on mine at full load with the boost + the hose. But I have the stock CRS and an old FAST system, so to add more hose power from there (and thus more retard), was going to have to move the crank sensor back some more, or switch to a delayed spark setup.
TurboTR
I'm running the Electromotive TEC3r w/the latest version of WinTEC4 control software. It will retard very accurately to 0 degrees mechanical. It uses a 60-2 crank wheel. Very tiny crank angle predicting going on with this system. If I need the retard to go ATDC, I would need to relocate the crank sensor the needed degrees wanted for the ATDC timing amount, and then add that additional amount back into my main timing table for normal running.Don I don't recall, but what EFI ystem are you running? And are you using the stock Buick ref angle of 10 deg BTDC, or do you have a new crank sensor at about 50 deg BTDC? I suspect the latter, but am asking because generally with a narrow ref angle predictive spark setup you can't get any less timing than ~ 10 deg BTDC (the ref angle). Maybe yours can, but just wondering if you are certain it can achieve the programmed 0 deg advance? Could be important here with all the stuff you're doin'
I was down to about 12 deg total advance on mine at full load with the boost + the hose. But I have the stock CRS and an old FAST system, so to add more hose power from there (and thus more retard), was going to have to move the crank sensor back some more, or switch to a delayed spark setup.
TurboTR
I'm currently playing around with 15 to 8 degrees on the system, trying to determine which is best. I've got 2 datalogs from this weekend with an example of both timing strategies. I'm comparing the rpm rise rate of the two at this very moment.
Todd. I'm still keeping you on my mind. After I think I have things close enough, I would still like to take advantage of your services in regards to the cylinder pressure tracing.
Similar threads
