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Definitely interesting how much their philosophy has changed. I actually emailed Haltech about that - the discrepancy between their base map and that video Haltech Matt posted. I got a generic response that was basically "You should be tuning it yourself on a dyno".
Came across this post in the other thread:
Originally Posted by gxl90rx7
i was messing around with injector angle today with the haltech.. at idle, i confirmed there is a rich spot at around 285 degrees and again around 480 degrees, with about 0.5 AFR swing between. i suspect the 480 degree rich spot is due to fuel banging off a closed port, probably helping mix with air. im probably going to just use 280 degree at idle and linearly advance it to 310 degrees to redline
That seems to suggest that there is an optimum close port and an optimum open port value which both give similar results.
This is really going to get interesting for me when I want to locate a third set of injectors out higher up in the intake manifold.
Not sure where to even start, really. If I put them inline with the secondaries and use the secondary Injector Firing Angle for the third stage, it'll be enough fuel at that small location to create a puddling effect. I really think it has to be further up the intake manifold (closer to TB).
So that's another thing that I don't see anyone talking about here... Injector location along the runner dictates Injector Firing Angle, no? The secondaries are much further up vs. the primaries being ON the block itself.
This is probably the last part of tuning... After a "perfectly" tuned map, fluctuate at 5-10pts at a time to see how it affects AFR. Build a trend by going in either direction maybe 50pts. From there you should be able to identify ideal numbers.
Share them and remember that each manifold is different.
It looks like tricky tuning without a bunch of dyno time
That said, most people run ID injectors and there are only a few different porting/manifold possibilities (at least for FDs).
There must be a map out there of someone with a stock port engine/manifold and properly tuned injection timing - which should work for anyone else with stock ports and stock manifold, right?
The forum is here to pool knowledge - a chart of ideal injection angles for various engine configurations (even between ECUs, since many use the same type of measurement) would be helpful to a lot people
It looks like tricky tuning without a bunch of dyno time
That said, most people run ID injectors and there are only a few different porting/manifold possibilities (at least for FDs).
There must be a map out there of someone with a stock port engine/manifold and properly tuned injection timing - which should work for anyone else with stock ports and stock manifold, right?
The forum is here to pool knowledge - a chart of ideal injection angles for various engine configurations (even between ECUs, since many use the same type of measurement) would be helpful to a lot people
No, this data can DEFINITELY be found on the street while tuning. I already explained how to identify ideal range, at least how it's been taught to me. The firing angle that produces the richest AFR is going to be the most optimized for the system (think about that for a minute).
You have to remember that not all of us have FDs. Of the turbocharged vehicles, we have S4 Turbo II, S5 Turbo II, S6 REW, Cosmo RE, etc, and of course anything moving away from stock porting is likely going to change the outcome to some degree. It would take an absolute crapload of time to develop these figures, but rest assured, when my S5 Turbo II block in my FB is up and running, this will be the last thing I identify using a fuckload of sensors after the car is relatively well tuned. It is the LAST step before final tuning power runs, IMO.
I'm confident I can tune no-load/low-RPMs by holding different RPMs with the car parked, but I don't think I can minimize variables sufficiently to tune WOT/high-RPMs without a dyno.
Which might be fine, because injector timing at high RPM/high load is less important anyway since the injector is open the majority of the time (and open-port injection is a no-brainer).
Tuning no-load/low RPMs to figure out whether open or closed-port injection is more favorable down there should give me most of the info I need, I think.
I'd like to think that whichever is more efficient in the low range will also provide the best throttle response... but would that make sense? Or do you think clean/efficient combustion and ideal throttle response might require different injection angles?
For what it's worth, I've experimented with injector firing angle (on a different ECU, not Haltech) and noticed a pretty wide range that gave similar throttle response from idle. I haven't tried adjusting injector firing angle in search of richest mixture or best vacuum at idle, will give that a shot and also try to find someone with a setup that can measure HC/CO gases.
I have been reading a lot on this and the "Street Rotary" book has this image which leads me to believe that open port can be achieved in 3 different ranges (90-270, 450-630 and 810-990). What difference would it make? That's where I'm lost... I guess Haltech goes "backwards" (420-->300) in order for not to miss the open port at higher rpm's??? Maybe???
Last edited by Angel Guard Racing Team; 10-31-19 at 12:14 PM.
Reason: Typo
@$lacker, I tested seat of the pants at idle. When giving a pretty consistent throttle blip starting from idle RPM, the engine would accelerate clean in a certain 'window' of firing angle and sputter and hesitate if the firing angle was advanced by about 50-100 or retarded by about 50-100 degrees from there. There isn't smog testing where I live now, so it's been difficult to find a working emissions gas analyzer. I got permission to use one at a local college but it didn't give any readings and the people who let me borrow it hadn't used it themselves.
@Angel Guard Racing Team , if you look carefully at that diagram the injector needs to be fired every 360 degrees to supply fuel as each of the three rotor faces / combustion chambers sweep by.. For instance, if you want to fire at 90 degrees on that chart you will also need to fire at 450 and at 810. Thanks for posting that chart, by the way. I've been looking for something like that.
My guess is that idle improves at those angles since there is no overlap with exhaust which could "evaporate" part of the fuel that has just entered the engine.
1. 45° ATDC The intake stroke is just beginning. The exhaust port has just closed, and on a stock or street ported engine, the intake port has been open for approximately 15°.
2. 90° ATDC The intake port is almost completely open, and the chamber is starting to expand at a fairly rapid rate.
3. 180° ATDC The intake port is all the way open, and has just passed the point of maximum flow. Maximum flow occcurs at approximately 135° ATDC, which corresponds with the maximum rate of chamber volume increase.
4. BDC of the intake stroke. The intake chamber is now at its largest possible volume. The intake port is partially open, and the port is still flowing in the forward direction, even though the chamber is no longer increasing in volume. This is due to the inertia of the column of air flowing in the induction system. This effect is referred to as inertial supercharging, and is described in further detail in the airflow section of my webpage. This will also be addressed in a later article.
5. 45° ABDC The chamber has started to decrease in volume, and with the exception of a stock US model 12A, which has an intake port closing of 40° ATDC, the intake port is still partially open. At high rpm, the intake port is still flowing in the forward direction due to inertial supercharging. At low rpm, airflow in the port has reversed, and some of the intake charge is being squeezed back into the induction system by the pressure of the intake chamber which is decreasing in volume. This is the result of the low velocity in the induction system. This is a very important point to consider, as this alone affects the operating range of the engine more than than any other factor.
6. 90° ABDC The intake port is completely closed, and air fuel mixture is being compressed.
7. 135° ABDC Same as #6.
8. 180° ABDC More of the same.
9. TDC of the compression stroke. The mixture is fully compressed, and ignition has started.
10. 90° ATDC The expansion cycle has started, and is already 45° past the point of maximum torque transfer to the eccentric shaft, which occured at 45° ATDC.
11. 135° ATDC The expansion stroke continues, but the torque transferred to the output shaft is now down to about 35% of its peak.
12. 180° ATDC The exhaust port is still closed, and the torque transfer to the eccentric shaft is approximately 15% of its peak.
13. 225° ATDC At this point, the exhaust port has been open for approximately 30°, and exhaust flow is quite high.
14. BDC of the exhaust stroke. This is typically the point of maximum flow through the exhaust port. Even though the chamber volume is not decreasing at an appreciable rate, the chamber pressure is very high, and this is responsible for a large percentage of the total exhaust flow.
15. 90° ABDC The chamber volume is decreasing, and is 45° away from the point of maximum rate of decrease of the chamber volume.
16. 180° ABDC The exhaust chamber volume continues to decrease, and at approximately this point, a bridge ported, or peripheral ported engine will have started to open the intake port.
17. 225° ABDC The exhaust port is still open, and the chamber volume is decreasing at a relatively slow rate. At this point, a mildly bridge ported engine will have just opened the intake port.
18. TDC of the intake stroke. Here we are at the beginning, ready to start all over again. Note that the exhaust port is still open, but the intake port, for a non bridge ported engine has not opened yet.
Port Timing
IO = Intake opens IC = Intake closes EO = Exhaust opens EC = Exhaust closes
US Model First Generation RX-7
IO 32° ATDC IC 40° ABDC EO 75° BBDC EC 38° ATDC
European Model Model First Generation RX-7
IO 32° ATDC IC 50° ABDC EO 75° BBDC EC 48° ATDC
First and Second Generation 6-Port 13B
Primary intake (Part throttle/cruise) IO 32° ATDC IC 40° ABDC Secondary intake (Part to full throttle) IO 32° ATDC IC 30° ABDC Auxiliary high speed ports (Full throttle above approximately 4000 rpm) IO 45° ATDC IC 70° ABDC EO 71° BBDC EC 48° ATDC
Second and Third Generation Turbo 13B
IO 32° ATDC IC 50° ABDC EO 71° BBDC EC 48° ATDC
Racing Beat "Street Port"
IO 25° ATDC IC 60° ABDC EO 84° BBDC EC 48° ATDC
Racing Beat "J-Bridge Port"
IO 115° BTDC IC 72° ABDC EO 88° BBDC EC 57° ATDC
Mazda Factory Peripheral Port
IO 86° BTDC IC 75° ABDC EO 73° BBDC EC 65° ATDC
Not to be one of 'those guys' but could you be more specific? On a side port I've really never had to deviate, however on a few of the periph builds I've built or been involved with I had to spend a few hours on the dyno dialing it in.
For a side port, this guy gets it. I haven’t done p-port, so I can’t speak to that. Look at the phase chart I commented on earlier and, knowing Haltech is referencing TDC compression, it becomes pretty obvious what the ballpark area you need to be in is. From there, play with the injection timing up and down by 20* at idle and the sweet spot presents itself.
06-09-17, 10:43 PM
