Secondary injector timing in VE
 

I noticed in my logs that my secondary injectors are only coming on at wot above 7k rpm in VE tuning mode. I Thats maybe 2% of the time when driving on the street. They primarys are 450cc rx8 injectors. The secondary injectors are 550cc FiveOmotorsports modified rx8 injector. So my question is, In VE tuning is there anyway to get the secondaries to come on a little earlier? This is a NA motor 13b sp itb injection. With a adaptronic 440d select

Short Answer is No. It's baked in to something like 96% Duty Cycle on Primaries before starting the secondaries.

Double check Primary and Secondary Injector Deadtimes and be sure they match what you have in there.

Are you reaching target AFRs? Realistically, that's what matters. If you have insufficient airflow for your NA setup, that's going to come down to porting/optimization.

The injector dead times for the the 550 secondaries came with the injectors from 5.0motorsports. The rx8 yellow 450cc injector dead times i found on a miata form. They seem to work. There is very little info on the rx8 injector dead times for some reason. The a/f ratios are ok. Not ideal im sure. I dont think air flow is a problem. Ida style itb with taper bore 52mm 50mm 48mm. With plenty of fresh air. https://cimg5.ibsrv.net/gimg/www.rx7...7654d005f5.jpg

Pic of the air filter feeding the tb through a 5inch hose.

Holy shit, that's retarded

This thread covered it HERE. Oops, 97%. :ret: :dunno:

What is the car running at light throttle? Part throttle? Full throttle? When it comes to AFR. You should first focus on smoothing everything out.

Car runs good. Well not at the moment. Waiting on a o2 sensor. Had the key on ignition off adjusting my fuel preasure reg. Completely forgot about o2 heater. Burned it up. Wanted to maybe trigger the wide band to come on with rpm signal to prevent that in the future. But thats whole other topic. But the car runs good but can be a bit rich at times. Not perfect Im thinking its the rx8 yellow injector dead times. U need to make a complete map on a dyno tuning every square before u should mess with manual secondary timing? https://cimg9.ibsrv.net/gimg/www.rx7...ea1eb57bee.png

These are the primary dead times im using. This was the only info i could find on them.

Ryan is correct that with the Select ECU's you are not able to adjust the staging. The M1200 Modular ECU would be a direct replacement for e440d and would let you control your staging more effectively. There is gains to be had in an NA application with Injection staging and Injection timing. The amount of HP gain main not be worth it to you for the price tag.

Cheers,

Shawn Christenson

I have found a way, I'm going by memory. On the page where you set the engine size and injector size. At the bottom, in WARI, there is a box that sets the minimum injector off time in us, increasing this forces the injectors to stay off for this time, and as a result, the secondarys come on. I have mine set at 3200uS, and my secondarys come on at 4200rpm at wot. The down side is that the max primary duty cycle drops as the rpm rises since the time they stay off is constant.

In what way does that effect driveability. I was just thinking of going to a smaller injector. Or swap the my secondary 550cc injectors. Use them as my primarys. To put them to good use

Yep, its baked in as a peak and hold function on the older adaptronic ECUs and you aren't able to alter it. Primary runs to ~96% duty then the secondaries come online and slowly rise in duty as needed. Newer platforms, at least those I'm familiar with, utilize the "common" staging as a standard where at (for example) 80% primary duty the primary falls to a lower set duty say 30% and the secondary rises to match that 30% and then they both rise at the same duty together up until max or the next staging point where the convergence balance happens again. You can then move the primary max and secondary min staging set points around to suit whatever your engine port/injector size/turbo spool combination likes.

To the OP, if you truly only need 96 % of your primary injectors and like 2% of your secondaries at max fueling, I would try to move to a larger set of injectors with good atomization or run a bit higher fuel pressure and keep it all as a single stage which will not only simplify things and make it smoother but minimize the change of a fueling mishap at WOT high rpm which could lead to a problem. Injectors have what is known as a non-linear range low pulse width range in which the injector can not maintain steady consistent predictable flow. If you are using only 2% duty on your secondaries all the way up top I believe you are risking having some unpredictable fueling up top where it matters. Injector dynamics wrote an excellent article explaining this phenomenon which you can find here.

Regardless, in an effort to get away from the 96% primary stage with 2% likely non-linear sketchy secondary on top I would explore either running higher fuel pressure or doing that and upgrading primary injector size to keep it to a single stage. I believe in simplifying where ever possible. The less shit that you have going on with a rotary, is less shit that can go wrong and become the source of failure which is important given our margins are so small with these things.

Skeese

I dont think it affect driveability at all. But I would prefer my staging to work simmilar to Mazda OEM, the injectors have been intentionally placed further up the intake for a reason. Maybe aftermarket injectors have a better spray pattern than OEM where they dont need to be as far up the intake, but I am using OEM injectors. Just looking at my log, I hit 82% duty cycle on my secondary injectors at 7400RPM, my primary injectors are at 58%, but the secondary injectors come on at 74% primary duty, which is at around 4500RPM at WOT. I have S4 460cc primary and secondary injectors.

To the OP, Skeese made a great point.

Fuel pressure is going to be a nice factor here. You could even go the opposite direction and intentionally run LESS fuel pressure so the secondary injectors get some playtime. I'm near you (San Jose) and might have something "spare" in the garage that could work. I'll report back if what I have in mind fits the application.

Im going to swap the injectors around. Make the 550cc my primarys. 450cc my secondarys. Hopefully i have enough length on my wiring harness. All i have to do is swap plugs. I currently have fuel pressure at 43psi. The paperwork that came with the 550cc injectors from Five0motorsports. Says if i increase the pressure to 60psi i would have to change my deadtimes as well. That would increase my flow to 640cc. Im thinking of increasing it to say around 50psi and sticking with the dead times i have. See what happens. Hopefully any day now my o2 sensor should be in the mail. Cant do much without it.

Sounds like a solid plan to me. I think you'll definitely pick up enough flow with those changes to not only get you out of the secondary range but also gain some headroom in the first stage above your WOT peak fuel demand, which is a good thing. Let us know how that turns out, interested to see results and feedback.

Skeese

I'd say start with 60psi if that's the new plan.

Shouldn't be an issue to program in the new deadtimes. See if Five0Motorsports could snag values for you for 50psi, 55psi, and 60psi. I think that changing from 43psi to 50psi on the same deadtimes is a recipe for stacked calculation issues. Best to just test/estimate values in.

You can try to see the trends of the Bosch Injectors of what they do for 43psi to 60psi and apply a multiplier to your current values. At least it'll be closer than leaving and hoping.

I agree. On the paper work that came with the injectors it has static flow for 50psi but no dead times. How could i calculate the dead times for 50psi with the info they gave me.
https://cimg5.ibsrv.net/gimg/www.rx7...f136a3fe55.jpg
https://cimg8.ibsrv.net/gimg/www.rx7...073a383127.jpg

Now that's a good question. I'm not sure of a specific right way to do it, but I would plug all those values into excel and trend the dead time percent change between the fuel pressures you have times for. I would think you would be Annie to characterize the curve and make a pretty educated guess at where you need to be. I'll try and do it today at work if time allows and will report back.

Skeese

Skeese

What do you mean? You have them right here. The second column is 60psi Deadtimes listed perfectly. Just drop these in for your Primary Injector Dead Times, put fuel pressure up to 60psi, and drop these into your primary injector slots and you're ready to rock.

Well damn. I didn't even look at the picture.

I wanted to run 3.5bar 50psi instead of 60psi. I only have one bosch 044 fuel pump. Not sure it could keep up.

Nevermind i just looked up the specs on the Bosch 044 fuel pump. Its capable of 72psi. So shouldnt have any problem with 60psi.

Uhh, you're just reading flow specs at 72psi (5 Bar). It's capable of anything, it's a pump.


https://cimg2.ibsrv.net/gimg/www.rx7...b1061b403f.jpg

This fuel pump flows so fuckin' well at high pressures, it's laughable when comparing it to a Walbro... That being said, the efficiency of the Walbros at low pressure (like for a lift pump, which is why I have a F90000274 for my internal swirl pot) is unmatched. Crazy high flow with that twin turbine configuration.

Run it at 60psi. Or 70psi. Or 80psi. Or 90psi. Whatever it takes to get your car under 85% duty cycle on 2x Primary Injectors. You have probably 5-6x the actual pump you need for 2x 550cc injectors. A stupid little 255HP could handle that.

60psi
640cc x 2 = 1280cc/min of injector. With headlosses and the fact that you don't want to sustain over 85% duty cycle (fuck Adaptronic on this...)
1280 x 0.85 x (1/16.66666) = 65.28 LPH needed for your system to operate.

So your Bosch 044 is flowing about 436 LPH at 60psi which is (436 / 65.28) = 6.68x The Fuel Pump You Need.

70psi
685cc x 2 = 1370cc/min
1370 x 0.85 x (1/16.6666) = 69.87 LPH

80psi
750cc x 2 = 1500cc/min
1500 x 0.85 x (1/16.6666) = 76.5 LPH

60 psi worked just fine. the map was a little lean around the idle areas and would also stumble when i stabed the throttle. Once adjusted it ran pretty good. The map needs to be fine tune again because its not perfect. I had forgot to change primary injector size from 550 to 640cc on the Tuning Modes page. Because thats the correct flow rate for 60psi. But now it runs like shit. So im double checking everything now. I think its something else other than the injector flow rate that i changed. Im definitely heading in the right direction with two big primary injectors. Because even with the ruff map it was hauling ass. The five0motorsport modifed rx8 injectors i have are not great. So im thinking of just running two quality primary injectors. And plugging up the other injector holes. Think 750cc would be too big? Im always learning something new, and the car keeps getting better and better. Thats what i love about this whole standalone ecu swap.

Honestly, you have to fully retune the car after each one of these changes. You should know that though. You can start by doing a global change of a fuel percentage, but yea, it's expected to NOT be plug and play when entirely changing the injector setup like you are.

Find a set of ID725s and a F750 Fuel Filter and you'll be set. I'm not sure why the Rx8 injectors aren't working out for you. They should be just fine at 60+psi with the corrected deadtimes (you did change your deadtime chart, right?).

Ya dead times all changed. Fuel pressure is set to 60psi. Why is the whole map too lean now? With a bigger injector wouldnt it make it too rich if anything?