efr8374 fuel system
 

Need a little help tweaking my fuel system. Turblown IWG short runner 8374 setup, Power FC, newly rebuilt stockport FD with an ok/mediocre tune. Currently running 850 primaries 1600/1680 whatever Ford/Bosch injectors, supra pump. It runs ok, but I'm not satisfied for two main reasons, I don't trust the resistors, and I don't like the big old school 850 primaries. I'm not made of money. Give me some cost effective options. I'm leaning towards going back to 550 primaries, dropping some ID1700s in the KG seconday rail. This should improve driveability/tuneability a ton, no?

Stock primaries and id2000 secondaries. Id1700s jumped in price 7 weeks ago fyi( $48 per unit ).

Skimmed through that thread you linked, looks like folks are having trouble getting their parts? Secondly, don't need a rail, already have a good aftermarket secondary, and as for the injectors, not interested in no name or unproven injectors, id or ev14 only if I'm going to the trouble of swapping them. Technically only need enough headroom for around 400hp for my needs and keep my injectors under 90% duty cycle.

I noticed that. What gives? 2000s cheaper than 1700s? I have access to a good tune for 550/1600s, with an 8374. My thought process was if I went to the 550/1700s, that tune could get me by till I get a better tune, as Im not too handy with a datalogit. I tried and failed, lol.

There are threads on this once every two weeks. Simply just go search on this forum... it's covered thoroughly.

Personally, I'd say save for a better ECU like a Haltech Elite and run the injectors you have. Control starts at the SOURCE, just like with audiophile grade music. You can have a set of Focal Utopias and use some crap 128kbps streaming service pumped into them and guess what, they'll still sound like shit.

Bosch EV14 850cc Primaries are cheap to buy and the ID1700x's are awesome (I'm selling mine, new in box, if the 2550x come out in a reasonable timeframe). Anything over 400whp and I'd suggest another fuel pump (staged using a relay/hobbs switch at least).

Shoot me a PM if you really feel lost, but I promise you this is handled thoroughly on here.

Upgrade the fuel pump anyway. I had issues with my supra pump at 14psi with the 8374. IMO the fuel system should be slightly over built. Better to be safe than sorry.

Perfectly satisfied with the PFC. Tried and true. Lots of well sorted setups still running it. Problems with the supra pump? Not enough fuel for a 8374 @ 14 psi? What was your porting, hp level and af/r's? Supra pump should be ok up to 450 or so?

EXACTLY, to add to this (not trying to shut down your FS items), the Bosch EV14 2200cc are also fairly cheap. I am running an unnecessary amount of fuel on my setup, 7700 worth of cc for a 400 rwhp engine. Not a single issue controlling the bosch ev14 injectors through a haltech.

Fairly large Steetport. Running id 850 pri and 2k sec. at 14-15 psi was looking at the fuel pressure in the logs. Wasn't holding and was constantly going up and down. Normal driving was fine but get on it that's when i saw the issues. Swapped pumps and it's fine. This was a year ago. I have read varying things on the surpa pump. I wouldn't trust it past 400 unless you can overvolt it. i think it is fine for the stock twins and 99 twins but get a good single turbo and you just need a better pump. I had 99 twins and was happy with it when i did my full rebuild. But since then i swapped to the 8374.

What pump did you switch to? After some more calculations, I think I will have plenty injector with a 550/1700setup, looks like the pump will be the choke point, if anything..

Here's a really helpful injector/pump calculator utility I found earlier today. Someone went to a lot of trouble...
Calculations

I went with what Hc post above in the stickies to get my max fuel for the turbo. Even thou I won't be pushing that much power on it. So my ID 850's and ID2k's net me around 6kcc of fuel. I'm running the walbro 465lph pump. https://walbrofuelpumps.com/walbro-f...-fuel-pump-e85.

Here's why I'm glad i did. My cat got clogged and i got a resonated mid-pipe. So I had a straight threw 3in exhaust. Now be for this happened i was rock solid at 14-15 psi. Once that mid-pipe when in I could not control my boost. I was hitting 20+ lbs and couldn't go full throttle. But if i didn't have the fuel set up i would be rebuilding right now. I'm honestly thinking about getting the id1050x for pri.

1050 primaries might be a little too big from a drivability stand point

+1 on the pump. switch that supra one for either an 044 or walbro 465

I agree. I'm going to give the 550/1700 ev14 and a new walbro pump combo a shot with this other tune and report back.

Controlling the stock 850s in the primary position with a PFC has always been finicky but it's doable though not worth the effort in my opinion. I like my id1050x's as my primaries and depending on the ECU I've been able to control id1750x's well enough to pass smog as well.

You can idle on ID2000s just fine, so that whole drivability issue is bullshit. That's why you pay for a quality injector that's characterized. The ID2000s can do something like 15uL per injection at their smallest controlled (consistent) measurement, and the rotary engine in stock porting needs almost twice that to attain a stoichiometric AFR.

Walbro 450lph is great until you have any decent boost pressure. Fuel pressure calculations are simple, so let's run through them to really identify what your system NEEDS. Go bigger here, because always being over 80-85% Duty Cycle is a recipe for failures.

Fuel Pressure to identify which pump you need is going to be your peak boost pressure + engine off, pump on pressure + losses in the lines/system. So for instance if you plan on running 43.5psi (3 Bar) base pressure and 15psi boost pressure on your turbo, we can estimate at least 5psi drop on the fuel system in the lines and filters. So that ends up being that the pump is working at 43.5 + 15 + 5 = 63.5psi. Given the picture below, the best case scenario, that pump is running around 360lph at 13.5v using a F90000267 Walbro 450lph pump. The Supra pump is FAR less than this at 230lph at 14v.

https://cimg7.ibsrv.net/gimg/www.rx7...8c7ddc1da1.jpg

https://cimg3.ibsrv.net/gimg/www.rx7...417061ceb8.jpg


So enough with the fake news bullshit. Run the math, realize that fuel evaporates if it's cycled through abundantly and not properly controlled, and you sure as shit need a fuel damper such as the Radium Engineering XR on your aftermarket fuel rails to help with the large injection opening since we have half the injection time (and therefore need twice the fuel) of a reciprocating engine.

The Bosch EV14 stuff is fine. Minimum 850cc Primaries, 1700cc Secondaries. I'd suggest ID1050x Primaries and ID1700x Secondaries for Pump Gas. If you plan on going e85, you're in for a hell of a lot larger configuration.

Everything you need here https://www.irperformance.com/produc...n-fuel-system/

I can tayor the fuel system with various injector sizes to suit your needs but 750/2000 covers most setups. Alternately I can do a stepup kit to keep your primaries and add a secondary rail, injectors, and regulator for about half that price.

Sounds good. Just talked to one of y'all on the phone yesterday about injectors, actually. PM sent

That's a pretty bold statement. Have you done this on an RX-7 with a PowerFC? Have you done this on an RX-7 with any other ECU?

I wouldn't want to try with a PFC but I have with an M600 on a big street port 3 rotor. I've also idled ( barely, and at 1350) a RacingBeat periph 20b using ITBs. :shrug: the ID injectors are nice.

*to clarify, with the 2000s I didn't even try to sniff as these were both race engines*

On a PFC? I know it can be done with other ecus that have a higher resolution, but on a PFC?

Exactly my question!

I have not done 2000CC on primaries, but I've done 1650cc worth of fuel through bosch ev14 injectors as primaries, on a haltech sport 1000.

You continue to point out the flaw in his plan. Change the ECU first and throw that turd in the garbage where it belongs.

My plan? You are preaching to the choir brother. Your post was confusing, there is no way in hell OP will idle on those injectors on a PFC. Some people learn the hard way, just got to let them be,

I'm the OP. No plans to run 2000s in the near future. Certainly not in the primary position. That would be for someone with big power goals, high boost or e85, which I have absolutely no desire to run. Only looking to stay where I'm currently at which is ~400hp on pump e0 93 and keep duty cycle below 85%. I was just looking for a slightly better injector setup for idling, tip in, driveability etc. I've now got it sorted. Thanks to those of you in this thread who lent helpful comments.

Fixed. :)

Yea, you're welcome brother. Just run the math and it's pretty easy. Change the fuel pump first and foremost, then go from there.

nothing wrong with the PFC ... perhaps a little limited with certain things, but calling it a turd and belongs in the garbage IMHO is wrong
it is a tried and trued ecu. half of the rx7 owners (if not more) use it; you get support and most people know how to play with it..
I switched ecus over the years and due to the simplicity and the ease of troubleshooting i went back to the pfc and i am quite happy with it.
as for the 2000s being too big for the secondaries, they are not... but perhaps not needed for 16psi boost
my 725s/2000s are maxed out at 30psi on an efr8374 (1.05 ewg)..

It was okay to use in the 90s. Same shit for people running a 12-1 CAS on a rotary in today's day and age. Why?! If you're asking so much from the engine and only know where it's at 12pts on a full rotation, you're nuts...

Yup, and simplicity, really? Must be cause I've been on the stand alone bandwagon for way too long! BTW - We were talking about 2000cc on the primaries, not secondaries...

I agree the PFC isn't garbage and would choose it over a handful of other crappy modern ecu's if I had to, but the un-debatable fact is the PFC has NO engine protection. If your fuel pump craps, filter clogs, injector clogs, voltage drops to the pump causing fuel pressure drop, air intake temp gets too high or any number of common failures occur then you risk running lean and detonating.

The PFC is great and does its job well but should anything in the system fail, change or even hiccup when you're in boost the ECU will just keep on spraying fuel and firing plugs as if all was fine. Even if the car is tuned and maintained perfectly, with time something will fail and if you don't have protection in place to catch it you may very well end up with a blown motor.

Skeese

Skeese, would a new ecu be able to tell if one of your injector connectors came loose?

This is what happened to my first engine, it had the shitty metal locking clips, I went with the spring loaded version after that.

Under load (when engine protection is most often used) it would create a very lean condition. So yes.

Exactly. And you'd have an AFR based leanout cut that cuts the ignition if you cross into a preset dangerous lean condition in boost. If the car is tightly tuned you can set it aggressively close to the target and catch any issue.

Not to mention that EGT would tell you immediatly that you had an injector issue, and for that matter you could have any EGT split high enough trigger a limp mode to protect you there too. The software is very free form, the key is knowing WTF you're doing and why.


Skeese

I've had mine on ID 2000 primaries and secondaries (staged) for 3+ years. Mild streetport, functioning IAC, no vacuum leaks, and much time tuning enrichments (start up, temp, etc)

Idles spot on at 800 rpm. For the first 1-2 minutes on cold start up it idles smoothly at 1350rpm. This is on an old and outdated electromotive TEC GT ecu.

Many people ditch the IAC when going to an aftermarket ecu. When I got my car over 10 years ago it was already single and I asked what an unplugged plug was for (new nothing at the time) and the tuner at the shop said, "ehh, IAC, don't worry about it". I quickly learned they are there for a reason.

Use the IAC and spend time tuning at idle and off throttle transitions and it will work fine.

This was a good read, I have an EFR 8374 and I have been wondering what injectors to run. Thanks guys great info on here.

I've also been idling on ID2000's without any issue, but at about 1800 rpms on E85 at about a 12.5 AFR :patriot:

I 100% agree on the ISC. People that that as the car becomes more and more modified that it becomes unnecessary, but in truth its the opposite. I've tuned stock and street port cars to crank, warm up, idle low, and come off throttle all extremely smooth and consistent without using an ISC. As the port increases and the idle air demand from engine becomes more choppy, violent and picky the ISC becomes damn near necessary to balance the airflow and keep things smooth-ish across the much wider range of engine behavior. I'm actually modding my intake to use a mac valve tied to the same ISC duty to extend my range of control with it.

Skeese

I agree it's nice to have idle air control even on a stripped-down race car. If you ditch the OEM ISC on an FD, at least keep the thermowax throttle stop to give it a little more air when cold.

The Mac valves most people use for boost control don't flow enough air to work well as an ISC. Look at Bosch IAC valves, they sell fancy aftermarket motorsport ones that are easy to retrofit by adding pipes or hoses. You can also find similar ones that were installed on some European cars. Google shows the one from the early 2000's 325i engines that looks similar to what I'm thinking of.
https://www.carparts.com/details/BMW...EPB313213.html

I'm also currently in the market to upgrade my fuel system, however, I'd love to use Bosch EV14 550cc primaries and 2000cc secondaries, the only concern I have is to get accurate injector data to put in the ECU. That's what I like about Injector Dynamics, but if I can avoid it, I'd rather not pay such a premium, especially since I'm importing to the EU, which makes everything even more expensive. My other idea was to just keep the stock primary rail and injectors, and upgrade the secondary rail, but I'd definitely need to clean my OEM primaries. I'd love to buy a new primary + secondary rail and put Bosch EV14 injectors in, to have it completely new.

I run an efr 8374 IWG.

I run a powerFC.

I run 650CC and 2000CC injectors on my car which are Bosch EV14's. Everything on my car runs great. I tuned the car myself with the powerFC and the car has never run smoother.

The problem with advanced ECU's is they are dependent on the inputs of a whole bunch of sensors, many which are not stock to the RX7. So you end up installing a whole slew of sensors, Fast reacting IAT sensor, Knock sensors, AFR widebands, Exhaust temp, etc, etc, etc. These are all installed somehow afterwards. What if one of these sensors fail? What if your Intake air temp sensor breaks off and goes through your turbo and engine (this has happened). What if these ecu's permenently run shitty because of problems with your aftermarket sensors? What if you short your rewire of your fuel pump and your car keeps shutting off? The stock systems are robust, The best solution IMO is to use the stock robust sensors and have things be steady. Then perform maintenance on the car.

Its not a matter of how great and smooth the car runs...NOW. Its a matter of longevity. If anything in your mechanical/fluid system has ANY problems, the PFC will keep on spraying and firing coils and you will blow that engine up.

All of these factors are addressed by:

1. Not running shitty cheap sensors, while most are re-branded, the majority of all of these "aftermarket" sensors trace back to legitimate manufactures like honeywell or bosch. Most of the quality replacements that are used derived from the OEM industry where sensor designs have gone through rigorous testing and reliability screening to quality for automotive use.
2. Knowing WHAT sensor you bought for WHAT purpose and using it in the correct application.
3. Using a high end ECU that allows for the sensor calibration of the input to be changed to match the data properties of the new sensor, which should come with said sensor if you bought a non-shitty one from a real manufacturer. If you have a PFC and your sensor input scalings are all hard coded into the ECU so that you are stuck running the factory sensors, that is an ancient ECU problem, not sensor problem.
4. Wiring things correctly, which is basically doing what the instructions say combined with a small level of electrical understanding, which isn't difficult.
5. If you do all of those things and the car still runs poorly, the tuner doesn't know what they are doing.

If you are incapable of selecting the right sensor for the application, buying a real sensor from a known manufacturer, wiring a sensor correctly, or copy and pasting scale data into a tune file then yes, you should probably stick with the factory 25+ year old electronics. Its a matter of competency, and it doesn't require alot.

Skeese

No. You have the OPTION to run these extra and new sensors and expand functionality if you wish, also virtually every ECU that is worth a damn can be scaled correctly to run just fine off of the stock sensors, and furthermore to infer that sensors manufactured by Honeywell and company are somehow shittier because they are 'aftermarket' is stupid. Who do you think manufactured the sensors for Mazda?

Is the PFC simple? Sure, and this can be both a blessing and a curse. Can you easily overlook an issue with a more complex ECU and have a crappily running vehicle? Sure, though you also have a far more in depth set of tools for diagnostics.

Please don't preach information that is just patently not true.

How the hell did you come up with Tuning4Life after a statement like that?! No.

The gentlemen above laid it out far more eloquently than necessary for you. If the three of us (always arguing on design or functionality shit) agree on something, that speaks worlds to how far off you are.

If an ECU doesn't have sensors, how the hell is it supposed to compensate the fuel model to make things efficient? That's right, let's just pull all of them off and lock timing too while we're at it.

Modern reliability comes in the form of knowing WHEN THINGS FAIL, as to implement a "limp home mode" or immediately cutting ignition to protect your expensive investment. We do that by a multitude of sensors and an ECU that recognizes what normal voltage and resistance values are for those sensors. You can put up warnings for things to flash a light on your dash or simply limit wastegate DC% or RPM. It makes absolutely no sense to argue that the simplicity of an ancient ECU is even remotely close to as safe or reliable as something modern.

Look, I call it laziness, but you can call it whatever you'd like. This topic was about the Fuel System, which I think I covered pretty thoroughly, and despite now knowing that information, it won't matter because your ECU doesn't understand it fully and cannot implement it correctly.

Apparently Tuning4Life only involves the use of the worlds most simple ECU that is software preconfigured to the unmodified factory platform and only works with factory sensors and wiring......but YOLO #2ning4lyfe bro

Skeese

I'm going against the grain, but this is the kind of post I was looking for when I started this thread. I'm of the same basic school of thought as this guy. Flame away. Most of us here aren't expert tuners with a wealth of knowledge of the latest and greatest standalones. A powerFC is tried and true, over and again for a reliable single turbo setup on pump gas. A basic, solid tune with mostly stock sensors and a fresh engine, correctly installed, with good cooling setups running good gas, a good ignition, big enough injectors, a sufficient fuel pump, should be able to run very well with a pfc. with a properly rich street and dyno tune. Not all of us want or need the ability to support 500+ hp, or a 20b or ethanol or whatever.

Hey man, it's your chicken and you can choke it however you'd like. In fact if you've made an informed decision and you're looking for a simpler setup then I applaud you. The only beef I have with statements like his is the whole misinformation bit.

+1. Power FC with a Data Logit is super simple and even a novice can tune fairly decent with a little research.

That being said Tuning4life post was complete ignorance. Nothing about it was correct or makes any sense. It reminded me of my grandpa trying to tell me how horrible fuel injection was. He meant well but had no idea what he was talking about.

It seems normal (or at least, common) for people to pick a 'side' and then want to defend 'their side' simply because it's the one they picked. This can be especially true for aftermarket ECUs because they are expensive and complex. It's really unlikely that most enthusiasts can afford the time and money to learn more than one or two different ECUs on our own personal cars, so it's really difficult for most of us to truly make an valid claim like 'I have used both these ECUs and can tell you why I prefer this one.'

That said, there are tuners out there who have spent thousands of hours during their careers working with various ECUs on various platforms. I personally know a few tuners with that sort of experience, but they don't specialize in rotary engines so I'm not sure if their opinions would be very helpful for this discussion. Unfortunately the rotary scene is such a small niche it's hard to find experienced tuners who have worked with various ECUs and still chat about it on forums. Overall I'm still hopeful, and still interested to see these sorts of discussions. Hooray for forums, even if we've got limited amounts of info to work with.