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,