Obsolete injectors
 

Please stop using the obsolete Bosch 850 injectors for the primaries!
It has been know for years that for a street car, getting a lean idle and good injector transition is difficult.

I run 550/1600 at around 400 WHP without any problems.
If I had to redo mine, I would go ID725/ID2000 which are so superior to the Bosches.

I couldnt agree more.

I should have said Bosch or stock Nippo-crappies!

The ID injectors are rebadged Bosch EV14, a style of injector used in newer cars. The 850CC top feeds are Bosch EV1, a very old design that is the same style of injector used on the old turbo 12A engines in the first gen cars.

https://www.rx7club.com/attachment.p...1&d=1287810542

The OEM 850cc side feeds were never designed to be run in the primary position so it's no surprise they don't run well when installed there. There's really no point in running 850cc side feed primaries. For anyone. Ever.

I was considering some FD 850s as primaries. Not anymore.

Thanks Raymond, where do you find this stuff?

where to buy?/supplier? lol.

I think he got the picture from here http://www.injectordynamics.com/questionsanswered.html scroll about halfway down.


John

Marketing...

I have known for a while that they are Bosch Injectors rebadged.
It just makes sense to use a newer more accurate design.

Is there a good reason for anyone to replace the 550s, unless they're defective or you want to make huge power?
Seems like 550/2000 would be the easiest route, with no idle problems

good call.
sounds logical to me.
can someone with more experience chime in on this?

Chuck, is there something wrong with my logic? Or would the transition to the second stage (both injectors flowing) be significantly more difficult with a setup like that?

The newer Bosch EV-14/ID injectors are much more stable at higher fuel pressures and you get better atomization there. I would recommend that everyone stop using old logic from old injectors about running standard current sizes and start trying to run smaller injectors at higher fuel pressures instead. Beef up that fuel system. Run 60+ psi. It will run smoother. Just to give you an example, let's use standard injector numbers for clarity reasons. A 2nd gen n/a has 4-460 cc injectors while the TII has 4-550 cc injectors. If you were to install the 460's in the TII and then raise fuel pressure up to 60 psi, assuming the injectors were still linear of course, you'd have the same amount of fuel but with better atomization. That's the way to go. There are still too many people using ancient fuel system logic. Higher fuel pressure is where it's at but you need a modern injector to do it.

In a 15 year old car I think I would rather have "normal" fuel pressure and no fuel leaks than great atomization and my car on fire, but that's just me (a guy with stock lines)

So will these work well without having to buy the fjo unit?

^^Correct, with the ID injectors you don't need the FJO driver, nor do you need the hack-solution resistors.

It is good for a street car. I would go with 725/2000 because:

The following is theoretical as I have not seen any data on it!

Our TBs have three intake paths. The single bottom one supplies air to the two primary ports. The two top ones, supply air to the two secondary ports. Then we have the ratio of the ports sizes and flow characteristics. So estimating, lets say that the primary ports flow 30% of the air into the engine.

For optimum fuel dispersant from the injectors, we want proportional fuel flow for air flow. If it takes 550+2000 = 2550cc of injectors for fuel, then 30% of that is 750. Thus we would want a set of 765/1785. So having 550/2000 is not optimum but since we can not buy cheap custom injectors, we have to live with what the Mazda design gives us.

Here is an experiment that shows how bad the Mazda intake/injector/system design is. This is more applicable to us that removed the secondary vacuum throttle plates. Measure the TPS voltage when the secondary ports just start to open. Then while cruising determine the cruise speed for that TPS voltage and when the secondaries just start to flow fuel. Mine was like about 58mph and 110mph.

In between 58 and 110, all ports are flowing some air but all fuel goes into the primary port air flow. Not optimum mixing.

You know more about all this stuff, but my understanding is that the secondary injectors don't become active until your primaries reach a certain duty cycle (40% or something)
If that's the case, wouldn't the secondaries become active at an earlier (more appropriate) time if you were using smaller/stock primaries?

Yes, and I am running stock 550 primaries. The PFC setup shows 40% but logs at about 48%. I have been running 30% setup which logs at about 37% duty cycle.

Thus I have exceeded you question twice in my setup, and my previuosly posted results are better than stock!

The reason to buy the ID/Bosch EV14 injectors (which are now also being sold by fiveomotorsport) is because they are Bosch, not because they are ID. You can trust them because Bosch designed them and they weren't put together in somebody's garage. All ID or any other vendor does is flow test them and resell them in various configurations for different styles of fitment.

Whatever limitations this design has, Mazda must have had some work around on the factory computer. We only have a limited understanding of how Mazda controlled things on a 100% stock car.

Hey arghx, i want to order some of the new bosch EV14's.. Is there a standard size injector o ring that is used or do i have to order a specific set. I have the KG parts primary rail with 850cc in there now (yes i know, pain in the ass for idle), and the Rotorsports racing secondary rail with the bosch 1600's.

What would be the best setup for me to go to. I am running a S475 with twin bosch 044's and will be trying to push about 600+ to the wheels soon.

So do i go: 725/2000, or do the 1000/2000 setup?
Thanks for the help. And i was looking for u at the track yesterday. Heard u were suppose to come. I forgot his name, but a guy that knows u with a red fd ran a nice 11.9 time. I didnt geet to run my car because of too much fuel at the time.

https://www.rx7club.com/single-turbo-rx-7s-23/comprehensive-injector-dynamics-fitment-guide-920186/ sounds like you have a 14mm bore fuel rail

I'd do 725/2000 . Start at 43.5psi base pressure. if injector duty cycles are too high, raise fuel pressure to drop them down. If you are doing E85 you might have to go as big as 2000/2000 but I'm no expert on E85 fuel setups.

That might have been Scott. I was out of town visiting friends for the weekend.

What settings do you use in the Datalogit for such large injectors?

One thing about these injectors, the voltage vs. lag is supplied which allows proper setup of both lag tables which means the lag diference in the inj only table would be 0.
You set them up like any other injector by the rules the PFC listsa except for lag.