With apexi intake, U type intercooler and exhaust and a "350l/m" pump my apexi is saying low 90s injector duty with ~1300cc high flowed secondaries. Stock injectors are going to struggle to flow enough for 16psi boost unless you are well up in the hills or have an aftermarket fuel reg wound up.

 

Slides which pump do you have? I am considering replacing my supra pump.

 

I have autoexe intake, super U intercooler, full 3.5inch exhaust, enfini y-pipe.
On 16psi @ 6000rpm in 4th gear at 15C ambient temp at close to sea level, my O2 WB shows high 11s AFR. That sounds sufficient.

Btw, with stock FRP, the following happens:



From Adaptronic site:
"The perfect fuel pressure regulator would be a flat line, indicating that the pressure is completely constant against the flow rate. The Turbosmart FPR2000 is the closeset to this flat line. The worst is actually the purple line, which is the factory fuel pressure regulator off the MAzda RX7 FD. See that firstly, the slope is pretty steep in its linear section. In fact it’s four times that of the FPR2000 (dark blue line). Secondly, above about 4 L/minute (240 L/hr), the pressure rises very sharply. This means that if you’re going to put a fuel pump in your RX7 above 240 L/hr, you better upgrade the pressure regulator also."

I am in no way advocating this setup. Just showing my observation and data point.

 

Holy crap. Thanks for that. This could be the info I am looking for. I am having some odd issues and I am really thinking it could be the fpr. I am running g the 3kai with supra pump and 2200 secondaries getting ready to drop them to id1300x. I've been wondering of I should install a new reg also.

 

The Supra pump is a very mild upgrade. You may need a bit more, like a Walbro 255.

I've been running the Walbro 255 for years with bored out 1300cc secondaries in a stock rail with stock FPR, zero problems. I don't think you will have a problem. I think the stock FPR only becomes a problem at very high flow rates.

Worst case the car would go very rich and you'll sort it out.

Dale

 

Dale I thought the Supra pump outflowed the Walbro 255.

 

OK, I re-looked this up. The Supra pump does flow more but at the expense of MUCH higher amp draw. Also the Supra pump only flows more than the Walbro at higher voltages, if you are closer to 12v the Walbro will out-flow it.

RRE Instructions

http://mkiv.com/techarticles/fuel_pu...t_2/index.html

The Walbro 255 will handle anything the twins can put out. It's also kinder on the stock wiring.

Dale

 

Dale- What injector settings are you running in your power FC? I have stock 850s that were modified to 1300 similar to yours. FC tweak gives me warnings because of the higher CC but 850cc settings. Curious to see if you had changed yours to something different??

 

Awesome comparison and noted. I am all about less for more.

 

I would run that by Xavier. I forgot what he said about that. well, I am sure he is not for the bored out 850s that's for sure.

 

I kind of question this as that is only at 200lph and the stock fuel pump is over that. Is this at high power or idle/cruis?. I would assume the factory fpr can handle a descent amount before freaking out as people have been doing it for awhile. Mayne at idle O could see the pressure backing up and skyrocketing?
I will find out soon I hope with my fuel pressure guage!!... The one I keep talking about and not installing lol.

 

Basically that graph is showing that at a certain flow rate the stock FPR can't keep up and your fuel pressure goes super high. But that flow rate is pretty high, it's hard to know exactly by that graph but around 4000cc/minute which is a TON of fuel. If you are running stock twins you will never run into this problem.

I've NEVER heard of someone running the stock FPR and the fuel pressure skyrocketing. The good thing is the car would go crazy rich, you would know it's happening, and it's not going to hurt anything.

The only time this could be a problem that I could see is running huge fuel injectors with a single turbo and going for big power at which time you aren't running the stock rails anyhow.

@iceman4357 I have NO idea what settings I'm running, I copied them from someone else ages ago. Here's a thread on the topic -

https://www.rx7club.com/power-fc-for...ata-fd-226162/

Search around some more, this has been covered in the past.

Dale

 

Kind of funny getting stuff off Andy's old website quoted at me by people who have never met him.

If you look at the scale and understand the square root relationship you will understand you can still idle with an elevated idle fuel pressure, it's still less than a lof of people run as base pressure these days. Is it ideal? No, but the non linearity isn't at the end of the curve that breaks things with non fuel pressure compensated fuel models. Remember you start on the right and work back towards zero bypass flow as fuel demand increases.


High 11s AFRs sounds like soft springs or bowed seals waiting to happen?

I'll check the pump but I wouldn't necessarily recommend it, I had someone do a heap of work for me when I was living in a town house and couldn't easily do it myself. I think it's something like an aeroflow 044 silhouette 350L rated external pump, fabricated surge tank under the car fed by a factory in tank pump. If I was starting fresh I would go B2A or radium drop in surge tank/pump hanger setup or make one.

 

Yeah, I have emailed him about it. FC tweak raises a flag because the settings are for 850 and it flows 1300. Xavier wants me to replace the injectors, which isnt a bad thing to be more accurate and have new technology. Was just curious what others run for injector lag with similar old school setup.

 

Ok so an update from me. I decided to swap the 1300 for the id1700s for a little more head room.
the RP rail says the 2200s are 38mm. These ID1700s are 34mm. I am so ignorant about how all this works.
I assume there is a spacer for the 4mm? Thats a big difference.
I am actually in Dallas so I guess I will try and stop by RP on Monday.

 

Going to bump this thread to discuss something that has not been brought up: fuel temperature sensors. I am running a PFC and am wanting to upgrade my secondaries only. In a tuning group I am part of we discussed this,

"Gasoline density decreases approximately 1% for every 10 degrees C. A fuel temp increase of 40C during consecutive laps, will lower the fuel density by 4%. Meaning that without any correction, a cell running at an AFR of 10.6:1 during the first lap, will be running at about 11.0:1 after a few laps of driving. The PFC is able to compensate for this variation only if the fuel temp sensor is fitted, so it's worth keeping this sensor functional."

With that being said, I think the FFE step up kit is the most complete kit for a near stock FD. I would like to just order the FFE and be done; however, it does not come with provisions for a fuel temperature sensor. How are you guys compensating lean out with higher fuel temperatures with the FFE and CJ kits? I would assume this could be done, by coolant temperature, but is not as accurate?

I have an RP rail sitting in storage, that I was planning on adapting an aftermarket fuel pressure regulator. I also was looking at getting the radium kit, but realize that will require a few adapters to fit with the stock fuel lines.

 

I don't think anybody is fitting fuel temp sensors directly to the rails, I'm not aware of any that have that provision. I know the CJM rail can come with provisions for a FPD, but that's about it.

I'd think the best way to add a temp sensor in would be to add a sensor port in the fuel line itself. Just thinking, I'd try to add it on the return side so it sees lower pressure.

 

There's a top hat on the injector that gets replaced to make them the correct length. Inexpensive part.

 

Awesome thanks

 

If you're going to be using an aftermarket FPR, most of them come with a couple of extra ports (normally with plugs) that can be used to install fuel pressure or temperature sensors. So assuming you can make it all fit, that's a possible option. Here's a picture of my engine when it was on the engine stand; red arrow is pointing to the plugged spare port on my FuelLab FPR. So this thread has me thinking, I've got a spare temp input on my Link G4+ that I can put to use for fuel temperature compensation, in addition to the fuel pressure sensor it already has.

 

Ok sorry, but where do I get said hat. I thought they only came in like 3 sizes? I didn't think 38mm is one of the sizes.​​​​​​​

 

​​​​​​​It might not be, best to call ID and ask. I know the drop-down menu on sizing was extensive on the Turbosource website when I ordered mine.

 

I stopped by RP yesterday, and I got another set of o-rings and RX8 rubber grommets (lack of the better word) that go on the bottom. The clip will be used from the 2200s. Chris said the 34mm with this setup should fit just fine. I love those guys over there. Very helpful and always a pleasure to do business with. I stopped by T1 racing development/ ID to exchange the 1300s for the 1700s. What a cool place that is. Kind of out there in the middle of no where, but very, very nice people. A cool facility that seems very well organized and managed. Some cool metal in there also. A lot of GTR and lambos. So, this whole Dallas trip is working out good! I am getting many other things done besides what I am out here for.

 

Yep, Tony Palo (T1) is a badass... like his Injector Dynamics partner, Paul Yaw. Very lucky to have T1 and RP here in DFW.

 

Was more so asking, if it is possible to make corrections based solely on coolant temperature. More so are there ways around the fuel temperature sensor for a safe and functional set up.

That sounds like a really good idea Pete. I am still going to stick with my RP rail, but that does make a convincing option.