Alright, i just got my engine back. It's freshly rebuilt. New housings, 3mm seals, nice street port. I also have a 60-1 single turbo waiting to go on. I've been reading for hours/days as much as i can on everything i need to do to get this done as smoothly as possible. (the kit is kinda piece by peice) My questions at this point are regarding the fuel system. Im shooting for around 400 hp on pump gas, Maybe a little more with race gas. I will be running a Power FC.
So far the fuel system is stock. I know i need a pump, i also know i need larger injectors. This is where im unsure of what route to go. Can i run the stock fuel rails? Do i "need" to replace the fuel pulsation dampner? Do I need a different fuel pressure regulator? If I do go with a different regulator does the stock one get discarded or is it used also? I notice alot of people replace the fuel rails. is that nesessary or is it for cosmetic purposes and simplicity reasons? Where can I find stock mount secondairy injectors for a good price? I've heard some people using 850 cc primaries... though some people report idle problems. I'm sure i have more questions then this, but this is a good start. I dont have tons or money to spend, but I would like to know my options. Whatever method thats cheapest that wont ruin my new engine is preferable, but im open to all suggestions. I also found this... http://kgparts.com/newfuel.htm
ANyways thanks for anyone that will help.

 

i dont know about FDs, but FC you dont have to replace the fuel rails. you should run 720/1680 injectors with a healthy fuel pump. the FPR will need to be replaced. with that turbo you should easily be able to make 400 on pump.

-masin

 

400 rwhp is attainable on pump gas with stock FD rails, stock 550 primaries (for emissions purposes if it's an issue), and 1300cc secondaries (bored out stock 850's) and an upgraded pump, either Supra pump or other Denso Hiflow pump. All these items are stock bolt in/no fuss/no modifications necessary parts that retain all emissions and the configuration of the OEM setup yet still flow more. IMO it's the minumum you can get by with but it works. KGparts secondary fuel rails require disabling ACV setup (bad for emissions). FPR is a good thing but you need the pump that can sustain the higher pressure. FPR will require reworked hoses. All this among other things. Search the forum. LOTS of info on single T fuel setups.
HTH,
Crispy

 

thanks for the info. where can i get my 850's bored out? Emissions isnt an issue for me. With aftermarket fuel rails does the fuel pulsation dampner still get used? So the stock FPR can be used? I have been reading alot of different setups on the forums. It's hard to tell what is acceptable, what is unsafe, and what is just wasted money. So im trying to find out what is really needed and what isnt.

 

My my my So many questions
Many places but RC engineering is one of them. I had a coupon so got mine through SR Motorsports

Some say you don't need it. Some say you do. I don't have aftermarket rails so I can't attest to the fact.

If it screws into the KG rails I don't see why not.
Aftermarket FPRs are overrated IMO for all but real high power needs where increased fuel pressure is necessary because even with bigger injectors the injectors can't handle the supply at OEM pressures. However with the aftermarket rails you might HAVE to install one. See my point about sticking with the OEM rails?

I might also suggest you rewire your fuel pump. The OEM wiring is pretty bad to the pump and results in a voltage under heavy loads. Less voltage to the pump = less output from the pump = drop in pressure - bad things happening

HTH,
Crispy

 

i disaggree on the FPR being overated. the stock one is good for stock. it is not adjustable so that really doesnt help you ina tuning situation.

 

Thanks for the further info. Haha i do have alot of questions, and this is just for the fuel. I have a 100 other things i need to tackle on this project.
I did read about the rewire/new relay for the pump also.
i haven't looked real close at my stock fuel rails... if i was to change the fpr do i just remove the stock one and put the new one in the same way?

 

Why in the heck would one "tune" with a FPR. That's why we have programmable ECU's!
Thus I disagree. I'm running a stock FPR with a GT35R single turbo. I have 1300cc secondaries in a stock secondary rail, supplied by an upgraded pump. Driven by a PowerFC, at a mild 14.5 psi boost I'm seeing 85-90% injector duty cycle and a rock solid fuel pressure. And I can tell ya it's got a whole lot more going on at the wheels than "stock." I submit an aftermarket FPR is NOT necessary.
Crispy

 

i didnt say you would tune with the FPR. your situation is a perfect example of where an after market FPR and/or bigger injectors would come in handy. at 85-90% duty cycle that rock solid fuel pressure wont help you a bit when the injector sticks closed. at that duty cycle you could simply turn the pressure up and then you have more fuel, which would bring ur duty cycle down into a safe zone.

and i also didnt intend for this to turn into an argument, more of a simple suggestion. so im sorry for cluttering your thread.

-masin

 

Agreed. *IF* I wanted to run more than 400rwhp.

Neither would an FPR But we aren't talking about parts failure. That's all hypothetical. Hmmm what am I trying to say....with a properly functioning fuel system I'll still assert 400rwhp is attainable without an aftermarket FPR

85% IMO is safe. 90% I'll agree I'm at the limit. But then again I'm running very rich AFR's 10-10.5 at WOT. If I want to drop duty cycle I'll just lean it out a little

Don't apologize. I think it's good for the thread starter to hear differing opinions.
Peace,
Crispy

 

im not talking hypothetical when i say the injector sticking shut. if they over heat(high duty cycles cause this) they will either stick open or closed. but deffinately aggreed that you can achieve 400whp on stock FPR and rails. im using stock rails with a bit more than 400hp.

good luck with ur new setup and keep the questions coming!

 

haha i dont mind healthy debates. Actually im a moderator on another car forum so i have seen much much worse. I appreciate the suggestions. I think im leaning towards retaining as much of the stock system as possible to keep the cost down. Ill probably try to find some 1200cc or 1300 cc stock mount injectors. Or get mine enlarged. If i start exceeding 90% duty ill get a bigger FPR. I was really surprised how expensive it is to get the injectors enlarged. maybe i'll get lucky and find someone selling some cheap. Should i get my primary 550's flow tested and cleaned? I really dont want to skimp on the fuel system but damn its expensive!

 

oh yeah its expensive alright. i probably have $1k in my fuel system and i have stock rails!! i would get your primaries cleaned and get a set of 1680cc secondaries. i dont know about FDs, but on an FC you have to get them machined and they drop into the stock fuel rails. talk to kieth at KG Parts he can tell you for sure. i just have bigger injectors so i dont run out of fuel. whats the point of having to buy one set of injectors then changing your setup (i.e. bigger turbo) and then having to buy another set? your tuner should be able to handle big injectors just fine. some guys even go with 850 primaries. i have 720/1680s with a TO4S.

masin

 

i think the FD requires a new fuel rail for larger then 1300 cc (bored stock injectors). The stock injectors are side feed where as most the large aftermarket ones are top feed. Is my understanding. Though for the price of getting the large ones bored out ($350) You can about get a fuel rail and larger injectors, probably selling the old ones and come out about the same or maybe better if you really look for deals. Although i think an aftermarket FPR is required at that point adding to the cost. Another option is to replace the 550 primaries with 850's but i heard some ppl have trouble with low speed and idle maps. All the choices. I need to just pick one and go with it. otherwise the car wont even move and thats no fun at all! ~Brent

 

Dude,
Since this is for an FD....
You are correct. Anything larger than 1300 and you will need a secondary new rail. The 1680's are top feed. The OME rail is side feed. Replace the rail and you will need that aftermarket FPR plus more in the form a few more $$'s for lines and fittings etc. The problem with going much larger than 1300 on the secondary side is tuning the transition from the stock 550's to the HUGE 1680's. It's difficult enough with the stock 550's to 1300's.

Definitely get the 550's cleaned and tested. I make it a point of ving it done every single time mine are out. Cheap insurance.

Might I suggest several alternatives. Bored 1300 secondarires. A very simple drop in solution with NO reworking of the fuel system necessary. Try them. (look for a set used FS) If that's not enough fuel then:
1) add that aftermarket FPR and increase the fuel pressure to deliver more fuel
or
2) Put the stock 850's (the ones you pulled out of your secondary rail if you didn't send them in for a core) in the primary rails (slight modification to the rails is needed - nothing significant ).
or
3) both

If ya want to go nuts and spend the money then the aftermarket rails, 1680 secondaries, new lines, fittings, and aftermaket FPR is your answer. But be prepared to spend well in excess of $1000 when all is said and done.

Crispy
- I'm choosing option #3 as I have emissions hassles to deal with and can't use aftermarket rails

 

Yeah thats the logical steps i've come up with for my situation also. Thanks for everyones help. I posted another question regarding the gaskets i should replace before i bolt up my accessories, but it hasnt recieved as much attention as the fuel question. If anyone has an opinion the thread is here. https://www.rx7club.com/single-turbo-rx-7s-23/what-gaskets-seals-do-i-need-628706/
~Brent

 

you wanna do it right? just call up keith or go to www.kgparts.com and get the ultimate kit. new primary and secondary rails. 850 primaries 1680cc secondaries. the setup will allow for horsepower leg room. i have the kit and have been very very happy with everything. im shooting for 450+ pump with some ai, and hoping for more with the c16 but not sure what numbers i'll get with that.

 

I agree. Dont go the bored out way.

I went that way and ended up doing it over once I learned more. If you run the numbers is isnt alot more expensive to make the switch to topfeed injectors (sell your injectors and buy rails, harness connectors, injectors and resistors).

I run 720/1680's. Get a FPR and dont use the pulsation dampener. rewire the pump. For more than 350 you will have to upgrade pump or possibly go dual pumps.
I have done my fuel system 5 or 6 times and spent waaaayyyy too much money on it.

You will spend more money than you want on it even if you do it right the first time but at least you wont waste a bunch of money like i did.

 

i forgot to elaborate on the positives. you get rid of the fuel pulsation dampener thats prone to leaking and causing fires, the lines you run are all new so you wont have any problems, you have 0 mileage injectors, and you will most likely never run out of fuel.

the aeromotive fpr that comes with the kit has a build in pulsation dampener built in. theres no way you lose here.

 

I really agree with these suggestions. Yeah, it is a lil pricey, but even like you said the fuel system should be done correctly. It is not really worth having that nice newly ported motor and a "well it will just have to do" fuel system... If you are shooting for around 400whp you could even go with the extreme fuel kit that is just new secondary rail, 1680cc inj, fpr, lines, fittings, ect for around $500. Really that is not that bad of a price. Keith from KG and Jason from RX7Store both have em and at the same price. (same kits both KG kits...)

 

at the minimum i would go with the kg secondary rail with the 1680's. its the same story for idle but secondary you get that added fuel that you need.

FWI: i would just get the ultimate kit. Keith is a good guy... tell him Lance sent you

 

I run 1000/1680..... idles at 980, massive street port also on the primaries, rock on idle, cold/hot starting and emmision perectly within line....it does get pricey.... but is anything cheap on our 7s once u blow a motor?

If you plan for 400 as crispy said, then his is the option which is the best solution...beyond that, dont bother.... do it the way it should!

Cheers

G