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Nismo 740cc injectors

GIGOLO

By GIGOLO,
in Engines & Forced Induction

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GIGOLO Rising Star

GIGOLO

Posted
Posted

Hi

Has anyone got the nismo 740cc injectors running off an Apexi PFC and found any problems with idle or take off?

I have a 1996 gts-t and I'm currently looking at upgrading my injectors to allow enough boost to get to 250rwkw and I have spoken to a few workshops who believe I may get some small problems with injectors that are too large for the application (550cc whould be plenty).

I was thinking of getting these from Nengun, which list them for about $940 plus $50 delivery, but can anyone who has ordered these from Nengun let me know what additional costs such as duties and taxes they paid so i can get a clear idea of final costs?

I currently have all the other support systems PFC, FMIC, Turbo, pump.....etc

I was also adivsed to get a new stock or adjustable fuel pressure regulator as the one on the car is now 8 years old and running at stock boost (6psi?) most of its life and may cause a point of weakness in the system, so for about $150 its cheap insurance. Has any had a stock FPR fail?

Cheers guys

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R31Nismoid Grand Master

R31Nismoid

Posted
Posted

i paid the same, delivered from nengun. Nothing more to pay like tax or anything.

with my PFC, the Nismo 740cc's were no problem at all.

My car runs smooth, idles smooth. You wouldnt even know its got 740's in it.

Im still using my stock fuel reg with no problems. No need to spend $$$ on an aftermarket one

R31Nismoid Grand Master

R31Nismoid

Posted
Posted

boost has nothing to do with it. Its how much fuel you need for the given airflow.

but i was running 16psi taking it to 7500rpm, which will turn into 20psi once i get a bigger (again) fuel pump, and my turbo back on the car

which turbo u running that needs 20psi to make 250rwkw?

japsky33 Enthusiast

japsky33

Posted
Posted

Gigolo,

If your car is running ok now then your FPR is fine.Any good mechanic will do a run with a fuel pressure gauge whilst on the dyno checking your readings regardless.

As for the 740cc thats a huge over kill for 250rwkw but that’s fine it’s good if you plan to go further in the future anyway.

As for idling problems there’s no way if your tuner has a clue you should experience any issues with these size injectors and at a sensible base fuel pressure.

BR,

JH

Hi

Has anyone got the nismo 740cc injectors running off an Apexi PFC and found any problems with idle or take off? 

I have a 1996 gts-t and I'm currently looking at upgrading my injectors to allow enough boost to get to 250rwkw and I have spoken to a few workshops who believe I may get some small problems with injectors that are too large for the application (550cc whould be plenty).

I was thinking of getting these from Nengun, which list them for about $940 plus $50 delivery, but can anyone who has ordered these from Nengun let me know what additional costs such as duties and taxes they paid so i can get a clear idea of final costs?

I currently have all the other support systems PFC, FMIC, Turbo, pump.....etc

I was also adivsed to get a new stock or adjustable fuel pressure regulator  as the one on the car is now 8 years old and running at stock boost (6psi?) most of its life and may cause a point of weakness in the system, so for about $150 its cheap insurance. Has any had a stock FPR fail?

Cheers guys

GIGOLO Rising Star

GIGOLO

Posted
  • Author
Posted

As I understand it, the fuel pressure rises with the ammount of boost pressure, but the injector duty cycle varies with airflow (AFM/ECU).

I have a T3/4 with unknown specs, but makes 215rwkw at 13psi. 20 psi was just an estimate to get 250rwkw at 7000rpm.

I was advised to get a the FPR by Jim at CRD - even a new stock one, as he has seen some of the stock ones fail if they are not always up to the job. Also makes easier to get the tune spot. So for 150 it may save a 4000 rebuild

R31Nismoid Grand Master

R31Nismoid

Posted
Posted

you'll know if its failed right off the bat. The car will just run rich as, thats what mine did and blew a huge fuel-cloud out the rear end when on boost.

save yourself some $$$ and buy one when you actually need one. Not before.

japsky33 Enthusiast

japsky33

Posted
Posted

Generally if your FPR fails you will be over fueled to the point you will have black smoke pouring out the back.

So the whole rebuild thing is ass.

Your injector duty cycles have nothing to do with that at all bascially 10.5 - 12ms (depends on ECU) is max injector duty before there fully opened so the ratio is worked out depending on where your tune is at that point!

IE: (EXAMPLE)

18psi - 6500rpm - 80% load = 6.5ms so therefore your around 60% IDC offuisly the ms on the injectors are decided on your AFR where the tuner feels is best.

I think your mechanic is probably saying you can get close to your 250rwkw with standard injectors a fuel pressure reg to up the rail pressure and some more boost.

You can make 10million HP theres no extra load on your FPR. :)

BR,

JH

As I understand it, the fuel pressure rises with the ammount of boost pressure, but the injector duty cycle varies with airflow (AFM/ECU).

I have a T3/4 with unknown specs, but makes 215rwkw at 13psi. 20 psi was just an estimate to get 250rwkw at 7000rpm. 

I was advised to get a the FPR by Jim at CRD - even a new stock one, as he has seen some of the stock ones fail if they are not always up to the job. Also makes easier to get the tune spot. So for 150 it may save a 4000 rebuild

  • 2 weeks later...
aridyne Enthusiast

aridyne

Posted
Posted

Well just off topic slightly, I have purchased some Nismo 740cc injectors for my R33, I am yet to see them yet.. I am wondering when the bloody hell they would be sent. Anyone dealt with Nengun before? how long does it normally take to get stock from them? I can't even track via EMS yet. If anyone has dealt with them let me know please how it went?

Once I get them (hopefully soon) I will be installing them onto my R33 running a FMIC and Haltech ECU and Haltech Ignition Systems. Obviously I will be upgrading the pump and fuel rail to suit.

Aridyne!

GTR-Ben Proficient

GTR-Ben

Posted
Posted
So a failed FPR will not cause it to lean out and detonate? Because this is what I was told when visiting CRD with my car on the weekend.  

Thanks for all the info R31 Nismoid and Japsky33.  

If there is no real danger then  i may as well hold off and save some $$$.

It depends how it failed.. quite often I see them not working right, or the pressure pipe has blown or split.. this certainly makes the car lean out.

I can't see it failing and holding more pressure, making the car rich?

aridyne Enthusiast

aridyne

Posted
Posted
4 weeks for mine. that was more Customs fault as it seemed to sit there for a week.

give it a good 4 weeks

Mmm I wish he would hurry up so I can get them to my installer and work out what else I require to get my car running hunky dory... and without fear of hammering the throttle and not killing a injector and then the rest:(

Anyone grabbed a new set of those HKS Cam gears.. the new models that they are trying to sell against the Tomei?

BBQ Community Regular

BBQ

Posted
Posted
with my PFC, the Nismo 740cc's were no problem at all.

My car runs smooth, idles smooth. You wouldnt even know its got 740's in it.

Im still using my stock fuel reg with no problems. No need to spend $$$ on an aftermarket one

did you have to get injector collars with them at all ?

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