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Need Clarification On How Much Power Can Safely Get From 700cc Injectors?

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The Dan Grand Master

The Dan

Posted
Posted

As a simple rule of thumb, you can usually use the following formula as a guide:

(Injector CC / 5) X No. of Injectors.

That will give you flywheel hp. This is only an indication and things like rail pressure and rpm will effect their overall capability.

I would say 650-700whp would be a safe upper limit. Up the base rail pressure to 45psi and you might get them to squeeze out to 750whp but things become unsteady at that point if you haven't got the supporting hardware

R31Nismoid Grand Master

R31Nismoid

Posted
Posted

Personally - I'd say 650rwhp would be the upper limit when you take into account acceleration enrichment and similar things.

I like safety blankets :P

But yeah, in the region around 400rwkw basically on PULP - rules change with Ethanol, race fuel and so on of course

Brockas Proficient

Brockas

Posted
Posted

Can anyone give actual figures for injectors they've used instead of just theoretical estimates? I will be pushing the limits of 700cc injectors very shortly.

So far they've done 403wkw with standard fuel pressure on 98 ron.

The Dan Grand Master

The Dan

Posted
Posted
Can anyone give actual figures for injectors they've used instead of just theoretical estimates? I will be pushing the limits of 700cc injectors very shortly.

So far they've done 403wkw with standard fuel pressure on 98 ron.

These aren't just theoretical estimates. I gave him the ability to work it out for himself. Maybe he is going to purchase injectors and needs to know so he can decide whether or not to go for larger or smaller items.

Out of the many cars I have fitted 700cc injectors to, only 3 have ever really 'pushed close to the limit'. 420rwkw roughly for all with more room to move... none were running standard rail pressure or standard fuel pumps

Nismoid and I wouldn't have posted if we didn't have actual figures in mind.

FineLine Grand Master

FineLine

Posted
Posted
These aren't just theoretical estimates. I gave him the ability to work it out for himself. Maybe he is going to purchase injectors and needs to know so he can decide whether or not to go for larger or smaller items.

Out of the many cars I have fitted 700cc injectors to, only 3 have ever really 'pushed close to the limit'. 420rwkw roughly for all with more room to move... none were running standard rail pressure or standard fuel pumps

Nismoid and I wouldn't have posted if we didn't have actual figures in mind.

You and Nismopid are tight aye Dan. :D

Brockas Proficient

Brockas

Posted
Posted
These aren't just theoretical estimates. I gave him the ability to work it out for himself. Maybe he is going to purchase injectors and needs to know so he can decide whether or not to go for larger or smaller items.

Out of the many cars I have fitted 700cc injectors to, only 3 have ever really 'pushed close to the limit'. 420rwkw roughly for all with more room to move... none were running standard rail pressure or standard fuel pumps

Nismoid and I wouldn't have posted if we didn't have actual figures in mind.

Wasn't supposed to come across as having a go, was just curious to see what figures people have seen on the dyno. 650rwhp is a nice figure, but I've never seen 700's do that before (personally, not saying it isn't possible).

At 403wkw we were at 97% duty, so basically maxxed, but will be pushing the fuel pressure up a bit more this time, think the single nismo pump was letting it down.

The Dan Grand Master

The Dan

Posted
Posted
Wasn't supposed to come across as having a go, was just curious to see what figures people have seen on the dyno. 650rwhp is a nice figure, but I've never seen 700's do that before (personally, not saying it isn't possible).

At 403wkw we were at 97% duty, so basically maxxed, but will be pushing the fuel pressure up a bit more this time, think the single nismo pump was letting it down.

Yeah, the fuel pump could be starting to let you down. If you have the 245L/hr Nismo pump, they are good for up to around 600whp I think. CBF doing the calculations right now but yeah, I think I worked out that the bigger GTR pump (265L/hr??) is good for up to around 750hp or so.

You may find that if you increase the pump size, your duty cycle will decrease. Or you could try increasing the fuel line size.

What size fuel line are you running?

Beer Baron Grand Master

Beer Baron

Posted
Posted
Yeah, the fuel pump could be starting to let you down. If you have the 245L/hr Nismo pump, they are good for up to around 600whp I think. CBF doing the calculations right now but yeah, I think I worked out that the bigger GTR pump (265L/hr??) is good for up to around 750hp or so.

You may find that if you increase the pump size, your duty cycle will decrease. Or you could try increasing the fuel line size.

What size fuel line are you running?

GTR nismo pump flows 276L per hour. with the stock/nismo wiring. and with good power feed with flow every mil of that if not more.

a set of 6 700cc injectors can flow 252 L per hour at 100% open. so in my eyes nismo GTR pump is the perfect match for 700cc injectors. it should be just able to oversupply them.

edit: I've run nismo GTR pumps in a number of my cars, with stock 440 njectors, 600cc injectors and the sard 700cc inejctors. no problems with any of those set-ups, but never really stretched any of those systems.

SimonR32 Grand Master

SimonR32

Posted
Posted
Can anyone give actual figures for injectors they've used instead of just theoretical estimates? I will be pushing the limits of 700cc injectors very shortly.

So far they've done 403wkw with standard fuel pressure on 98 ron.

poo poo did 627rwhp on 700cc injectors

single 044 in tank, i think fuel pressure was 3 bar or whatever standard is

i wouldnt think ur going to push the limits of them with a gt35r :D

SimonR32 Grand Master

SimonR32

Posted
Posted
GTR nismo pump flows 276L per hour. with the stock/nismo wiring. and with good power feed with flow every mil of that if not more.

a set of 6 700cc injectors can flow 252 L per hour at 100% open. so in my eyes nismo GTR pump is the perfect match for 700cc injectors. it should be just able to oversupply them.

edit: I've run nismo GTR pumps in a number of my cars, with stock 440 njectors, 600cc injectors and the sard 700cc inejctors. no problems with any of those set-ups, but never really stretched any of those systems.

remember that a nismo pump flows 276l/hr at a specific pressure (i think around 3 bar), when you increase the pressure with boost (say 1.5 bar) it actually flows less than that...

Beer Baron Grand Master

Beer Baron

Posted
Posted

all pumps are rated at a particular quoted pressure. at least the nismo one is quoted at the actual base pressure of a modern EFI system. 3 bar. sure pumps flow changes with pressure (they will increase to a point, then hold, then drop and some like walbro's will drop drastically at a given pressure).

all skyline systems run a 3 bar system + boost. I haven't seen a nismo pump @ base + 1.5 bar be unable to supply 6 X 700cc injectors at around 90% duty. They are designed for boosted EFI applications so they do handle pressure a lot better than some pumps that are designed for high flow, low pressure systems. which is where people get caught out.

when you say it flows less than 276l/ph @ base + 1.5bar, how much less does it flow? I'd be keen to know what you found as I'm running one in the new car too. and in my previous experience it doesn't flow less than quoted.

The Dan Grand Master

The Dan

Posted
Posted
GTR nismo pump flows 276L per hour. with the stock/nismo wiring. and with good power feed with flow every mil of that if not more.

a set of 6 700cc injectors can flow 252 L per hour at 100% open. so in my eyes nismo GTR pump is the perfect match for 700cc injectors. it should be just able to oversupply them.

edit: I've run nismo GTR pumps in a number of my cars, with stock 440 njectors, 600cc injectors and the sard 700cc inejctors. no problems with any of those set-ups, but never really stretched any of those systems.

Yeah, I think Power Enterprise and HKS rate them at 265, Nismo rate them at 276. I always like to stay ont he lower side.

With what Cerbera is saying, the flow charts for that pump are:

post-10554-1241683893_thumb.jpg

And yeah +1 on the GTR version being a perfect match for 700cc's

Nosure Proficient

Nosure

Posted
Posted

I have nismo fuel pump, and 800cc injector. run 1.28bar, make 312kws on all 4. the tuner told me this is the limit of this fuel pump. if go up boost, the afr will leaning out. now the afr is between 11.5-12 which is safe. but my injector duty only about 70%. tuner suggest me replace a fuel pump or surge tank setup.

does that mean my nismo fuel pump failure? or it was really tue limit of nismo fuel pump.

my car is gtr 34.

rtune Experienced

rtune

Posted
Posted
I have nismo fuel pump, and 800cc injector. run 1.28bar, make 312kws on all 4. the tuner told me this is the limit of this fuel pump. if go up boost, the afr will leaning out. now the afr is between 11.5-12 which is safe. but my injector duty only about 70%. tuner suggest me replace a fuel pump or surge tank setup.

does that mean my nismo fuel pump failure? or it was really tue limit of nismo fuel pump.

my car is gtr 34.

Is your pump still on the FPCM circuit? because what FPCM does is vary the ground in order to vary

the available current to the pump, so that at low RPM the pump isn't working very hard.

This works great with stock but at higher boost and injector

and fuel rail pressures, the pump draws more current. When it starts to need more than the FPCM

can deliver, the car will lean right out, the measured voltage over the pump will suddenly dip..

if you direct wire the pump to the alternator, it'll get 14v, not variable power, and do the best it is

ever going to do.. it'll also be one less point of failure..

Racepace told me this week that the stock GTR pump is good till over 400kw, when hardwired.

He also said they have been unable to pick any significant difference between the nismo pump and

the stock pump, the suggestion being that if the stock pump isn't good enough, you're going to need

a more elaborate fuel setup rather than just fixing it with a nismo pump.

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