anyone know the limit of the factory pump?

whats the most power made on the factory pump with bigger injectors?

 

iffy 700 crank.

 

That is a variable. Their are plenty of cars running 5bar FPRs with stock fuel pumps that don't have issues. But I have also seen a bunch of premature fuel pump failures caused by running the 5 bar though the stock pump. The best and safest thing to do is upgrade your injectors so that you are not bandaiding a fuel supply issue with more pressure. With bigger injectors and stock FPR you don't run the risk of over working the stock pump and causing an early failure. As some of you know a fuel pump failure at full boost is bad. I personally wouldn't run anything with 16gs and bigger without bigger injectors because the risk outweighs the cost. Plenty of people do it without issues, but that doesn't make it the best idea.

 

The WSM says that OEM 996 turbo fuel pump -when tested for flow- should flow minimum of 1250cc/ 30 sec, that is 150 l/hr. No maximum stated.

Here's a graph from AMS's thread about fuel pumps:




While searching for new fuel pump options I bumped to this thread: https://www.6speedonline.com/forums/9...-upgraded.html

Jean posted few very interesting comments about 996 injector DC, their limits and hp figures. Quoted here:

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The Bosch 044 flows a maximum of 200 Ltrs per hour at 72PSI pressure, i.e. 317lbs of fuel per hour.

The 996TT on average has a Brake Specific Fuel Consumption of 0.55, meaning it requires 0.55 lbs of fuel per hour to produce 1HP.

With that being said, the Bosch 044 has a maximum output of 317/0.55 = 576 FWHP.

This is the maximum the Bosch fuel pump can produce even with the best injectors in the world.

With the Stock 996TT injectors (44lbs) and the stock FPR 3.8 Bar, the 996TT can produce a maximum of 460 HP at 85% duty cycle (540 at 100% theoretical).

Therefore if you have a 044 with stock injectors and stock FPR, your car will see a maximum of 460HP since you will be limited by the injector size.

If you move to a 5 Bar FPR with stock injectors and the 044, your new limit will 526 HP at 85% duty cycle

All the numbers above are Flywheel Horsepower. Hope it helps.

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I have not see anyone giving a technical answer to the question asked so I am trying to help.

The 044 pump flows 200 Ltrs/Hr at 72 PSI as I mentioned earlier, after 20 minutes of operation. I am not talking about the stock 996TT pump, which in fact flows less than the 044.

In "free flow" mode, the 044 pump flows up to 300ltr/Hr. => 476lbs/Hr, however it will die before you turn around the first corner using it this way.

Absolute Maximum HP for a 996TT with a 044 in free flow mode= 476/0.55= 865 HP. Maximum HP with a single usable 044 fuel pump... <600 BHP provided it has larger injectors and FPR.

As to maximum HP with stock injectors and FPR, yes the numbers I posted are correct (around 460BHP@ 85% duty cycle), have the dyno checked if you get more than that.

Concerning BFSC, yes the lower the more efficient the engine. 0.55 is actually pretty low for a turbocharged car (meaning the engine is very efficient). N/A Porsche engines go lower than that.

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I think I have written this somewhere before..Running a 996TT with stock 44lb injectors and a stock FPR (3.8Bar), your car will have "approximately" the following numbers:

@85% duty cycle: 460 FWHP
@90% Duty Cycle: 486 FWHP

If you move to a 5 Bar FPR with stock injectors then you get:

@85% duty cycle: 526 FWHP
@90% Duty Cycle: 557 FWHP

If you move to a 5 Bar FPR and 60lbs injectors you get:

@85% duty cycle: 556 FWHP
@90% Duty Cycle: 589 FWHP

And you have to check whether your fuel pump can keep up by measuring as before its flow rate and divide by BSFC...

BLKMGK is right, you can run at 90% duty cycle (I do) or more, only it is not really safe or recommended from an AFR stability perspective unless you have a state of the art custom program (on an engine dyno) and a great ECU like Motronic to protect you.

The Hybrid turbos will not improve efficiency on your engine, meaning , they will not improve the HP that you can get from one lb of fuel per hour, they can hold better efficiency levels at higher RPMs or boost levels, but that is not related to engine efficiency per se.

Things like head work, twin plug, compression and better breathing can get you anywhere from 5-15% improvement on engine efficiency perhaps...a bit optimistic.

Anything beyond this is dyno related I guess.

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Bosch 044 data sheet: http://www.bosch-motorsport.de/pdf/c...mps/FP-200.pdf

 

I ran lean when testing on the dyno and Chris (USP) added a pump @ 620 whp having 72lb injectors

 

We saw fuel pressure drop a ton at 530-540 AWHP on a mustang. Or about 700whp on a dynojet

 

Whats the max. output of a gt2 fuelpump and a 044 in serial connection?

 

rumor is the gt2 pump has a little more pumping volume (I can not confirm or deny) but that setup is a band-aid fuel system. The more you "work" the fuel the greater the chance of air ration.