2g fuel pump upgrade - necessary for evo injectors?

[JasonStern]

so I am considering evo8 injectors for my build, and while everything I've read says I need to upgrade my fuel pump to at least a 3000gt/evo8/walbro 190, nothing has really explained why I need to. I definitely know that I need to rewire my fuel pump to meet my performance needs, but I'm still confused as to why the 2G upgrade guide recommends a fuel pump before any sort of datalogging, which seems like a better use of money when upping boost.

from RRE Instructions:

the stock Denso 2G Eclipse Stock Pump @ 14V flows 156.47ltr/hr @ 43psi, so:

156.47ltr/hr * 1000cc/ltr * 1/60hr/min = 2607cc/min

while the evo injectors are rated at 560cc, people claim they report they spray closer to 580cc, so:

580cc/min x 4 cylinders = 2320cc/min

...which is fine, but doesn't take into consideration the higher PSI the fuel pump operates at while under boost, thus the lower actual flow. so if we look at the stock 2g pump at 58psi, we see that it flows 131.23ltr/hr:

131.23ltr/hr * 1000cc/ltr * 1/60hr/min = 2187cc/min

thus at 15psi of boost, the stock 2g fuel pump runs out of fuel, but that's at 100% duty cycle, which is bad. since I intend to never go above 80-85% duty cycle, that brings the needed flow rate to:

2320cc/min * 0.85 = 1972cc/min

...which is still met at 15psi with a nearly 10% buffer/safety net. with 8.5 compression, only 91 octane available, and summer temperatures occasionally exceeding 100 degrees, I'm doubting I will be able to safely push a t28 much farther than 1 bar anyway without alcohol/meth injection, so what exactly am I missing?

 

[2GFWDbeast]

Because the stock pump doesn't flow enough for bigger injectors. You could possible do a rewire on the stock fuel pump and get way with it. But you still might fuel cut depending on how much boost your going to run.

 

[CurtC]

Judging by the information you posted from Road Race I think you'll be fine as long as it's re-wired. Just keep an eye on your wideband, (assuming you have one).

 

[JasonStern]

Because the stock pump doesn't flow enough for bigger injectors.

for 650cc injectors - yes, but I'm not seeing why a rewired 2G (not 1G) pump shouldn't be sufficient for 560cc injectors...

Judging by the information you posted from Road Race I think you'll be fine as long as it's re-wired. Just keep an eye on your wideband, (assuming you have one).

yes. I ordered a wideband last week and don't plan on upping the boost on the T25 (let alone installing the T28) until I have the wideband installed. I don't plan on installing new injectors until I get a cable for EvoFlash and EvoScan.

likewise, if I can find a cheap VR4/Evo8 fuel pump, I'll probably pick it up and install it for peace of mind, but so far I haven't had any luck. and if it isn't needed, then I'd rather focus my money on areas of the car that I would be better off upgrading.

thanks!

 

[gofer]

If you plan on running 15psi the max airflow a 2g (rewired) fuel pump can support is 39 lbs/min, be sure to rewire it because it can only support 29.6 lbs/min without the rewire. The t28 is happy at 21psi though so if you want to run more boost the only thing stopping you is a $80 Evo fuel pump...

Stock 2g pump (Rewired)

10psi = 42.08lbs/min
11psi = 41.51lbs/min
12psi = 40.92lbs/min
13psi = 40.30lbs/min
14psi = 39.67lbs/min
15psi = 39.00lbs/min
16psi = 38.32lbs/min
17psi = 37.61lbs/min
18psi = 36.88lbs/min
19psi = 36.13lbs/min
20psi = 35.35lbs/min
21psi = 34.55lbs/min
22psi = 33.72lbs/min
23psi = 32.88lbs/min
24psi = 32.01lbs/min
25psi = 31.11lbs/min​

 

[JasonStern]

thank you for the chart. that is rather helpful.

The t28 is happy at 21psi though

unfortunately my bank account isn't.

so if you want to run more boost the only thing stopping you is a $80 Evo fuel pump...

...and larger injectors since the EVO 8s will be maxed out, a larger intercooler to handle the increased airflow, a bigger clutch to handle the additional power, etc.

for now, I'm trying to go down the cheap and reliable path. if funds ever permit, I'll look more at the fast and reliable path. I haven't restored the car to street legal status yet or maxed the T25 out, so I still need to do that before installing the T28, then continue to address whatever weak links appear. yes, it might cost me more long-term by buying two sets of injectors, but I'm okay with that. by putting off upgrading the fuel pump, I can get evoscan/evoflash quicker, which seems more important at this stage.

 

[gofer]

Its your build/money man so don't let me, or anyone else for that matter, sway you away from your original plans. I can tell you that I wish I could go back and choke slam my dumbass about 3 years ago for spending the money twice on fuel injectors and engine management/logger programs.

You sound like you've got a solid list of parts and the know-how to get your car built the way you want it. Good luck, I haven't seen a good t28 build in years...

 

[JasonStern]

Its your build/money man so don't let me, or anyone else for that matter, sway you away from your original plans. I can tell you that I wish I could go back and choke slam my dumbass about 3 years ago for spending the money twice on fuel injectors and engine management/logger programs.

I haven't purchased it yet, but as far as engine management/data logging, I plan on buying an OpenPort 2.0 cable and using EvoFlash/EvoScan, so I don't think I will need to repurchase any tuning devices/software. I can already log off the Innovative UEGO with my netbook, although in a much more limited way as I cannot map the data to the ECU values.

Seeing as how I haven't tuned a car in over five years and this will be the first car I will actually modify the fuel maps on, I kind of want to start with smaller injectors as it's cheaper/easier to tune for due to the smaller deviation from the stock maps.

I purchased the evo injectors used for $70 shipped, so I'm relatively confident that, should I decide to upgrade, I can resell them and recover a reasonable amount for them.

Plus, my old Starion was fairly reliable and my old Talon was considerably reliable when moderately modded. I'd definitely like to get some miles on the car, so keeping the build tame (at least for now) seems like a smart idea.

You sound like you've got a solid list of parts and the know-how to get your car built the way you want it. Good luck, I haven't seen a good t28 build in years...

thanks! although I still haven't received the t28 (purchased it used here in the classifieds), so hopefully I didn't get scammed.

 

[ThatGS-T]

What would Max safe boost be without fuel pump rewire on a stock 2g pump?

 

[2gmitsueclipse]

What would Max safe boost be without fuel pump rewire on a stock 2g pump?

I wouldn't personally go over stock boost levels without at least rewiring the fuel pump. Boost level is a relative term. Airflow would be more appropriate. The information you seek can be found here:

http://www.dsmtuners.com/threads/injector-and-fuel-pump-supported-airflow.366003/

 

[idt512]

Years ago i ran 17psi on a T28 with a rewired stock pump and Evo 560cc injectors. Wideband showing 10.3 and still had a good bit to go. Dont know the duty-cycle of the injectors, but as far as the pump it held up fine