how much hp can a stock fuel system hold

[cronot07]

hey i was wondering thinking about getting a turbo upgrade for my car but was wondering actually how much hp can my stock fuel system would be able to hold and what parts would i have to upgrade in the process

 

[Spln_Hrd]

i wanna rate it in psi, not hp because hp changes alot with turbo set-up, exhaust, intake ect.

most people will tell you 16, i would say 18 psi stock before you hit fuel cut, but thats just my car.

parts you need to upgrade to run BIG BOOST. fuel pump, fuel pressure regulator(for more consistant results and a better tune), fuel injectors, and the next mod is your choice of what to tune it with, you can go with something like the hks s-afr(just like a apexi safc-II which most people on here will recomend), and a datalogger, or you can get dsmlink.

the reason you need to do this is so that you can make your mas airflow sensor think there is less air coming in so you don't max out your injectors and hit 100% duty cycle(fuel cut) but you want to have larger injectors at a smaller pulse so you get the same amount of fuel with the intake thinking there is less air, because if you run to much air and not enough fuel you will lean and and either cause detonation(premature fire in the cylinder) or you will lean out and it will make to much heat and you will have invisable pistons.

good luck, tuning isn't fun and takes skill. if you don't know what you are doing either read alot or take it to a profesional and don't mess with the settings.

 

[cronot07]

now tell me what you think about this i'm pretty sure my turbo is blowing oil white smoke is comming from the exhaust when i step on it and when i start the car up in the morning so i think that's what's going on now if i got a new or slightly used stock turbo would that fix the problem or would i be better of just getting a new bigger turbo all together considering the fact that i'm getting my full 2.5" exhaust put on shortly

 

[Spln_Hrd]

don't put a t-25 back on, its the sh!tiest turbo made!!!!!

get a 14b at least, i recomend a 16g though. i am sure someone will argue that a 14b car can be just as fast as a 16g powered car, but i have felt the differance and it was worth it for the 16 imo.

and the exhaust i recomend a 3 inch, if your gonna pay that much money get something you know you won't get sick of. if you bolt on a 16g and a 3 inch turbo back in the same weekend, you will sh!t your pants the next time you drive the car. i put both of these mods on seperatly and i was VERY impressed with the extra top end power.

and if you do get the 3 inch i recomend ditching the stock o2 housing for a tubular 3 inch too, OPEN THE TURBO UP!!! turbo cars don't need back pressure so don't give it any(well some is good so you don't have boost creep like a mofo)

 

[cronot07]

now with the 14b would i still have to upgrade the entire fuel system like you said up top or would i have to only upgrade the fuel pump and pressure regulator

 

[CowPimp]

17psi is what I run with just an upgraded fuel pump (190lph from a 3000GT) and no fuel pump rewire. I have an FP Big28 turbocharger. What you will be able to run will depend on what other mods you have, but something like 15-16psi for a turbo with similar airflow characteristics should suffice with just a rewired pump, a few more psi with a better pump.

I definitely suggest upgrading your turbo if your old one is dying. That is exactly what I did. Putting on a 14B is a pretty cheap way of doing it, but a big 16G is the way to go if you have the cash. I would suggest you look into a big T28 if you had an AWD. The extra bit of lag and increased spool time of the big 16G will be better for a FWD car that will be fighting for traction as it is.

 

[Spln_Hrd]

cowpimp, what do you spool at on your t-28?

my 16g spools at 2900 rpm, i am just curious to see the differance.

btw i don't mind the lag, but maybe other do. i never thought of it as a important issue

 

[cronot07]

now what's the average pricing on fuel pumps these days cash is a bit limited but if it's in like the $400 area i might be able to afford something like that with a single paycheck i was looking on ebay for 14b turbos and they seem to be few and far between

 

[98spydert]

I'd almost prefer the lag. Goin through a residential area from stop sign to stop sign you really don't need the turbo to spool at all. Just makes fuel consumption even worse.

 

[cronot07]

thanks folks i think i made up my mind on what i'm gonna do your advise really helped

 

[corvette-killer]

Ebay- for a 255lb walbro $100 or less, that all I've seen guys use for upto 500+ hp

 

[Carmenpzito]

now tell me what you think about this i'm pretty sure my turbo is blowing oil white smoke is comming from the exhaust when i step on it and when i start the car up in the morning so i think that's what's going on now if i got a new or slightly used stock turbo would that fix the problem or would i be better of just getting a new bigger turbo all together considering the fact that i'm getting my full 2.5" exhaust put on shortly

um dude, white smoke is a good indication of burning coolant (or rich fuel mix). 1st do a compression check to see if your head gasket is sealing. if your turbo was blowing oil there would be blue-ish smoke while and after boosting, you would also be able to smell it. No sence replacing a turbo just to get the same problem!

ok wow, old post my bad.

 

[Splitpi]

RRE Instructions

Stock 2G @ 43 psi @ 12 v = 130.60 ltr/hr
Stock 2G @ 58 psi @ 12 v = 99.68 ltr/hr
Stock 2G @ 73 psi @ 12 v = 50.47 ltr/hr
Stock 2G @ 43 psi @ 14 v = 156.47 ltr/hr
Stock 2G @ 58 psi @ 14 v = 131.23 ltr/hr
Stock 2G @ 73 psi @ 14 v = 88.33 ltr/hr

Also, I crunched the numbers to give a better estimate polynomial for interpolation rather than using a linear interpolation.

if using 12.5 volts (stock) on the the stock 2G use this equation:

flow (ltr/hr) = -9.145*(pressure ratio)^2 - 3.485*(pressure ratio) + 143.22

if using 14 volts (rewire) on the the stock 2G use this equation:

flow (ltr/hr) = -8.83*(pressure ratio)^2 + 1.25*(pressure ratio) + 164.05

This is where it gets complicated because the polynomial was solved with 1 = 43 psi, 2 = 58 psi and 3 = 73 psi. So say I am running 16 psi of boost. That means my fuel pressure is 43 psi (the base pressure) + 16 psi (of 1:1 matching to boost pressure) = 59 psi.

Using the 1,2,3 value range, I realize I am closest 2 (58 psi) So I calculate using the 2 value:
pressure ratio = (2 - 1) + (59) / 58 = 2.017
flow = -8.83*(2.017)^2 + 1.25*(2.017) + 164.05 = 130.64 ltr/hr

16.667 cc/min = 1 ltr/hr.

130.64 * 16.667 = 2177.33 cc/min

With 4 injectors:
2,485.7 / 4 = 544.33 cc/min max flow.

Incidentally, if I choose to not rewire and used the stock 12.5 volts and ran the same boost level, the fuel pump would only flow 98.99 ltr/hr = 1649.78 cc/min = 412.44 cc/min per injector. Quite the difference the voltage makes!

Due to each engine being unique in how it produces power and so many factors... I will just guess a BSFC range of .55 to .65
Using the numbers above:

2G Stock @ 16 psi @ 12.5V = 314.24 (crank) to 241.7 (crank) hp.... potentially
2G stock @ 16 psi @ 14V = 377 (crank) to 318.8 (crank) hp ... potentially

Quite the range... isn't it! And these are the maximum calculated flow and HP numbers ... I would never expect to see these numbers and would infact down rate it by 10 to 15% as the maximum real world values.

Edit: my numbers were off...

Easier way to calculate the fuel ratio.
Fuel ratio = 1 + (New Fuel Pressure - 43) * (1/15)

So:

2G Stock @ 16 psi @ 12.5V = 279.9 (crank) to 236.8 (crank) hp.... potentially
2G stock @ 16 psi @ 14V = 372.1 (crank) to 314.8 (crank) hp ... potentially

 

[Noogabox]

In the end I dont think anything over 260Hp with the stock pump is going to be reliable. Get a fuel pump. They are in-expensive insurance. walbro 255L High Pressure is $100-$115. You could use a Supra TT pump and I have heard it makes less noise ,but also will likely cost twice as much as a Walbro. Just get a better pump and put a wiring kit on it to get better voltage.