Fuel System Upgrades

[XpL0d3r]

Boosting next month, I just have a couple questions on the fuel system.

I just purchased a new Walbro 255lph fuel pump.. I hear I should also get a new FPR as the stock one's can't handle the new pump? Should I also get a new fuel rail as well or will the stocker be fine? I'm running dsm 450cc blue tops.

If I have to get a new FPR, will any generic ebay one do? Or should I actually spend money on it... I know "you get what you pay for".. but some ebay parts aren't too too bad... just curious.

Also, anything I should know before installing the new fuel pump?

Thanks.

 

[sohclubkid]

put your fuel pump in, and get an AEM FPR... the B&M ones aret very consistent from what i hear

 

[2NRSTV]

Yes, I would recommend a high flow fuel rail. And also, B&M makes a FPR mod where to cut the top off your FPR and install a new one instead of buy a whole new one.

Edit: damn you're fast. Also, the B&M ones are more consistent when you drill the fuel inlet. I forget where I learned that from or what drill bit size to use though, it was a really long time ago when I did mine.

 

[sohclubkid]

Yes, I would recommend a high flow fuel rail. And also, B&M makes a FPR mod where to cut the top off your FPR and install a new one instead of buy a whole new one.

Edit: damn you're fast. Also, the B&M ones are more consistent when you drill the fuel inlet. I forget where I learned that from or what drill bit size to use though, it was a really long time ago when I did mine.

ehh, you dont need a larger rail till your pushing over 400... and the old one aka endyne is where you learned to drill the hole.

just slap an AEM FPR on your stock rail and you'll be good to go.

 

[Kensai]

You don't need an FPR or a fuel rail, you'll be fine.

 

[got traction]

You don't need an FPR or a fuel rail, you'll be fine.

x2 i get 50psi of fuel with a stock fuel rail and stock regulartor

 

[rwlsvtec_03]

you dont need a "high flow" fuel rail. Stock is very sufficient.
Only reason you would want/need another.. Fuel pressure sender can hook directly in an AEM considering stock you would run sender into fuel line or I guess you could tap into rail also(wouldn't suggest).

 

[2slo4u]

Yep. Keep it stock.

 

[2NRSTV]

What I don't get is the Injector Size would dictate that it's about a 230HP build, assuming he's going to be at an 80% duty cycle, but the fuel pump is way overkill assuming that to build 230HP, he's running at a total pressure of 62.5 compensating for an estimated 5psi pressure loss maybe more.

Someone check my math.

XpL0d3r: What HP are you looking for at what PSI?

 

[XpL0d3r]

What I don't get is the Injector Size would dictate that it's about a 230HP build, assuming he's going to be at an 80% duty cycle, but the fuel pump is way overkill assuming that to build 230HP, he's running at a total pressure of 62.5 compensating for an estimated 5psi pressure loss maybe more.

Someone check my math.

XpL0d3r: What HP are you looking for at what PSI?

Looking to get around 250whp, give or take. I would say ~10 PSI at the most, as I'm keeping the internals all stock. Really depends on what the tuner says is safe. Will be tuned with Crome... Snail is a Garrett T3/T4 .50 trim .48 a/r.

Are you saying I don't need to install the new fuel pump?

 

[sohclubkid]

Looking to get around 250whp, give or take. I would say ~10 PSI at the most, as I'm keeping the internals all stock. Really depends on what the tuner says is safe. Will be tuned with Crome... Snail is a Garrett T3/T4 .50 trim .48 a/r.

Are you saying I don't need to install the new fuel pump?

my suggestions (now since i didnt know your goal before)
1. install the fuel pump... it wont hurt anything.
2. leave the rail and FPR stock
3. dont tune on chrome...

 

[XpL0d3r]

my suggestions (now since i didnt know your goal before)
1. install the fuel pump... it wont hurt anything.
2. leave the rail and FPR stock
3. dont tune on chrome...

Will do 1 and 2... as for 3.. I'm pretty content after comparing what it can do to Neptune. It's either Crome or Neptune, and they're pretttty comparable... Why do you dislike it?

 

[sohclubkid]

Will do 1 and 2... as for 3.. I'm pretty content after comparing what it can do to Neptune. It's either Crome or Neptune, and they're pretttty comparable... Why do you dislike it?

neptune is the way to go... ive heard a few bad things about chrome from tuners, all of which say neptune is much better to tune with.

 

[XpL0d3r]

neptune is the way to go... ive heard a few bad things about chrome from tuners, all of which say neptune is much better to tune with.

hmm okay. Well I'm actually going to visit a guy who may very well be my tuner for this project. He said he does Crome and has tuned similar setups to mine and running mid 13's. His pricing was much cheaper compared to the Neptune tuner nearby (Neptune guy wants $600, but that includes the software.. which still isn't too bad).

I'm debating. I've heard good things about both.

 

[rwlsvtec_03]

just get hondata and call it a day!

 

[sohclubkid]

hmm okay. Well I'm actually going to visit a guy who may very well be my tuner for this project. He said he does Crome and has tuned similar setups to mine and running mid 13's. His pricing was much cheaper compared to the Neptune tuner nearby (Neptune guy wants $600, but that includes the software.. which still isn't too bad).

I'm debating. I've heard good things about both.

honestly, its up to you. but a tune is not the thing to cheap out on IMO. a tuner i know tuned on chrome for years, and said it always seemed to do odd things and be kind of a pain to work with, so he tried neptune and has been tuning with it ever since.

neptune with tunerview FTW

 

[XpL0d3r]

^ Nah. lol.

honestly, its up to you. but a tune is not the thing to cheap out on IMO. a tuner i know tuned on chrome for years, and said it always seemed to do odd things and be kind of a pain to work with, so he tried neptune and has been tuning with it ever since.

neptune with tunerview FTW

True, definitely nothing to cheap out on at all. I'm going to talk to the guy in person this Thursday actually, so I will see what he says.

 

[sohclubkid]

^ Nah. lol.



True, definitely nothing to cheap out on at all. I'm going to talk to the guy in person this Thursday actually, so I will see what he says.

LMAO @ hondata

and definatly talk to both tuners... figure out who can tune to your needs for a streetable DD.

 

[got traction]

i love my s300, but most people are too cheap to buy it

 

[2NRSTV]

This is what frustrates me. A guy is trying to build his engine and wondering what parts to get and everyone gives him answers, but no rhyme or reason as to why.

Here are the facts:
Desired HP: 250
Desired PSI: 10
B.S.F.C.: .60
Safe Duty Cycle: 80%

Finding Injector Size:
(250HPx.60B.S.F.C.) over (4# Inj.x.80Duty Cycle) = 46.87lbs./hr per injector of fuel.

46.87lbs./hr = 492.13cc/min.
This means the you need at least 492.13. and at 10 psi, the new flow rate of those injectors will be 528.5cc/min.

Finding needed fuel pressure.
43.5stock FR+10 boost+5 assumed pressure loss= 58.5psi of fuel, but a straight 60 to be safe. But be warned that fuel pressure loss can be up to 10psi., so 65-70psi would be safer to run.
If your stock FRP can run it, then go ahead and use it, but that is highly doubted.

FRP: 65 to be safe
Required Fuel: 150lbs/hr

150lbs/hr = 23.66gal/hr

At 65psi FRP and 23.66 gal/hr, a 190ltr/hr Fuel Pump is needed.