Just wondering if anyone on this board was running around 300whp or more on 450cc injectors. Let me know what your duty cycle is and if your at stock fuel pressure or not. Im planning to go retune and turn up the boost (currently at 6psi at 238whp). I was just wondering if i can hit the 300 mark with my dsm 450s. I have a walbro 255 BTW. Thanks in advance!

 

Its gonna be close at 300whp w/ stock fuel pressure. I made 323whp with 450ccs but with the aid of alky injection and even at that I had a close call on the dyno.

I'm currently running a larger alky injection nozzle than before so it really dropped my injector duty down. According to Crome duty is 87%@ 7500rpms and 19psi.

i would bump up the fuel pressure just to be safe.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sohc_turd &raquo;</TD></TR><TR><TD CLASS="quote">Its gonna be close at 300whp w/ stock fuel pressure. I made 323whp with 450ccs but with the aid of alky injection and even at that I had a close call on the dyno.

I'm currently running a larger alky injection nozzle than before so it really dropped my injector duty down. According to Crome duty is 87%@ 7500rpms and 19psi.

i would bump up the fuel pressure just to be safe.</TD></TR></TABLE>

So do you think its very doable as long as I up the fuel pressure? What is the longterm problem for running injectors at a high duty cycle?

 

i am pretty much max out on my 550's on 350 horsepower. And by maxed out i mean 80% duty which you should not go over because there is a good chance you can lock a injector in the open position or even worse the closed position. Fuel is one thing you dont want to overlook.

 

My DSM 450's were maxed out @ 306whp on my stock B18b.

 

I think that it depends on what your (brake specific fuel consumption) BSFC is. I was pushing it with my 450s @ just over 300hp. Then again I was only at 38psi of fuel pressure @ idle. You can get away with 300hp on 450s if you make sure that you have enough fuel pressure.

 

1. So how much fuel pressure would you recommend to run at idle, 50psi, in order to achieve 300whp on 450cc's?
2. BTW, 450's cant safely go more than 300whp or so?

 

dude, i was running 70psi at idle on my 450's.....walbro high pressure fuel pump, my duty cycle was almost 75% at 17psi on my f23 w/ a drag kit w/ a t3/t4b
https://honda-tech.com/zerothread?id=1018437

@14psi i was runnning with a stock SScamarro on the highway. made 209whp/221wtq@8psi on a hot summer day.

 

Just bump up the fuel pressure to 50psi as a starting point then tune from there. It'll just be trial and error untill you find what fuel pressure will be enough. Either that, or get some larger injectors.

I'm in the same boat, i want more HP but i'm limited to my injectors, or rather my pocket book.

 

mines at 42psi...stock b16, 440 rc injectors and im makin real good power.

 

I would sell the 450's on eBay, and buy some 750cc or larger. That will give you room to grow.

 

Im just going to up the fuel pressure and get new injectors when i have a built block because i really dont have room to grow anymore after around 300whp on my stock block

 

My old setup maxed out 450's at 335whp... obviously it was heavily pushing the limits (and to add to it, on stock block... fortunately a great tuner, cause no room for error there).

 

I've made 366whp on RC440's @ 95psi base fuel pressure & 106PSI peak pressure w/ 98% duty cycle. 11.7:1 AFR's to 8,500rpms.

I wouldnt recommend running at the ragged edge like that tho

 

i maxxed out my 450s real bad over the winter, ran real lean and cracked a nice hole in my sleeve. they were doing ok, a/f at 11.8:1 up to about 300whp (10psi t3t4 lsvtec). i spiked up to about 14 psi or around 350whp and they lost it

 

Good info guys!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDMs1eeper &raquo;</TD></TR><TR><TD CLASS="quote">I've made 366whp on RC440's @ 95psi base fuel pressure & 106PSI peak pressure w/ 98% duty cycle. 11.7:1 AFR's to 8,500rpms.

I wouldnt recommend running at the ragged edge like that tho </TD></TR></TABLE>

wow , haha that fuel pressure is hella high. Good info guys!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by xtremeazian &raquo;</TD></TR><TR><TD CLASS="quote">

wow , haha that fuel pressure is hella high. Good info guys!</TD></TR></TABLE>

LOL, talk about hydraulic needle effect....... dayum!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by blackeg &raquo;</TD></TR><TR><TD CLASS="quote">i maxxed out my 450s real bad over the winter, ran real lean and cracked a nice hole in my sleeve. they were doing ok, a/f at 11.8:1 up to about 300whp (10psi t3t4 lsvtec). i spiked up to about 14 psi or around 350whp and they lost it</TD></TR></TABLE>

if you dont mind me asking what type of engine management were you runing

 

not 450cc's, but i just tuned a car on CROME PRO yesturday and it was making 295whp @ 90% DC. a/f was in the mid 11's and the car was running a stock regulator. fuel pressure only went up to 60psi

 

boy this sue is cutting it close, I am in the same boat and my goal is 300whp on my GSR but peopel keep telling me @ 15psi I'll be making more. I have the 450 dsm's in my hand but I don't want them to lock up closed or open.

It is completely rediculous to charge $300 for 4 fuel injectors though, that is absurd BS.

 

wow....i've never heard of anyone running 95psi base fuel pressure. that's crazy. hahaha, that's like double mine.

 

haha yea, walbro's get very loud at that pressure