h22slohatch

how much hp can you put on dsm 450 injectors,i would appreciate some kind of info.

_gurusan_

At OEM fuel pressure anything above 280+whp would be pushing it, you need some buffer room.

at 50psi i'd say 300 whp

JDMracer17

i couldn't achieve over 245hp in my 240 with the stock 370cc's, but you didnt ask about them, just thought i would throw that out there

Schister66

i'm looking for about 250whp in my GSR....im thinking about DSM450s...would those be too small??

whoneedzvtec

i made 380whp with a walbro h.p. @ 56 and dsm 450's

PINKS

300 with the stock fpr would be pushing them, grab a cheap b&m adjustable and bumpt it to 55 and youve got easy 350 wheel hp

TurboJesse

i maxed mine @ 320whp @ stock fp.

damnraz

not to jack this thread or anything but what's the max hp that I can get w/ rc 310's and a walbro 255lph fuel pump, I'm looking towards 250whp as my goal, but I would like to reach 280-300whp

_gurusan_

the 310s are just too small

dohckiller

the rule of thumb is:

size injector / 5 = HP supported by that injector

so let's say you want to hit 500 hp .. then 500 x 5 = 2500cc total flow by all four injectors, so that's 2500 / 4 injectors = 625cc

--

or how much hp are those 450cc good for ? Well, 450 / 5 = 91.8 hp per injector, so 19.8 x 4 injectors = 367.2 hp max power



the above doesn't mention the fuel pressure and the Air/Fuel ration, both of which play a big role as well

Blanket Jackson

Friend of mine put down 285@7psi on DSM's. Walbro 255.

h22slohatch

yeah,i want to get about 320hp on them,so i see some of you guys have done it,sweet!

BlueShadow

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dohckiller &raquo;</TD></TR><TR><TD CLASS="quote">the rule of thumb is:

size injector / 5 = HP supported by that injector

so let's say you want to hit 500 hp .. then 500 x 5 = 2500cc total flow by all four injectors, so that's 2500 / 4 injectors = 625cc

--

or how much hp are those 450cc good for ? Well, 450 / 5 = 91.8 hp per injector, so 19.8 x 4 injectors = 367.2 hp max power



the above doesn't mention the fuel pressure and the Air/Fuel ration, both of which play a big role as well</TD></TR></TABLE>

Not to mention BSFC and duty cycle isn't taken into account. I use the formula on rceng to figure out how much HP a set of injectors are good for.

http://www.rceng.com/technical.htm

First thing you do is: convert CC/min to LB/min by dividing it by 10.5
Then the formula is: (LB/min x injector duty cycle) / BSFC = HP per injector
Then you take the HP per injector and multiply it by the number of injectors you are using

450 / 10.5 = 42.8 LB/min
(42.8 x 0.90) / 0.60 = 64.2 HP per injector
64.2 x 4 = 255 HP @ 90% injector duty cycle, .60 BSFC, and 45 psi of fuel pressure

I usually do it for 0.60 BSFC and 0.5 BSFC to give me a high and low limit for the injectors.
(42.8 x 0.90) / 0.50 = 77 HP per injector
77 x 4 = 308 HP @ 90% injector duty cycle, .50 BSFC, and 45 psi of fuel pressure

So I figure 450's are good for 255-308HP. To figure out how much more you can get out of the injector do this:

(new fuel pressure / old fuel pressure) SQUARE ROOT
Then you multiply by the injector size

So to figure out how many more cc's you can get out of a set of DSM 450's by raising fuel pressure 10 psi:

(55 / 45) SQUARE ROOT = 1.1055
1.1055 x 450 = 497
So by raising fuel pressure from 45 to 55 psi, you go from 450cc's to 497 cc's. Then you use the above formulas to figure out how much HP you can get out of 497cc's. I already did it, and it's about 284-340 HP, at 90% duty cycle 0.60-0.50 BSFC, and 55 psi of fuel pressure.

Boostedgsrswap

I make over 350 hp on dsm 450cc injectors At 10.8 lbs I was at 350 it’s now sitting on 12 so you can do the math Afrs are 11.2-11.5 we’re they should be stock gsr with skunk 2 intake 70mm throttle body 50 trim turbo ramhorn manifold hope this helps

Dark_Teg

13 years later I bet he figured it out already.