Sprockets

iTrader: (6)

I spoke with RC and they told me that 650s would be more than enough for 350whp. 750s would have been only $20 more, but they informed me that it's more difficult to get larger injectors that size to idle, so I went with 650 saturated. According to the calculator on RC's website:

Desired Crankshaft Horsepower: 400
Number of injectors: 4
Brake Specific Fuel Consumption: .60
Maximum Injector Duty Cycle: .8
Fuel Pressure: 43.5

=793cc

Is this accurate, or are the saturated 650s about right?

BTW, I'm using Hondata.

Chris F

If a stock ITR making ~200 HP has 240 cc injectors, you're probably OK

EDIT: (OK, obviously overlooking the difference in fuel pressure, and subtracting your boost pressure from that... but that ought to be more than enough. According to that calculator a bone stock ITR needs 300CC injectors.)


Modified by ccfries at 11:31 PM 7/27/2004

ATS*Mark

you should be fine with 550's if all you want is 400 crank hp

Sprockets

iTrader: (6)

But for a turbo, the BSFC has to be .60-.65, so that changes things. Damn, I'm so stupid I should have gotten the 750s.

You're right, I just did it for an ITR and got 282cc with .45 BSFC & 314cc with .50 BSFC. Strange.

Sprockets

iTrader: (6)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Hella_JDM &raquo;</TD></TR><TR><TD CLASS="quote">you should be fine with 550's if all you want is 400 crank hp</TD></TR></TABLE>

I typed in 400 because 350whp x 1.15 (drivetrain loss) = 402.5

Some people run higher fuel pressures and get more out of smaller injectors. I have an AEM fpr, but I wouldn't feel safe turning that thing up too much.

crazyitr

I blew up my motor cause my 550's maxed out with a medium size turbo and 14lbs of boost. I had a boost spike in fifth gear and melted two pistons.
Get the 720's . . . . better safe than sorry

Sprockets

iTrader: (6)

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

no doubt!

lugnuts

well at least you have the correct user name picked out haha. just kidding. your motor will have a BSFC of way less then .65, no fear your 650 cc injectors will be fine.

Stewie

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ccfries &raquo;</TD></TR><TR><TD CLASS="quote">If a stock ITR making ~200 HP has 240 cc injectors, you're probably OK

EDIT: (OK, obviously overlooking the difference in fuel pressure, and subtracting your boost pressure from that... but that ought to be more than enough. According to that calculator a bone stock ITR needs 300CC injectors.)


Modified by ccfries at 11:31 PM 7/27/2004</TD></TR></TABLE>


I thought about that too, but than I realized that making that comparison would be inaccurate. A Type R makes 200 hp through many power strokes displacing a small amount of air at a time. This means that the injector gets to open many times while still staying at an ideal duty cycle.

With FI, your displacing more air for each power stroke, which mean the injectors have to spray more fuel each time they open hence, higher duty cycle.

also, you have to increase the Brake Specific Fuel Consumption for FI like the site says.

Sprockets

iTrader: (6)

I ordered the 750s today. I think I made the right choice.

adictionbass

this is just my thinking, but when i go to the worksheet it starts out with a fuel pressure of 175 PSIG. No i was thinking that is way way way too high, but now devide that by 4 and what do you get? 43-44 PSI which is right where it should be for each injector. So for that worsheet, should you put in 175 or 43-44??

Sprockets

iTrader: (6)

43

adictionbass

so 750s wont be good for my 400-450 whp goal... ****. i was pretty sure 750s would handle it.