I'm planning out a turbo setup with a max. goal of 275-300whp on a B18C1. I was advised towards 310cc injectors, but according to two different formulas on RC's website http://www.rceng.com/technical.htm It's telling me I need about 610cc any suggestions?

~james

 

depending on fuel management.
youll need 440-550's

 

Anyone care to explain, for example, if you disagree with RC's saying 600-650cc, then why?

 

Depends on fuel pressure. At stock 45-50psi (WOT), I belive 440's max out around 325-350whp.

 

id get 550s, there not much more then 440s and just in case you do want to boost more in the future, itll leave you a little room for more.

 

anyone want to comment on RC's calculator though? I can't bring myself to just ignore that. Also, something that might be affecting the calculations is that i don't know what fuel pressure I'll be running. I plan on an adj. FPR, new fuel rail, walbro 255, and undetermind injectors...
SO, suggestions on fuel pressure, and injectors, and explanation of discrepancy between H-T peeps and RC calculator, that's what I'm looking for.
~james

 

i went for 550's for future expansion

 

550's good to ~325-340 whp...

Jeffrey Atwood

 

I say go to 550, esp since now RC makes 550 in saturated. I wish they did back when I bought mine, just in case I decided to build the bottom end and run like 18psi.

 

Ok, so far, no one has even adressed that i asked the question, much less attempted to answer it, about why RC says otherwise..I'm not saying I doubt what you are all saying, I'm just wondering why RC says different. Anyone?
~james

 

We don't know why someone would suggest 310s for a B18C trying to reach 300whp. That is way small for that hp level! 310cc might be good for like 220whp or something around there. 440 are recommended for around 275whp, they ca go higher, but you'll max the duty cycle on them. In order to run friendlier duty cycles I recommend the 550's.

 

I dont see what the problem is? Its coming out right at about 450cc for 300hp.
Your not using the calculator right maybe.

 

300 x .5(BSFC) = 150
150 / 4(# of injectors) = 37.5 lbs/hr
37.5 + 20%(safely marginal) = 45 lbs/hr
45 x 10.5 = 472.5 cc/hr

I would go for 550cc.


Modified by porsche997 at 12:21 AM 7/12/2003

 

it's all in the brake specific fuel consuption, i like to run about, 45 psi of fuel, which is what most aftermarket pumps put out. but the bsfc is where it gets tricky, make shure your dyno is not correcting for altitude and then get your base bsfc. for a low boost turbo (6-10 psi) i figure . 52 bsfc. even at 375 hp ive never seen over .57 bigger injectors are almost allways better, as long as your engine manegement can handel them. if you want some 450's, ive got a set of dsm, ballenced, and clened by rc with a risitor box for sale. but a set of saturated (high impeedence) 550's would be better.

 

Go with the 550s , I am at 286WHP and my 450s are maxed, I am at 45psi fuel pressure,
The 550s should take you to 340-350WHP, give you a little room.

 

great thanks for all the info. I'm not using the calculator wrong, I just was following their saying .6-.65 BMFC for turbo, and didn't know what to put for a fuel pressure. so RC 550's will be good? This is good info
~james

wait, I just went back and did it again though...with the following numbers, someone please tell me where I'm going wrong.

Actual Desired <U>Crankshaft</U> HP. = 340 (should be about 300whp)
# of injectors = 4
Brake Specific Fuel Consumtion Desired = .58
Max. Duty Cycle = 0.80
PSI = 45psig

and it says injector required 637cc/min

anyone care to explain?

 

im blown away, ive seen people run only 310cc injectors.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SleepyEG &raquo;</TD></TR><TR><TD CLASS="quote">anyone want to comment on RC's calculator though? I can't bring myself to just ignore that. Also, something that might be affecting the calculations is that i don't know what fuel pressure I'll be running. I plan on an adj. FPR, new fuel rail, walbro 255, and undetermind injectors...
SO, suggestions on fuel pressure, and injectors, and explanation of discrepancy between H-T peeps and RC calculator, that's what I'm looking for.
~james</TD></TR></TABLE>


What everyone seems to be missing....is the fact that you plan on running an Adjustable FPR....Which I believe you mean a boost dependent FMU (bandaid). That changes things dramitically.

Without using the bandaids: Id go 440-550's. (with Hondata, Safc, Ems...whatever)
With the right FMU: I'd go 310-370's. It will be easier to idle the 310...IMO.

 

Im using stock FPR, no FMU and 550's.
Laid down 280whp at 8psi.

 

what air fuel ratio are you running at that power levels?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CRVRX &raquo;</TD></TR><TR><TD CLASS="quote">Go with the 550s , I am at 286WHP and my 450s are maxed, I am at 45psi fuel pressure,
The 550s should take you to 340-350WHP, give you a little room. </TD></TR></TABLE>


what air fuel ratio are you running at that power levels?

 

I'm planning on using Hondata, not a hack FMU..

 

Yep so with Hondata, just get the RC 550's like many of us have been saying all along.

 

ok. I'm not trying to argue with any of you. What I'm saying is...
NO ONE has explained why, RC Engineering, a very respectable company, is telling me to use 650cc's ?? Someone please shed some light on this. If someone who is an engineer like myself could explain, that'd be great.
~james

 

i used 370cc walboro 255, fmu 10:1, stock regulator, vafc and made 305whp