JDM ITR (b18c-r) motor- with complete skunk2 valvetrain (skunk2 stage 2 cams), port and polished, stock block, 70mm Throttle body, fpr, intake, jdm dc 4-1 header to 2.5 straight pipe, vafc, port matched intake manifold (itr manifold) and exhaust manifold, and thats pretty much it.....looking to get rc saturated injectors but we are not sure on what size this set up will need and/or benefit from most...Should we go with rc 270cc, 310cc, 370cc or anything even larger than this? Thanks for the help .

And what is the exact size of the jdm type r stock injectors if anyone knows off hand is it 250cc? And will we defintely benefit from larger than stock type r injectors with the set up above? thanks again for the help

 

Stock injectors are 240cc

Don't go any larger than a 310cc.

The benefit: larger injectors will allow you to run lower idle and atmospeheric fuel pressures.

 

yeap 310cc is perfectly fine evn 270cc... IMO I would just go with the 310's

 

id definitely agree with those 2 guys, 270s r fine id go 310s just for future good measure w/ upgraded compression. i got some 310s used for 1 race season RC saturated for sale if interested. $270 shipped.

 

I would hit up some prelude injectors. 290cc is perfect for that app.
EVIL

 

THanks very much for the help....

 

440cc...

Why you ask? 440's because if you really have it breathing enough to "need" those cams, you may need a little more fuel than you think at OE fuel pressures... If I remember right, seems that the OE 240cc's are running at, or over 80% duty cycle on a stock R. Also, it leaves "head room" for a future bigger bore bottom end, Venom 2000, etc, etc... but don't rely on me, ask SGT, Lip, and the others running "bigger" cams...

 

considering stage 2' are close to Jun 3's, if not identical, don't you find it odd that Jun Japan would use only 270 injectors on their Stage 4 Bseries 2L crate motor making 250 PS?

http://www.junauto.co.jp/products/co.../index.html?en

http://www.junauto.co.jp/products/co.../index.html?en

440's would require ECU reprogramming. 310's as Hondata.com states is the limit of the stock ECU calibration curves. The reason for the huge injectors used by the gurus is not because they need to push that high...they use the high flow rate to lean down so that their duty cycles and FP's aren't as high. But as you say, they can tell you what they do or not tell you what they do, ....you only get as much info as they allow.

If you look at this website it gives a table that assumes a BSFC (brake specific fuel consumption) of 0.55 lb/hp/hr and relates the highest hp obtainable to a given flow rate at 85% max. duty cycle:

http://www.sdsefi.com/techffhp.htm


BSFC for N/A motors range from 0.45-0.50 lb/hp/hr and SC ones are around 0.55-0.60 lb/hp/hr and so these tables slightly oversize your injector for N/A needs but it's a good start as a guide for you. As I said, I found it quite an eye opener to see Jun Japan only use 270 injectors for a 250 PS (248 hp) motor and this may be a testimony to their engine's volumetric and burn efficiencies. I suspect 290 cc/min injectors will more than satisfy most people looking to make 200 whp N/A.




[Modified by Michael Delaney, 11:28 AM 10/25/2002]

 

please keep the comments coming....THANKS!

 

ttt