Do I need larger Injectors
 

Here is the efi_Live log on my C5


click here for log illustration

BPW RPM Duty%

18.8 6000 93.5%
19.8 4800 80.0%

C5 A4 2.73 Magnuson Roots Blower 5.5#, xpipe and headers
stock internals.

What injectors came with the blower?
Fuel pressure at 6000rpm?

If your fuel pressure goes down,that will pulse the injectors more.

Injectors are 39#@43psi
Bosch 24508208 or 0 280 155 811.
The C5 has 58psi fuel pressure

yes most definetly. Ill buy your injectors ;)

Seriously though, whenever we see more thna 85-90% dutycycle, we up the injector sizing. Usually takes 420 rwhp in a six speed (less in an auto) to do so.

if you are interested in sellign your injectors if you deem it necessary o do so, send me an email jeff@fbodycentral.com

Your more than likely fine - 90% is pretty much done, but unless you do anything else to significantly increase your power they will be fine.

If you are going to roadrace, etc. and be at high DC for extended periods of time (10-20-30 minutes, etc) then it might be worthwile, but otherwise i wouldn't bother

most injectors go static around 85%, during the transition they can "float" before going static. Bad idea.

of course you can disagree, but talk to rc engineering if you doubt this. They make some nice schtuff ;)

AH,I see.The magnuson chargers I've done had 42's.So I figured you'r did too.
With how close you are to maxxing the injector I would look into 48lb or so.

I guess I have some injectors for sale now.
The 39# injectors were included with the Magnuson Kit that I have had for 2 seasons now.

If I go with 42# injectors would the IFR table be multiplied by 42/39 or 1.07? hopefully this is all I would have to do.

Thanks for your input, it is not often that there is a clear consenses.

I honestly wouldnt spend the money on injectors for only a 107 increase in capacity.

In a 400 hp car maxed, then woudlnt they max at 428 hp? Id get some 44-48 lbs

I can check with a friend of mine to see what kinda deals he gets on the accell stuff he carries

find a lightning svt and jack their injectors cheap. i think i paid $200 for 8 with very low mileage. didnt even need new o-rings.

remember they are 42# @3.0bar rated

I used the calculation found at www.rceng.com
The 39# injector is good for only 480BHP.
42#-520 and 48#-600BHP.

With MAF at 390 I am guessing I will be around 500BHP