What do you think about 42lb fuel injectors?

**spookyz28** · 03-25-2007, 09:23 PM

I have a 2000 Z28 camaro Mods are long tube headers, stage 3 port and pollished heads, Manley Nextec Beehive springs and valves, Weiand aluminium intake port matched to the heads, 1.8 Krauer Roller rockers, custom grinde LS7 Hot Cam with a lift of .625, 57 series FIPK breather filter, and the SLP cold ram air box. My question is, when I get the dyno tune can I go with 42 LB injectors? I did not touch the bottom end of the motor. When I get the tune will I be able to adjust the flow rate of the injectors to a constant fuel flow? or will I have to go with smaller ones? With these mod's we are expecting 500 to 550 at the flywheel.

**BlackLT1Z28** · 03-26-2007, 05:06 PM

Technically, you can go with bigger injectors, but unless you're running FI, I don't think you'll need them. And really, the dyno tune will really be able to tell you if you need more fuel and if your injectors are maxed out. I'm thinkin since you're running all motor, the stock injectors should suffice.

**M6HUGGERSS** · 03-31-2007, 09:10 AM

depends on duty cycle of your injectors....
get the car dynoed, your tuner can tel you for sure...

sounds like you should be fine!

**Killer_bluebird** · 03-31-2007, 11:44 PM

I would say yes. I have a cam only car with a MS4 cam and I'm seeing duty cycles well above 80%. I'm making about 410rwhp or so. I need to re-dyno the car again after I finish the tune. But it sounds like you are making more power than I am so I would highly recommend them. You will need to have the car re-tuned for the bigger injectors (it is not a complete tune just changing the pertinent values in the pcm to match the extra flow of the new injectors). But since you haven't tuned it yet it can all be done in the same shot. My .02

**BlackLT1Z28** · 04-01-2007, 05:30 PM

But the MS4 cam is a HUGE cam.
Don't know the specs of the LS7 hotcam.

**danziger** · 04-01-2007, 05:42 PM

If you really have to upgrade (which I don't think you do yet), I would go with the SVO 30lb injectors. They will flow plenty at the LS1's rail pressure, cost less and will be easier to tune.

**Killer_bluebird** · 04-01-2007, 08:22 PM

Originally Posted by BlackLT1Z28

But the MS4 cam is a HUGE cam.
Don't know the specs of the LS7 hotcam.

It is not a matter of size of the cam but horse power. You can use the calculator at the bottom of this page. In order to keep you injector duty cycles within less than 80% you'll need bigger injectors for your current target hp (500 fwhp). 30# SVO should work as well but for the price you might as well get 42# SVO's and have extra room to grow. Of course this is my opinion and you can just wait until you are dyno tunning and see what the tuner says. But that will mean that if you are running out of injectors you will have to order a set, wait for them to come, install them, re-tune and re-dyno, and 1-2 weeks later you get to finally have fun with the car. Ask your tuner what he thinks if he has done other LS1/6 he will have a good idea of what you'll need for your target power level.

P.S. the only reason the SVO 30# will work is because they are rated at 30# @ 43.5psi an LS1 will run around 58-60psi so in reality they will flow more like a 35# injector.