Max Maft 6.22 setup and Lucas injector information.

I emailed Intense to find out what was the max numbers that there Lucas injectors could handle. Here is the email I got from brian at intense.
Here is some info regarding your injector question.

The 42 pound injectors that you are referring to are rated using a fuel pressure of 39.7 psi. The static fuel pressure on a LSJ is 56 psi. The 42 pound injector is now equal to that of a 49.88 pound injector. Given this information, We give it a rating of approx. 350 flywheel hp. So depending on drivetrain loss. These injectors should support wheel hp in the high 200's keep in mind that your target air/fuel ratio is going to play a big factor in how much hp they can support.

So with that said the Lucas injectors flow about 49lbs or 520 cc at 56 PSI of fuel pressure.
Brake specific should be 55 TO .60 for supercharged engines and fuel pressure 56 PSI.
The injectors are good for about 295 Fly wheel horsepower or 270 wheel horsepower.
With that concluded 2.8 Pulley is the lowest pulley size you should go and best safe.

Also with the maft and cobaltproformance 50lb injectors I only recommend 2.7 pully size and PRO-II Programmable RPM Control Decoder to increase the RPM revlimter to 7200.
That should give you 19 lbs of boost and will run very well. There is a small problem with running a 2.6 with out adjusting timing. Which can not be done with the maft. When runing the car with the 2.6 Pulley when you first crank the car the timing is so far advance around 2k that there is high nock till the car warms up and degrease timing. This was a very enoying problem that could cause damage over the overall life of the motor or be a real issue up north in the cold winters. I live in florida so after it ran for 10 minutes it was ok. But I did not like waiting.



2007 CObalt ss SC
MAFT Version 6.22
Intake airbox mod.
2.7 ZZP Interchangeable Pulley system
3 step colder ngk IRIDIUM spark plugs
50# Injectors
Injector Wiring Harness
19.0 psi boost 7.2k RPMs
Devils own Meth/Water Injection M3 Nozzle Not really used unless at track.
293 HP 260 TQ AF 11.5 all the way till 5500 it dipped 12.4 held till 7k

Still have Idle problem when the ac is on and it is over 99 degree outside.
The idle dips and surges a lttile while at a light. Not bad enough to be problem but easy to stall if your not aware of it.


I am sellling 42lb lucas injectors. I sent them back and got them replaced under warranty.
I would like 75$ plus shipping.

 

These 42# Lucas injectors are exactly the one I'm running right now. The flow is 42.29 lb/hr @ 43.5PSI, this is not rated at 39.7 PSI !

http://www.racetronix.com/621031.html

Also, you must always calculate the flow at the differential pressure which is the fuel rail MINUS the maximum intake manifold pressure.

These injectors are OK up to 250whp (Dynojet), but not more with the Eaton M62 with a small pulley.

GM Stage 2 injectors are also 42# @ 43,5 PSI and are maxed at 250whp with the M62 boosting around 15-17 PSI.

 

if your bat **** looney, like i am. the 42's will support more than 250 to the tire, but require more tuning, and possibly race gas. or water injection.

 

Manifold pressure does not have any effect on you injectors unless your direct injected which we are not. who started that rumor lol.
I never heard that lol

 

I do not see anything funny there. Think about it. There is 60 PSI of pressure in the fuel rail (this is at ONE side of the injectors), but you have 15 PSI (as an example) of boosted air in the intake manifold (this is the OTHER side of the injectors).

The pressure in the intake manifold force again the one in the fuel rail ! ALSO, at idle, the negative pressure (vaccum) in the intake manifold ADDS to the one in the fuel rail. Remember the shitty idle with 50# injectors in a Cobalt ... this is because at idle the differential pressure is 60 - (-10) or 60 + 10 = 70 PSI !!!!!

So guess what will be the differential fuel pressure passing through the injectors at high boost (high RPM). Sixty minus fifteen equals forty five, nothing else !

Not on a safe (85% or less) IDC (at least when boosting 15+ PSI).

 

qchadf- where u at in o-town? im over at ucf

 

Well the guys at intense know what the are doing.
If they say it will support the numbers I would belive them.
Intense have been working on cars sense 1996 They are experts on gm blower cars.

 

For your own information you could ask your Intense guy if my post was right or wrong about the differential pressure.

Also, it has been shown that the 42# Injectors Duty Cycle are too high (near 100%) on the 250whp Cobalts.

 

stock stage 2 runs higher idc than i do with a 2.8. like i said, it all lies in the hands of the tuner.

 

Where did you get your #50 injectors and harrness from and how much did you pay for them?

 

rob561 I am in orlando Pine hills area.

I got the 50lb injectors from cobaltproformance. I reused the same wiring harness from intense.

Jmc007


I will double check with intence today about your post.

 

Ok I got a answer from intense that I was not ready for.
Yes you lose the differential pressure from the intake under boost effect the fuel pressure.
ok I was wrong. But this does not effect the results to much from what intense said the lsj setup raise the fuel pressure 1 lb for every 1 psi of boost by altering the fuel pump voltage. voltage alters from 11.8 to 13.0 Volts giving about 8-9 lb pressure change. So if you are runing 17lbs of boost you see 9-10 lbs fuel pressure drop. Which is why you can only run about 295 Flywheel horspower at 90%DIC. If the car was NA or nitrous the car could support 340 HP flywheel on the 42lbs injectors. They sugested increase the fuel pressure 1 psi of pressure for every 1 lb of boost,, Like what you can do with a FMU.
With this new information I really really do not suggest runing a pulley smaller than a 2.8 with 42 lbs injectors. infact I would run the 50lb for anything over 265 Wheel horepower.
I am thinking with my the 50lb injectore and 2.7 pulley I might max out the injectors in the winter time because I probly will see 25 more hp from the cold. Ouch Has any one setup a FMU yet.

 

this is a big grey area, still.

 

I got the fuel rail pressure logged on a dyno pull and it stayed constant to exactly 60 PSI whatever at idle or at 6500 RPM on high load. The PCM increase the voltage, so is the flow also, but not the pressure. The pressure is set by a simple mechanical spring in the fuel pressure sender unit in the gas tank.

 

so the whole point of this is that your saying is that if your 42lb injectors are maxed out and you have a 2.8 your somewhere around 270whp? or am i completely off with this lol?

 

left field on that one batman