Are 42lb injectors really necessary?

JBushman73

Founding Member
Aug 29, 2001
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Roanoke, VA
Ordered the P1SC. Procharger only asks that you use a higher grade gasoline and the larger injectors aren't necessary. My car is bone stock and I plan on keeping it that way with the exception of the SC. Most dealers say that 42lb injectors are a requirement.

Are 42lbs really necessary?:shrug:

Thanks.:nice:
 
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injector size is a function of total airflow into the motor.


300hp needs 24lb

i use 30# for the mid 300's.(just guessing)

04-03 cobra 42lb for 390hp.

i have directly experimented with 19lb and fuel pressures to find out limits at the 325hp level. my findings are NOT TOO GOOD. drivability issues (surging,tip in leanout).

i could get it plenty rich blowing flames out of the tailpipes. but the drivability was worthless. changing to 30# and tuning(maf) solved all those issues. now i can set pressures normal and keep the duty low, and run it high for WOT track tuning without all the issues.

get the right injectors. maybe 42lb isn't right, maybe it is, but bigger than stock for sure.
 
I appreciate all the feedback.

Based on a post or two it sounds like I may need to go with a larger MAF.

Does bigger = rich or does biggest = richer?

I won't be able to get a tune for a long time and if I get a larger MAF I wan't to be sure I'm still not running to lean a ping ping ping.
 
JBushman73 said:
I appreciate all the feedback.

Based on a post or two it sounds like I may need to go with a larger MAF.

Does bigger = rich or does biggest = richer?

I won't be able to get a tune for a long time and if I get a larger MAF I wan't to be sure I'm still not running to lean a ping ping ping.

If you can't get a tune, get an FMU or something to ensure the car runs pig rich, otherwise your motor will go POP! the first time you get on it. :p
 
Go with the bigger injector and FMU until you can get it dyno tune. You won't be sorry you went with the bigger injector from the start. We just did a procharger p1sc install on an05 mustang I know a different car and different engine but the stock injector would not work. The duty cycle on the injector was right around 100% and the car would hardly run. Once the 42lbs were installed and the new tune was loaded it put down 480 to the tires.
 
First let me ask you this, are you buying the supercharger as a kit, that comes with injectors, chip etc. ? I think there must be some confusion. Procharger would NOT reccomend running the stock GT injectors. If they said that, they are talking about the injectors that come with the kit. Also, you can not change the MAF or larger injectors without a tune, and if your car is a 99+ you can't run an fmu.
 
JBushman73 said:
I appreciate all the feedback.

Based on a post or two it sounds like I may need to go with a larger MAF.

Does bigger = rich or does biggest = richer?

I won't be able to get a tune for a long time and if I get a larger MAF I wan't to be sure I'm still not running to lean a ping ping ping.


changing MAF's without a tune is not smart at all. theoretically, it would make you go lean because the new MAF would send out lower voltages than the new MAF making the computer think you aren't getting as much air as you used to.
 
jstreet0204 said:
First let me ask you this, are you buying the supercharger as a kit, that comes with injectors, chip etc. ? I think there must be some confusion. Procharger would NOT reccomend running the stock GT injectors. If they said that, they are talking about the injectors that come with the kit. Also, you can not change the MAF or larger injectors without a tune, and if your car is a 99+ you can't run an fmu.

I did buy the kit. It does come with a chip designed for my year.(04) It doesn't come with injectors. Procharger sent me some information and it said was to bolt it on and run 91 octane or better. I think I'll go with 30lb. To me it just seems like 42 is a waste since I don't plan on modding the car anymore after the S/C.
 
JBushman73 said:
I did buy the kit. It does come with a chip designed for my year.(04) It doesn't come with injectors. Procharger sent me some information and it said was to bolt it on and run 91 octane or better. I think I'll go with 30lb. To me it just seems like 42 is a waste since I don't plan on modding the car anymore after the S/C.

Well, here are a few things you need to know. Did the dealer you got the kit from state that the 42's were required? If so that is likely what the chip is burned for. YOU NEED TO KNOW THIS. If you buy 42's and the chip was burned for 42's you will be ok. If you by 30's and the chip was burned for 42's you will have to get a new tune. If the chip was burned for stock injectors, you will need a new tune for either. Same thing goes for the MAF. The difference in price between 30's an 42's is not that much and you may end up cheaper with 42's if you don't have to pay for the retune. If you do not have access to a wideband this is critical information, so DO NOT assume anything. It is not likely that the chip is burned to stock injectors, since anyone selling superchargers should know that the stock injectors are not going to hold up over 300hp in a supercharged application. Also going with a larger injector than you need, will give you room to go, and will not hurt anything. Post back and let us know what you find out.
 
JBushman73 said:
I think I'll go with 30lb. To me it just seems like 42 is a waste since I don't plan on modding the car anymore after the S/C.
I wouldn't recommend 30lb injectors for that kit (or any blower for that matter) if you plan on seeing more than 6psi. I'd go 36's minimum and 42's optimum. It's better to be running a little more injector than needed, than a little less. :)
 
jstreet0204 said:
Well, here are a few things you need to know. Did the dealer you got the kit from state that the 42's were required? If so that is likely what the chip is burned for. YOU NEED TO KNOW THIS. If you buy 42's and the chip was burned for 42's you will be ok. If you by 30's and the chip was burned for 42's you will have to get a new tune. If the chip was burned for stock injectors, you will need a new tune for either. Same thing goes for the MAF. The difference in price between 30's an 42's is not that much and you may end up cheaper with 42's if you don't have to pay for the retune. If you do not have access to a wideband this is critical information, so DO NOT assume anything. It is not likely that the chip is burned to stock injectors, since anyone selling superchargers should know that the stock injectors are not going to hold up over 300hp in a supercharged application. Also going with a larger injector than you need, will give you room to go, and will not hurt anything. Post back and let us know what you find out.

Street,

Called procharger and the chip they are supplying me requires 42 lb injectors.

Now I just need to know where I can find some on a poor mans budget.

You guys have any suggestions?:shrug: