30lbs injectors, too big?
 

i have an 89, vert with: a powerdyne supercharger(6psi) 70mm TB, 65mm mass air, 30lbs injectors, and adjustable fuel pressre regulator,headers, and an x pipe.

my question is are my injectors too big? will it damage anything if i run big injectors and turn down the fuel pressure to compensate? how much fuel pressure should i run? how much timming? what kind of spark plugs, how much gap spacing for the spark plugs? thanks any advice would be great!!

Re: 30lbs injectors, too big?
 

you gotta list a little more than that. Stock H/C/I I assume? Are you using an FMU? To answer your question though, I don't think 30's are too big. The best way to know though would be to put it on a dyno and check the air/fuel ratio on there, or just buy an aftermarket wideband O2 sensor.

Re: 30lbs injectors, too big?
 

30's are just right IMO.

Re: 30lbs injectors, too big?
 

hey,
yes i am using an fmu, the one that comes with the powerdyne kits, if that helps any. if you mean stock computer by saying Stock H/C/I I, than yes. Now that i have upgraded to 30lbs injectors will i have to change the chip in the fmu? can you run an supercharger without an fmu?
im am kind of a newbie at this so please bare with me. I hope that helps

Re: 30lbs injectors, too big?
 

H/C/I is just a short way of saying heads/cam/intake. I was just wondering if these parts were aftermarket or not.
Yes you can run a supercharger without an FMU, as that is the preferred way, as long as you have enough injector, and fuel pump. How big is your pump?

30's will give plenty of fuel without an FMU on an otherwise stock engine with only 6psi boost. I don't think I'd try it with the stock fuel pump though, I'd put in a 190 or 255lph to give you room to expand.

Check out the forums at www.superchargerhelp.com sometime, there's a ton of good blower info over there.

Re: 30lbs injectors, too big?
 

Sweet, its good to here that you can run the supercharger without the fmu, otherwise i would have to buy the chip from powerdyne. i also have an 9lbs pully that im goign to put on in a couple weeks, do u still theink i can run without an fmu? why is it preferred to run without an fmu?

yes the h/c/i are all stock, and i have upgraded the fuel pump to an 255lph. is there any other changes that you would suggest to make everything run well? perhaps an ignition box? i only wish i could afford an aftermarket h/i/c but i am only a student so money is a factor.

Re: 30lbs injectors, too big?
 

You could pick up a used MSD-6AL pretty cheap. I know what you mean about the student thing, I came from the same boat, and have been slowly upgrading my college-budget bought parts.

The FMU is a way to cheat your fuel system into providing the extra fuel needed with boost. Although it can work fine in a lot of applications, it just isn't the most efficient way to do it. Having correctly sized injectors is the key to a properly running blower car.

Re: 30lbs injectors, too big?
 

Now that you upgraded your injectors, be sure you upgrade the Mass air meter to match the size injectors.

Also, ignition is highly recommended, MSD Boost retard is a must, it helps with timing per lb of boost. More boost equals more timing, if there is no curve and/or coordination between the two you will blow a head gasket very quick.

Good luck.

Re: 30lbs injectors, too big?
 

He'll need some real good luck if he follows that advice! :D

You need to RETARD timing (less) with boost. An MSD 6 BTM would be a wise investment.

Re: 30lbs injectors, too big?
 

huh? That's exactly what I said. more boost equals more timing, so he'll have to get the BTM to retard the timing per lb of boost or else the head gasket will blow quick...

Re: 30lbs injectors, too big?
 

oh, sorry. The way I read more boost equals more timing was that the more boost you have, the more timing you have to put in it.