Can injectors be TOO big??

[50FoxBodyGT]

I'm about to put my new 306 back in my car and have put 30# injectors in it. There haven't been too many mods: GT40 heads, Ecam, 65mm TB. Will the injectors just not be fully utilized in my application or will they actually decrease performance because they are too big? Can injectors be TOO BIG?

 

[just4bob50]

Yes injectors can be to big depending on how the tune is going to be done. If your just going to go with a calibrated MAF for 30lb injectors I would consider running your fuel pressure at about 35 psi with the vac. line off. If you have a chip that a tuner can burn then larger injectors can be used. I went with 42lb'ers when I had just 6lbs of boost and a stock motor, and it was one of the best decisions Ive made. Every time Ive upgraded since Ive just needed a retune and didnt have to buy parts over.

 

[50FoxBodyGT]

Ahh, makes sense. Any chip recommendations? I'm assuming the car doesn't have a burnable chip in it. The previous owner never mentioned anything like that to me.

 

[just4bob50]

Ahh, makes sense. Any chip recommendations? I'm assuming the car doesn't have a burnable chip in it. The previous owner never mentioned anything like that to me.

I went with an SCT chip because most of the tuners in my area use their products. That way if I wanted to change tuners I wouldnt have to buy tuning equipment over. www.SCTflash.com Their web site has a dealer and tuner locator in it.

 

[88Stang331]

I'm in the same situation. I have 30lb injectors, 80mm ProM, along with the stuff in my sig, and soon to be tfs 1 cam, and 306.

 

[HISSIN50]

Tune issues unrelated, I'd want to make sure that pressure doesnt need to be dropped too much. Otherwise spray pattern issues can arise (with injectors, it's often better to keep them runnin at a pretty stout duty cycle).

Good luck.

 

[v8only]

for your combo, stock factory 19# injectors will work just fine. Shelf the 30# injectors or save all that money and run the 19's. Down the line when you start doing more to it, consider bigger injectors.

 

[ninety15.0]

I would also reccomend you use the stock 19's. I just recently did my gt-40 head swap and put the 24's on there and i have a few more mods than you do... I had to dial the fuel pressure back to 36 vac off to get the thing to run well. as hissin mentioned the spray pattern is a cause for concern...so run them at almost full duty cycle (+90%) if you can.

 

[blk9450]

i had 30#'s on a stock shortblock with ported intake ported e7's and headers/exhaust. it ran great, i dont believe 30#'s are too big if you are moving up into them, theats what i did and have no regrets about it