foru2nv4

I add a saleen series IV supercharger to my 2003 GT and swapped out rearend gears to 4.10 gears. My car does have the PCM programmed thru saleen, 30 Lbs fuel injectors but I upgraded to a bigger Throttle body and put 285X35X18 rims in the rear and 255X35X18 rims in front and a smaller pulley on the supercharger series IV. My question is when I am in first gear and 2nd gear and third gear the car hesitates at around 4000 rpm range, so does that mean all those upgrades the the supercharged car is starvin for gas at that range of rpm? Do I need a bigeer fuel pump or injectors? Do I need both or one or the other? Need help?

massred98gt

new tune and prob the 255lb svt focus fuel pump

foru2nv4

so what size fuel pump do i have stock right now? Like I said it does hesitate at 4000 rpm range with pedal to the medal but when I let off it seems to correct itself like its not to much flow of fuel. I thought the mustang GT has the 255 Lbs fuel pump. Lookin for sum kinda fuel pump or injectors or both to compensate for the hisitation due to my modifification.

foru2nv4

Mod is a saleen series IV twin screw supercharger and 4.10 gears anf fatter tires in the back on bigger rims.

sinister99GT

smaller pulley adds boost , + gear change (if its automatic),needs to be tuned, i had to install a boost a pump on my 99 with 36# injectors with 9# of boost with the stock throttle body.

grogan

im running a vortech at 10 psi with a 255 svt focus pump and 60 lb injectors. with my 10.2 a/f tune (street/ daily driver tune) at 4k to 6.5k rpms in drive, its an automatic. my car bogs down aswell. this is so u can run the **** out of the car and not blow anything up..at least thats what my tuner told me (jpc racing)

sinister99GT

go to kenne bell.net they explain in detail about the returnless fuel system , the problems and what you should do. click on tech info and you will find it there.i am sure it doesnt just apply to there product.

foru2nv4

Thanks I will look into it and try to post back on if I solved the problem.

foru2nv4

Okay I did read the KenneBell site and didnt really learn anything. U need 2 b a scientist 2 understand what they are gettin at on that site with their and equations. I guess my question is what is the size of the fuel pump in a 2003 Mustang Gt? Supecharged with a saleen series IV, with smaller pulley, $.10 gears and 30Lbs injectors, like I said in 3rd gear (manual) at 4000 rpms floored the car hesitates and stumbles and jerks back n forth. Feels like a starving problem for the fuel to the engine. Anyone have suggestions? And what is the stock size of the pump?

foru2nv4

To answer Grogan I thought thats why they have a fuel shut off when u reach a certain rpm or redline. By the way what is a 10.2 tune?