Need Help On Injector Sizing!

[DoWork]

Hey guys,

I am sorry to ask so many questions, but I am really trying to learn here and get this all sorted out. Unfortunately, there are like NO performance shops in my area, and car guys are pretty few and far between(except the import guys).

It has come to my attention while fixing my hack job of a car that I MAY have stock injectors. This doesnt seem right to me, especially for the build of my car. I can't help but think this is really holding me back, and may be why my car is on only 9-10lbs of boost.

Mods that I know of include(at least ones that MAY impact fueling):

-Classic FAST
-Walboro GSL 392, -6 feed, 3/8" steel return, and soon to have a fuel cell
-Hooker Headers
-Ported Stock intake/plenum
-Accufab TB
-FMIC
-Billet AFPR
-3.5"(?) DP
-Catless
-T&D Roller Rockers, unknown ratio
-I was told it had a cam in it, but I am unsure of the specs
-4.1l Production block, Speedpro Hypers
-Ported iron heads
-Aftermarket turbo(I really have NO idea what size it is, but I have included pics, maybe someone has a guess)

Turbo Pics:

Please excuse the dirtiness and crappy wiring in the pics. That has since been corrected

At any rate, what would eb a good sized injector to use with something like this? If I HAVE to spring for new injectors, I would rather stay away from Meth, unless instructed otherwise. You guys are the experts, help me out here please!

Thanks in advance,
-Todd

 

[696]

Meth might not be a bad idea, unless you plan on running race gas it's "cheap" insurance. If you haven't do a search and check it out.
As far as injector size, might as well go 60's and do it right the 1st time...unless you can find a deal.

 

[Major Nutz]

I would get either 72's or 83's. Also I would replace those Hooker headers with the stockers as the cause really slow spooling.

P.S. there is a set of 55's for $75 in the classified section. That might be easier on your wallet.

 

[hungerbuhler1]

83's would be good. And meth would be a good idea like others have posted

 

[DoWork]

So I guess meth is a yes then? LOL. I'm glad you guys have said that. I just wasnt sure if it was 100% necessary with a large injector.

I would get either 72's or 83's. Also I would replace those Hooker headers with the stockers as the cause really slow spooling.

P.S. there is a set of 55's for $75 in the classified section. That might be easier on your wallet.

I was going to ask about the 55's, but I want sure if they would work out. What would I gain by ponying up the extra cash for 72-83's over the 55's? I dont know that I trust my motor enough to run some crazy high boost. Would I be able to make it safely on the 55's and meth at say, like 22lbs, or would the bigger injectors really be needed?

 

[Major Nutz]

So I guess meth is a yes then? LOL. I'm glad you guys have said that. I just wasnt sure if it was 100% necessary with a large injector.



I was going to ask about the 55's, but I want sure if they would work out. What would I gain by ponying up the extra cash for 72-83's over the 55's? I dont know that I trust my motor enough to run some crazy high boost. Would I be able to make it safely on the 55's and meth at say, like 22lbs, or would the bigger injectors really be needed?

72-83's= room to grow! 55's should work for you though if you don't get too crazy. Alky is a good choice as well.

 

[49-blues]

I have a new set of 72s with a extreme extender chip for $375. Shipped-these have not been fired up yet-I'm going to 120s.matt-347-680-8642 ( paypal at: mytquick87@yahoo.com)

 

[pacecarta]

the advice on this board is getting worse every day


why not ask what injectors he has right now,
get the numbers off them and post it up ,
unless they turnout to be stock or ridiculously small without knowing what turbo its hard to say what injector he needs or if what he has is enough without some data (that turbo could be a turbonetics 44 or a 76 with that housing


you have a FAST .. get a laptop download c-comWP from fuelairspark.com
connect to the car and look at the program it will have the injector size listed in the program if the injector size listed doesnt match the ones in the car you have could a problem
, look at the dash and see if there are any codes indicating a problem could be you have a bad WB sensor

save yourself a copy of the current GCT
the then take a log of the car under throttle and post it and the gct file in this forum , Performance ECM Upgrades - TurboBuick.Com


throwing injectors at it may not be the answer unless you just have $$$ burning a hole in your pocket , looks like you have a fuel press gauge , does it work? whats base FP and does the fuel pressure rises 1:1 under boost , who knows you could have a bad pump or filter or even a bad fuel pressure regulator

only able to get 10psi ..you could have fouled plugs or bad wires or a bad coilpack or a 9psi spring in the gate and setup tuner style so 10psi might be all it will do set that way

btw you'll need the laptop and the c-com anyway if you change injectors youll need to make several changes to the current program to be able to run them anyway and you'll need to understand how to use c-com... or pay someone who does know c-com to look at your car and tune it .

btw 72s and an extreme chip aren't going to work very well with this posters current setup

 

[DoWork]

72-83's= room to grow! 55's should work for you though if you don't get too crazy. Alky is a good choice as well.

I am going to go Alky/Meth for sure. I havent quite decided what system I am going to go with yet.

I do however, see what you are saying about the bigger size of injectors. You made a good point. Plus, it would also help keep duty cycles lower and keep things happier. I think I am going to wait and save up for a decent sized injector rather that barely sliding by on a 55lb unit. Thanks again for your help!

I have a new set of 72s with a extreme extender chip for $375. Shipped-these have not been fired up yet-I'm going to 120s.matt-347-680-8642 ( paypal at: mytquick87@yahoo.com)

I am somewhat interested, but, I wouldnt really be needing the chip. My car is already on a classic FAST. Before I worry about purchasing injectors, I still need to pick up a fuel cell, remote battery mount, kills switch, and a trunk firewall. I am mostly just trying to get all my ducks in row so that I know what I have to come up with $$$$ wise. Hopefully some of my stuff sells soon so that I can order all of that and pick up some injectors by the end of the month. The end of summer is on its way, and I want to be able to enjoy my car this year instead of staring at it and getting pissed.

On a side note, does anyone have ANY guess as to what size my turbo is?

 

[BlackBandit]

the advice on this board is getting worse every day


why not ask what injectors he has right now,
get the numbers off them and post it up ,
unless they turnout to be stock or ridiculously small without knowing what turbo its hard to say what injector he needs or if what he has is enough without some data (that turbo could be a turbonetics 44 or a 76 with that housing


you have a FAST .. get a laptop download c-comWP from fuelairspark.com
connect to the car and look at the program it will have the injector size listed in the program if the injector size listed doesnt match the ones in the car you have could a problem
, look at the dash and see if there are any codes indicating a problem could be you have a bad WB sensor

save yourself a copy of the current GCT
the then take a log of the car under throttle and post it and the gct file in this forum , Performance ECM Upgrades - TurboBuick.Com


throwing injectors at it may not be the answer unless you just have $$$ burning a hole in your pocket , looks like you have a fuel press gauge , does it work? whats base FP and does the fuel pressure rises 1:1 under boost , who knows you could have a bad pump or filter or even a bad fuel pressure regulator

only able to get 10psi ..you could have fouled plugs or bad wires or a bad coilpack or a 9psi spring in the gate and setup tuner style so 10psi might be all it will do set that way

btw you'll need the laptop and the c-com anyway if you change injectors youll need to make several changes to the current program to be able to run them anyway and you'll need to understand how to use c-com... or pay someone who does know c-com to look at your car and tune it .

btw 72s and an extreme chip aren't going to work very well with this posters current setup

Read this post again. Until you know what you have injector wise it's pretty much dumb to plan on buying something else. Just my opinion. The only thing I disagree with the idea that 72's and an extreme chip won't work well unless pacecarta is alluding to the fact that since you have FAST you don't need a chip for a STOCK ECU!

 

[DoWork]

the advice on this board is getting worse every day


why not ask what injectors he has right now,
get the numbers off them and post it up ,
unless they turnout to be stock or rediculously small without knowing what turbo its hard to say what injector he needs or if what he has is enough without some data (that turbo could be a turbonetics 44 or a 76 with that housing

I am not sure of the injectors I have now. I posted a thread on it earlier today....heres a link, maybe you can offer some insight

need help with injector identification


you have a FAST .. get a laptop download c-comWP from fuelairspark.com
connect to the car and look at the program it will have the injector size listed in the program if the injector size listed doesnt match the ones in the car you have could a problem

I am in need of a laptop as the harddrive went out on the old one. I am having a rough time finding one with a serial port though. Plus, FAST told me some of the serial adapters may not work with the system
,
look at the dash and see if there are any codes indicating a problem could be you have a bad WB sensor

I replaced the sensor earlier this year

save yourself a copy of the current GCT
the then take a log of the car under throttle and post it and the gct file in this forum , Performance ECM Upgrades - TurboBuick.Com


throwing injectors at it may not be the answer unless you just have $$$ burning a hole in your pocket , looks like you have a fuel press gauge , does it work? whats base FP and does the fuel pressure rises 1:1 under boost , who knows you could have a bad pump or filter or even a bad fuel pressure regulator

I definatley do not have money to throw at it. Fuel pressure gauge DOES work now that it has been replaced with an mechanical one mounted on the hood. When the old pump was still alive, FP did rise 1:1 as it should. I am currently re-vamping the fuel system. I replaced all the feed line (-6), and made a new return (3/8" steel). I am also running 2 new Aeromotive filters, so I am good there.

only able to get 10psi ..you could have foulded plugs or bad wires or a bad coilpack or a 9psi spring in the gate and setup tuner style so 10psi might be all it will do set that way

It is on 10lbs VIA the WG, as I was told that the car would not make even 15lbs on the current injector. I have attached pictures at the bottom of this post of what apparently happened last time someone tried more boost on this car.



That has made me a little leary of turning up the boost until I know EXACTLY what is going on with this car.

btw youll need the laptop and the c-com anyway if you change injectors youll need to make several changes to the current program to be able to run them anyway and youll need to understand how to use c-com... or pay someone who does know c-com to look at your car and tune it .

Got that covered. A friend of mine in IL has offered to tune my car for me. He has done more than a few C-Com cars in the past. I also plan on learning it myself. Honestly, in the end, I want to be 100% self sufficent on this car.

btw 72s and an extreme chip arent going to work very well with this posters current setup

Thank you for your input sir. I have reply to your comments, and they are highlighted in red

 

[DoWork]

Read this post again. Until you know what you have injector wise it's pretty much dumb to plan on buying something else. Just my opinion. The only thing I disagree with the idea that 72's and an extreme chip won't work well unless pacecarta is alluding to the fact that since you have FAST you don't need a chip for a STOCK ECU!

I have read and re-read it. I also posted a link to my thread from earlier today about the injectors that are currently in my car. I also told the guy who offered the chip/injectors I wouldnt be able to do much with it because I had no use for the chip.

I guess maybe I shouldnt have started a new thread and kept everything in the old one. Someone had said they looked stock and I guess I ran with it. Like I have said in the past, please pardon all the stupid questions, I am REALLY trying to learn all of this, and you guys have been of TREMENDOUS help thus far, and I really thank you for that. I learn more every day I am on this site

 

[BlackBandit]

No such thing as a stupid question. Just didn't seem like you were listening to the best advice in the thread. Do you have a multi meter? I would say it's a pretty safe assumption to say someone didn't sink all that money in performance parts into the car without doing the injectors. You could unplug an injector and put a multimeter across the terminals and see how much resistance is there. If its 2-4 ohms it's probably safe to assume they are at lease 57 lb injectors. Or follow pace's instructions on how to check in FAST.

EDIt: You snuck the reponses in the quote in you reply by me. You're saving yourself a Butt ton in cash by not running it hard until you know what you have and what's going on!

 

[pacecarta]

besides the injector you need to know what fuel the program running in the fast box is setup for , if its setup for race fuel 15psi could be very damaging if you only have 92 in the tank as the timing will be way too high for pump gas


the turbonetics racegate usually is shipped with a 9psi spring , like i said the wastegate may plumbed to be tuner style to prevent it from running more than 10 psi

you said 'you' replaced the O2 ..was it from FAST or a FASTvendor ?
did someone look at the program to see if the O2 is working properly and just because im curious since we have such little data to go by ..why was it changed?

 

[Jeff Rand]

You might have to pull the injectors out to get a number. If you can retrieve the number then go to this site for the the flow information:
Jeff

Stan Weiss' - Electronic Fuel Injector (EFI) Flow Data Table

 

[DoWork]

besides the injector you need to know what fuel the program running in the fast box is setup for , if its setup for race fuel 15psi could be very damaging if you only have 92 in the tank as the timing will be way too high for pump gas


the turbonetics racegate usually is shipped with a 9psi spring , like i said the wastegate may plumbed to be tuner style to prevent it from running more than 10 psi

you said 'you' replaced the O2 ..was it from FAST or a FASTvendor ?
did someone look at the program to see if the O2 is working properly and just because im curious since we have such little data to go by ..why was it changed?

I changed the O2 because the turbo was hung so low that the 02 was butted up against the WP housing and the wires were starting to show some wear. I replaced it with an NTK L2H2 unit like was in it. I am going to do my best to get more data soon. I thank you for hanging in there with me.

As for the tune, when I bought the car I was told it was tuned on 91. We have nothing but 93 here, so I am good there. I am guessing my timing/fueling is ok with the little bit of boost I run as EGT has yet to climb over 15ish even under full boost. I would really like to get a laptop hooked up to it though to see what my a/f looks like.

You might have to pull the injectors out to get a number. If you can retrieve the number then go to this site for the the flow information:
Jeff

Stan Weiss' - Electronic Fuel Injector (EFI) Flow Data Table

I found a few more numbers, and I was about to head over to google to check them out. They are 1026 and 1018.

 

[DoWork]

No such thing as a stupid question. Just didn't seem like you were listening to the best advice in the thread. Do you have a multi meter? I would say it's a pretty safe assumption to say someone didn't sink all that money in performance parts into the car without doing the injectors. You could unplug an injector and put a multimeter across the terminals and see how much resistance is there. If its 2-4 ohms it's probably safe to assume they are at lease 57 lb injectors. Or follow pace's instructions on how to check in FAST.

EDIt: You snuck the reponses in the quote in you reply by me. You're saving yourself a Butt ton in cash by not running it hard until you know what you have and what's going on!

I will have to find a multimeter tomorrow and check it out. Thanks!

 

[87GN_70GS]

Unless you want to change pumps for the heck of it, your fuel injector size is limited by your current fuel pump. A GSL 392 will only supply enough fuel for 60 # injectors (almost static). You could run bigger injectors, but you will either need a bigger fuel pump or will have to make sure your inj duty cycle is trimmed back.

 

[87GN_70GS]

Do you also have an in-tank pump in addition to the 392 external?

 

[DoWork]

Do you also have an in-tank pump in addition to the 392 external?

Nope, just the external.

Unless you want to change pumps for the heck of it, your fuel injector size is limited by your current fuel pump. A GSL 392 will only supply enough fuel for 60 # injectors (almost static). You could run bigger injectors, but you will either need a bigger fuel pump or will have to make sure your inj duty cycle is trimmed back.

No, I dont really wanna change pumps for the heck of it. I just want my car to run. That kinda upsets me seeing as I was told it was a great pump to have, and because I backed out on those injectors last night.