I may put my 350 injectors in my 305 for now to see if my injectors are bad or not. I can't figure out anything else thats wrong. Its down to this and the ECM/PROM or a short somewhere. If I did this and turned down my FP would it run fine? TIA

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'91 GTA:
www.fbody.com/members/91WS6GTA

[This message has been edited by GTA91 (edited March 14, 2001).]

[This message has been edited by GTA91 (edited March 14, 2001).]

 

IIRC you don't have a lot of adjustment down in FP to go with an AFPR, but by all means give it a go. Somewhere on the PROM board TRAX posted a conversion of injector ratings @ psi to figure out what a 19lb @ 50 psi, or an SVO 24lber rated at 39 to 45, etc.
...ed

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Ed Maher - Moderator @ The Carb Board
92 Z28 Convertible - Quasar blue / Tan top
LB9 4L60 GU2 G80 - stock, soon to be sleeper
-=ICON Motorsports=-

- Definitely prototypes, high powered mutants of some kind. Too weird to live, too cool to die

 

if your mostly stock this will only hurt you. You'll especially take a blow in the low/mid RPM range. You need prom work to run those.

If you are looking for injectors, I have a set of 19lbers off my 1le I'll sell for cheap. Email me

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91 Formula
305 TPI 5speed
1LE/G92/WS6

Paxton SN92 polished kit, SLP airfoil, ported/polished plenum, March pulleys, Crane AFPR(43psi),Crane Gold 1.6rrs,MSD coil,MSD6AL (5200rpm limit),Holley 9mm wires,Ac delco R43ts plugs,stock chip,Ford SVO 24# injectors,Bosch O2sensor,SLP 1 5/8" headers,SLP catback,shortened shifter,3:73s w/Auburn posi,170* t-stat,JET 195* fan switch, Macewen white face gauges, Autometer gauges, Zoom hi-performance clutch.

 

Why not just pour a gallon of gas down the throttle body?

I agree with Form completely. Not that long ago someone else asked the same question. The answer is no more than 95% of the time. You should be making at least 330 HP or mild mods and blower to run those. If you have that kind of money, just drop in a 350? You'll be very happy. Those are severe overkill on a 305. Buy 19#er's or don't do it. The ECM is programmed for 19 lbs.; no more, no less. Look around the site, test your injectors first. They are a pain to change if you haven't done them 3000 times. I also have some 19 lb./hr injectors, but mine are SVO (slightly different flow rates between Ford and GM fuel pressures). Better to test you injectors every way you can before determining they are at fault. Set the pressure a 50 psi with the correct injectors. Check a fuel filter first.

Just my $.02

[This message has been edited by dhirocz (edited March 14, 2001).]

[This message has been edited by dhirocz (edited March 14, 2001).]

 

Thanks guys.


* I wouldn't be running these forvere... only until my 350 is done. Also, why couldn't I turn the pressure down some and run them? Ed says this may be possible... anyone else?

* I MAY do this.... just comtemplating it until the 350 is done... and BTW I wouldn't pour a gallon of gas down the TB!

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'91 GTA:
www.fbody.com/members/91WS6GTA

 

No ones saying they won't work. But they won't work WELL. To give you an example. I have ford svo 24#ers right now with 10lbs of boost. My fuelpressure is around 42#s no vacuum. Currently, my fastchip prom is being re-programmed, so I had no choice but to run my stock prom in the meantime. I am VERY RICH. The car runs like crap and is bad on gas...even with all the air from the supercharger.
Just imagine that on your car. It's not too good on the piston rings either.

dhirocz is right, changing injectors isn't easy.

[This message has been edited by theformula (edited March 14, 2001).]

 

Ok then, thanks. It was just a thought. I really don't think they're that hard to change. Its just a simple process of tearing it all apart and putting it back together. I do that stuff all the time. Oh well, later

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'91 GTA:
www.fbody.com/members/91WS6GTA

 

Here's my understanding of how these things work: the car will run fine. Yes FINE. Not running rich or crappy or anything, and here's why. Once the car goes into closed loop for the first time, the computer will begin to monitor the air-fuel ratio through the O2 sensor. It will see that the car is running rich, and it will shorten the injector pulses. After the computer has made these adjustments for the 22lbs, it will store this info in it's long term memory. Meaning that the next time you start the car up, the computer will have already adjusted it's injector pulse width to accomodate the new injectors. Basically what I'm saying is that the computer is smart enough to figure out the problem and correct it. But I might add that I don't know what the car will do at full throttle because at WOT the computer goes back into open loop. So you may run too rich when you put it to the floor, and your car will therefore run slower. What do you guys think? Anyone agree?
If you have a scan tool, you can watch the computer make these changes by looking at the block learn multiplier and the integrator. But I'm assuming most people don't have a scanner, so I won't go into the details now.

 

To some extent the computer will compensate for larger injectors at closed loop operation, I've heard you can go about 15% more fuel and still be OK. However, like you said, at startup and WOT the car will run pretty rich. So it really depends on how you drive and whether you keep your foot out of it or not. The 22lbs. are so borderline that the computer may not fully compensate and you may get an O2 sensor trouble code for rich exhaust.

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1990 IROC 350
Mods: Too busy trying to make it run right to mod it.
Airfoil, Dynomax cat-back, Accel coil, 180 t-stat, Bald Eagle tires,
Hypertech fan switch, Ruger P95DC, hot wife, new oil filter,
thick rubber floormats, towels in the seats.
18.0 @ 85MPH since I'm one big-a$$ MF
"It's better to have and not need than to need and not have."

 

exactly jethroiroc. The computer can only correct so much. And the difference is very minimal, the car will run like crap but go ahead and do it.

 

Thanks guys... hopefully my 19's are n't abd and I can hold off until I get the L98 done. Later

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'91 GTA:
www.fbody.com/members/91WS6GTA