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Which 24lb injectors on 305 TPI engine

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Old 11-04-2015, 02:34 AM
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Which 24lb injectors on 305 TPI engine

Hello

Which Injectors are of good quality for my engine ?

I would prefere Bosch, but i canīt find any fitting Bosch Injector for my 1989 Iroc-Z with 305 TPI engine.

Please help.
Old 11-04-2015, 04:00 AM
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Re: Which 24lb injectors on 305 TPI engine

For a 305, you don't need anything bigger than 22lb injectors. Your stock engine has 19lb injectors.
Old 11-04-2015, 10:41 AM
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Car: 91 Black Formula KR
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Re: Which 24lb injectors on 305 TPI engine

Yes, the 19lb were the factory size for 305.
Southbay Fuel Injectors have a good price on Bosch & Adjustable Fuel Pressure regulator... I have both and am happy with them...
These injectors do make a louder "tick" than stock, but otherwise perform really well...

Rafael
Old 11-04-2015, 11:22 PM
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Re: Which 24lb injectors on 305 TPI engine

In this Winter i do some modifications. Cam, porting, exhaust, ...
I expect about 320HP, and therefore i think i will need 24lb ??
Is that calculation incorrect ?
Old 11-05-2015, 09:22 AM
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Re: Which 24lb injectors on 305 TPI engine

320hp from a 305?
Old 11-05-2015, 02:49 PM
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Car: 1986 Camaro SC
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Re: Which 24lb injectors on 305 TPI engine

Originally Posted by blacksunshine'91
320hp from a 305?
he could make 320, probably not with those mod's. i make around 450-475 with my 305
Old 11-05-2015, 09:38 PM
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Re: Which 24lb injectors on 305 TPI engine

450hp on a 305?? I bet there is not Factory about your 305, and how many thousands after thousands do you have in it? I'm not saying you are "fluffing" your numbers but your signature does not indicate the bore and I didn't think only a cam and heads and throttle body and injectors and headers could get you there. Looks like all your stuff is bolt on, but how many hours of tuning with a PC do you have? I hope I'm not coming across as some kind of tool, I just want HP but want to keep my 305 and EVERYBODY said I'm a fool and it could not be done cost wise compared to the LT1 or LS1
A friend of mine has a real old 700cc Yamaha Fazer ( baby VMAX) that spanks new liter super bikes, and he can claim it is a factory block... So yes I would LOVE to have my 1985 IROC make 450hp just to say my stock block spanked some GEN IV's & GEN V's & Mustangs
Old 11-05-2015, 11:49 PM
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Re: Which 24lb injectors on 305 TPI engine

Why do you think 320 is not possible ?
My 1989 Iroc has the peanut cam inside, this fact alone should add about 50 HP (with the XR264HR cam).

I calculated that way.:

-Cam 50hp
-porting the Intake and heads 20hp
-Full Exhaust + CAT delete 20hp
-Ignition system 10hp
-AC and Smog delete 5HP
-Underdrive P. 5HP
-Programming (98Oct.) 10hp
Old 11-06-2015, 05:03 AM
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Car: '89 Chevrolet Camaro IROC-Z
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Re: Which 24lb injectors on 305 TPI engine

Few years ago I bought Bosch 3 19lb injectors (yellow ones) for my LB9 here: https://secure.fuelinjectorconnectio...injectors.html

Good price, fast shipping, and injectors worked with no problems at all since then...
Old 11-06-2015, 07:24 AM
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Re: Which 24lb injectors on 305 TPI engine

Originally Posted by Thornburg
450hp on a 305?? I bet there is not Factory about your 305, and how many thousands after thousands do you have in it? I'm not saying you are "fluffing" your numbers but your signature does not indicate the bore and I didn't think only a cam and heads and throttle body and injectors and headers could get you there. Looks like all your stuff is bolt on, but how many hours of tuning with a PC do you have? I hope I'm not coming across as some kind of tool, I just want HP but want to keep my 305 and EVERYBODY said I'm a fool and it could not be done cost wise compared to the LT1 or LS1
A friend of mine has a real old 700cc Yamaha Fazer ( baby VMAX) that spanks new liter super bikes, and he can claim it is a factory block... So yes I would LOVE to have my 1985 IROC make 450hp just to say my stock block spanked some GEN IV's & GEN V's & Mustangs

it all depends on what you want out of the car, i'm kicking myself now that i didn't swap to a 350. when people say just get a 350 there's a reason, i would be making more power with a 350..

numbers aren't fudged.

it's a 88 305 roller block bored .20 over with stock bottom end

never counted the hours i have in tuning... 14#'s of boost helps. dyno'd 420 ft lbs to the rear wheels.
Old 11-07-2015, 05:25 PM
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Re: Which 24lb injectors on 305 TPI engine

Fuel injector connection will have injectors for your car. They sent me Bosch Design 3's 22# for my 1992 350tpi and they have worked perfectly since 2009.
Old 11-07-2015, 06:20 PM
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Re: Which 24lb injectors on 305 TPI engine

Does anyone have the code for Southbay for member discount? Thanks
Old 11-07-2015, 10:39 PM
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Car: 1985 Camaro Z28 IROC
Engine: 5.0L TPI H.O. 215HP STOCK
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Re: Which 24lb injectors on 305 TPI engine

Sounds like pretty sweet set-up, and ya 14# of boost sure does make a difference!!! When you say it is a roller set-up, does that mean you have a roller cam and roller rocker? Please forgive me, I have been into motorcycles for past few years and haven't been into cars since dropping a 455 into my 82 Cutlass back in 1995...so kind of re-learning everything
Old 11-07-2015, 10:41 PM
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Re: Which 24lb injectors on 305 TPI engine

I think I will change my injectors, but if I go above 19# do I have to reprogram my ECM or get a chip?
Thanks in advance for help and understanding
Old 11-08-2015, 07:51 AM
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Re: Which 24lb injectors on 305 TPI engine

Originally Posted by Zylinder
Why do you think 320 is not possible ?
My 1989 Iroc has the peanut cam inside, this fact alone should add about 50 HP (with the XR264HR cam).

I calculated that way.:

-Cam 50hp
-porting the Intake and heads 20hp
-Full Exhaust + CAT delete 20hp
-Ignition system 10hp
-AC and Smog delete 5HP
-Underdrive P. 5HP
-Programming (98Oct.) 10hp
IMO....dont think youre going to get the numbers youre hoping for. just did a 350 tpi with a crane 2032 cam, accel base manifold, slp runners, summit brand aluminum heads, 24lb injectors, AFPR, hooker headers, cat delete (w/ electric cutout), programming, never had any smog pump, reduced restriction intake from filter to throttle body, 3:73's, few suspension upgrades and the most important......aerofoil!!

i dont think i'm anywhere over 300hp, if i am, its not by a lot. i think you'd need to do much more to the 305 to get from 215 to 320. maybe i'm way off, but if that's your goal i think you're going to need to consider shelling out more dough to get in the motor and do some bigger upgrades.

also you want to spank the newer cars, one thing i'm realizing with my current setup is that it is actually hard to get the rubber to stick to the pavement, i'm leaving smoke all over, the newer cars stick better IMO.

not trying to blow up your dreams, i think you need to consider heads too, maybe an HSR since they will improve h.p. by a lot, however its going to cut away your torque too. i wish you good luck and i hope you prove me wrong with your build!
Old 11-08-2015, 07:55 AM
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Re: Which 24lb injectors on 305 TPI engine

Originally Posted by Thornburg
I think I will change my injectors, but if I go above 19# do I have to reprogram my ECM or get a chip?
Thanks in advance for help and understanding
you will have to get your PROM reburned. there are several guys here who do good work with it, or if you want to venture into it yourself, there are boards here for burning your own PROM chip, i couldnt get my ALDL cable to work to the my laptop, so i would never be able to understand it lol.
Old 11-09-2015, 11:22 PM
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Re: Which 24lb injectors on 305 TPI engine

Ok, but what HP Range can i expect with this modifications ?
I dont think the 19lb will work properly with this mods.
Old 11-10-2015, 08:01 PM
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Re: Which 24lb injectors on 305 TPI engine

Hey all,
I need to get into the housing and check my PROM the engineer at work said e way it behaves it might already be done.
So my Ford buddy ran an under drive pulley, would that help my 5.0L and how will it hurt daily driving or engine longevity?
Old 11-11-2015, 11:09 PM
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Re: Which 24lb injectors on 305 TPI engine

Originally Posted by Zylinder
Ok, but what HP Range can i expect with this modifications ?
I dont think the 19lb will work properly with this mods.
i'm not an expert, but i know that most sites will boast HP gains at best case scenario like "this k&n air filter will boost yhou at 15 hp!", but in my honest opinion i wouldnt expect more than 40-50 hp. basically i wouldnt expect it to be doing 10's on the 1/4. these motors arent really built for high hp, they are built for high torque. if you want to get higher hp, may want to consider an HSR, or see if theres a possiblility to do an LT1 intake swap on a 305. Siamesing the intakes is also helpful.

how old is the motor? is it worth just pulling and having it worked over?
Old 11-11-2015, 11:18 PM
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Re: Which 24lb injectors on 305 TPI engine

Originally Posted by Thornburg
Hey all,
I need to get into the housing and check my PROM the engineer at work said e way it behaves it might already be done.
So my Ford buddy ran an under drive pulley, would that help my 5.0L and how will it hurt daily driving or engine longevity?
underdrive pulley would be a good question. i dont have any experience or knowledge on them. i'm all for bolt on upgrades so id be curious of any benefits / disadvantages of them too.

to get the prom out, you need to drop the cover under the dash on the passenger side, hidden up in there you should be able to see the side profile of a silver box (ECM). should be 3 screws holding it up there. take that down and there is a small rectangular panel held in by 4 screws on top, take the screws out and viola theres the prom back there......if i'm remembering all this correctly

Last edited by racerx520; 11-11-2015 at 11:26 PM.
Old 11-12-2015, 09:28 AM
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Re: Which 24lb injectors on 305 TPI engine

Originally Posted by banksGTA
Does anyone have the code for Southbay for member discount? Thanks


if you haven't purchased your injectors yet, the code is tg11.
we are doing some work on the website so if you have a problem with the code just give us a call.


516-442-4707
Old 11-16-2015, 12:11 AM
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Re: Which 24lb injectors on 305 TPI engine

The Engine is from 1989 and has about 60000Miles on it.




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