Jackal8069

So, I know I'm probably being redundant as this type of thing is being asked all the time, but I'm at the onset of spending $$$ for parts for my new setup.

Firstly, I want a 12 second car. I'm not looking to be origninal, or different, or even flashy. I just want a N/A 12 second RS So, looking back at my stacks from years of Chevy High Performance mags, I found this setup:



They dyno'd the 355 version to 380hp and ~400 ft-lbs of torque. I like my fuel injection, and I like a good idle. Would the 670cfm Holley TBI support this motor?

I'm thinking the only real problem would be fuel flow.

Thanks in advance!

BTW, on a side note, for anyone that has done a manifold swap, any drilling/modifications to the Weiand manifold to be done? I do want to retain the EGR setup...

9c1Caprice

Theres quite a bit of posts on this. here's one
Check the sticky at the top

Here's one off the beaten path.
Ed Wright on the TBI

Jackal8069

Thanks for the linx! The second one at Yahoo was good.

Hrm, I work with alot of electro-mechanical systems at my job. So if there were to come about injectors that would flow 100+ then the fuel-feed problems would be history right?

*looks promiscuously at his CAD design computer* hrmmm.....

9c1Caprice

from what I've heard, its unlikely to get the fuel rails to run a 100% duty cycle, or "railed." 80%-85% is more of the "norm"

But, if you figure something out that the rest of us dont know, like making the TBI support more power, please share with the rest of us.

steve8586iroc

The 85# injectors that come in the GM 454tb will flow over 100# at a higher psi than stock and I belive the tb can be borred out to 2.2". With a little tuning you could see 330 to 350 hp. I'm hoping I will see the later when I get a chance to get my engine installed this summer.

Steve

Ronny

iTrader: (1)

i believe 90 LB injectors are available GM. GM rates the injector at 12 lbs FP. a VAFPR can bump it up at higher MAP. only problem with VAFPR is that it will override the ECU. and confuse it with changing map values. i am running 90 lbs now but had 65 lbs with VAFPR before i started tuning by burning chips. the 383 would require a 900 cfm 4 barell system IMHO. this all requires chip tuning.

9c1Caprice

Application: Color Ident: LB/HR Rating: Part #:

*L03/305 green/white 40# 1712400,5235279

*350-truck orange/black 55# 17112493

*350-L05/9C1 yellow/brown 65# 17112560,17084327,17112412
(1989-91)

*350-L05/9C1 yellow/brown 68# 17100372,17100373
('92-'93)

*454-truck purple 90# 17111784
(1987-'89)

*454-truck NA NA 17112249
(1990)

*454-truck blue/black 80# 17112560
(1991-on)

This should help people out ordering or at the junkyard.
I dont see alot of separation on here between the two 9c1 injectors on here. The 9c1 caprices got a better exhaust and got slightly bigger injectors. FYI.

Ronny

iTrader: (1)

i have in box a new 1995 dual TB 454(2.00inch) for a C2500 truck. the injectors are 17104288 acr. i was told by another member in a post they are 65 lbs and run a 20 lbs FP. i would say the color is reddish/purple. i need to set base pulse width accurately. if they are 65 lbs i will swap them out for 90 lbs as i have a set. i wish to run 11 lbs of FP. can you verify these are 65 lbs?

9c1Caprice

I have #65 injectors. Those wouldnt come in a 454. My colors are yellow/brown.

Reading your post, it sounds like you have the #90's, though me just reading this is not the most reliable way to figure out what you have. Checking the wire color is pretty dead on . I cant match your p/n. I want able to bring up the P/N you gave, though

Ronny

iTrader: (1)

someone posted a comment to me when i brought this up a week ago that they are 65 lbs at 20 lbs. maybe GM ran higher FP in newer trucks? whn i asked gmpartsdirect.com for the part number for 1995 c2500 7.4 L they came up with a different #? i doubt they were swapped out b4 sale. my 85 pump i think only runs 20 lbs max.

9c1Caprice

Lets put down the facts here and do this right. Can you take a pic of the injectors?

If the injectors came with the brand new 454 injector and are 454 injectors, then they are going to be more than 65#. - especially if they are rated at 65# for 20psi, though I doubt that this psi rating was stock for a gm tbi system. 65# of fuel at 20 psi is still 65# of fuel. 65# injectors are for 9c1 caprices. Ive heard that some of the later gm tbi's ran at a higher psi than the usual 12-14 max, but I think 20 may be a little high. Can anyone verify or falsify this?

Here's a similar thread of info by grumpy. its a good post and would help you out.
Here

Here's another.

Brent

iTrader: (1)

According to Mitchell, the 1995 and 1994 454 TBI fuel pressure spec is 26-32psi. They use injector part # 17113080.

The 1995 and 1994 5.0L and 5.7L spec is 9-13psi.

9c1Caprice

Great. Lets find out if his injectors match your info so he can get his constant correct.

Ronny

iTrader: (1)

this may seem wacko but i am wondering if dual TB 7.4 L TB may have been used on a motor home or a truck with governor that needs very low fuel flow requirements. refering to a specialized TB. again someone confirmed 65-68 lbs and i trust that but not consistent with other postings i have seen past 8 months. i will run the part # at chev dealer tonight and confirm the TB application and the inj application. i bet they dont know flow rate. the other set of injectors i am using now i believe were in the 1992 chev 454SS truck. anyway that year i believe used the largest inj GM made(90). apparently they made a decision to increase injector size for whatever reason. the calculator i saw showws 90 lbs at 12 lbs FP at 80% DC will support 360 HP. i can not see why GM needed to increase injector size unless it was a diif design(inj) or vendor that just happened to flow more. i think the 90 lbswas 1990-?. also what is the green throttle stop that appears as a diaphragm that apparently is hooked to VAC? why needed if ECU/IAC/prom handles idle/load control??? again this TB may be a odd ball. hope not! THANK YOU !!

Ronny

iTrader: (1)

i will take photo and post but it looks like another GM injector with that part # on it. top is purple...

Ronny

iTrader: (1)

RROB stated 1994 CHEV ran 68 lb injectors at higher than 13 lbs. i assume he is refering to 7.4L NOT 5.7L ...not sure.

9c1Caprice

Now a stock 68# injector designed and rated to run at at 13 psi is totally different than a 68# injector designed and rated at 20 psi. You seem to know that. Going to the dealership to check out the p/n is a good idea.

Did you see bulldog's post on the first link i sent? its the fifth one down. he posted a pic on where to look for the colors if there is any confusion.

Ronny

iTrader: (1)

are the colors are clearly visable witout taking the top off of the injector pod? i cant remember? i have a set of 65's actually two diff sizes in crossfire i can look at. what i see is a ring in between the electrodes that is purple. is that the color i should be looking for OR is the top of pod obstructiong view? anyway i would think the part # will be somewhere to be referenced. bulldog? dont see that post in this thread. what is member name?

9c1Caprice

Hit this link
its the fifth post down. His user name is bulldog92. His post asks/answers some of your questions. The post right below that answers another one you have. There's a nice picture to look at too. Good posts.

RBob

iTrader: (1)

It may be that those injectors are rated at for 65/68 #/hr at 13psi (like the others) and then run at 30 PSI for the 90+#/hr flow required for a BBC.

Or. . . maybe they are just truely 90's, as the single color purple ones with a different number are supposed to be. I'm thinking that the different number is GM updating/changing the part number scheme.

Can you hook up the TB (or just the injector pod) to a fuel pump and pressure gauge and check what the fuel pressure is regulated too?

RBob.

Ronny

iTrader: (1)

found it. same injector in his post as mine! however no response to his Q same as mine. i emailed him. apparently that inj is not common to our applications? his was from 1995 c3500 7.4L. getting closer. if i can get the FP from chev dealer tonight that may allow me to reverse calculate flow as the constant is 7.4L for both injectors i own. thanks.

9c1Caprice

I hope that works out for you.
Good luck.